POLYMER-LlPID MATERIALS FOR DELIVERY OF NUCLEIC ACIDS

RELATED APPLICATIONS

[0001] This application claims priority under 35 U. S.C. § 1 19(e) to U.S. Provisional

Applications No. 62/516,574, filed June 7, 2017, the content of which is incorporated herein by reference in its entirety.

GOVERNMENT FUNDING

[0002] This invention was made with Government support under Contract No. W81XWH-14- 1-0100 awarded by the U.S. Army Medical Research and Material Command, and under Grant No. R01 EB016101 awarded by the National Institutes of Health. The Government has certain rights in the invention.

BACKGROUND OF THE INVENTION

[0003] Human bone marrow harbors about 10,000 bona fide hematopoietic stem cells as well as millions of downstream progenitors and releases billions of blood cells into the circulation every day (7). The organ produces a cellular ensemble that accomplishes vital tasks including oxygen transport, defense against pathogens and clotting (7, 2). The activities of its inhabitants, such as cell quiescence, proliferation, differentiation and migration, are adjusted to current systemic needs and regulated by non-hematopoietic bone marrow niche cells (2, 3). This cast of supporting cells includes endothelial cells, which instruct hematopoietic cell behavior via a mix of soluble and cell surface-bound signals (7, 4). Niche cells receive circulating and neuronal signals from outside the marrow and relay them to hematopoietic stem and progenitor cells (HSPC) (5).

[0004] Over the past decade, many niche cell steady-state functions have been discovered, leading to approved drugs for stem cell mobilization prior to transplantation (6). Drugs, such as Filgrastim, that disrupt the interactions between SDF-1 and its receptor CXCR4 on leukocytes and HSPC are now widely utilized as agents to mobilize stem cells into the bloodstream for bone marrow transplantation (7). Such agents have primarily been applied in the realm of

hematology/oncology; however, recent evidence suggests that leukocyte and HSPC release from bone marrow plays an essential role in many other chronic inflammatory conditions, including cardiovascular disease (8). Broadly speaking, the number of circulating leukocytes and the production of blood components in the hematopoietic niche correlate closely with mortality, and if the bone marrow fails altogether, the organism succumbs within a week or two (9, 10).

Therefore, technologies that modulate cell behavior within the hematopoietic niche could improve our fundamental understanding and treatment of a range of disease processes that are governed by bone marrow-derived leukocytes.

[0005] RNA interference (RNAi) therapeutics are a potentially attractive means to influence protein expression within the hematopoietic niche, as they can be used to silence nearly any gene within the body to achieve therapeutic effects (11). Because the gene sequences are known, siRNA drugs can be screened for in silico, produced and validated within very short time spans. However, while potent siRNAs can be rapidly identified, systemic delivery to the appropriate tissue can prove challenging.

[0006] Nucleic acids (e.g., siRNA) cannot easily be delivered effectively to bone marrow cells in vivo. Thus, in vivo therapeutics for the treatment of bone marrow diseases are limited to small molecules, antibodies, and proteins. Currently the only methods to deliver nucleic acids to bone marrow cells are ex vivo, where cells are harvested from patients and then subsequently treated with nucleic acids. These cells are then administered systemically to patients, where the engraftment of the treated cells back into bone marrow is extremely low (< 1%). New technology useful in treating and targeting bone marrow cells with nucleic acids directly within patients, for treating a range of diseases including bone marrow cancers, immunological disorders, and hematological disorders, is therefore needed.

[0007] One such technology is the use of nanoparticles as drug delivery vehicles (13). For siRNA delivery, nanoparticle's key advantages are: (i) preventing nucleic acid degradation by serum endonucleases in blood, (ii) avoiding renal clearance from the bloodstream, (iii) delivering cargo to specific cells by tailoring nanoparticle surface chemistry and (iv) mediating target cell entry and endosomal escape to enable nucleic acid release into the cytoplasm (11, 14). Delivery materials differ in efficiency, toxicity and biodistribution, and certain nanoparticles have avidity to certain cell types, tissues and organs (15), particularly to hepatocytes, leukocytes and endothelial cells (16-22). It has previously been reported that nanoparticulate formulation, consisting of low molecular weight polyamines and lipids, that mediated potent gene silencing in endothelial cells residing in the lung (77). Nanoparticulate formulations that mediate potent gene silencing in the hematopoietic niche have not been previously reported.

SUMMARY OF THE INVENTION

[0008] The present disclosure describes the development of an siRNA formulation capable of delivering siRNA to endothelial cells in the hematopoietic niche. A library of nanoparticles based on a new class of nanoparticle-forming materials generated by combinatorial chemical synthesis was first screened. The materials were synthesized by reacting low-molecular weight polyamines with epoxide-terminated lipids using an epoxide ring-opening reaction. By screening a library of these nanoparticles in vivo, a new polymer-lipid hybrid nanoparticle capable of efficient delivery to bone marrow endothelial cells was developed. In a series of proof-of- concept experiments, endothelial cell expression of two quintessential hematopoietic niche factors was silenced, thereby altering HSPC behavior and systemic leukocyte supply.

[0009] The present invention provides a composition (e.g., nanoparticle) comprising both: a conjugated polyethyleneimine (PEI) polymer (also referred to herein as a "conjugated lipomer" or "lipomer") of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle. Compositions (e.g., pharmaceutical compositions) of the particle are also provided. In certain embodiments, the particle, or composition, is useful, for example, as a delivery system for biologically active agents (e.g., nucleic acids to bone marrow in vivo). In certain embodiments, the particle, or composition, is useful for targeting bone marrow. The conjugated polyethyleneimine polymers are preferably prepared from low molecular weight linear polyethyleneimine (LPEI) and branched

polyethyleneimine (BPEI) polymers, i.e., having a number average molar mass (Mn) of < 2000 (i.e., approximately < 2 kDa).

[0010] In one aspect of the invention, provided is a composition comprising a conjugated lipomer of Formula (I):

or a pharmaceutically acceptable salt thereof,

wherein:

each instance of L is independently selected from the formulae:

group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted

carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl;

substituted or unsubstituted heteroaryl; a substituted or unsubstituted polyethyleneimine; or a group of the formula (iii'):

or the two R ² groups are joined to form a substituted or unsubstituted heterocyclyl;

each instance of R ³ is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted

heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a hydrophilic polymer;

each instance of R ⁴ is independently hydrogen, acyl; silyl; a hydroxyl protecting group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or

unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted

carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; or substituted or unsubstituted heteroaryl; A is -N(R ⁵ ) ₂ , wherein each instance of R ⁵ is independently hydrogen; acyl; silyl;

sulfonyl; an amino protecting group; substituted or unsubstituted alkyl; substituted or

unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted

heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a group of the formula (iii'):

Z is hydrogen; acyl; silyl; sulfonyl; an amino protecting group; substituted or

unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or

unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl, or a group of the formula (iii'):

or Z and the nitrogen atom to which it is attached form a substituted or unsubstituted heterocyclyl group; and

a lipid-polyethylene lycol (PEG) conjugate of Formula (II):

or a pharmaceutically acceptable salt thereof,

wherein:

each instance of R is independently unsubstituted C ₆ -C ₂ o alkyl;

R^ is substituted or unsubstituted alkyl; and x is an integer between 15 to 135, inclusive.

[0011] In certain embodiments, the particle is a nanoparticle.

[0012] Provided are compositions comprising the conjugated lipomers in the form of a particle (e.g., a nanoparticle or microparticle). For example, in certain embodiments, provided is a composition including a particle, wherein the particle comprises a conjugated lipomer, e.g., a conjugated lipomer of Formula (I), and, optionally an excipient. In certain embodiments, the composition is a pharmaceutical composition or a cosmetic composition. In certain

embodiments, the particle encapsulates an agent, e.g., an agent to be delivered. In certain embodiments, the biologically active agent is delivered to the subject in vivo. In certain embodiments, the agent is delivered to bone marrow in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow cells of the subject. In certain

embodiments, the composition further comprises an agent. In certain embodiments, the composition further comprises a biologically active agent {e.g., a therapeutic or diagnostic agent). In certain embodiments, the agent is a small molecule, organometallic compound, nucleic acid, protein, peptide, polynucleotide, metal, targeting agent, an isotopically labeled chemical compound, drug, vaccine, immunological agent. In certain embodiments, the agent is a polynucleotide (e.g., DNA or RNA). In certain embodiments, the RNA is RNA/ ^' , dsRNA, siRNA, shRNA, miRNA, or antisense RNA. In certain embodiments, the polynucleotide and the one or more conjugated lipomers are not covalently attached.

[0013] In certain embodiments the conjugated lipomer is of the formula:

[0014] In certain embodiments, the lipid-PEG conjugate of Formula (II) is of the formula:

(CisPEGlOOO),

or a pharmaceutically acceptable salt thereof. [0015] In certain embodiments, the composition includes a particle, wherein the particle comprises a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle. In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C1) and about 10 molar percent of C ₁₄ PEG2OOO, wherein the composition is used to synthesize a particle.

[0016] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₆ PEG2000, wherein the composition is used to synthesize a particle.

[0017] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₈ PEG750, wherein the composition is used to synthesize a particle.

[0018] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₈ PEG1000, wherein the composition is used to synthesize a particle.

[0019] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₈ PEG2000, wherein the composition is used to synthesize a particle.

[0020] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₈ PEG3000, wherein the composition is used to synthesize a particle.

[0021] In certain embodiments, the composition comprises about 90 molar percent of conjugated lipomer (e.g., 7C 1) and about 10 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle.

[0022] In certain embodiments, the composition comprises 68 molar percent of conjugated lipomer 7C 1 and 32 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 76 molar percent of conjugated lipomer 7C1 and 24 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 92 molar percent of conjugated lipomer 7C1 and 8 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 96 molar percent of conjugated lipomer 7C1 and 4 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle.

[0023] In yet another aspect, provided are methods of delivering a biologically active agent to a subject comprising:

administering the composition comprising the biologically active agent to the subject, wherein the composition includes a particle, wherein the particle comprises:

a biologically active agent;

a conjugated lipomer of Formula (I):

or a pharmaceutically acceptable salt thereof, described herein; and a lipid-polyethylene glycol (PEG) conjugate of Formula (II):

or a pharmaceutically acceptable salt thereof. In certain embodiments, the particle is a

nanoparticle. In certain embodiments, the biologically active agent is delivered to the subject in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow cells in vivo. In certain embodiments, the biologically active agent is targeted to bone marrow cells in vivo.

[0024] In certain embodiments, the conjugated lipomer of the composition is of Formula (I) described herein. In certain embodiments, the lipid-PEG conjugate of the composition is of Formula (II) described herein. In certain embodiments, the composition is a pharmaceutical composition or a cosmetic composition. In certain embodiments, the agent in the composition is a biologically active agent {e.g., a therapeutic or diagnostic agent). In certain embodiments, the biologically active agent is a small molecule, organometallic compound, nucleic acid, protein, peptide, polynucleotide, metal, targeting agent, an isotopically labeled chemical compound, drug, vaccine, or immunological agent. In certain embodiments, the biologically active agent is a polynucleotide (e.g., DNA or RNA). In certain embodiments, the RNA is RNAz, dsRNA, siRNA, shRNA, miRNA, or antisense RNA. In certain embodiments, the biologically active agent is formulated in the composition by encapsulating the biologically active agent via microfluidic mixing. In certain embodiments, the microfluidic mixing is conducted in a microfluidic device. In certain embodiments, for compositions with the nanoparticle comprising a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II), these compositions of both components were made via microfluidics based synthesis. In certain embodiments, in the microfluidics based synthesis, a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) complex with nucleic acids via electrostatic interactions to form nanoparticles. In certain embodiments, for a particle comprising a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II), microfluidic devices using chaotic mixing to form particles via electrostatic interactions.

[0025] In certain embodiments, the step of administering the biologically active agent to the subject comprises administering the composition intravenously.

[0026] The present invention also provides particles comprising both: a conjugated polyethyleneimine (PEI) polymer (also referred to herein as a "conjugated lipomer" or

"lipomer") of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) described herein. In certain embodiments, the particle is a nanoparticle.

[0027] The present invention also provides methods of using the compositions to treat proliferative diseases (e.g., cancers (e.g., bone marrow cancer, leukemia, lymphoma, breast cancer metastasis, leukemia, lymphoma, multiple myeloma, prostate cancer metastasis)), inflammatory diseases, autoinflammatory diseases, autoimmune diseases, genetic diseases (e.g., bone marrow diseases), immunological disorders, and/or hematological disorders in a subj ect.

[0028] The present invention also provides methods of using the compositions for

Hematopoietic stem cell transplantation (HSCT). Most patients who would benefit from HSCT are not able to undergo the procedure due to the morbidity associated with the process. Two major areas where HSCT can improve is (i) improving the quantity and purity of HSCs harvested from bone marrow, and (ii) improving gene delivery and correction in HSCs so to better constitute hematopoietic lineages in bone marrow. In certain embodiments, the composition is useful as a delivery system for biologically active agents (e.g., nucleic acids) to key cellular targets in bone marrow.

[0029] The present invention also provides methods of using the compositions for treating epithelial and blood cancers (e.g., epithelial and blood cancers that metastasize to and colonize within bone marrow). Patients which have metastasis in bone and bone marrow have poor prognosis. Cancers that colonizes in bone and bone marrow failed to be treated, in part, but not limited to, due to inefficient delivery of drugs to these tissues. In certain embodiments, the composition delivers nucleic acids to bone. In certain embodiments, the composition delivers nucleic acids to bone marrow. In certain embodiments, provided are methods of silencing targets within tumor cells within these tissues, enabling these tumors to now respond to chemo-, radio-, and immunotherapies. In certain embodiments, the nucleic acids silence targets within tumor cells within these tissues. In certain embodiments, the targets within the tumor cells are

"undruggable." In certain embodiments, the cancer is breast cancer, metastatic breast cancer, prostate cancer, multiple myeloma, leukemia, or lymphoma.

[0030] Another aspect of the present disclosure relates to kits comprising a container with a particle or composition thereof, as described herein. The kits described herein may include a single dose or multiple doses of the particle or composition. The kits may be useful in a method of the disclosure. In certain embodiments, the kit further includes instructions for using the particle or composition. A kit described herein may also include information (e.g. prescribing information) as required by a regulatory agency, such as the U.S. Food and Drug Administration (FDA).

[0031] The details of one or more embodiments of the invention are set forth herein. Other features, objects, and advantages of the invention will be apparent from the Detailed Description, Examples, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figures 1A to 1H show a data for composing a bone marrow endothelial cell (BMEC)- targeting nanoparticle. (Figure 1A) Synthesis scheme of the epoxide-modified polymer-lipid hybrid material. (Figure IB) Nanoparticles consisting of lipid hybrid, siRNA and a PEG-lipid conjugate were synthesized via microfluidic mixing. (Figure 1C) PEG-lipid conjugate parameters varied to form a library of unique nanoparticles for siRNA delivery to BMEC. The best silencing efficiency was obtained with NicheEC-15 (lipid tail length = C ₁₈ ; PEG mol% = 10%; PEG MW = 5000). (Figure ID) Tie2 silencing in femoral bone marrow of C57BL/6 mice 48 h after injection of each nanoparticle containing siRNA against Tie2 (dosage: 1.0 mg/kg; n=5 each). (Figure IE) Cryo-TEM micrograph of NicheEC-15. (Figure IF) Hydrodynamic diameter of NicheEC-15. {Figure 1G) Tie2 silencing in bEnd.3 and sorted BMEC 24 hrs after addition of siLuc or siTie2 to the culture medium. Tie2 expression after exposure to siLuc was adjusted to 100% (n=3 each). {Figure IFF) Confocal microscopy of bEND.3 cells 2 h after adding

NicheEC15 to the culture medium. Nuclei were stained with SYTO 13 and cell membranes with Wheat Germ Agglutinin (WGA). In the upper panels the nanoparticle was visualized by siRNA labeled with Alexa Fluor 647 (AF647); in the lower row an unlabeled control siRNA was used. Data are shown as mean ± s.e.m.

[0033] Figures 2A to 2H show in vivo uptake of NicheEC-15 in BMEC. {Figure 2A) Decline in fluorescence intensity was measured over time following a single injection of NicheEC-15 AF647-siRNA. The in vivo circulation half-life of NicheEC-15 was calculated to be 13.8 min (n=5). {Figure 2B) Dose response curve of Tie2 silencing in whole bone marrow after in vivo injection of NicheEC-15 or 7C1 nanoparticles encapsulating siTie2 by bDNA assay (dose range 0.01 - 1.0 mg/kg, n=4-5). {Figure 2C) Time course of Tie2 expression in whole bone marrow following a single 1.0 mg/kg injection of NicheEC-15 or 7C1 encapsulating siTie2 by bDNA assay. Femurs were harvested 1-18 days post-injection (n=4-5). {Figure 2D) Intravital microscopy of the skull bone marrow 2 h after injection of NicheEC-15 with AF647-siRNA cargo. The vasculature was stained by injecting PE labeled CD31 and Seal antibodies and Osteosense was used to visualize the bone surface. {Figure 2E) Mice were harvested 2 h after injection of 2 mg/kg NicheEC-15 AF647-siRNA. BMEC were gated as shown in the representative FACS plots. Histograms of endothelial cells (EC) are overlaid with all CD45+ cells and EC of uninjected control mice. {Figure 2F) Mean fluorescence intensity of uninjected mice, CD45+ leukocytes, BMEC and lung EC 2 hrs after injection of 2 mg/kg AF647-siRNA encapsulated into the 7C1 or NicheEC-15 nanoparticles (n=4-8). {Figure 2G) The mean fluorescence intensity (MFI) of BMEC was divided by MFI of lung EC for 7C1 and the NicheEC-15. The value is 1.19 for 7C1 and 3.17 for NicheEC-15. {Figure 2H) Comparison of Tie2 silencing in whole bone marrow and lung after in vivo injection of NicheEC-15 or 7C1 encapsulating siTie2 by a bDNA assay (dose: 1.0 mg/kg, n=4-5). Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01, ****p < 0.0001.

[0034] Figures 3 A to 3M show the effects of siSdfl silencing on the bone marrow. Mice were injected with 2 mg/kg siSdfl or control siRNA targeting luciferase (siLuc) on day 0 and day 3 and harvested on day 5. {Figure 3 A) Sdfl expression in whole bone marrow by qPCR. {Figure 3B) Sdfl by ELISA in bone marrow plasma. (Figure 3C) qPCR for Sdfl in sorted BMEC.

(Figure 3D) Number of blood LSK by flow cytometry. (Figure 3E) Colony forming units (CFUs) per ml of whole blood. (Figure 3F) Representative dot plots for LSK, CMP, MEP and GMP. (Figure 3G to 3 J) Number of LSK, CMP, MEP and GMP in the femoral bone marrow. (Figure 3K) Representative dot plots of bone marrow neutrophils and monocytes. (Figure 3L to 3M) Number of monocytes and neutrophils per femur. Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.

[0035] Figures 4 A to 4F show the release of bone marrow monocytes and neutrophils after si Sdfl treatment. (Figure 4A) Representative dot plots 2 h after injection. (Figure 4B) Percentage of neutrophils and monocytes in the blood by flow cytometry. (Figure 4C) Representative intravital microscopy imaging of Cx3crl+ cells in the skull bone marrow. Baseline images were taken before injection and cells were tracked by imaging every 10 to 30 min for a total of 2.5 h. The location of cells compared to the baseline and the last imaging after 2.5 h is highlighted with white circles. Circles 3-6 and 8 in the bottom righthand panel mark the area of cells that have left the niche. (Figure 4D) Percentage of Cx3crl+ cells in the same area after 2.5 hrs compared to baseline which was adjusted to 100%. (Figure 4E) Same setup as in (c); neutrophils were labeled with an Ly6g antibody. (Figure 4F) Similar to (d), the percentage of neutrophils after 2.5 hrs compared to baseline. Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01, ***p < 0.001, ****P < 0.0001.

[0036] Figures 5 A to 51 show the effects of siMcpl treatment during LPS-induced

inflammation. (Figure 5A) Experimental setup. (Figure 5B) Mcpl expression in whole bone marrow by qPCR. (Figure 5C) Mcpl levels by ELISA in bone marrow plasma. (Figure 5D) Representative dot plots of bone marrow neutrophils and monocytes. (Figure 5E) Number of monocytes per femur. (Figure 5F) Number of Lyec^ ¹¹ monocytes per femur. (Figure 5G) Representative dot plots of blood neutrophils and monocytes. (Figure 5H) Number of monocytes per ml of blood. (Figure 57) Number of Ly6c ^Mgl1 monocytes per ml of blood. Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01, ****P < 0.0001.

[0037] Figures 6A to 6K show the effects of siMcpl treatment on inflammatory cells 24 hours after MI. (Figure 6A) Mcpl expression in whole bone marrow by qPCR. (Figure 6B) Mcpl levels by ELISA in bone marrow plasma. (Figure 6C) Representative dot plots of bone marrow neutrophils and monocytes. (Figure 6D) Number of monocytes per femur. (Figure 6E) Number of Ly6chigh monocytes per femur. {Figure 6F) Representative dot plots of blood neutrophils and monocytes. {Figure 6G) Number of monocytes per ml of blood. {Figure 6H) Number of Ly6chigh monocytes per ml of blood. {Figure 61) Representative dot plots of neutrophils and monocytes in the infarct. {Figure 6J) Number of monocytes per mg infarct tissue. {Figure 6K) Number of Ly6chigh monocytes per mg infarct tissue. Data are shown as mean ± s.e.m. *P < 0.05, **P < 0.01.

[0038] Figures 7 A to 7C show the siRNAs screen for Sdfl gene silencing. {Figure 7A) Sdfl gene expression in Hepal-6 cells after treatment with 500 pM of each of 24 different siRNAs for 24 hrs (n=4 each). Results with target-specific siRNAs were normalized to mean activity of two unspecific control siRNAs. The best four siRNAs are highlighted with arrows. {Figure 7B) Sdfl knockdown dose response curves in Hepal-6 after treatment with XD-5171, XD-5173, XD-5180 and XD-5181 siRNAs for 24 hrs (n=4). The best siRNA (XD-5171) which was used for subsequent experiments is highlighted with a box. {Figure 7C) Sdfl silencing in endothelial cells in vitro (doses 1-60 nM). bEnd.3 cells were treated with NicheEC-15 containing the XD-5171 siRNA for 24 hrs prior to qPCR analysis (n=4-5 each). Data are shown as mean ± s.e.m.

[0039] Figures 8 A to 8C show the siRNAs screen for Mcpl gene silencing. {Figure 8 A) Mcpl gene expression in Hepal-6 cells after treatment with 500 pM of each of 24 different siRNAs for 24 hrs (n=4 each). Results with target-specific siRNAs were normalized to mean activity of two unspecific control siRNAs. The best four siRNAs are highlighted with arrows. {Figure 8B) Mcpl knockdown dose response curves in Hepal-6 after treatment with XD-5136, XD-5137, XD-5143 and XD-5146 siRNAs for 24 hrs (n=4). The best siRNA (XD-5137), which was used for subsequent experiments, is highlighted with a box. {Figure 8C) Mcpl silencing in endothelial cells in vitro (doses 1-60 nM). bEND.3 cells were treated with NicheEC-15 containing the XD- 5137 siRNA for 24 hrs prior to qPCR analysis (n=4-5 each). Data are shown as mean ± s.e.m.

[0040] Figure 9 shows sequences of siRNA. Capital letters represent unmodified nucleotides; lower case letters represent 2'-OCH ₃ modified nucleotides.

[0041] Figure 10 lists the components of the nanoparticles of Figure ID.

DEFINITIONS

[0042] Definitions of specific functional groups and chemical terms are described in more detail below. The chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75 Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito, 1999; Smith and March Mar ch 's Advanced Organic Chemistry, 5 ^th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; and Carruthers, Some Modern Methods of Organic Synthesis, 3 ^rd Edition, Cambridge University Press, Cambridge, 1987.

[0043] Compounds described herein can comprise one or more asymmetric centers, and thus can exist in various isomeric forms, e.g., enantiomers and/or diastereomers. For example, the compounds described herein can be in the form of an individual enantiomer, diastereomer or geometric isomer, or can be in the form of a mixture of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be isolated from mixtures by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; or preferred isomers can be prepared by asymmetric syntheses. See, for example, Jacques et al,

Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen et al., Tetrahedron 33 :2725 (1977); Eliel, E.L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); and Wilen, S.H. Tables of Resolving Agents and Optical Resolutions p. 268 (E.L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, IN 1972). The invention additionally encompasses compounds as individual isomers substantially free of other isomers, and alternatively, as mixtures of various isomers.

[0044] When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example "Ci_ ₆ alkyl" is intended to encompass, Ci, C ₂ , C ₃ , C ₄ , C ₅ , C ₆ , Ci_ 6, Ci-5, Ci-4, Ci-3, Ci_ ₂ , C ₂ _6, C ₂ _5, C ₂ ^, C ₂ _ ₃ , C ₃ _6, C ₃ _ ₅ , C _3- , C ₄ _6, C4-5, and C5-6 alkyl.

[0045] As used herein, "alkyl" refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 50 carbon atoms ("Ci_ ₅₀ alkyl"). In some embodiments, an alkyl group has 1 to 40 carbon atoms ("Ci_ ₄₀ alkyl"). In some embodiments, an alkyl group has 1 to 30 carbon atoms ("Ci-30 alkyl"). In some embodiments, an alkyl group has 1 to 20 carbon atoms ("Ci_ ₂ o alkyl"). In some embodiments, an alkyl group has 1 to 20 carbon atoms ("Ci-10 alkyl"). In some embodiments, an alkyl group has 1 to 9 carbon atoms ("Ci_ ₉ alkyl"). In some embodiments, an alkyl group has 1 to 8 carbon atoms ("Ci_ ₈ alkyl"). In some embodiments, an alkyl group has 1 to 7 carbon atoms ("C ₁ -7 alkyl"). In some embodiments, an alkyl group has 1 to 6 carbon atoms ("Ci_ ₆ alkyl"). In some embodiments, an alkyl group has 1 to 5 carbon atoms ("Ci_5 alkyl"). In some embodiments, an alkyl group has 1 to 4 carbon atoms alkyl"). In some embodiments, an alkyl group has 1 to 3 carbon atoms ("C ₁ -3 alkyl"). In some

embodiments, an alkyl group has 1 to 2 carbon atoms ("C ₁ - ₂ alkyl"). In some embodiments, an alkyl group has 1 carbon atom ("Ci alkyl"). In some embodiments, an alkyl group has 2 to 6 carbon atoms ("C ₂ -6 alkyl"). Examples of Ci_ ₆ alkyl groups include methyl (Ci), ethyl (C ₂ ), n- propyl (C ₃ ), isopropyl (C ₃ ), n-butyl (C ₄ ), tert-butyl (C ₄ ), sec-butyl (C ₄ ), iso-butyl (C ₄ ), n-pentyl (C ₅ ), 3-pentanyl (C ₅ ), amyl (C ₅ ), neopentyl (C ₅ ), 3-methyl-2-butanyl (C ₅ ), tertiary amyl (C ₅ ), and n-hexyl (C ₆ ). Additional examples of alkyl groups include n-heptyl (C ₇ ), n-octyl (C ₈ ) and the like. Unless otherwise specified, each instance of an alkyl group is independently

unsubstituted (an "unsubstituted alkyl") or substituted (a "substituted alkyl") with one or more substituents. In certain embodiments, the alkyl group is an unsubstituted Ci-50 alkyl. In certain embodiments, the alkyl group is a substituted Ci_ ₅₀ alkyl.

[0046] The term "heteroalkyl," as used herein, refers to an alkyl group, as defined herein, which further comprises 1 or more (e.g., 1 to 25) heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) included in the parent chain. In certain embodiments, the heteroalkyl group is an unsubstituted Ci_ ₅₀ heteroalkyl. In certain embodiments, the heteroalkyl group is a substituted Ci_ ₅₀ heteroalkyl.

[0047] As used herein, "alkenyl" refers to a radical of a straight-chain or branched

hydrocarbon group having from 2 to 50 carbon atoms and one or more carbon-carbon double bonds ("C ₂ -50 alkenyl"). In some embodiments, an alkenyl group has 2 to 40 carbon atoms ("C ₂ _ 40 alkenyl"). In some embodiments, an alkenyl group has 2 to 30 carbon atoms ("C ₂ -30 alkenyl"). In some embodiments, an alkenyl group has 2 to 20 carbon atoms ("C ₂ - ₂₀ alkenyl"). In some embodiments, an alkenyl group has 2 to 10 carbon atoms ("C ₂ - ₁₀ alkenyl"). In some

embodiments, an alkenyl group has 2 to 9 carbon atoms ("C ₂ -9 alkenyl"). In some embodiments, an alkenyl group has 2 to 8 carbon atoms ("C ₂ - ₈ alkenyl"). In some embodiments, an alkenyl group has 2 to 7 carbon atoms ("C ₂ _ ₇ alkenyl"). In some embodiments, an alkenyl group has 2 to 6 carbon atoms ("C ₂ _6 alkenyl"). In some embodiments, an alkenyl group has 2 to 5 carbon atoms ("C ₂ -5 alkenyl"). In some embodiments, an alkenyl group has 2 to 4 carbon atoms ("C ₂ -4 alkenyl"). In some embodiments, an alkenyl group has 2 to 3 carbon atoms ("C ₂ _ ₃ alkenyl"). In some embodiments, an alkenyl group has 2 carbon atoms ("C ₂ alkenyl"). The one or more carbon-carbon double bonds can be internal (such as in 2-butenyl) or terminal (such as in 1- butenyl). Examples of C ₂ _ ₄ alkenyl groups include ethenyl (C ₂ ), 1-propenyl (C ₃ ), 2-propenyl (C ₃ ), 1-butenyl (C ₄ ), 2-butenyl (C ₄ ), butadienyl (C ₄ ), and the like. Examples of C ₂ _ ₆ alkenyl groups include the aforementioned C ₂ _ ₄ alkenyl groups as well as pentenyl (C ₅ ), pentadienyl (C ₅ ), hexenyl (C ₆ ), and the like. Additional examples of alkenyl include heptenyl (C ₇ ), octenyl (C ₈ ), octatnenyl (C ₈ ), and the like. Unless otherwise specified, each instance of an alkenyl group is independently unsubstituted (an "unsubstituted alkenyl") or substituted (a "substituted alkenyl") with one or more substituents. In certain embodiments, the alkenyl group is an unsubstituted C ₂ _ ₅₀ alkenyl. In certain embodiments, the alkenyl group is a substituted C ₂ _ ₅₀ alkenyl.

[0048] The term "heteroalkenyl," as used herein, refers to an alkenyl group, as defined herein, which further comprises 1 or more (e.g., 1 to 25) heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) included in the parent chain. In certain embodiments, the

heteroalkenyl group is an unsubstituted C ₂ _ ₅₀ heteroalkenyl. In certain embodiments, the heteroalkenyl group is a substituted C ₂ - ₅ o heteroalkenyl.

[0049] As used herein, "alkynyl" refers to a radical of a straight-chain or branched

hydrocarbon group having from 2 to 50 carbon atoms and one or more carbon-carbon triple bonds ("C ₂ _5o alkynyl"). In some embodiments, an alkynyl group has 2 to 40 carbon atoms ("C ₂ _ 40 alkynyl"). In some embodiments, an alkynyl group has 2 to 30 carbon atoms ("C ₂ _3o alkynyl"). In some embodiments, an alkynyl group has 2 to 20 carbon atoms ("C ₂ _ ₂ o alkynyl"). In some embodiments, an alkynyl group has 2 to 10 carbon atoms ("C ₂ _i ₀ alkynyl"). In some embodiments, an alkynyl group has 2 to 9 carbon atoms ("C ₂ _ ₉ alkynyl"). In some embodiments, an alkynyl group has 2 to 8 carbon atoms ("C ₂ _ ₈ alkynyl"). In some embodiments, an alkynyl group has 2 to 7 carbon atoms ("C ₂ _ ₇ alkynyl"). In some embodiments, an alkynyl group has 2 to 6 carbon atoms ("C ₂ _6 alkynyl"). In some embodiments, an alkynyl group has 2 to 5 carbon atoms ("C ₂ _5 alkynyl"). In some embodiments, an alkynyl group has 2 to 4 carbon atoms ("C ₂ ^ alkynyl"). In some embodiments, an alkynyl group has 2 to 3 carbon atoms ("C ₂ _ ₃ alkynyl"). In some embodiments, an alkynyl group has 2 carbon atoms ("C ₂ alkynyl"). The one or more carbon-carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1- butynyl). Examples of C _I - _A alkynyl groups include, without limitation, ethynyl (C ₂ ), 1-propynyl (C ₃ ), 2-propynyl (C ₃ ), 1-butynyl (C ₄ ), 2-butynyl (C ₄ ), and the like. Examples of C ₂ _ ₆ alkenyl groups include the aforementioned C ₂ _ ₄ alkynyl groups as well as pentynyl (C ₅ ), hexynyl (C ₆ ), and the like. Additional examples of alkynyl include heptynyl (C ₇ ), octynyl (C ₈ ), and the like. Unless otherwise specified, each instance of an alkynyl group is independently unsubstituted (an "unsubstituted alkynyl") or substituted (a "substituted alkynyl") with one or more substituents. In certain embodiments, the alkynyl group is an unsubstituted C ₂ _ ₅₀ alkynyl. In certain embodiments, the alkynyl group is a substituted C ₂ _ ₅₀ alkynyl.

[0050] The term "heteroalkynyl," as used herein, refers to an alkynyl group, as defined herein, which further comprises 1 or more {e.g., 1 to 25) heteroatoms {e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus) included in the parent chain. In certain embodiments, the heteroalkynyl group is an unsubstituted C ₂ _ ₅₀ heteroalkynyl. In certain embodiments, the heteroalkynyl group is a substituted C ₂ - ₅ o heteroalkynyl.

[0051] As used herein, "carbocyclyl" refers to a radical of a non-aromatic cyclic hydrocarbon group having from 3 to 10 ring carbon atoms ("C ₃ _i ₀ carbocyclyl") and zero heteroatoms in the non-aromatic ring system. In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms ("C ₃ _8 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms ("C ₃ _6 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms ("C ₃ _6 carbocyclyl"). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms ("C ₅ _io carbocyclyl"). Exemplary C ₃ _ ₆ carbocyclyl groups include, without limitation, cyclopropyl (C ₃ ), cyclopropenyl (C ₃ ), cyclobutyl (C ₄ ), cyclobutenyl (C ₄ ), cyclopentyl (C ₅ ), cyclopentenyl (C ₅ ), cyclohexyl (C ₆ ), cyclohexenyl (C ₆ ), cyclohexadienyl (C ₆ ), and the like. Exemplary C ₃ _ ₈ carbocyclyl groups include, without limitation, the aforementioned C ₃ _ ₆ carbocyclyl groups as well as cycloheptyl (C ₇ ), cycloheptenyl (C ₇ ), cycloheptadienyl (C ₇ ), cycloheptatrienyl (C ₇ ), cyclooctyl (C ₈ ), cyclooctenyl (C ₈ ), bicyclo[2.2.1]heptanyl (C ₇ ), bicyclo[2.2.2]octanyl (C ₈ ), and the like. Exemplary C ₃ _ ₁₀ carbocyclyl groups include, without limitation, the aforementioned C ₃ _ ₈ carbocyclyl groups as well as cyclononyl (C ₉ ), cyclononenyl (C ₉ ), cyclodecyl (C ₁₀ ), cyclodecenyl (C ₁₀ ), octahydro-lH-indenyl (C ₉ ), decahydronaphthalenyl (Cio), spiro[4.5]decanyl (C ₁₀ ), and the like. As the foregoing examples illustrate, in certain embodiments, the carbocyclyl group is either monocyclic ("monocyclic carbocyclyl") or polycyclic {e.g., containing a fused, bridged or spiro ring system such as a bicyclic system ("tricyclic carbocyclyl") or tricyclic system ("tricyclic carbocyclyl")) and can be saturated or can contain one or more carbon-carbon double or triple bonds. "Carbocyclyl" also includes ring systems wherein the carbocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups wherein the point of attachment is on the carbocyclyl ring, and in such instances, the number of carbons continue to designate the number of carbons in the carbocyclic ring system. Unless otherwise specified, each instance of a carbocyclyl group is independently unsubstituted (an "unsubstituted carbocyclyl") or substituted (a "substituted carbocyclyl") with one or more substituents. In certain embodiments, the carbocyclyl group is an unsubstituted C ₃ _ 10 carbocyclyl. In certain embodiments, the carbocyclyl group is a substituted C ₃ _ ₁₀ carbocyclyl.

[0052] In some embodiments, "carbocyclyl" is a monocyclic, saturated carbocyclyl group having from 3 to 10 ring carbon atoms ("C ₃ _i ₀ cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 8 ring carbon atoms ("C ₃ _ ₈ cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 6 ring carbon atoms ("C ₃ _6 cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 6 ring carbon atoms ("C ₅ -6 cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 10 ring carbon atoms ("C ₅ _i ₀ cycloalkyl"). Examples of C ₅ _ ₆ cycloalkyl groups include cyclopentyl (C ₅ ) and cyclohexyl (C ₅ ). Examples of C ₃ _6 cycloalkyl groups include the aforementioned C5-6 cycloalkyl groups as well as cyclopropyl (C ₃ ) and cyclobutyl (C ₄ ).

Examples of C ₃ _ ₈ cycloalkyl groups include the aforementioned C ₃ _ ₆ cycloalkyl groups as well as cycloheptyl (C ₇ ) and cyclooctyl (C ₈ ). Unless otherwise specified, each instance of a cycloalkyl group is independently unsubstituted (an "unsubstituted cycloalkyl") or substituted (a

"substituted cycloalkyl") with one or more substituents. In certain embodiments, the cycloalkyl group is an unsubstituted C ₃ _ ₁₀ cycloalkyl. In certain embodiments, the cycloalkyl group is a substituted C ₃ _i ₀ cycloalkyl.

[0053] As used herein, "heterocyclyl" refers to a radical of a 3- to 14-membered non- aromatic ring system having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("3-14 membered heterocyclyl"). In heterocyclyl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. A heterocyclyl group can either be monocyclic ("monocyclic heterocyclyl") or polycyclic (e.g., a fused, bridged or spiro ring system such as a bicyclic system ("bicyclic heterocyclyl") or tricyclic system ("tricyclic heterocyclyl")), and can be saturated or can contain one or more carbon-carbon double or triple bonds. Heterocyclyl polycyclic ring systems can include one or more heteroatoms in one or both rings. "Heterocyclyl" also includes ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more carbocyclyl groups wherein the point of attachment is either on the carbocyclyl or heterocyclyl ring, or ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each instance of heterocyclyl is independently unsubstituted (an "unsubstituted heterocyclyl") or substituted (a "substituted heterocyclyl") with one or more substituents. In certain embodiments, the heterocyclyl group is an unsubstituted 3-14 membered heterocyclyl. In certain

embodiments, the heterocyclyl group is a substituted 3-14 membered heterocyclyl.

[0054] In some embodiments, a heterocyclyl group is a 5-10 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-10 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-8 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-6 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heterocyclyl"). In some embodiments, the 5-6 membered heterocyclyl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur.

[0055] Exemplary 3-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azirdinyl, oxiranyl, thiorenyl. Exemplary 4-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azetidinyl, oxetanyl and thietanyl.

Exemplary 5-membered heterocyclyl groups containing 1 heteroatom include, without limitation, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, dioxolanyl, oxathiolanyl and dithiolanyl. Exemplary 5-membered heterocyclyl groups containing 3 heteroatoms include, without limitation, triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclyl groups containing 1 heteroatom include, without limitation, piperidinyl, tetrahydropyranyl, dihydropyndinyl, and thianyl. Exemplary 6-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, piperazinyl, morpholinyl, dithianyl, dioxanyl. Exemplary 6-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, triazinanyl. Exemplary 7-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azepanyl, oxepanyl and thiepanyl. Exemplary 8- membered heterocyclyl groups containing 1 heteroatom include, without limitation, azocanyl, oxecanyl and thiocanyl. Exemplary bicyclic heterocyclyl groups include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzothienyl, tetrahydrobenzothienyl, tetrahydrobenzofuranyl, tetrahydroindolyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, decahydroisoquinolinyl, octahydrochromenyl, octahydroisochromenyl, decahy dronaphthyri dinyl , decahy dro- 1 , 8-naphthyri dinyl , octahy dropyrrol o [3 ,2-b ] pyrrol e, indolinyl, phthalimidyl, naphthalimidyl, chromanyl, chromenyl, lH-benzo[e][l,4]diazepinyl, 1,4,5, 7-tetrahydropyrano[3,4-b]pyrrolyl, 5,6-dihydro-4H-furo[3,2-b]pyrrolyl, 6,7-dihydro- 5H-furo[3,2-b]pyranyl, 5,7-dihydro-4H-thieno[2,3-c]pyranyl, 2,3-dihydro-lH-pyrrolo[2,3- b]pyridinyl, 2,3-dihydrofuro[2,3-b]pyridinyl, 4,5,6,7-tetrahydro-lH-pyrrolo[2,3-b]pyridinyl, 4,5,6,7-tetrahydrofuro[3,2-c]pyridinyl, 4,5, 6,7-tetrahydrothieno[3,2-b]pyri dinyl, 1,2,3,4- tetrahy dro- 1,6-naphthyri dinyl, and the like.

[0056] As used herein, "aryl" refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system ("C ₆ -i4 aryl"). In some embodiments, an aryl group has 6 ring carbon atoms ("C ₆ aryl"; e.g., phenyl). In some embodiments, an aryl group has 10 ring carbon atoms ("Ci ₀ aryl"; e.g., naphthyl such as 1-naphthyl and 2-naphthyl). In some embodiments, an aryl group has 14 ring carbon atoms ("C14 aryl"; e.g., anthracyl). "Aryl" also includes ring systems wherein the aryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continue to designate the number of carbon atoms in the aryl ring system. Unless otherwise specified, each instance of an aryl group is independently unsubstituted (an "unsubstituted aryl") or substituted (a "substituted aryl") with one or more substituents. In certain embodiments, the aryl group is an unsubstituted C ₆ -i4 aryl. In certain embodiments, the aryl group is a substituted C ₆ _i ₄ aryl.

[0057] As used herein, "heteroaryl" refers to a radical of a 5-14 membered monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen and sulfur ("5-14 membered heteroaryl"). In heteroaryl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. Heteroaryl polycyclic ring systems can include one or more heteroatoms in one or both rings. "Heteroaryl" includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the point of attachment is on the heteroaryl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heteroaryl ring system. "Heteroaryl" also includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more aryl groups wherein the point of attachment is either on the aryl or heteroaryl ring, and in such instances, the number of ring members designates the number of ring members in the fused polycyclic (aryl/heteroaryl) ring system. Polycyclic heteroaryl groups wherein one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, and the like) the point of attachment can be on either ring, i.e., either the ring bearing a heteroatom (e.g., 2-indolyl) or the ring that does not contain a heteroatom (e.g., 5-indolyl).

[0058] In some embodiments, a heteroaryl group is a 5-10 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-10 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-8 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-6 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heteroaryl"). In some embodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Unless otherwise specified, each instance of a heteroaryl group is independently unsubstituted (an "unsubstituted heteroaryl") or substituted (a "substituted heteroaryl") with one or more substituents. In certain embodiments, the heteroaryl group is an unsubstituted 5-14 membered heteroaryl. In certain embodiments, the heteroaryl group is a substituted 5-14 membered heteroaryl.

[0059] Exemplary 5-membered heteroaryl groups containing 1 heteroatom include, without limitation, pyrrolyl, furanyl and thiophenyl. Exemplary 5-membered heteroaryl groups containing 2 heteroatoms include, without limitation, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containing 3 heteroatoms include, without limitation, triazolyl, oxadiazolyl, and thiadiazolyl. Exemplary 5-membered heteroaryl groups containing 4 heteroatoms include, without limitation, tetrazolyl. Exemplary 6- membered heteroaryl groups containing 1 heteroatom include, without limitation, pyridinyl. Exemplary 6-membered heteroaryl groups containing 2 heteroatoms include, without limitation, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing 3 or 4 heteroatoms include, without limitation, triazinyl and tetrazinyl, respectively. Exemplary 7- membered heteroaryl groups containing 1 heteroatom include, without limitation, azepinyl, oxepinyl, and thiepinyl. Exemplary 5,6-bicyclic heteroaryl groups include, without limitation, indolyl, isoindolyl, indazolyl, benzotriazolyl, benzothiophenyl, isobenzothiophenyl,

benzofuranyl, benzoisofuranyl, benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzoxadiazolyl, benzthiazolyl, benzisothiazolyl, benzthiadiazolyl, indolizinyl, and purinyl. Exemplary 6,6- bicyclic heteroaryl groups include, without limitation, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl, cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl. Exemplary tricyclic heteroaryl groups include, without limitation, phenanthridinyl, dibenzofuranyl, carbazolyl, acridinyl, phenothiazinyl, phenoxazinyl and phenazinyl.

[0060] As used herein, the term "partially unsaturated" refers to a ring moiety that includes at least one double or triple bond. The term "partially unsaturated" is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aromatic groups (e.g., aryl or heteroaryl moieties) as herein defined. [0061] Alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl groups, as defined herein, are optionally substituted. In general, the term "substituted", whether preceded by the term "optionally" or not, means that at least one hydrogen present on a group (e.g., a carbon or nitrogen atom) is replaced with a permissible substituent, e.g., a substituent which upon substitution results in a stable compound, e.g., a compound which does not spontaneously undergo transformation such as by

rearrangement, cyclization, elimination, or other reaction. Unless otherwise indicated, a "substituted" group has a substituent at one or more substitutable positions of the group, and when more than one position in any given structure is substituted, the substituent is either the same or different at each position. The term "substituted" is contemplated to include substitution with all permissible substituents of organic compounds, any of the substituents described herein that results in the formation of a stable compound. The present invention contemplates any and all such combinations in order to arrive at a stable compound. For purposes of this invention, heteroatoms such as nitrogen may have hydrogen substituents and/or any suitable substituent as described herein which satisfy the valencies of the heteroatoms and results in the formation of a stable moiety.

[0062] Exemplary carbon atom substituents include, but are not limited to, halogen, -CN, -N0 ₂ , -N ₃ , -S0 ₂ H, -SO3H, -OH, -OR ^aa , -ON(R ^bb ) ₂ , -N(R ^bb ) ₂ , -N(R ^bb ) ₃ ⁺ X ^" , -N(OR ^cc )R ^bb , -SH, -SR ^aa , -SSR ^CC , -C(=0)R ^aa , -C0 ₂ H, -CHO, -C(OR ^cc ) ₂ , -C0 ₂ R ^aa , -OC(=0)R ^aa ,

-OC0 ₂ R ^aa , -C(=0)N(R ^bb ) ₂ , -OC(=0)N(R ^bb ) ₂ , - R ^bb C(=0)R ^aa , - R ^bb C0 ₂ R ^aa ,

- R ^bb C(=0)N(R ^bb ) ₂ , -C(= R ^bb )R ^aa , -C(= R ^bb )OR ^aa , -OC(= R ^bb )R ^aa , -OC(= R ^bb )OR ^aa , -C(= R ^bb )N(R ^bb ) ₂ , -OC(= R ^bb )N(R ^bb ) ₂ , - R ^bb C(= R ^bb )N(R ^bb ) ₂ , -C(=0) R ^bb S0 ₂ R ^aa , - R ^bb S0 ₂ R ^aa , -S0 ₂ N(R ^bb ) ₂ , -SC^R ³³ , -S0 ₂ OR ^aa , -OS0 ₂ R ^aa , -S(=0)R ^aa , -OS(=0)R ^aa , -Si(R ^aa ) ₃ , -OSi(R ^aa ) ₃ -C(=S)N(R ^bb ) ₂ , -C(=0)SR ^aa , -C(=S)SR ^aa , -SC(=S)SR ^aa , -SC(=0)SR ^aa , -OC(=0)SR ^aa , -SC(=0)OR ^aa , -SC(=0)R ^aa , -P(=0)(R ^aa ) ₂ , -P(=0)(OR ^cc ) ₂ , -OP(=0)(R ^aa ) ₂ , -OP(=0)(OR ^cc ) ₂ , -P(=0)(N(R ^bb ) ₂ ) ₂ , -OP(=0)(N(R ^bb ) ₂ ) ₂ , - R ^bb P(=0)(R ^aa ) ₂ ,

- R ^bb P(=0)(OR ^cc ) ₂ , - R ^bb P(=0)(N(R ^bb ) ₂ ) ₂ , -P(R ^CC ) ₂ , -P(OR ^cc ) ₂ , -P(R ^CC ) ₃ ⁺ X ^" , -P(OR ^cc ) ₃ ⁺ X ^" , -P(R ^CC ) ₄ , -P(OR ^cc ) ₄ , -OP(R ^cc ) ₂ , -OP(R ^cc ) ₃ ⁺ X ^" , -OP(OR ^cc ) ₂ , -OP(OR ^cc ) ₃ ⁺ X ^" , -OP(R ^cc ) ₄ , -OP(OR ^cc ) ₄ , -B(R ^aa ) ₂ , -B(OR ^cc ) ₂ , -BR ^aa (OR ^cc ), C _M o alkyl, C _W o perhaloalkyl, C ₂ -io alkenyl, C _2- 10 alkynyl, heteroCi-io alkyl, heteroC _2- io alkenyl, heteroC _2- io alkynyl, C ₃ . ₁₀ carbocyclyl, 3-14 membered heterocyclyl, C ₆ . ₁₄ aryl, and 5-14 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups; wherein X ^~ is a counterion;

or two geminal hydrogens on a carbon atom are replaced with the group =0, =S,

=NN(R ^bb ) ₂ , =N R ^bb C(=0)R ^aa , =N R ^bb C(=0)OR ^aa , =N R ^bb S(=0) ₂ R ^aa , = R ^bb , or =NOR ^cc ; each instance of R ^aa is, independently, selected from CMO alkyl, Ci-io perhaloalkyl, C _2- io alkenyl, C _2- io alkynyl, heteroCi-io alkyl, heteroC _2- ioalkenyl, heteroC _2- ioalkynyl, C3-10 carbocyclyl, 3-14 membered heterocyclyl, C _6- i ₄ aryl, and 5-14 membered heteroaryl, or two R ^aa groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of R ^bb is, independently, selected from hydrogen, -OH, -OR ^aa , -N(R ^CC ) ₂ , -CN, -C(=0)R ^aa , -C(=0)N(R ^cc ) ₂ , -C0 ₂ R ^aa , -S0 ₂ R ^aa , -C(= R ^cc )OR ^aa , -C(= R ^CC )N(R ^CC ) ₂ , -S0 ₂ N(R ^cc ) ₂ , -S0 ₂ R ^cc , -S0 ₂ OR ^cc , -SOR ³³ , -C(=S)N(R ^CC ) ₂ , -C(=0)SR ^cc , -C(=S)SR ^CC ,

-P(=0)(R ^aa ) ₂ , -P(=0)(OR ^cc ) ₂ , -P(=0)(N(R ^cc ) ₂ ) ₂ , CMO alkyl, CLIO perhaloalkyl, C ₂ -io alkenyl, C _2- io alkynyl, heteroCi.i ₀ alkyl, heteroC _2- i ₀ alkenyl, heteroC _2- i ₀ alkynyl, C ₃ . ₁₀ carbocyclyl, 3-14 membered heterocyclyl, C ₆ . ₁₄ aryl, and 5-14 membered heteroaryl, or two R ^bb groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups; wherein X ^~ is a counterion;

each instance of R ^cc is, independently, selected from hydrogen, CMO alkyl, CMO perhaloalkyl, C ₂ . ₁₀ alkenyl, C ₂ . ₁₀ alkynyl, heteroCi-io alkyl, heteroC _2- io alkenyl, heteroC _2- io alkynyl, C ₃ . ₁₀ carbocyclyl, 3-14 membered heterocyclyl, C ₆ . ₁₄ aryl, and 5-14 membered heteroaryl, or two R ^cc groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of R ^dd is, independently, selected from halogen, -CN, -N0 ₂ , -N ₃ , -S0 ₂ H, -SO ₃ H, -OH, -OR ^ee , -ON(R ^ff ) ₂ , -N(R ^ff ) ₂ , -N(R ^ff ) ₃ ⁺ X ^" , -N(OR ^ee )R ^ff , -SH, -SR ^ee , -SSR ^ee , -C(=0)R ^ee , -C0 ₂ H, -C0 ₂ R ^ee , -OC(=0)R ^ee , -OC0 ₂ R ^ee , -C(=0)N(R ^ff ) ₂ , -OC(=0)N(R ^ff ) ₂ , -NR ^ff C(=0)R ^ee , -NR ^ff C0 ₂ R ^ee , -NR ^ff C(=0)N(R ^ff ) ₂ , -C(=NR ^ff )OR ^ee , -OC(=NR ^ff )R ^ee , -OC(= R ^H )OR ^ee , -C(= R ⁱⁱ )N(R ⁱⁱ ) ₂ , -OC(= R ⁱⁱ )N(R ⁱⁱ ) ₂ , - R ⁱⁱ C(= R ⁱⁱ )N(R ⁱⁱ ) ₂ , - R ^H S0 ₂ R ^ee , -S0 ₂ N(R ^ff ) ₂ , -S0 ₂ R ^ee , -S0 ₂ OR ^ee , -OS0 ₂ R ^ee , -S(=0)R ^ee , -Si(R ^ee ) ₃ , -OSi(R ^ee ) ₃ , -C(=S)N(R ^ff ) ₂ , -C(=0)SR ^ee , -C(=S)SR ^ee , -SC(=S)SR ^ee , -P(=0)(OR ^ee ) ₂ , -P(=0)(R ^ee ) ₂ , -OP(=0)(R ^ee ) ₂ , -OP(=0)(OR ^ee ) ₂ , Ci _-6 alkyl, Ci _-6 perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, heteroCi _-6 alkyl, heteroC _2-6 alkenyl, heteroC _2-6 alkynyl, C _3- io carbocyclyl, 3-10 membered heterocyclyl, C _6- io aryl, 5-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^gg groups, or two geminal R ^dd substituents can be joined to form =0 or =S;

wherein X ^~ is a counterion;

each instance of R ^ee is, independently, selected from Ci _-6 alkyl, Ci _-6 perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, heteroCi _-6 alkyl, heteroC _2-6 alkenyl, heteroC _2-6 alkynyl, C ₃ . ₁₀ carbocyclyl, C _6- io aryl, 3-10 membered heterocyclyl, and 3-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^gg groups;

each instance of R ff is, independently, selected from hydrogen, Ci _-6 alkyl, Ci _-6

perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, heteroCi _-6 alkyl, heteroC _2-6 alkenyl, heteroC _2-6 alkynyl, C _3- io carbocyclyl, 3-10 membered heterocyclyl, C ₆ -io aryl and 5-10 membered heteroaryl, or two R ^ff groups are joined to form a 3-10 membered heterocyclyl or 5-10 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^gg groups; and

each instance of R ^gg is, independently, halogen, -CN, ^~ N0 ₂ , -N ₃ , ^~ S0 ₂ H, -S0 ₃ H, -OH, -OC _1-6 alkyl, -ON(C _1-6 alkyl) ₂ , -N(C _1-6 alkyl) ₂ , -N(C _1-6 alkyl) ₃ ⁺ X- - H(C _1-6 alkyl) ₂ ⁺ X- - H ₂ (Ci _-6 alkyl) ⁺ X ^" , - H ₃ ⁺ X ^" , -N(OCi _-6 alkyl)(Ci _-6 alkyl), -N(OH)(Ci _-6 alkyl), - H(OH), -SH, -SCi-6 alkyl, -SS(Ci _-6 alkyl), -C(=0)(Ci _-6 alkyl), -C0 ₂ H, -C0 ₂ (Ci _-6 alkyl), -OC(=0)(Ci. 6 alkyl), -OC0 ₂ (Ci _-6 alkyl), alkyl), - HC(=0)( Ci.6 alkyl), -N(Ci _-6 alkyl)C(=0)( Ci _-6 alkyl), - HC0 ₂ (Ci _-6 alkyl),

yl),

alkyl), alkyl) ₂ , -OC( H) H(Ci _-6 alkyl), -OC( H) H ₂ , - HC( H)N(Ci _-6 alkyl) ₂ , - HC(= H) H ₂ , - HS0 ₂ (Ci _-6 alkyl), -S0 ₂ N(Ci _-6 alkyl) ₂ , -S0 ₂ H(Ci _-6 alkyl), -S0 ₂ H ₂ , -S0 ₂ Ci _-6 alkyl, -S0 ₂ OCi _-6 alkyl, -OS0 ₂ Ci _-6 alkyl, -SOCi _-6 alkyl, -Si(Ci _-6 alkyl) ₃ , -OSi(Ci _-6 alkyl) ₃ -C(=S)N(Ci _-6 alkyl) ₂ ,

-C(=0)S(Ci _-6 alkyl), -C(=S)SCi _-6 alkyl, -SC(=S)SCi _-6 alkyl, -P(=0)(OCi _-6 alkyl) ₂ , -P(=0)(d. 6 alkyl) ₂ , alkyl) ₂ , Ci _-6 alkyl, Ci _-6 perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, heteroCi-6alkyl, heteroC _2- 6alkenyl, heteroC _2- 6alkynyl, C _3- io carbocyclyl, C _6- 10 aryl, 3-10 membered heterocyclyl, 5-10 membered heteroaryl; or two geminal R ^gg substituents can be joined to form =0 or =S; wherein X ^~ is a counterion.

[0063] The term "hydroxyl" or "hydroxy" refers to the group -OH. The term "substituted hydroxyl" or "substituted hydroxyl," by extension, refers to a hydroxyl group wherein the oxygen atom directly attached to the parent molecule is substituted with a group other than hydrogen, and includes groups selected from -OR ^aa , -ON(R ^bb ) ₂ , -OC(=0)SR ^aa , -OC(=0)R ^aa , -OC0 ₂ R ^aa , -OC(=0)N(R ^bb ) ₂ , -OC(= R ^bb )R ^aa , -OC(= R ^bb )OR ^aa , -OC(= R ^bb )N(R ^bb ) ₂ , -OS(=0)R ^aa , -OS0 ₂ R ^aa , -OSi(R ^aa ) ₃ , -OP(R ^cc ) ₂ , -OP(R ^cc ) ₃ ⁺ X ^" , -OP(OR ^cc ) ₂ , -OP(OR ^cc ) ₃ ⁺ X ^" , -OP(=0)(R ^aa ) ₂ , -OP(=0)(OR ^cc ) ₂ , and -OP(=0)(N(R ^bb )) ₂ , wherein X ^" , R ^aa , R ^bb , and R ^cc are as defined herein.

[0064] As used herein, the term "thiol" or "thio" refers to the group -SH. The term

"substituted thiol" or "substituted thio," by extension, refers to a thiol group wherein the sulfur atom directly attached to the parent molecule is substituted with a group other than hydrogen, and includes groups selected from -SR ^aa , -S=SR ^CC , -SC(=S)SR ^aa , -SC(=0)SR ^aa , -SC(=0)OR ^aa , and -SC(=0)R ^aa , wherein R ^aa and R ^cc are as defined herein.

[0065] In certain embodiments, the substituent present on a sulfur atom is a sulfur protecting group (also referred to as a "thiol protecting group"). Sulfur protecting groups include, but are not limited to, -R ^aa , -N(R ^bb ) ₂ , -C(=0)SR ^aa , -C(=0)R ^aa , -C0 ₂ R ^aa , -C(=0)N(R ^bb ) ₂ ,

-C(= R ^bb )R ^aa , -C(= R ^bb )OR ^aa , -C(= R ^bb )N(R ^bb ) ₂ , -S(=0)R ^aa , -S0 ₂ R ^aa , -Si(R ^aa ) ₃ , -P(R ^CC ) ₂ , -P(R ^CC ) ₃ ⁺ X ^" , -P(OR ^cc ) ₂ , -P(OR ^cc ) ₃ ⁺ X ^" , -P(=0)(R ^aa ) ₂ , -P(=0)(OR ^cc ) ₂ , and -P(=0)(N(R ^bb ) ₂ ) ₂ , wherein R ^aa , R ^bb , and R ^cc are as defined herein. Sulfur protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3 ^rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

[0066] As used herein, the term, "amino" refers to the group - H ₂ . The term "substituted amino," by extension, refers to a monosubstituted amino, a disubstituted amino, or a

tri substituted amino, as defined herein. [0067] The term "monosubstituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with one hydrogen and one group other than hydrogen, and includes groups selected from - H(R ^bb ), - HC(=0)R ^aa , - HC0 ₂ R ^aa , - HC(=0)N(R ^bb ) ₂ , - HC(= R ^bb )N(R ^bb ) ₂ , - HS0 ₂ R ^aa , - HP(=0)(OR ^cc ) ₂ , and

- HP(=0)(N(R ^bb ) ₂ ) ₂ , wherein R ^aa , R ^bb and R ^cc are as defined herein, and wherein R ^bb of the group - H(R ^bb ) is not hydrogen.

[0068] The term "di substituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with two groups other than hydrogen, and includes groups selected from -N(R ^bb ) ₂ , - R ^bb C(=0)R ^aa , - R ^bb C0 ₂ R ^aa , - R ^bb C(=0)N(R ^bb ) ₂ , - R ^bb C(= R ^bb )N(R ^bb ) ₂ , - R ^bb S0 ₂ R ^aa , - R ^bb P(=0)(OR ^cc ) ₂ , and - R ^bb P(=0)(N(R ^bb ) ₂ ) ₂ , wherein R ^aa , R ^bb , and R ^cc are as defined herein, with the proviso that the nitrogen atom directly attached to the parent molecule is not substituted with hydrogen.

[0069] As used herein, the term "tri substituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with three groups, and includes groups selected from— N(R ) ₃ and— N(R ) ₃ X ^~ , wherein R and X ^" are as defined herein.

[0070] As used herein, the term "sulfonyl" refers to a group selected from -S0 ₂ N(R ^bb ) ₂ , - S0 ₂ R ^aa , and -S0 ₂ OR ^aa , wherein R ^aa and R ^bb are as defined herein.

[0071] As used herein, the term "silyl" refers to the group -Si(R ^aa ) ₃ , wherein R ^aa is as defined herein.

[0072] As used herein, the term "acyl" refers a group wherein the carbon directly attached to the parent molecule is sp ² hybridized, and is substituted with an oxygen, nitrogen or sulfur atom, e.g., a group selected from ketones (-C(=0)R ^aa ), carboxylic acids (-C0 ₂ H), aldehydes (-CHO), esters (-C0 ₂ R ^aa -C(=0)SR ^aa , -C(=S)SR ^aa ), amides (-C(=0)N(R ^bb ) ₂ , -C(=0) R ^bb S0 ₂ R ^aa , - C(=S)N(R ^bb ) ₂ ), and imines (-C(= R ^bb )R ^aa , -C(= R ^bb )OR ^aa ), -C(= R ^bb )N(R ^bb ) ₂ ), wherein R ^aa and R ^bb are as defined herein.

[0073] As used herein, the term "halo" or "halogen" refers to fluorine (fluoro, -F), chlorine (chloro, -CI), bromine (bromo, -Br), or iodine (iodo, -I).

[0074] A "counterion" or "anionic counterion" is a negatively charged group associated with a positively charged group in order to maintain electronic neutrality. An anionic counterion may be monovalent (i.e., including one formal negative charge). An anionic counterion may also be multivalent (i.e., including more than one formal negative charge), such as divalent or trivalent. Exemplary counted ons include halide ions (e.g., F ^" , CP, Br ^~ , Γ), N0 ₃ ^" , C10 ₄ ^~ , OH ^~ , H ₂ P0 ₄ ^~ , HC0 ₃ ^" HS0 ₄ ^~ , sulfonate ions (e.g., methansulfonate, trifluoromethanesulfonate, p- toluenesulfonate, benzenesulfonate, 10-camphor sulfonate, naphthalene-2-sulfonate, naphthalene-l-sulfonic acid-5-sulfonate, ethan-l-sulfonic acid-2-sulfonate, and the like), carboxylate ions (e.g., acetate, propanoate, benzoate, glycerate, lactate, tartrate, glycolate, gluconate, and the like), BF ₄ ^" , PF ₄ ^" , PF ₆ ^" , AsF ₆ ^" , SbF ₆ ^" , B[3,5-(CF ₃ ) ₂ C ₆ H ₃ ] ₄ ] ^" , B(C ₆ F ₅ ) ₄ ^" , BPh ₄ ^" , Al(OC(CF ₃ ) ₃ ) ₄ ^~ , and carborane anions (e.g., CBnHi ₂ ^~ or (HCBiiMe ₅ Br ₆ ) ^~ ). Exemplary

2 2 2 2 2 counterions which may be multivalent include C0 ₃ , HP0 ₄ , P0 _{4 ,} B ₄ 0 ₇ , S0 ₄ , S ₂ 0 ₃ , carboxylate anions (e.g., tartrate, citrate, fumarate, maleate, malate, malonate, gluconate, succinate, glutarate, adipate, pimelate, suberate, azelate, sebacate, salicylate, phthalates, aspartate, glutamate, and the like), and carboranes.

[0075] As used herein, a "counterion" is a negatively charged group associated with a positively charged quarternary amine in order to maintain electronic neutrality. Exemplary counterions include halide ions (e.g., F ^" , CI ^" , Br ^" , Γ), N0 ₃ ^" , C10 ₄ ^" , OH ^" , H ₂ P0 ₄ ^" , HS0 ₄ ^" , sulfonate ions (e.g., methansulfonate, trifluoromethanesulfonate, p-toluenesulfonate, benzenesulfonate, 10-camphor sulfonate, naphthalene-2-sulfonate, naphthalene-l-sulfonic acid-5-sulfonate, ethan-l-sulfonic acid-2-sulfonate, and the like), and carboxylate ions (e.g., acetate, ethanoate, propanoate, benzoate, glycerate, lactate, tartrate, glycolate, and the like).

[0076] Nitrogen atoms can be substituted or unsubstituted as valency permits, and include primary, secondary, tertiary, and quarternary nitrogen atoms. Exemplary nitrogen atom substitutents include, but are not limited to, hydrogen, -OH, -OR ^aa , -N(R ^CC ) ₂ , -CN, -C(=0)R ^aa , -C(=0)N(R ^cc ) ₂ , -C0 ₂ R ^aa , -S0 ₂ R ^aa , -C(=NR ^bb )R ^aa , -C(=NR ^cc )OR ^aa , -C(=NR ^CC )N(R ^CC ) ₂ , - S0 ₂ N(R ^cc ) ₂ , -S0 ₂ R ^cc , -S0 ₂ OR ^cc , -SOR ³³ , -C(=S)N(R ^CC ) ₂ , -C(=0)SR ^cc , -C(=S)SR ^CC , - P(=0) ₂ R ^aa , -P(=0)(R ^aa ) ₂ , -P(=0) ₂ N(R ^cc ) ₂ , -P(=0)(NR ^cc ) ₂ , d_ ₁₀ alkyl, C ₂ _ ₁₀ alkenyl, C ₂ _ ₁₀ alkynyl, C ₃ _io carbocyclyl, 3-14 membered heterocyclyl, C ₆ -i ₄ aryl, and 5-14 membered heteroaryl, or two R ^cc groups attached to an N atom are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups, and wherein R ^aa , R ^bb , R ^cc and R ^dd are as defined above. [0077] In certain embodiments, the substituent present on the nitrogen atom is an nitrogen protecting group (also referred to herein as an "amino protecting group"). Nitrogen protecting groups include, but are not limited to, -OH, -OR ^aa , -N(R ^CC ) ₂ , -C(=0)R ^aa , -C(=0)N(R ^cc ) ₂ , -C0 ₂ R ^aa , -S0 ₂ R ^aa , -C(=NR ^cc )R ^aa , -C(=NR ^cc )OR ^aa , -C(=NR ^CC )N(R ^CC ) ₂ , -S0 ₂ N(R ^cc ) ₂ , -S0 ₂ R ^cc , -S0 ₂ OR ^cc , -SOR ^aa , -C(=S)N(R ^CC ) ₂ , -C(=0)SR ^cc , -C(=S)SR ^CC , C _wo alkyl (e.g., aralkyl, heteroaralkyl), C ₂ . ₁₀ alkenyl, C ₂ . ₁₀ alkynyl, heteroCi-io alkyl, heteroC _2- io alkenyl, heteroC _2- io alkynyl, C ₃ . ₁₀ carbocyclyl, 3-14 membered heterocyclyl, C ₆ . ₁₄ aryl, and 5-14 membered heteroaryl groups, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl,

heteroalkynyl, carbocyclyl, heterocyclyl, aralkyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups, and wherein R ^aa , R ^bb , R ^cc and R ^dd are as defined herein. Nitrogen protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3 ^rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

[0078] For example, nitrogen protecting groups such as amide groups (e.g., -C(=0)R ^aa ) include, but are not limited to, formamide, acetamide, chloroacetamide, trichloroacetamide, trifluoroacetamide, phenyl acetamide, 3-phenylpropanamide, picolinamide, 3- pyridylcarboxamide, N-benzoylphenylalanyl derivative, benzamide, p-phenylbenzamide, o- nitophenyl acetamide, o-nitrophenoxy acetamide, acetoacetamide, (Ν'- dithiobenzyloxyacylamino)acetamide, 3-(p-hydroxyphenyl)propanamide, 3-(o- nitrophenyl)propanamide, 2-methyl-2-(o-nitrophenoxy)propanamide, 2-methyl-2-(o- phenylazophenoxy)propanamide, 4-chlorobutanamide, 3-methyl-3-nitrobutanamide, o- nitrocinnamide, N-acetylmethionine derivative, o-nitrobenzamide and o- (benzoyloxym ethyl )b enz ami de .

[0079] Nitrogen protecting groups such as carbamate groups (e.g., -C(=0)OR ^aa ) include, but are not limited to, methyl carbamate, ethyl carbamate, 9-fluorenylmethyl carbamate (Fmoc), 9- (2-sulfo)fluorenylmethyl carbamate, 9-(2,7-dibromo)fluoroenylmethyl carbamate, 2,7-di-t-butyl- [9-(10,10-dioxo-10,10, 10, 10-tetrahydrothioxanthyl)]methyl carbamate (DBD-Tmoc), 4- methoxyphenacyl carbamate (Phenoc), 2,2,2-trichloroethyl carbamate (Troc), 2- trimethylsilyl ethyl carbamate (Teoc), 2 -phenyl ethyl carbamate (hZ), l-(l-adamantyl)-l- methyl ethyl carbamate (Adpoc), 1,1 -dimethyl -2-haloethyl carbamate, 1,1 -dimethyl -2,2- dibromoethyl carbamate (DB-t-BOC), 1,1 -dimethyl -2,2,2-trichloroethyl carbamate (TCBOC), 1- methyl- l-(4-biphenylyl)ethyl carbamate (Bpoc), l-(3,5-di-t-butylphenyl)-l-methylethyl carbamate (t-Bumeoc), 2-(2'- and 4'-pyridyl)ethyl carbamate (Pyoc), 2-(N,N- dicyclohexylcarboxamido)ethyl carbamate, t-butyl carbamate (BOC or Boc), 1-adamantyl carbamate (Adoc), vinyl carbamate (Voc), allyl carbamate (Alloc), 1-isopropylallyl carbamate (Ipaoc), cinnamyl carbamate (Coc), 4-nitrocinnamyl carbamate (Noc), 8-quinolyl carbamate, N- hydroxypiperidinyl carbamate, alkyldithio carbamate, benzyl carbamate (Cbz), p-methoxybenzyl carbamate (Moz), p-nitobenzyl carbamate, p-bromobenzyl carbamate, p-chlorobenzyl carbamate, 2,4-dichlorobenzyl carbamate, 4-methylsulfinylbenzyl carbamate (Msz), 9-anthrylmethyl carbamate, diphenylmethyl carbamate, 2-methylthioethyl carbamate, 2-methylsulfonylethyl carbamate, 2-(p-toluenesulfonyl)ethyl carbamate, [2-(l,3-dithianyl)]methyl carbamate (Dmoc), 4-methylthiophenyl carbamate (Mtpc), 2,4-dimethylthiophenyl carbamate (Bmpc), 2- phosphonioethyl carbamate (Peoc), 2-triphenylphosphonioisopropyl carbamate (Ppoc), 1,1- dimethyl-2-cyanoethyl carbamate, m-chloro-p-acyloxybenzyl carbamate, p- (dihydroxyboryl)benzyl carbamate, 5-benzisoxazolylmethyl carbamate, 2-(trifluoromethyl)-6- chromonylmethyl carbamate (Tcroc), m-nitrophenyl carbamate, 3,5-dimethoxybenzyl carbamate, o-nitrobenzyl carbamate, 3,4-dimethoxy-6-nitrobenzyl carbamate, phenyl(o-nitrophenyl)methyl carbamate, t-amyl carbamate, S-benzyl thiocarbamate, p-cyanobenzyl carbamate, cyclobutyl carbamate, cyclohexyl carbamate, cyclopentyl carbamate, cyclopropylmethyl carbamate, p- decyloxybenzyl carbamate, 2,2-dimethoxyacylvinyl carbamate, o-(N,N- dimethylcarboxamido)benzyl carbamate, 1, l-dimethyl-3-(N,N-dimethylcarboxamido)propyl carbamate, 1, 1-dimethylpropynyl carbamate, di(2-pyridyl)methyl carbamate, 2-furanylmethyl carbamate, 2-iodoethyl carbamate, isoborynl carbamate, isobutyl carbamate, isonicotinyl carbamate, p-(p'-methoxyphenylazo)benzyl carbamate, 1 -methyl cyclobutyl carbamate, 1- methylcyclohexyl carbamate, 1-methyl-l-cyclopropylmethyl carbamate, l-methyl-l-(3,5- dimethoxyphenyl)ethyl carbamate, 1 -methyl- l-(p-phenylazophenyl)ethyl carbamate, 1-methyl-l- phenyl ethyl carbamate, 1 -methyl- l-(4-pyridyl)ethyl carbamate, phenyl carbamate, p- (phenylazo)benzyl carbamate, 2,4,6-tri-t-butylphenyl carbamate, 4-(trimethylammonium)benzyl carbamate, and 2,4,6-trimethylbenzyl carbamate.

[0080] Nitrogen protecting groups such as sulfonamide groups (e.g., -S(=0) ₂ R ^aa ) include, but are not limited to, p-toluenesulfonamide (Ts), benzenesulfonamide, 2,3,6-trimethyl-4- methoxybenzenesulfonamide (Mtr), 2,4,6-trimethoxybenzenesulfonamide (Mtb), 2,6-dimethyl-4- methoxybenzenesulfonamide (Pme), 2,3,5,6-tetramethyl-4-methoxybenzenesulfonamide (Mte), 4-methoxybenzenesulfonamide (Mbs), 2,4,6-trimethylbenzenesulfonamide (Mts), 2,6- dimethoxy-4-methylbenzenesulfonamide (iMds), 2,2,5, 7,8-pentamethylchroman-6-sulfonamide (Pmc), methanesulfonamide (Ms), β-trimethylsilylethanesulfonamide (SES), 9- anthracenesulfonamide, 4-(4',8'-dimethoxynaphthylmethyl)benzenesulfonamide (D MBS), benzyl sulfonamide, trifluoromethylsulfonamide, and phenacylsulfonamide.

[0081] Other nitrogen protecting groups include, but are not limited to, phenothiazinyl-(lO)- acyl derivative, N'-p-toluenesulfonylaminoacyl derivative, N'-phenylaminothioacyl derivative, N-benzoylphenylalanyl derivative, N-acetylmethionine derivative, 4,5-diphenyl-3-oxazolin-2- one, N-phthalimide, N-dithiasuccinimide (Dts), N-2,3-diphenylmaleimide, N-2,5- dimethylpyrrole, N-l,l,4,4-tetramethyldisilylazacyclopentane adduct (STABASE), 5-substituted l,3-dimethyl-l,3,5-triazacyclohexan-2-one, 5-substituted l,3-dibenzyl-l,3,5-triazacyclohexan-2- one, 1-substituted 3,5-dinitro-4-pyridone, N-methylamine, N-allylamine, N-[2- (trimethylsilyl)ethoxy]methylamine (SEM), N-3-acetoxypropylamine, N-(l-isopropyl-4-nitro-2- oxo-3-pyroolin-3-yl)amine, quaternary ammonium salts, N-benzylamine, N-di(4- methoxyphenyl)methylamine, N-5-dibenzosuberylamine, N-triphenylmethylamine (Tr), N-[(4- methoxyphenyl)diphenylmethyl]amine (MMTr), N-9-phenylfluorenylamine (PhF), N-2,7- dichloro-9-fluorenylmethyleneamine, N-ferrocenylmethyl amino (Fcm), N-2-picolylamino N'- oxide, N-l,l-dimethylthiom ethyl eneamine, N-benzylideneamine, N-p- methoxybenzylideneamine, N-diphenylmethyl eneamine, N-[(2-pyridyl)mesityl]methyl eneamine, N-(N',N'-dimethylaminomethylene)amine, Ν,Ν'-isopropylidenediamine, N-p- nitrobenzylideneamine, N-salicylideneamine, N-5-chlorosalicylideneamine, N-(5-chloro-2- hydroxyphenyl)phenylmethyl eneamine, N-cyclohexylideneamine, N-(5,5-dimethyl-3-oxo-l- cyclohexenyl)amine, N-borane derivative, N-diphenylborinic acid derivative, N- [phenyl(pentaacylchromium- or tungsten)acyl]amine, N-copper chelate, N-zinc chelate, N- nitroamine, N-nitrosoamine, amine N-oxide, diphenylphosphinamide (Dpp),

dimethylthiophosphinamide (Mpt), diphenylthiophosphinamide (Ppt), dialkyl phosphoramidates, dibenzyl phosphoramidate, diphenyl phosphoramidate, benzenesulfenamide, o- nitrobenzenesulfenamide (Nps), 2,4-dinitrobenzenesulfenamide,

pentachlorobenzenesulfenamide, 2-nitro-4-methoxybenzenesulfenamide,

triphenylmethylsulfenamide, and 3-nitropyridinesulfenamide (Npys). [0082] In certain embodiments, the substituent present on an oxygen atom is an oxygen protecting group (also referred to herein as an "hydroxyl protecting group"). Oxygen protecting groups include, but are not limited to, -R ^aa , -N(R ^bb ) ₂ , -C(=0)SR ^aa , -C(=0)R ^aa , -C0 ₂ R ^aa , -C(=0)N(R ^bb ) ₂ , -C(= R ^bb )R ^aa , -C(= R ^bb )OR ^aa , -C(= R ^bb )N(R ^bb ) ₂ , -S(=0)R ^aa , -S0 ₂ R ^aa , -Si(R ^aa ) ₃ , -P(R ^CC ) ₂ , -P(R ^cc ) ₃ ⁺ X ^" , -P(OR ^cc ) ₂ , -P(OR ^cc ) ₃ ⁺ X ^" , -P(=0)(R ^aa ) ₂ , -P(=0)(OR ^cc ) ₂ , and -P(=0)(N(R ^bb ) 2)2, wherein X ^" , R ^aa , R ^bb , and R ^cc are as defined herein. Oxygen protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3 ^rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

[0083] Exemplary oxygen protecting groups include, but are not limited to, methyl, methoxylmethyl (MOM), methylthiomethyl (MTM), t-butylthiomethyl,

(phenyldimethylsilyl)methoxymethyl (SMOM), benzyloxym ethyl (BOM), p- methoxybenzyloxymethyl (PMBM), (4-methoxyphenoxy)methyl (p-AOM), guaiacolmethyl (GUM), t-butoxymethyl, 4-pentenyloxymethyl (POM), siloxymethyl, 2-methoxyethoxymethyl (MEM), 2,2,2-trichloroethoxymethyl, bis(2-chloroethoxy)methyl, 2-(trimethylsilyl)ethoxymethyl (SEMOR), tetrahydropyranyl (THP), 3-bromotetrahydropyranyl, tetrahydrothiopyranyl, 1- methoxycyclohexyl, 4-methoxytetrahydropyranyl (MTHP), 4-methoxytetrahydrothiopyranyl, 4- methoxytetrahydrothiopyranyl S, S-di oxide, 1 -[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin- 4-yl (CTMP), l,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl, 2,3, 3a,4,5, 6,7,7a- octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl, 1-ethoxy ethyl, l-(2-chloroethoxy)ethyl, 1 -methyl- 1 -methoxyethyl, 1 -methyl- 1 -benzyl oxy ethyl, 1 -methyl- 1 -benzyl oxy-2-fluoroethyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-(phenylselenyl)ethyl, t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl, benzyl (Bn), p-methoxybenzyl, 3,4-dimethoxybenzyl, o- nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl, p-phenylbenzyl, 2- picolyl, 4-picolyl, 3-methyl-2-picolyl N-oxido, diphenylmethyl, p,p'-dinitrobenzhydryl, 5- dibenzosuberyl, triphenylmethyl, a-naphthyldiphenylmethyl, p-methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenylmethyl, tri(p-methoxyphenyl)methyl, 4-(4' - bromophenacyloxyphenyl)diphenylmethyl, 4,4',4"-tris(4,5-dichlorophthalimidophenyl)methyl, 4,4',4"-tris(levulinoyloxyphenyl)m ethyl, 4,4',4"-tris(benzoyloxyphenyl)methyl, 3-(imidazol-l- yl)bis(4',4"-dimethoxyphenyl)methyl, l,l-bis(4-methoxyphenyl)-l '-pyrenylmethyl, 9-anthryl, 9- (9-phenyl)xanthenyl, 9-(9-phenyl-10-oxo)anthryl, l,3-benzodithiolan-2-yl, benzisothiazolyl S,S- dioxido, trimethylsilyl (TMS), triethylsilyl (TES), triisopropylsilyl (TIPS),

dimethylisopropylsilyl (IPDMS), diethylisopropylsilyl (DEIPS), dimethylthexylsilyl, t- butyl dimethyl silyl (TBDMS), t-butyldiphenylsilyl (TBDPS), tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl (DPMS), t-butylmethoxyphenylsilyl (TBMPS), formate, benzoylformate, acetate, chloroacetate, dichloroacetate, trichloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, phenoxyacetate, p-chlorophenoxyacetate, 3- phenylpropionate, 4-oxopentanoate (levulinate), 4,4-(ethylenedithio)pentanoate

(levulinoyldithioacetal), pivaloate, adamantoate, crotonate, 4-methoxycrotonate, benzoate, p- phenylbenzoate, 2,4,6-trimethylbenzoate (mesitoate), methyl carbonate, 9-fluorenylmethyl carbonate (Fmoc), ethyl carbonate, 2,2,2-trichloroethyl carbonate (Troc), 2-(trimethylsilyl)ethyl carbonate (TMSEC), 2-(phenylsulfonyl) ethyl carbonate (Psec), 2-(triphenylphosphonio) ethyl carbonate (Peoc), isobutyl carbonate, vinyl carbonate, allyl carbonate, t-butyl carbonate (BOC or Boc), p-nitrophenyl carbonate, benzyl carbonate, p-methoxybenzyl carbonate, 3,4- dimethoxybenzyl carbonate, o-nitrobenzyl carbonate, p-nitrobenzyl carbonate, S-benzyl thiocarbonate, 4-ethoxy-l-napththyl carbonate, methyl dithiocarbonate, 2-iodobenzoate, 4- azidobutyrate, 4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate, 2- formylbenzenesulfonate, 2-(methylthiomethoxy)ethyl, 4-(methylthiomethoxy)butyrate, 2- (methylthiomethoxymethyl)benzoate, 2,6-dichloro-4-methylphenoxyacetate, 2,6-dichloro-4- (1,1 ,3 ,3 -tetramethylbutyl)phenoxyacetate, 2,4-bis( 1 , 1 -dimethylpropyl)phenoxyacetate, chlorodiphenylacetate, isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate, o- (methoxyacyl)benzoate, a-naphthoate, nitrate, alkyl Ν,Ν,Ν',Ν'-tetramethylphosphorodiamidate, alkyl N-phenylcarbamate, borate, dimethylphosphinothioyl, alkyl 2,4-dinitrophenylsulfenate, sulfate, methanesulfonate (mesylate), benzylsulfonate, and tosylate (Ts).

[0084] These and other exemplary substituents are described in more detail in the Detailed Description, the Examples and in the claims. The invention is not intended to be limited in any manner by the above exemplary listing of substituents.

[0085] As used herein, a "polymer" refers to a compound comprising at least 3 (e.g., at least 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.) repeating structural units covalently bound together. [0086] As used herein, an "organic molecule" is a molecule comprising carbon, as defined herein. The organic molecule may also comprise a metal. In this instance, the organic molecule is also referred to as an "organometallic compound."

[0087] As used herein, an "inorganic molecule" is a molecule which comprises elements other than carbon, and encompasses large inorganic molecules and small inorganic molecules, as defined herein. If an inorganic molecule comprises a transition metal, it is also referred to herein as a "metal."

[0088] As used herein, the term "salt" or "pharmaceutically acceptable salt" refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge et al., describes pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences (1977) 66: 1-19. Pharmaceutically acceptable salts of the compounds of this invention include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecyl sulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2- naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N ⁺ (Ci_ ₄ alkyl) ₄ salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, sulfonate and aryl sulfonate. Further pharmaceutically acceptable salts include salts formed from the

quarternization of an amine using an appropriate electrophile, e.g., an alkyl halide, to form a quarternized alkylated amino salt.

[0089] As used herein, use of the phrase "at least one instance" refers to one instance, but also encompasses more than one instance, e.g., for example, from 1 instance to 50 instances.

[0090] As used herein, use of the phrase "molar mass averages" refers to different average values (e.g., M _n , M _w , M _v and M _z ) can be defined depending upon the statistical method that is applied. The weighted mean can be taken with the weight fraction, the mole fraction, or the volume fraction (see, e.g., R.J. Young and P. A. Lovell, Introduction to Polymers, 1991, incorporated herein by reference).

[0091] As used herein, use of the term "dispersity" refers to dispersity (D), which is a measure of the distribution of molecular mass in a given polymer sample and is calculated by dividing the weight average molar mass (M _w ) by the number average molar mass (M _n ). The dispersity of a given sample can have a value equal to or greater than 1. As the polymer chains approach uniform chain length, the dispersity approaches unity (1). The dispersity of a polymer can be modified, for example, using polymer fractionation (e.g., preparative SEC, Baker-Williams fractionation, continuous spin fractionation), or modifying the work-up procedure (e.g., by partially dissolving a polymer, an insoluble high molar mass fraction may be filtered off resulting in a large reduction in M _w and a small reduction in M _n , thus reducing polydispersity).

[0092] As used herein, use of the phrase "number average molar mass" or "M _n " is defined as the total weight of a sample, divided by the number of molecules in the sample, and is calculated

∑ M;N;

∑N;

as follows: , where M _n is the sum (∑) of Mi (mass of each molecule in a sample) multiplied by Ni (the number of molecules in the sample), which is divided by the sum (∑) of the number of molecules in the sample.

[0093] As used herein, use of the term "weight average molar mass" or "M _w " is defined as the sum (∑) of of (the square of Mi multipled by Ni (the number of molecules in the sample)), divided by the sum (∑) of Mi (mass of each molecule in a sample) multiplied by Ni (the number

∑ Mi ² Ni

M ^■ ,w

∑ M;N;

of molecules in the sample), which is is calculated as follows: [0094] As used herein, use of the phrase "Z average molar mass" or "M _z " is defined as the sum (∑) of (the cube of Mi multipled by Ni (the number of molecules in the sample)), divided by the sum (∑) of (the square of Mi (mass of each molecule in a sample) multiplied by Ni (the

M,

∑ M- ² N- number of molecules in the sample)), which is is calculated as follows: ^{1 1} .

[0095] . As used herein, use of the phrase "viscosity average molar m" or "M _v " is defined as

1/a

∑Mi ^{l +a} N _j

∑ M;N;

, wherein "a" is the exponent in the Mark-Houwink equation.

[0096] As used herein, use of the term "lipid" may refer to fats, fatty acids, waxes,

phospholipids, or steroids which are soluble in nonpolar organic solvents (e.g., ether, chloroform, acetone, and benzene) and generally insoluble in water. In certain embodiments, the lipid is a fat. In certain embodiments, the lipid is a phospholipid.

[0097] As used herein, use of the term "subject" to which administration is contemplated refers to, but is not limited to, humans (i.e., a male or female of any age group, e.g., a pediatric subject (e.g, infant, child, adolescent) or adult subject (e.g., young adult, middle-aged adult or senior adult)) and/or other non-human animals, for example mammals (e.g., primates (e.g., cynomolgus monkeys, rhesus monkeys); commercially relevant mammals such as cattle, pigs, horses, sheep, goats, cats, and/or dogs), birds (e.g., commercially relevant birds such as chickens, ducks, geese, and/or turkeys), reptiles, amphibians, and fish. In certain embodiments, the non- human animal is a mammal. The non-human animal may be a male or female and at any stage of development. A non-human animal may be a transgenic animal.

[0098] As used herein, and unless otherwise specified, the terms "treat," "treating" and "treatment" contemplate an action that occurs while a subject is suffering from the specified disease, disorder or condition, which reduces the severity of the disease, disorder or condition, or retards or slows the progression of the disease, disorder or condition ("therapeutic treatment"), and also contemplates an action that occurs before a subject begins to suffer from the specified disease, disorder or condition ("prophylactic treatment").

[0099] As used herein, use of the phrase the "effective amount" of a compound refers to an amount sufficient to elicit the desired biological response. As will be appreciated by those of ordinary skill in this art, the effective amount of a compound of the invention may vary depending on such factors as the desired biological endpoint, the pharmacokinetics of the compound, the disease being treated, the mode of administration, and the age, health, and condition of the subject. An effective amount encompasses therapeutic and prophylactic treatment.

[00100] As used herein, and unless otherwise specified, a "therapeutically effective amount" of a compound is an amount sufficient to provide a therapeutic benefit in the treatment of a disease, disorder or condition, or to delay or minimize one or more symptoms associated with the disease, disorder or condition. A therapeutically effective amount of a compound means an amount of therapeutic agent, alone or in combination with other therapies, which provides a therapeutic benefit in the treatment of the disease, disorder or condition. The term

"therapeutically effective amount" can encompass an amount that improves overall therapy, reduces or avoids symptoms or causes of disease or condition, or enhances the therapeutic efficacy of another therapeutic agent.

[00101] As used herein, and unless otherwise specified, a "prophylactically effective amount" of a compound is an amount sufficient to prevent a disease, disorder or condition, or one or more symptoms associated with the disease, disorder or condition, or prevent its recurrence. A prophylactically effective amount of a compound means an amount of a therapeutic agent, alone or in combination with other agents, which provides a prophylactic benefit in the prevention of the disease, disorder or condition. The term "prophylactically effective amount" can encompass an amount that improves overall prophylaxis or enhances the prophylactic efficacy of another prophylactic agent.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

[00102] The present invention provides compositions (e.g., nanoparticles) comprising conjugated lipomers of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II); and methods of use (e.g., delivering biologically active agents (e.g., nucleic acids) to a subject (e.g. bone marrow of a subject in vivo)). In certain embodiments, provided is a particle comprising conjugated lipomers of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle.

[00103] In one aspect, provided is a composition comprising a particle, wherein the particle comprises a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle. In certain embodiments, the composition comprising a particle comprises a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II), wherein: each instance of R ^A1 is independently unsubstituted C ₆ -C ₂ o alkyl; R^ is substituted or unsubstituted alkyl; and x is an integer between 15 to 135, inclusive.

[00104] In certain embodiments, the conjugated lipomer is of Formula (I):

or a pharmaceutically acceptable salt thereof; wherein:

group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl;

substituted or unsubstituted heteroaryl; a substituted or unsubstituted polyethyleneimine; or a group of the formula (iii'):

or the two R ² groups are joined to form a substituted or unsubstituted heterocyclyl;

each instance of R ³ is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a hydrophilic polymer;

each instance of R ⁴ is independently hydrogen, acyl; silyl; a hydroxyl protecting group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or

unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted

carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; or substituted or unsubstituted heteroaryl;

A is -N(R ⁵ ) ₂ , wherein each instance of R ⁵ is independently hydrogen; acyl; silyl;

sulfonyl; an amino protecting group; substituted or unsubstituted alkyl; substituted or

unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted

heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a group of the formula (iii'):

Z is hydrogen; acyl; silyl; sulfonyl; an amino protecting group; substituted or

unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or

unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl, or a group of the formula (iii'):

or Z and the nitrogen atom to which it is attached form a substituted or unsubstituted heterocyclyl group. [00105] In certain embodiments, the conjugated lipomer of Formula (I) comprises a polyethyleneimine of molecular weight that is about 650 g/mol or lower. In certain

embodiments, the conjugated lipomer of Formula (I) comprises a polyethyleneimine of molecular weight that is about 600 g/mol or lower. In certain embodiments, the conjugated lipomer of Formula (I) comprises a polyethyleneimine of molecular weight that is between about 600 g/mol to about 650 g/mol, about 500 g/mol to about 600 g/mol, between about 400 g/mol to about 500 g/mol, or between about 300 g/mol to about 400 g/mol. In certain embodiments, the conjugated lipomer of Formula (I) comprises a polyethyleneimine of molecular weight that is about 550 g/mol or lower, about 500 g/mol or lower, about 450 g/mol or lower, about 400 g/mol or lower, about 350 g/mol or lower, or about 300 g/mol or lower.

[00106] In certain embodiments, each instance of L ¹ is independently selected from the formulae:

[00107] In certain embodiments, the conjugated lipomer of Formula (I) comprises at least one instance of L of the formula (i) . in certain embodiments, the conjugated lipomer of Formula (I) comprises at least one instance of L ¹ of the formula (ii):

(ii). In certain embodiments, the conjugated lipomer of Formula (I)

comprises at least one instance of L of the formula:

[00108] As generally defined above, each instance of R ² is independently hydrogen; acyl; silyl; sulfonyl; an amino protecting group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted

heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; a substituted or unsubstituted polyethyleneimine; or a group of the formula (iii'); or the two R ² groups are joined to form a substituted or unsubstituted heterocyclyl.

[00109] In certain embodiments, each instance of R ² is independently hydrogen; acyl; silyl; sulfonyl; an amino protecting group; substituted or unsubstituted alkyl; substituted or

unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted

heteroalkynyl; a substituted or unsubstituted polyethyleneimine; or a group of the formula (iii'); or the two R ² groups are joined to form a substituted or unsubstituted heterocyclyl. In certain embodiments, at least one instance of R ² is hydrogen. In certain embodiments, at least one instance of R ² is substituted or unsubstituted Ci _-6 alkyl. In certain embodiments, at least one instance of R ² is methyl. In certain embodiments, at least one instance of R ² is ethyl. In certain embodiments, at least one instance of R ² is propyl. In certain embodiments, at least one instance of R ² is butyl.

[00110] In certain embodiments, each instance of R ² is independently hydrogen; substituted or unsubstituted alkyl; substituted or unsubstituted heteroalkyl; a substituted or unsubstituted polyethyleneimine; or a group of the formula (iii'); or the two R ² groups are joined to form a substituted or unsubstituted heterocyclyl. [00111] In certain embodiments, each instance of R ² is independently hydrogen; a substituted

or unsubstituted polyethyleneimine; or a group of the formula (iii'): ^or4 (iii').

[00112] In certain embodiments, at least one R ² is a substituted or unsubstituted

polyethyleneimine.

[00113] In certain embodiments, the conjugated lipomer of Formula (I) comprises at least one

instance of L ¹ of the formula (iii): (iii)

ain embodiments, at least one instance of L ¹ is of the formula (iii-a):

(iii-a). In certain embodiments, at least one instance of L ¹ is of the formula:

[00115] As generally defined within, n is an integer of between 3 to 45, inclusive. In certain embodiments, n is an integer of between 3 to 45, between 5 to 45, between 7 to 45, between 9 to 45, between 10 to 45, between 11 to 45, between 12 to 45, between 13 to 45, between 14 to 45, between 5 to 40, between 5 to 35, between 5 to 30, between 5 to 25, between 5 to 20, between 5 to 15, between 10 to 20, between 10 to 15, or between 40 to 45, inclusive. In certain

embodiments, n is an integer between 5 to 10, inclusive. In certain embodiments, n is an integer between 7 to 10, inclusive. In certain embodiments, n is 7, 8, 9, or 10. In certain embodiments, n is 6. In certain embodiments, n is 7. In certain embodiments, n is 8. In certain embodiments, n is 9. In certain embodiments, n is 10. In certain embodiments, n is 14. In certain embodiments, n is 43.

[00116] As generally defined above, each instance of R ³ is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or

unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a hydrophilic polymer.

[00117] In certain embodiments, each instance of R ³ is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted unsubstituted heteroalkynyl; or a hydrophilic polymer.

[00118] In certain embodiments, each instance of R ³ is independently substituted or unsubstituted alkyl; substituted or unsubstituted heteroalkyl; or a hydrophilic polymer.

[00119] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted alkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted Ci _-50 alkyl. In certain embodiments, at least one instance of R ³ is C ₆ -Ci6 substituted or unsubstituted alkyl. In certain embodiments, at least one instance of R ³ is C ₆ -Ci2 substituted or unsubstituted alkyl. In certain embodiments, at least one instance of R ³ is C ₁₂ unsubstituted alkyl. In certain embodiments, all instances of R ³ are C ₁₂ unsubstituted alkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-5 o alkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 4o alkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-30 alkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-2 o alkyl.

[00120] In certain embodiments, at least one instance of R ³ is an unsubstituted alkyl.

Exemplary unsubstituted alkyl groups include, but are not limited to, -CH ₃ , -C ₂ H ₅ , -C ₃ H ₇ , -C ₄ H -C5H11, -C ₆ Hi ₃ , -C ₇ Hi5, -C ₈ Hi ₇ , -C9H19, -C10H21, -CnH ₂₃ , -Ci ₂ H ₂ 5, -Ci ₃ H ₂₇ , -C14H2 , -C15H31, - Ci ₆ H ₃₃ , -Ci ₇ H ₃ 5, -Ci ₈ H ₃₇ , -Ci H ₃ , and -C ₂ oH ₄ i.

[00121] In certain embodiments, at least one instance of R ³ is substituted alkyl. For example in certain embodiments, at least one instance of R ³ is an alkyl substituted with one or more fluorine substituents. Exem lar substituted alk l rou s include, but are not limited to:

F F F F _F F _F F F F F F F F F

[00122] In certain embodiments, at least one instance of R is substituted or unsubstituted alkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _2-

50' alkenyl. In certain embodiments, at least one instance of R is substituted or unsubstituted C 8-50 alkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C 8-40 alkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C 8-30 alkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-2 o alkenyl. In certain embodiments, at least one instance of R ³ is a substituted C _8-2 o alkenyl

[00123] In certain embodiments, at least one instance of R ³ is an unsubstituted alkenyl.

Myristoleic -(CH ₂ ) _V CH=CH(CH ₂ ) ₃ CH ₃ ,

Palmitoliec -(CH ₂ ) _V CH=CH(CH ₂ ) ₅ CH ₃ ,

Sapienic -(CH ₂ ) ₄ CH=CH(CH ₂ ) ₈ CH ₃ ,

Oleic -(CH ₂ ) ₇ CH=CH(CH ₂ ) ₇ CH ₃ ,

Linoleic -(CH ₂ ) ₇ CH=CHCH ₂ CH=CH(CH ₂ ) ₄ CH ₃ ,

ot-Linolenic -(CH ₂ ) ₇ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH ₃ ,

Arachinodonic -(CH ₂ ) ₃ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CH(CH ₂ ) ₄ CH ₃ ,

Eicosapentaenoic -(CH ₂ ) ₃ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH ₃ ,

Erucic -(CH ₂ ) _n CH=CH(CH ₂ ) ₇ CH ₃ , and

Docosahexaenoic -(CH ₂ ) ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CHCH ₂ CH=CH-CH ₂ CH ₃ .

, 3

[00124] In certain embodiments, wherein R is defined as a C _6-5 o alkyl or C _6- 5 ₀ alkenyl groups, such groups encompass lipophilic groups (also referred to as a "lipid tail"). Lipophilic groups comprise a group of molecules that include fats, waxes, oils, fatty acids, and the like. Lipid tails present in these lipid groups can be saturated and unsaturated, depending on whether or not the lipid tail comprises double bonds. The lipid tail can also comprise different lengths, often categorized as medium (i.e., with tails between 7-12 carbons, e.g. , C ₇ . ₁₂ alkyl or C7-12 alkenyl), long {i.e., with tails greater than 12 carbons and up to 22 carbons, e.g., C13-22 alkyl or C13-22 alkenyl), or very long {i.e., with tails greater than 22 carbons, e.g., C23-30 alkyl or C23-30 alkenyl).

[00125] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted alkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _{2- 5} oalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 50 alkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 40 alkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 30 alkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 20 alkynyl. In certain embodiments, at least one instance of R ³ is an unsubstituted alkynyl. In certain embodiments, at least one instance of R ³ is a substituted alkynyl.

[00126] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted heteroalkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted Ci-50 heteroalkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-5 o heteroalkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-40 heteroalkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-30 heteroalkyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 2o heteroalkyl. In certain embodiments, at least one instance of R ³ is a substituted heteroalkyl.

[00127] In certain embodiments, at least one instance of R ³ is an unsubstituted heteroalkyl. Exe

[00128] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted heteroalkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C ₂ -50 heteroalkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-5 o heteroalkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 4o heteroalkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-3 o heteroalkenyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-20 heteroalkenyl. In certain embodiments, at least one instance of R ³ is a substituted heteroalkenyl. In certain embodiments, at least one instance of R ³ is an unsubstituted heteroalkenyl.

[00129] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted heteroalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _2- 5o heteroalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-5 o heteroalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8- 4o heteroalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-30 heteroalkynyl. In certain embodiments, at least one instance of R ³ is substituted or unsubstituted C _8-20 heteroalkynyl. In certain embodiments, at least one instance of R ³ is a substituted heteroalkynyl. In certain embodiments, at least one instance of R ³ is an unsubstituted heteroalkynyl.

[00130] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted carbocyclyl. In certain embodiments, at least one instance of R ³ is a substituted carbocyclyl. In certain embodiments, at least one instance of R ³ is an unsubstituted carbocyclyl.

[00131] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted heterocyclyl. In certain embodiments, at least one instance of R ³ is a substituted heterocyclyl. In certain embodiments, at least one instance of R ³ is an unsubstituted heterocyclyl.

[00132] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted aryl.

In certain embodiments, at least one instance of R ³ is an unsubstituted aryl. In certain

embodiments, at least one instance of R ³ is a substituted aryl.

[00133] In certain embodiments, at least one instance of R ³ is substituted or unsubstituted heteroaryl. In certain embodiments, at least one instance of R ³ is a substituted heteroaryl. In certain embodiments, at least one instance of R ³ is an unsubstituted heteroaryl. [00134] In certain embodiments, at least one instance of R ³ is hydrophilic polymer. As used herein, a "polymer" refers to a compound comprised of at least 3 (e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.) repeating covalently bound structural units. By extension, a

"hydrophilic polymer" is a polymer, as defined herein, further comprising at least one group (e.g., an oxygen, nitrogen, and/or sulfur atom) in the repeating structural unit capable of hydrogen bonding. The hydrophilic polymer is preferably biocompatible (i.e., non-toxic).

Exemplary hydrophilic polymers include, but are not limited to, polypeptides (e.g., poly-L- lysine), cellulose polymers (e.g., hydroxyethylcellulose, ethylcellulose, carboxymethylcellulose, methylc cellulose, hydroxypropylmethylcellulose (HPMC)), dextran polymers, polymaleic acid polymers, poly(acrylic acid) polymers, poly(vinylalcohol) polymers, polyvinylpyrrolidone (PVP) polymers, and polyethyleneglycol (PEG) polymers.

[00135] In certain embodiments, at least one instance of R ³ is hydrophilic polymer. In certain embodiments, the hydrophilic polymer as R ³ is a polyethyleneglycol polymer, e.g., of the formula (v):

wherein:

R ⁷ is hydrogen; acyl; silyl; a hydroxyl protecting group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or unsubstituted heterocyclyl; substituted or unsubstituted aryl; or substituted or unsubstituted heteroaryl; and

v is an integer between 3 to 400, inclusive.

[00136] In certain embodiments, R ⁷ is hydrogen. In certain embodiments, R ⁷ is acyl. In certain embodiments, R ⁷ is a hydroxyl protecting group. In certain embodiments, R ⁷ is substituted or unsubstituted alkyl. In certain embodiments, R ⁷ is a substituted alkyl. In certain embodiments, R ⁷ is an unsubstituted alkyl. In certain embodiments, R ⁷ is -CH ₃ (a "polyethyleneglycol monomethylether" polymer). In certain embodiments, R ⁷ is substituted or unsubstituted alkenyl. In certain embodiments, R ⁷ is substituted or unsubstituted alkynyl. In certain embodiments, R ⁷ is substituted or unsubstituted heteroalkyl. In certain embodiments, R ⁷ is substituted or

unsubstituted heteroalkenyl. In certain embodiments, R ⁷ is substituted or unsubstituted heteroalkynyl. In certain embodiments, R is substituted or unsubstituted carbocyclyl. In certain embodiments, R ⁷ is substituted or unsubstituted heterocyclyl. In certain embodiments, R ⁷ is substituted or unsubstituted aryl. In certain embodiments, R ⁷ is and substituted or unsubstituted heteroaryl.

[00137] In certain embodiments, v is an integer between 3 to 300, 3 to 200, 3 to 100, 3 to 90, 3 to 80, 3 to 70, 3 to 60, 3 to 50, 5 to 50, 10 to 50, 15 to 50, 20 to 50, 20 to 40, 20 to 30, 20 to 25, 30 to 50, and 40 to 50, inclusive. PEGiooo corresponds, on average, to a v of about 22.7, wherein R ⁷ is -OCH ₃ . PEG ₂₀₀₀ corresponds, on average, to a v of about 45.4.

[00138] In certain embodiments, the number average molar mass (Mn) of the

polyethyleneglycol polymer is <10,000. In certain embodiments, the number average molar mass (Mn) of the polyethyleneglycol polymer is < 10,000, < 9000, < 8000, < 7000, < 6000, < 5000, < 4000, < 3000, or < 2000. In certain embodiments, the number average molar mass (Mn) of the polyethyleneglycol polymer is between about 100 to about 10,000, inclusive; e.g., between about 100 to about 5000, between about 100 to about 4000, between about 100 to about 3000, between about 100 to about 2500, between about 100 to about 2000, between about 100 to about 1500, between about 100 to about 1000, between about 100 to about 900, between about 100 to about 800, between about 100 to about 700, between about 100 to about 600, between about 100 to about 500, between about 100 to about 400, between about 100 to about 300, between about 100 to about 200, between about 100 to about 1500, between about 2500 to about 10000, between about 2500 to about 9000, between about 2500 to about 8000, between about 2500 to about 7000, between about 2500 to about 6000, between about 2500 to about 5000, between about 2500 to about 4000, or between about 2500 to about 3000, inclusive. In certain embodiments, the number average molar mass (Mn) of the polyethyleneglycol polymer is 1000 (PEGiooo)- In certain embodiments, the number average molar mass (Mn) of the

polyethyleneglycol polymer is 2000 (PEG ₂ ooo)- A 1 : 1 mixture of PEGiooo and PEG2000 is referred to herein as PEGI.SK·

[00139] In certain embodiments, at least one instance of R ³ is a hydrophilic polymer, and at least one instance of R ³ is a substituted or unsubstituted alkyl.

[00140] As used herein, when the group R ³ is depicted as bisecting a carbon-carbon bond, e.g., of the group of the formula (iii), it is understood that R ³ may be substituted at either carbon. [00141] In certain embodiments, the conjugated lipomer comprises two different R ³ groups. For example, in certain embodiments, the conjugated lipomer comprises a mixture of two different R ³ groups, wherein the first R ³ group is a substituted or unsubstituted alkyl, and the second R ³ group is a hydrophilic polymer (e.g., a polyethyl eneglycol polymer). In certain embodiments, the conjugated lipomer comprises a mixture of two different R ³ groups, wherein the first R ³ group is an unsubstituted alkyl, and the second R ³ group is a polyethyleneglycol polymer. In certain embodiments, the conjugated lipomer comprises a mixture of two different R ³ groups, wherein the first R ³ group is selected from the group consisting of -CH ₃ , -C ₂ H ₅ , - C ₃ H ₇ , -C ₄ H ₉ , -C ₅ H ₁₁ , -C ₆ Hi ₃ , -C ₇ Hi ₅ , -C ₈ Hi ₇ , -C ₉ H ₁₉ , -C ₁₀ H ₂₁ , -CnH ₂₃ , -Ci ₂ H ₂ 5, -Ci ₃ H ₂₇ , - Ci ₄ H ₂₉ , -Ci ₅ H ₃ i, -Ci ₆ H ₃₃ , -Ci ₇ H ₃₅ , -Ci ₈ H ₃₇ , -Ci ₉ H ₃₉ , and -C ₂₀ H ₄ i, and the second R ³ group is PEGiooo- In certain embodiments, the conjugated lipomer comprises a mixture of two different R ³ groups, wherein the first R ³ group is selected from the group consisting of -CH ₃ , -C ₂ H ₅ , - C ₃ H ₇ , -C ₄ H ₉ , -C ₅ H ₁₁ , -C ₆ Hi ₃ , -C ₇ Hi ₅ , -C ₈ Hn, -C ₉ H ₁₉ , -C ₁₀ H ₂₁ , -CnH ₂₃ , -Ci ₂ H ₂ 5, -Ci ₃ H ₂₇ , - Ci ₄ H ₂₉ , -Ci ₅ H ₃ i, -Ci ₆ H ₃₃ , -Ci ₇ H ₃₅ , -Ci ₈ H ₃₇ , -Ci ₉ H ₃₉ , and -C ₂₀ H ₄ i, and the second R ³ group is PEG ₂ ooo-

[00142] In certain embodiments, the conjugated lipomer comprises three different R ³ groups. For example, in certain embodiments, the conjugated lipomer comprises a mixture of three different R ³ groups, wherein the first R ³ group is a substituted or unsubstituted alkyl, the second R ³ group is a first hydrophilic polymer (e.g., a polyethyleneglycol polymer, e.g., PEGiooo), and the third R ³ group is a second hydrophilic polymer (e.g., a different polyethyleneglycol polymer, e.g., PEG ₂ ooo)- In certain embodiments, the conjugated lipomer comprises a mixture of three different R ³ groups, wherein the first R ³ group is an unsubstituted alkyl, the second R ³ group is PEGiooo, and the third R ³ group is PEG ₂₀ oo- In certain embodiments, the conjugated lipomer comprises a mixture of three different R ³ groups, wherein the first R ³ group is selected from the group consisting of -CH ₃ , -C ₂ H ₅ , -C ₃ H ₇ , -C ₄ H ₉ , -C ₅ Hn, -C ₆ Hi ₃ , -C ₇ Hi ₅ , -C ₈ Hn, -C ₉ H ₁₉ , - C ₁₀ H ₂₁ , -CnH ₂₃ , -Ci ₂ H ₂ 5, -Ci ₃ H ₂₇ , -Ci ₄ H ₂₉ , -C ₁₅ H ₃₁ , -Ci ₆ H ₃₃ , -Ci ₇ H ₃ 5, -Ci ₈ H ₃₇ , -Ci ₉ H ₃₉ , and - C ₂₀ H ₄ i, the second R ³ group is PEGiooo, and the third R ³ group is PEG ₂₀ oo- In certain

embodiments a 1 : 1 mixture of PEGiooo and PEG ₂₀ oo is used. In this instance, the mixture of the second R ³ group and the third R ³ group are referred to herein as PEGI.SK·

[00143] In certain embodiments, the conjugated polymer comprises more of formula (iii) than of formula (i). For example, in certain embodiments, the ratio of groups of the formulae (i) to (iii) is between about 0: 10 to about 9:10, inclusive. In certain embodiments, the ratio of groups of the formulae (i) to (iii) is between about 0: 10 to about 9:10; between about 1 : 10 to about 8:10; between about 1 : 10 to about 7:10; between about 1 : 10 to about 6:10; between about 1 : 10 to about 5:10; or between about 2: 10 to about 4:10, inclusive. In certain embodiments, the ratio of groups of the formulae (i) to (iii) is between about 3 : 10 to about 4:10, inclusive.

[00144] Alternatively, in certain embodiments, the conjugated polymer comprises more of formula (i) than of formula (iii). For example, in certain embodiments, the ratio of groups of the formulae (iii) to (i) is between about 0: 10 to about 9:10, inclusive. In certain embodiments, the ratio of groups of the formulae (iiii) to (i) is between about 0: 10 to about 9:10; between about 1 : 10 to about 8:10; between about 1 : 10 to about 7:10; between about 1 : 10 to about 6:10; between about 1:10 to about 5:10; or between about 2:10 to about 4:10, inclusive. In certain

embodiments, the ratio of groups of the formulae (iii) to (i) is between about 3: 10 to about 4:10, inclusive.

[00145] In certain embodiments, wherein the conjugated lipomer comprises two different R ³ groups, the ratio of the second R ³ group to the first R ³ group is between about 0.01 : 10 to about 10:10, inclusive. In certain embodiments, the ratio of the second R ³ group to the first R ³ group is between about 0.02:10 to about 10:10; between about 0.03:10 to about 10:10; between about 0.04:10 to about 10:10; between about 0.05:10 to about 10:10; between about 0.06:10 to about 10:10; between about 0.07:10 to about 10:10; between about 0.08:10 to about 10:10; between about 0.08:10 to about 9:10; between about 0.08:10 to about 8:10; between about 0.08:10 to about 7: 10; between about 0.08: 10 to about 6:10; between about 0.08: 10 to about 5:10; between about 0.08:10 to about 4:10; between about 0.08:10 to about 3:10; between about 0.08:10 to about 2:10; or between about 0.08: 10 to about 1 : 10, inclusive. In certain embodiments, the ratio of the second R ³ group to the first R ³ group is about 0.1:10.

[00146] In certain embodiments, wherein the conjugated lipomer comprises three different R ³ groups, the ratio of the sum of the second and third R ³ groups to the first R ³ group is between about 0.01 : 10 to about 10:10, inclusive. In certain embodiments, the ratio of the sum of the second and third R ³ groups to the first R ³ group is 0.02: 10 to about 10:10; between about 0.03: 10 to about 10:10; between about 0.04:10 to about 10:10; between about 0.05:10 to about 10:10; between about 0.06:10 to about 10:10; between about 0.07:10 to about 10:10; between about 0.08:10 to about 10:10; between about 0.08:10 to about 9:10; between about 0.08:10 to about 8:10; between about 0.08: 10 to about 7:10; between about 0.08: 10 to about 6:10; between about 0.08:10 to about 5:10; between about 0.08:10 to about 4:10; between about 0.08:10 to about 3:10; between about 0.08:10 to about 2:10; or between about 0.08:10 to about 1:10, inclusive. In certain embodiments, the ratio of the sum of the second and third R ³ groups to the first R ³ group is about 0.1:10.

[00147] Exemplary conjugated lipomers of Formula (I) include, but are not limited to, any of the following LPEI conjugated polymers and BPEI conjugated polymers, or salts thereof, provided in Tables 1 and 2, defining the one or more Li groups present along the polymer backbone.

[00148] In certain embodiments, at least one instance of R ⁴ is hydrogen. In certain

embodiments, at least one instance of R ⁴ is acyl. In certain embodiments, at least one instance of R ⁴ is silyl. In certain embodiments, at least one instance of R ⁴ is a hydroxyl protecting group. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted alkyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted alkenyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted alkynyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted heteroalkyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted heteroalkenyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted heteroalkynyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted carbocyclyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted heterocyclyl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted aryl. In certain embodiments, at least one instance of R ⁴ is substituted or unsubstituted heteroaryl.

[00149] In certain embodiments, A is -N(R ⁵ ) ₂ , wherein at least one instance of R ⁵ is hydrogen. In certain embodiments, A is -N(R ⁵ ) ₂ , wherein each R ⁵ is hydrogen. In certain embodiments, A is -N(H) ₂ . In certain embodiments, A is -N(R ⁵ ) ₂ , wherein each instance of R ⁵ is independently hydrogen; acyl; silyl; sulfonyl; an amino protecting group; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted heteroalkyl; substituted or unsubstituted heteroalkenyl; substituted or unsubstituted heteroalkynyl; substituted or unsubstituted carbocyclyl; substituted or

unsubstituted heterocyclyl; substituted or unsubstituted aryl; substituted or unsubstituted heteroaryl; or a group of the formula (iii'); or two R ⁵ groups are joined to form a substituted or unsubstituted heterocyclyl. In certain embodiments, at least one instance of R ⁵ is hydrogen. In certain embodiments, at least one instance of R ⁵ is acyl. In certain embodiments, at least one instance of R ⁵ is silyl. In certain embodiments, at least one instance of R ⁵ is sulfonyl; an amino protecting group. In certain embodiments, at least one instance of R ⁵ is substituted or

unsubstituted alkyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted alkenyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted alkynyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted heteroalkyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted heteroalkenyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted heteroalkynyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted carbocyclyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted heterocyclyl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted aryl. In certain embodiments, at least one instance of R ⁵ is substituted or unsubstituted heteroaryl. In certain embodiments, at least one instance of R ⁵ is of the formula i _n certain embodiments, two R ⁵ groups are joined to form a substituted or unsubstituted heterocyclyl.

[00150] In certain embodiments, Z is hydrogen. In certain embodiments, Z is acyl. In certain embodiments, Z is silyl. In certain embodiments, Z is sulfonyl. In certain embodiments, Z is an amino protecting group. In certain embodiments, Z is substituted or unsubstituted alkyl. In certain embodiments, Z is substituted or unsubstituted Ci _-6 alkyl (e.g., substituted or

unsubstituted methyl, ethyl, or propyl). In certain embodiments, Z is substituted or unsubstituted

H ₂ embodiments, Z is substituted or unsubstituted alkenyl. In certain embodiments, Z is substituted or unsubstituted alkynyl. In certain embodiments, Z is substituted or unsubstituted heteroalkyl. In certain embodiments, Z is substituted or unsubstituted heteroalkenyl. In certain embodiments, Z is substituted or unsubstituted heteroalkynyl. In certain embodiments, Z is substituted or unsubstituted carbocyclyl. In certain embodiments, Z is substituted or unsubstituted heterocyclyl. In certain embodiments, Z is substituted or unsubstituted aryl. In certain embodiments, Z is substituted or unsubstituted heteroaryl. In certain embodiments, Z is a group of the formula (iii'): ). In certain embodiments, Z and the nitrogen atom to which it is attached form a substituted or unsubstituted heterocyclyl group.

00151] In certain embodiments, the conjugated lipomer is of the formula:

("7C1"). In certain embodiments, the conjugated lipomer is not of formula ("7C1"). Lipid-PEG Conjugate

[00152] In certain embodiments, the lipid-polyethylene glycol (PEG) conjugate is of Formula

(II)

or a pharmaceutically acceptable salt thereof,

wherein:

each instance of R is independently unsubstituted C6-C20 alkyl;

is substituted or unsubstituted alkyl; and x is an integer between 15 to 135, inclusive.

[00153] In certain embodiments, the polyethylene glycol (PEG) of the lipid-PEG conjugate has a molecular weight of approximately 600 g/mol to 750 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 5000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 4500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 4000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight that is not between approximately 2000 g/mol and approximately 5000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight that is not between approximately 2000 g/mol and approximately 3000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight that is not between approximately 2000 g/mol and approximately 4000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight that is not between approximately 3000 g/mol and approximately 5000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight that is not between

approximately 4000 g/mol and approximately 5000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 3500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 3000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 2500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 2000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 1500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 750 g/mol and approximately 1000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 900 g/mol to 1100 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 1000 g/mol to 2500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 1500 g/mol to 2450 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 2000 g/mol to 3000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 2500 g/mol to 3000 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 4000 g/mol to 5500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate of Formula (II) has a molecular weight between approximately 4500 g/mol to 5500 g/mol. In certain embodiments, the PEG of the lipid-PEG conjugate has a molecular weight of approximately 600 g/mol to 750 g/mol, approximately 900 g/mol to 1100 g/mol, approximately 1500 g/mol to 2450 g/mol, approximately 2500 g/mol to 3000 g/mol, or approximately 4500 g/mol to 5500 g/mol.

[00154] The lipid-PEG conjugate of Formula (II) includes substituent R ^A1 . In certain embodiments, each instance of R ^A1 is independently unsubstituted C6-C ₂₀ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₆ -Ci ₅ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₆ -Ci ₂ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₄ -C ₁₈ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₃ -C ₁₈ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₃ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₄ alkyl. In certain embodiments, at least one instance of R ^A1 is not unsubstituted C ₁₄ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₅ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₆ alkyl. In certain embodiments, at least one instance of R ^A1 is not unsubstituted C ₁₆ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₇ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁₈ alkyl. In certain embodiments, at least one instance of R ^A1 is not unsubstituted C ₁₈ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₁ alkyl. In certain embodiments, at least one instance of R ^A1 is unsubstituted C ₂ o alkyl.

[00155] The lipid-PEG conjugate of Formula (II) includes substituent R^. In certain embodiments, R^ is substituted or unsubstituted alkyl. In certain embodiments, R^ is substituted or unsubstituted C ₁ -C ₁₂ alkyl. In certain embodiments, R^ is substituted or unsubstituted Ci-C ₆ alkyl. In certain embodiments, R^ is unsubstituted methyl. In certain embodiments, R is ethyl. In certain embodiments, R is propyl. In certain embodiments, R'

In certain embodiments the lipid-PEG conjugate of Formula (II) is of the formula:

(CisPEGlOOO),

or a pharmaceutically acceptable salt thereof.

[00157] As generally defined within, x is an integer between 15 to 135, inclusive. In certain embodiments, x is an integer between 110 to 135, inclusive. In certain embodiments, x is 113. In certain embodiments, x is an integer between 15 to 120, inclusive. In certain embodiments, x is an integer between 20 to 115, inclusive. In certain embodiments, x is an integer between 15 to 115, inclusive. In certain embodiments, x is about 15. In certain embodiments, x is about 16. In certain embodiments, x is an integer between 20 to 100, inclusive. In certain embodiments, x is an integer between 20 to 75, inclusive. In certain embodiments, x is an integer between 20 to 50, inclusive. In certain embodiments, x is about 22. In certain embodiments, x is about 25. In certain embodiments, x is an integer between 20-25. In certain embodiments, x is about 45. In certain embodiments, x is an integer between 25-46. In certain embodiments, x is an integer between 50 to 75, inclusive. In certain embodiments, x is 67. In certain embodiments, x is an integer between 55 to 70, inclusive. In certain embodiments, x is 16, 22, 45, 67, or 113.

[00158] In certain embodiments, the molar percentage of the lipid-PEG conjugate in the composition comprising a conjugated lipomer of Formula (I) and the lipid-PEG conjugate of Formula (II) is about 5 molar percent to about 50 molar percent. In certain embodiments, the molar percentage of the lipid-PEG conjugate in the composition is about 4 molar percent to about 50 molar percent. In certain embodiments, the molar percentage of the lipid-PEG conjugate in the composition is about 4 molar percent to about 32 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 4 molar percent, about 5 molar percent, about 8 molar percent, about 10 molar percent, about 12 molar percent, about 15 molar percent, about 16 molar percent, about 18 molar percent, about 20 molar percent, about 24 molar percent, about 25 molar percent, about 28 molar percent, about 30 molar percent, about 32 molar percent, about 35 molar percent, about 38 molar percent, about 40 molar percent, about 45 molar percent, or about 50 molar percent. [00159] In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 4 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 8 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 10 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 16 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 24 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 32 molar percent.

[00160] In certain embodiments, the molar percentage of the conjugated lipomer in the composition comprising a conjugated lipomer of Formula (I) and the lipid-PEG conjugate of Formula (II) is about 60 molar percent to about 96 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 68 molar percent to about 96 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 60 molar percent, about 62 molar percent, about 65 molar percent, about 68 molar percent, about 70 molar percent, about 72 molar percent, about 75 molar percent, about 76 molar percent, about 80 molar percent, about 82 molar percent, about 84 molar percent, about 85 molar percent, about 90 molar percent, about 92 molar percent, or about 96 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 68 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 76 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 84 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 92 molar percent. In certain embodiments, the molar percentage of the conjugated lipomer in the composition is about 96 molar percent.

[00161] In certain embodiments, the composition includes a particle, wherein the particle comprises a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle. In certain embodiments, the composition includes a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of C ₁₄ PEG2OOO, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₆ PEG2000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₈ PEG750, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₈ PEG1000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₈ PEG2000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₈ PEG3000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 84 molar percent of conjugated lipomer 7C1 and 16 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 68 molar percent of conjugated lipomer 7C1 and 32 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 76 molar percent of conjugated lipomer 7C1 and 24 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 92 molar percent of conjugated lipomer 7C1 and 8 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition comprises 96 molar percent of conjugated lipomer 7C1 and 4 molar percent of Ci ₈ PEG5000, wherein the composition is used to synthesize a particle. In certain embodiments, the composition does not comprise 2 molar percent of PEG. In certain embodiments, the composition does not comprise 5 molar percent of PEG. In certain embodiments, the composition does not comprise 10 molar percent of PEG. In certain embodiments, the composition does not comprise 15 molar percent of PEG. In certain embodiments, the composition does not comprise 20 molar percent of PEG.

Particles

[00162] The composition comprising a conjugated lipomer of Formula (I); and a lipid- polyethylene glycol (PEG) conjugate of Formula (II) of the present invention may also be used to form drug delivery devices {e.g., particles). The inventive composition comprising a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) have several properties that make them particularly suitable in the preparation of drug delivery devices. These include: 1) the ability of the lipomer to complex and "protect" labile agents; 2) the ability to buffer the pH in the endosome; 3) the ability to act as a "proton sponge" and cause endosomolysis; and 4) the ability to neutralize the charge on negatively charged agents. The present invention provides particles comprising both: conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II). In certain embodiments, the particle is a nanoparticle.

[00163] In certain embodiments, the composition comprising a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) are used to form particles containing the agent to be delivered. The inventive composition comprising a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) may be used to encapsulate agents including, but not limited to, organic molecules, inorganic molecules, nucleic acids, proteins, peptides, polynucleotides, targeting agents, isotopically labeled organic or inorganic molecules, vaccines, immunological agents, etc. Other exemplary agents are described in greater detail herein. These particles may include other materials, such as polymers {e.g., synthetic polymers {e.g., PEG, PLGA), natural polymers {e.g., proteins, phospholipids)).

[00164] In certain embodiments, the diameter of the particles range from between 1 micrometer to 1,000 micrometers. In certain embodiments, the diameter of the particles range from between from 1 micrometer to 100 micrometers. In certain embodiments, the diameter of the particles range from between from 1 micrometer to 10 micrometers. In certain embodiments, the diameter of the particles range from between from 10 micrometer to 100 micrometers. In certain embodiments, the diameter of the particles range from between from 100 micrometer to 1,000 micrometers. In certain embodiments, the particles range from 1-5 micrometers. In certain embodiments, the diameter of the particles range from between 1 nm to 1,000 nm. In certain embodiments, the diameter of the particles range from between from 1 nm to 100 nm. In certain embodiments, the diameter of the particles range from between from 1 nm to 10 nm. In certain embodiments, the diameter of the particles range from between from 10 nm to 100 nm. In certain embodiments, the diameter of the particles range from between from 100 nm to 1,000 nm. In certain embodiments, the particles range from 1-5 nm. In certain embodiments, the diameter of the particles range from between 1 pm to 1,000 pm. In certain embodiments, the diameter of the particles range from between from 1 pm to 100 pm. In certain embodiments, the diameter of the particles range from between from 1 pm to 10 pm. In certain embodiments, the diameter of the particles range from between from 10 pm to 100 pm. In certain embodiments, the diameter of the particles range from between from 100 pm to 1,000 pm. In certain embodiments, the particles range from 1-5 pm.

[00165] The inventive particles may be prepared using any method known in this art. These include, but are not limited to, spray drying, single and double emulsion solvent evaporation, solvent extraction, phase separation, simple and complex coacervation, and other methods well known to those of ordinary skill in the art. In certain embodiments, methods of preparing the particles are the double emulsion process and spray drying. The conditions used in preparing the particles may be altered to yield particles of a desired size or property (e.g., hydrophobicity, hydrophilicity, external morphology, "stickiness", shape, etc.). The method of preparing the particle and the conditions (e.g., solvent, temperature, concentration, air flow rate, etc.) used may also depend on the agent being encapsulated and/or the composition of the matrix.

[00166] Methods developed for making particles for delivery of encapsulated agents are described in the literature (for example, please see Doubrow, M., Ed., "Microcapsules and Nanoparticles in Medicine and Pharmacy," CRC Press, Boca Raton, 1992; Mathiowitz and Langer, J. Controlled Release 5: 13-22, 1987; Mathiowitz et al, Reactive Polymers 6:275-283, 1987; Mathiowitz et al, J. Appl. Polymer Sci. 35:755-774, 1988; each of which is incorporated herein by reference).

[00167] If the particles prepared by any of the above methods have a size range outside of the desired range, the particles can be sized, for example, using a sieve. The particle may also be coated. In certain embodiments, the particles are coated with a targeting agent. In other embodiments, the particles are coated to achieve desirable surface properties (e.g., a particular charge).

Agents

[00168] The agents to be delivered by the systems of the present invention may be therapeutic, diagnostic, or prophylactic agents. Any chemical compound to be administered to an individual may be delivered using the inventive complexes or particles. The agent may be an organic molecule (e.g., a drug), inorganic molecule, nucleic acid, protein, peptide, polynucleotide, targeting agent, isotopically labeled organic or inorganic molecule, vaccine, immunological agent, etc. [00169] In certain embodiments, the agents are organic molecules with pharmaceutical activity, e.g., a drug. In certain embodiments, the drug is an antibiotic, anti-viral agent, anesthetic, steroidal agent, anti-inflammatory agent, anti -neoplastic agent, anti-cancer agent, antigen, vaccine, antibody, decongestant, antihypertensive, sedative, birth control agent, progestational agent, anti-cholinergic, analgesic, anti-depressant, anti -psychotic, β-adrenergic blocking agent, diuretic, cardiovascular active agent, vasoactive agent, non-steroidal antiinflammatory agent, nutritional agent, etc. For example, in certain embodiments, the agent is a small molecule, organometallic compound, nucleic acid, protein, peptide, polynucleotide, metal, targeting agent, an isotopically labeled chemical compound, drug, vaccine, or immunological agent.

[00170] In certain embodiments, the agent is a polynucleotide. In certain embodiments, the polynucleotide carries out RNA interference In certain embodiments, the polynucleotide or nucleic acid is a double- or single-stranded genomic and cDNA, RNA, any synthetic and genetically manipulated polynucleotide, or both sense and antisense polynucleotides.

[00171] In certain embodiments, the nucleic acid is a single- or double-stranded molecule, i.e., DNA-DNA, DNA-RNA or RNA-RNA hybrids, or "protein nucleic acids" (PNAs) formed by conjugating bases to an amino acid backbone. In certain embodiments, the nucleic acid is a nucleic acid containing carbohydrates or lipids. In certain embodiments, the polynucleotide is DNA or RNA. In certain embodiments, the DNA is single-stranded DNA (ssDNA), double- stranded DNA (dsDNA), plasmid DNA (pDNA), genomic DNA (gDNA), complementary DNA (cDNA), antisense DNA, chloroplast DNA (ctDNA or cpDNA), microsatellite DNA,

mitochondrial DNA (mtDNA or mDNA), kinetoplast DNA (kDNA), provirus, lysogen, repetitive DNA, satellite DNA, or viral DNA. In certain embodiments, the RNA is single- stranded RNA (ssRNA), double-stranded RNA (dsRNA), small interfering RNA (siRNA), messenger RNA (mRNA), precursor messenger RNA (pre-mRNA), small hairpin RNA or short hairpin RNA (shRNA), microRNA (miRNA), guide RNA (gRNA), transfer RNA (tRNA), antisense RNA (asRNA), heterogeneous nuclear RNA (hnRNA), coding RNA, non-coding RNA (ncRNA), long non-coding RNA (long ncRNA or IncRNA), satellite RNA, viral satellite RNA, signal recognition particle RNA, small cytoplasmic RNA, small nuclear RNA (snRNA), ribosomal RNA (rRNA), Piwi-interacting RNA (piRNA), polyinosinic acid, ribozyme, flexizyme, small nucleolar RNA (snoRNA), spliced leader RNA, viral RNA, or viral satellite RNA. In certain embodiments, the RNA is RNA/ ^' , dsRNA, siRNA, shRNA, miRNA, or antisense RNA.

[00172] In certain particular embodiments, the agent is siRNA. An siRNA molecule used in a composition (e.g., nanoparticle) of the invention is a duplex consisting of a sense strand and complementary antisense strand, the antisense strand having sufficient complementary to a a target mRNA to mediate RNAi. Preferably, the siRNA molecule has a length from about 10-50 or more nucleotides, i.e., each strand comprises 10-50 nucleotides (or nucleotide analogs). More preferably, the siRNA molecule has a length from about 16-30, e.g., 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 nucleotides in each strand, wherein the antisense strand is sufficiently complementary to a target region. Preferably, the strands are aligned such that there are at least 1, 2, or 3 bases at the end of the strands which do not align (i.e., for which no complementary bases occur in the opposing strand) such that an overhang of 1, 2 or 3 residues occurs at one or both ends of the duplex when strands are annealed. siRNA may comprise chemically modified nucleotides (e.g., the 2' OH-group may be replaced by a group selected from H, OR, R, F, CI, Br, I, SH, SR, NH ₂ , NHR, NR ₂ , COOR, or OR, wherein R is substituted or unsubstituted Ci-C ₆ alkyl) or internucleotide linkages (e.g., phosphorothioate linkages).

[00173] Generally, siRNAs can be designed by using any method known in the art. siRNA targeting a particular mRNA transcript will comprise a sequence that is homologous to a section (e.g., 5-50 nucleotides) of DNA. Representative Genbank accession numbers providing DNA and mRNA sequence information are: SDF-1 : NC_000072 REGION: 117168535..117181368 (NCBI Reference Sequence: NC_000072.6); MCP-1 : NC_000077 REGION:

82035577..82037452 (NCBI Reference Sequence: NC_000077.6); Tie2: NC_000070 REGION: 94739289..94874976 (NCBI Reference Sequence: NC_000070.6), and are incorporated herein by reference.

[00174] In certain particular embodiments, the siRNA targets Sdf-1, Mcp-1, or Tie2.

[00175] In a particular embodiment, the siRNA targets Tie2 and comprises a sense strand having the sequence: GAAGAuGcAGuGAuuuAcAdTsdT; and an antisense strand having the sequence: UGuAAAUcACUGcAUCUUCdTsdT (lower caes letters correspond to 2'-OCH ₃ modified nucleotides). [00176] In certain embodiments, the siRNA targets a protein of a hematopoietic stem and progenitor cells (HSPC). In certain embodiments, the siRNA targets a protein of a bone marrow endothelial cells (BMEC).

[00177] In certain embodiments of the present invention, the agent to be delivered may be a mixture of agents.

[00178] Diagnostic agents include gases; metals; commercially available imaging agents used in positron emissions tomography (PET), computer assisted tomography (CAT), single photon emission computerized tomography, x-ray, fluoroscopy, and magnetic resonance imaging (MRI); and contrast agents. Examples of suitable materials for use as contrast agents in MRI include gadolinium chelates, as well as iron, magnesium, manganese, copper, and chromium. Examples of materials useful for CAT and x-ray imaging include iodine-based materials.

[00179] Prophylactic agents include, but are not limited to, antibiotics, nutritional

supplements, and vaccines. Vaccines may comprise isolated proteins or peptides, inactivated organisms and viruses, dead organisms and viruses, genetically altered organisms or viruses, and cell extracts. Prophylactic agents may be combined with interleukins, interferon, cytokines, and adjuvants such as cholera toxin, alum, Freund's adjuvant, etc. Prophylactic agents include antigens of such bacterial organisms as Streptococcals pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Streptococcus pyrogenes, Corynebacterium diphtheriae, Listeria monocytogenes, Bacillus anthracis, Clostridium tetani, Clostridium botulinum, Clostridium perfringens, Neisseria meningitidis, Neisseria gonorrhoeae, Streptococcus mutans,

Pseudomonas aeruginosa, Salmonella typhi, Haemophilus parainfluenzae, Bordetella pertussis, Francisella tularensis, Yersinia pestis, Vibrio cholerae, Legionella pneumophila, Mycobacterium tuberculosis, Mycobacterium leprae, Treponema pallidum, Leptospirosis interrogans, Borrelia burgdorferi, Camphylobacter jejuni, and the like; antigens of such viruses as smallpox, influenza A and B, respiratory syncytial virus, parainfluenza, measles, HIV, varicella-zoster, herpes simplex 1 and 2, cytomegalovirus, Epstein-Barr virus, rotavirus, rhinovirus, adenovirus, papillomavirus, poliovirus, mumps, rabies, rubella, coxsackieviruses, equine encephalitis, Japanese encephalitis, yellow fever, Rift Valley fever, hepatitis A, B, C, D, and E virus, and the like; antigens of fungal, protozoan, and parasitic organisms such as Cryptococcus neoformans, Histoplasma capsulatum, Candida albicans, Candida tropicalis, Nocardia asteroides, Rickettsia ricketsii, Rickettsia typhi, Mycoplasma pneumoniae, Chlamydial psittaci, Chlamydial trachomatis, Plasmodium falciparum, Trypanosoma brucei, Entamoeba histolytica, Toxoplasma gondii, Trichomonas vaginalis, Schistosoma mansoni, and the like. These antigens may be in the form of whole killed organisms, peptides, proteins, glycoproteins, carbohydrates, or

combinations thereof.

Targeting Agents

[00180] The conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) and particles, may be modified to include targeting agents since it is often desirable to target a particular cell, collection of cells, or tissue. A variety of targeting agents that direct pharmaceutical compositions to particular cells are known in the art (see, for example, Cotten et al, Methods Enzym. 217:618, 1993; incorporated herein by reference). The targeting agents may be included throughout the particle or may be only on the surface. The targeting agent may be a protein, peptide, carbohydrate, glycoprotein, lipid, small molecule, nucleic acids, etc. The targeting agent may be used to target specific cells or tissues or may be used to promote endocytosis or phagocytosis of the particle. Examples of targeting agents include, but are not limited to, antibodies, fragments of antibodies, low-density lipoproteins (LDLs), transferrin, asialycoproteins, gpl20 envelope protein of the human immunodeficiency virus (HIV), carbohydrates, receptor ligands, sialic acid, aptamers, etc. If the targeting agent is included throughout the particle, the targeting agent may be included in the mixture that is used to form the particles. If the targeting agent is only on the surface, the targeting agent may be associated with (i.e., by covalent, hydrophobic, hydrogen bonding, van der Waals, or other interactions) the formed particles using standard chemical techniques.

Pharmaceutical Compositions

[00181] The present invention contemplates a composition comprising a particle (e.g., a nanoparticle) comprising a conjugated lipomer and a lipid-PEG conjugate, which may be useful in a variety of medical and non-medical applications. For example, pharmaceutical compositions comprising a conjugated lipomer and a lipid-PEG conjugate as components may be useful in the delivery of an effective amount of an agent to a subject in need thereof. Nutraceutical compositions comprising a conjugated lipomer and a lipid-PEG conjugate as components may be useful in the delivery of an effective amount of a nutraceutical, e.g., a dietary supplement, to a subject in need thereof. Cosmetic compositions comprising a conjugated lipomer and a lipid- PEG conjugate as components may be formulated as a cream, ointment, balm, paste, film, or liquid, etc., and may be useful in the application of make-up, hair products, and materials useful for personal hygiene, etc. Compositions comprising a conjugated lipomer and a lipid-PEG conjugate as components may be useful for non-medical applications, e.g., such as an emulsion or emulsifier, useful, for example, as a food component, for extinguishing fires, for disinfecting surfaces, for oil cleanup, etc.

[00182] In certain embodiments, the composition comprises one or more conjugated lipomers. "One or more conjugated lipomers" refers to one or more different types of conjugated lipomers included in the composition, and encompasses 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more different types of conjugated lipomers.

[00183] In certain embodiments, the composition comprises a lipid-PEG conjugate of Formula (II)

or a pharmaceutically acceptable salt thereof.

[00184] In certain embodiments, a conjugated lipomer and a lipid-PEG conjugate as components of a composition are useful either for delivery of an effective amount of an agent to a subject in need thereof {e.g., a pharmaceutical composition, a cosmetic composition) or for use as an excipient. For example, cosmetic compositions may further use the conjugated lipomer and a lipid-PEG conjugate as excipients rather than as a delivery system encapsulating an agent to be delivered. In certain embodiments, the composition is a pharmaceutical composition. In certain embodiments, the composition is a cosmetic composition.

[00185] In certain embodiments, the composition further comprises an agent, as described herein. For example, in certain embodiments, the agent is a small molecule, organometallic compound, nucleic acid, protein, peptide, polynucleotide, metal, targeting agent, an isotopically labeled chemical compound, drug, vaccine, or immunological agent. In certain embodiments, the agent is a polynucleotide. [00186] In certain embodiments, the polynucleotide and the one or more conjugated lipomers and/or lipid-PEG conjugate are not covalently attached.

[00187] In certain embodiments, the one or more conjugated lipomers and lipid-PEG conjugate are in the form of a particle. In certain embodiments, the particle is a nanoparticle or mi crop article. In certain embodiments, the particle encapsulates an agent. The agent to be delivered by the particles may be in the form of a gas, liquid, or solid. The conjugated lipomers may be combined with polymers (synthetic or natural), surfactants, cholesterol, carbohydrates, proteins, lipids etc. to form the particles. These particles may be combined with an excipient to form pharmaceutical and cosmetic compositions.

[00188] Once the complexes, liposomes, or particles have been prepared, they may be combined with one or more excipients to form a composition that is suitable to administer to animals including humans.

[00189] As would be appreciated by one of skill in this art, the excipients may be chosen based on the route of administration as described below, the agent being delivered, time course of delivery of the agent, etc.

[00190] In certain embodiments, provided is a composition comprising a conjugated lipomer, a lipid-PEG conjugate and, optionally, an excipient. As used herein, the term "excipient" means a non-toxic, inert solid, semi-solid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. Some examples of materials which can serve as excipients include, but are not limited to, sugars such as lactose, glucose, and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as sodium carboxymethyl cellulose, ethyl cellulose, and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients such as cocoa butter and suppository waxes; oils such as peanut oil, cottonseed oil; safflower oil; sesame oil; olive oil; corn oil and soybean oil; glycols such as propylene glycol; esters such as ethyl oleate and ethyl laurate; agar; detergents such as Tween 80; buffering agents such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; and phosphate buffer solutions, as well as other non-toxic compatible lubricants such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, releasing agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the composition, according to the judgment of the formulator. The compositions of this invention can be administered to humans and/or to animals, orally, rectally, parenterally, intracisternally, intravaginally, intranasally, intraperitoneally, topically (as by powders, creams, ointments, or drops), bucally, or as an oral or nasal spray.

[00191] Liquid dosage forms for oral administration include emulsions, microemulsions, solutions, suspensions, syrups, and elixirs. In addition to the active ingredients (i.e.,

microparticles, nanoparticles, liposomes, micelles, polynucleotide/lipid complexes), the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

[00192] Injectable preparations, for example, sterile injectable aqueous or oleaginous suspensions may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution, suspension, or emulsion in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, U.S.P. and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil can be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid are used in the preparation of injectables. In certain embodiments, the particles are suspended in a carrier fluid comprising 1% (w/v) sodium carboxymethyl cellulose and 0.1% (v/v) Tween 80.

[00193] The injectable formulations can be sterilized, for example, by filtration through a bacteria-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

[00194] Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the particles with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol, or a suppository wax which are solid at ambient temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the particles.

[00195] Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the particles are mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or di calcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin,

polyvinylpyrrolidinone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets, and pills, the dosage form may also comprise buffering agents.

[00196] Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

[00197] The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes.

[00198] Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

[00199] Dosage forms for topical or transdermal administration of an inventive

pharmaceutical composition include ointments, pastes, creams, lotions, gels, powders, solutions, sprays, inhalants, or patches. The particles are admixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives or buffers as may be required. Ophthalmic formulation, ear drops, and eye drops are also contemplated as being within the scope of this invention.

[00200] The ointments, pastes, creams, and gels may contain, in addition to the particles of this invention, excipients such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc, and zinc oxide, or mixtures thereof.

[00201] Powders and sprays can contain, in addition to the particles of this invention, excipients such as lactose, talc, silicic acid, aluminum hydroxide, calcium silicates, and polyamide powder, or mixtures of these substances. Sprays can additionally contain customary propellants such as chlorofluorohydrocarbons.

[00202] Transdermal patches have the added advantage of providing controlled delivery of a compound to the body. Such dosage forms can be made by dissolving or dispensing the microparticles or nanoparticles in a proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate can be controlled by either providing a rate controlling membrane or by dispersing the particles in a polymer matrix or gel.

[00203] Also encompassed by the disclosure are kits (e.g., pharmaceutical packs). The kits provided may comprise a composition or particle described herein and a container (e.g., a vial, ampule, bottle, syringe, and/or dispenser package, or other suitable container). In some embodiments, provided kits may optionally further include a second container comprising a pharmaceutical excipient for dilution or suspension of a composition or particle described herein. In some embodiments, the composition or particle described herein provided in the first container and the second container are combined to form one unit dosage form.

[00204] Thus, in one aspect, provided are kits including a first container comprising a composition or particle described herein. In certain embodiments, the kits are useful for treating a disease (e.g., proliferative disease, inflammatory disease, autoinflammatory disease, autoimmune disease, genetic disease (e.g., bone marrow disease), hematological disease, immunological disorder, and/or hematological disorder) in a subject in need thereof. In certain embodiments, the kits are useful for preventing a disease (e.g., proliferative disease,

inflammatory disease, autoinflammatory disease, autoimmune disease, genetic disease (e.g., bone marrow disease), hematological disease, immunological disorder, and/or hematological disorder) in a subject in need thereof. [00205] In certain embodiments, a kit described herein further includes instructions for using the particle or composition included in the kit. A kit described herein may also include information as required by a regulatory agency such as the U.S. Food and Drug Administration (FDA). In certain embodiments, the information included in the kits is prescribing information. In certain embodiments, the kits and instructions provide for treating a disease (e.g., proliferative disease, inflammatory disease, autoinflammatory disease, autoimmune disease, genetic disease (e.g., bone marrow disease), hematological disease, immunological disorder, and/or

hematological disorder) in a subject in need thereof. In certain embodiments, the kits and instructions provide for preventing a disease (e.g., proliferative disease, inflammatory disease, autoinflammatory disease, autoimmune disease, genetic disease (e.g., bone marrow disease), hematological disease, immunological disorder, and/or hematological disorder) in a subject in need thereof. A kit described herein may include one or more additional pharmaceutical agents described herein as a separate composition.

Methods of Treatment and Uses

[00206] In one aspect, provided are methods for delivering an agent to a cell, comprising contacting the cell with a composition as described herein, e.g., a composition comprising a conjugated lipomer, a lipid-PEG conjugate, and an agent. In a particular embodiment, the composition is a nanoparticle. In a particular embodiment, the composition is NicheEC-15. In a particular embodiment, the agent is siRNA. In a particular embodiment, the cell is a

hematopoietic stem and progenitor cell (HSPC) or a bone marrow endothelial cells (BMEC).

[00207] In another aspect, provided are methods for delivering an agent to a subject, comprising administereing to the subject a composition as described herein, e.g., a composition comprising a conjugated lipomer, a lipid-PEG conjugate, and an agent. In a particular embodiment, the composition is a nanoparticle. In a particular embodiment, the composition is a pharmaceutical composition comprising a nanoparticle. In a particular embodiment, the pharmaceutical composition comprises NicheEC-15. In a particular embodiment, the agent is siRNA.

[00208] In another aspect, provided are methods of using a composition comprising a particle (e.g., a nanoparticle), wherein the particle comprises a conjugated lipomer and a lipid-PEG conjugate, e.g., for the treatment of a disease, disorder or condition from which a subject suffers. It is contemplated that the conjugated lipomer and lipid-PEG conjugate composition will be useful in the treatment of a variety of diseases, disorders or conditions, especially as a system for delivering agents useful in the treatment of that particular disease, disorder or condition (e.g., delivery of a biologically active agent (e.g., nucleic acids) to bone marrow for the treatment of cancer (e.g., bone marrow cancer)) or a bone marrow disease (e.g., genetic disease). In certain embodiments, the biologically active agent is delivered to the subject in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow cells of the subject. In certain embodiments, the biologically active agent is targeted to bone marrow cells of the subject.

[00209] For example, in one aspect, provided is a method of treating a disease comprising administering to a subject in need thereof an effective amount of a composition comprising a conjugated lipomer and a lipid-PEG conjugate, e.g., a composition comprising a conjugated lipomer of the Formula (I), or a pharmaceutically acceptable salt thereof, and a lipid- PEG conjugate of Formula (II). In certain embodiments, the method further comprises administering a biologically active agent (e.g. an anti-cancer agent or agent for treating bone marrow disease). In certain embodiments, the composition comprising a conjugated lipomer and a lipid-PEG conjugate encapsulates the biologically active agent (e.g. the anti-cancer agent or agent for treating bone marrow disease). In certain embodiments, the composition comprising a conjugated lipomer and a lipid-PEG conjugate and the biologically active agent form a particle (e.g., a nanoparticle, a microparticle, a micelle, a liposome, a lipoplex).

[00210] In another aspect, provided are methods of treating a disease in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a composition as described herein, e.g., a composition comprising a conjugated lipomer, a lipid- PEG conjugate, and an agent. In a particular embodiment, the subject is a mammal. In another particular embodiment, the subject is a human. In certain embodiments, the disease is selected from the group consisting of cardiovascular disease, lung disease, proliferative disease, inflammatory disorders, and immunological disorders.

[00211] Exemplary cancers include, but are not limited to, acoustic neuroma, adenocarcinoma, adrenal gland cancer, anal cancer, angiosarcoma (e.g., lymphangiosarcoma,

lymphangioendotheliosarcoma, hemangiosarcoma), appendix cancer, benign monoclonal gammopathy, biliary cancer (e.g., cholangiocarcinoma), bladder cancer, breast cancer (e.g., adenocarcinoma of the breast, papillary carcinoma of the breast, mammary cancer, medullary carcinoma of the breast), brain cancer (e.g., meningioma; glioma, e.g., astrocytoma,

oligodendroglioma; medulloblastoma), bronchus cancer, carcinoid tumor, cervical cancer (e.g., cervical adenocarcinoma), choriocarcinoma, chordoma, craniopharyngioma, colorectal cancer (e.g., colon cancer, rectal cancer, colorectal adenocarcinoma), epithelial carcinoma,

ependymoma, endotheliosarcoma (e.g., Kaposi's sarcoma, multiple idiopathic hemorrhagic sarcoma), endometrial cancer (e.g., uterine cancer, uterine sarcoma), esophageal cancer (e.g., adenocarcinoma of the esophagus, Barrett's adenocarinoma), Ewing sarcoma, eye cancer (e.g., intraocular melanoma, retinoblastoma), familiar hypereosinophilia, gall bladder cancer, gastric cancer (e.g., stomach adenocarcinoma), gastrointestinal stromal tumor (GIST), head and neck cancer (e.g., head and neck squamous cell carcinoma, oral cancer (e.g., oral squamous cell carcinoma (OSCC), throat cancer (e.g., laryngeal cancer, pharyngeal cancer, nasopharyngeal cancer, oropharyngeal cancer)), hematopoietic cancers (e.g., leukemia such as acute lymphocytic leukemia (ALL) (e.g., B-cell ALL, T-cell ALL), acute myelocytic leukemia (AML) (e.g., B-cell AML, T-cell AML), chronic myelocytic leukemia (CML) (e.g., B-cell CML, T-cell CML), and chronic lymphocytic leukemia (CLL) (e.g., B-cell CLL, T-cell CLL); lymphoma such as Hodgkin lymphoma (HL) (e.g., B-cell HL, T-cell HL) and non-Hodgkin lymphoma (NHL) (e.g., B-cell NHL such as diffuse large cell lymphoma (DLCL) (e.g., diffuse large B-cell lymphoma (DLBCL)), follicular lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), mantle cell lymphoma (MCL), marginal zone B-cell lymphomas (e.g., mucosa- associated lymphoid tissue (MALT) lymphomas, nodal marginal zone B-cell lymphoma, splenic marginal zone B-cell lymphoma), primary mediastinal B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma (i.e., "Waldenstrom's macroglobulinemia"), hairy cell leukemia (HCL), immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma and primary central nervous system (CNS) lymphoma; and T-cell NHL such as precursor T-lymphoblastic lymphoma/leukemia, peripheral T-cell lymphoma (PTCL) (e.g., cutaneous T-cell lymphoma (CTCL) (e.g., mycosis fungiodes, Sezary syndrome), angioimmunoblastic T-cell lymphoma, extranodal natural killer T-cell lymphoma, enteropathy type T-cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, anaplastic large cell lymphoma); a mixture of one or more leukemia/lymphoma as described above; and multiple myeloma (MM)), heavy chain disease (e.g., alpha chain disease, gamma chain disease, mu chain disease), hemangioblastoma, inflammatory myofibroblastic tumors, immunocytic amyloidosis, kidney cancer (e.g., nephroblastoma a.k.a. Wilms' tumor, renal cell carcinoma), liver cancer (e.g., hepatocellular cancer (HCC), malignant hepatoma), lung cancer (e.g., bronchogenic carcinoma, small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), adenocarcinoma of the lung),

leiomyosarcoma (LMS), mastocytosis (e.g., systemic mastocytosis), myelodysplastic syndrome (MDS), mesothelioma, myeloproliferative disorder (MPD) (e.g., polycythemia Vera (PV), essential thrombocytosis (ET), agnogenic myeloid metaplasia (AMM) a.k.a. myelofibrosis (MF), chronic idiopathic myelofibrosis, chronic myelocytic leukemia (CML), chronic neutrophilic leukemia (CNL), hypereosinophilic syndrome (HES)), neuroblastoma, neurofibroma (e.g., neurofibromatosis (NF) type 1 or type 2, Schwann omatosis), neuroendocrine cancer (e.g., gastroenteropancreatic neuroendoctrine tumor (GEP- ET), carcinoid tumor), osteosarcoma, ovarian cancer (e.g., cystadenocarcinoma, ovarian embryonal carcinoma, ovarian

adenocarcinoma), papillary adenocarcinoma, pancreatic cancer (e.g., pancreatic

andenocarcinoma, intraductal papillary mucinous neoplasm (IPMN), Islet cell tumors), penile cancer (e.g., Paget' s disease of the penis and scrotum), pineal oma, primitive neuroectodermal tumor (PNT), prostate cancer (e.g., prostate adenocarcinoma), rectal cancer, rhabdomyosarcoma, salivary gland cancer, skin cancer (e.g., squamous cell carcinoma (SCC), keratoacanthoma (KA), melanoma, basal cell carcinoma (BCC)), small bowel cancer (e.g., appendix cancer), soft tissue sarcoma (e.g., malignant fibrous histiocytoma (MFH), liposarcoma, malignant peripheral nerve sheath tumor (MPNST), chondrosarcoma, fibrosarcoma, myxosarcoma), sebaceous gland carcinoma, sweat gland carcinoma, synovioma, testicular cancer (e.g., seminoma, testicular embryonal carcinoma), thyroid cancer (e.g., papillary carcinoma of the thyroid, papillary thyroid carcinoma (PTC), medullary thyroid cancer), urethral cancer, vaginal cancer and vulvar cancer (e.g., Paget' s disease of the vulva).

[00212] Anti-cancer agents encompass biotherapeutic anti-cancer agents as well as

chemotherapeutic agents.

[00213] Exemplary biotherapeutic anti-cancer agents include, but are not limited to, interferons, cytokines (e.g., tumor necrosis factor, interferon a, interferon γ), vaccines, hematopoietic growth factors, monoclonal serotherapy, immunostimulants and/or

immunodulatory agents (e.g., IL-1, 2, 4, 6, or 12), immune cell growth factors (e.g., GM-CSF) and antibodies (e.g. HERCEPTIN (trastuzumab), T-DM1, AVASTIN (bevacizumab), ERBITUX (cetuximab), VECTIBIX (panitumumab), RITUXAN (rituximab), BEXXAR (tositumomab)).

[00214] Exemplary chemotherapeutic agents include, but are not limited to, anti-estrogens (e.g. tamoxifen, raloxifene, and megestrol), LHRH agonists (e.g. goscrclin and leuprolide), anti- androgens (e.g. flutamide and bicalutamide), photodynamic therapies (e.g. vertoporfin (BPD- MA), phthalocyanine, photosensitizer Pc4, and demethoxy-hypocrellin A (2BA-2-DMHA)), nitrogen mustards (e.g. cyclophosphamide, ifosfamide, trofosfamide, chlorambucil, estramustine, and melphalan), nitrosoureas (e.g. carmustine (BCNU) and lomustine (CCNU)),

alkylsulphonates (e.g. busulfan and treosulfan), triazenes (e.g. dacarbazine, temozolomide), platinum containing compounds (e.g. cisplatin, carboplatin, oxaliplatin), vinca alkaloids (e.g. vincristine, vinblastine, vindesine, and vinorelbine), taxoids (e.g. paclitaxel or a paclitaxel equivalent such as nanoparticle albumin-bound paclitaxel (ABRAXANE), docosahexaenoic acid bound-paclitaxel (DHA-paclitaxel, Taxoprexin), polyglutamate bound-paclitaxel (PG-paclitaxel, paclitaxel poliglumex, CT-2103, XYOTAX), the tumor-activated prodrug (TAP) ANG1005 (Angiopep-2 bound to three molecules of paclitaxel), paclitaxel -EC- 1 (paclitaxel bound to the erbB2-recognizing peptide EC-1), and glucose-conjugated paclitaxel, e.g., 2'-paclitaxel methyl 2- glucopyranosyl succinate; docetaxel, taxol), epipodophyllins (e.g. etoposide, etoposide phosphate, teniposide, topotecan, 9-aminocamptothecin, camptoirinotecan, irinotecan, crisnatol, mytomycin C), anti-metabolites, DHFR inhibitors (e.g. methotrexate, dichloromethotrexate, trimetrexate, edatrexate), IMP dehydrogenase inhibitors (e.g. mycophenolic acid, tiazofurin, ribavirin, and EICAR), ribonuclotide reductase inhibitors (e.g. hydroxyurea and deferoxamine), uracil analogs (e.g. 5-fluorouracil (5-FU), floxuridine, doxifluridine, ratitrexed, tegafur-uracil, capecitabine), cytosine analogs (e.g. cytarabine (ara C), cytosine arabinoside, and fludarabine), purine analogs (e.g. mercaptopurine and Thioguanine), Vitamin D3 analogs (e.g. EB 1089, CB 1093, and KH 1060), isoprenylation inhibitors (e.g. lovastatin), dopaminergic neurotoxins (e.g. l-methyl-4-phenylpyridinium ion), cell cycle inhibitors (e.g. staurosporine), actinomycin (e.g. actinomycin D, dactinomycin), bleomycin (e.g. bleomycin A2, bleomycin B2, peplomycin), anthracycline (e.g. daunorubicin, doxorubicin, pegylated liposomal doxorubicin, idarubicin, epirubicin, pirarubicin, zorubicin, mitoxantrone), MDR inhibitors (e.g. verapamil), Ca ²⁺ ATPase inhibitors (e.g. thapsigargin), imatinib, thalidomide, lenalidomide, tyrosine kinase inhibitors (e.g., axitinib (AG013736), bosutinib (SKI-606), cediranib (RECENTIN™, AZD2171), dasatinib (SPRYCEL®, BMS-354825), erlotinib (TARCEVA®), gefitinib (IRES S A®), imatinib (Gleevec®, CGP57148B, STI-571), lapatinib (TYKERB®, TYVERB®), lestaurtinib (CEP-701), neratinib (HKI-272), nilotinib (TASIGNA®), semaxanib (semaxinib, SU5416), sunitinib (SUTENT®, SU11248), toceranib (PALLADIA®), vandetanib (ZACTEVIA®, ZD6474), vatalanib (PTK787, PTK/ZK), trastuzumab (HERCEPTIN®), bevacizumab (AVASTIN®), rituximab (RITUXAN®), cetuximab (ERBITUX®), panitumumab (VECTIBIX®), ranibizumab (Lucentis®), nilotinib (TASIGNA®), sorafenib (NEXAVAR®), everolimus (AFINITOR®), alemtuzumab (CAMPATH®), gemtuzumab ozogamicin (MYLOTARG®), temsirolimus (TORISEL®), ENMD-2076, PCI-32765, AC220, dovitinib lactate (TKI258, CHIR-258), BIBW 2992 (TOVOK™), SGX523, PF-04217903, PF-02341066, PF-299804, BMS-777607, ABT-869, MP470, BIBF 1120 (VARGATEF®), AP24534, TNJ-26483327, MGCD265, DCC-2036, BMS- 690154, CEP-11981, tivozanib (AV-951), OSI-930, MM-121, XL-184, XL-647, and/or XL228), proteasome inhibitors (e.g., bortezomib (VELCADE)), mTOR inhibitors (e.g., rapamycin, temsirolimus (CCI-779), everolimus (RAD-001), ridaforolimus, AP23573 (Ariad), AZD8055 (AstraZeneca), BEZ235 (Novartis), BGT226 (Norvartis), XL765 (Sanofi Aventis), PF-4691502 (Pfizer), GDC0980 (Genentech), SF1126 (Semafoe) and OSI-027 (OSI)), oblimersen, gemcitabine, carminomycin, leucovorin, pemetrexed, cyclophosphamide, dacarbazine, procarbizine, prednisolone, dexamethasone, campathecin, plicamycin, asparaginase,

aminopterin, methopterin, porfiromycin, melphalan, leurosidine, leurosine, chlorambucil, trabectedin, procarbazine, discodermolide, carminomycin,, aminopterin, and hexamethyl melamine.

[00215] In another aspect, provided are methods for delivering a biologically active agent to a subject comprising: administering a composition comprising the biologically active agent to the subject, wherein the composition includes a particle, wherein the particle comprises: a biologically active agent; a conjugated lipomer of Formula (I), or a pharmaceutically acceptable salt thereof, described herein and a lipid- PEG conjugate of Formula (II), or a pharmaceutically acceptable salt thereof, described herein. In certain embodiments, the biologically active agent is delivered to the subject in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow in vivo. In certain embodiments, the biologically active agent is delivered to bone marrow cells in vivo. In certain embodiments, the biologically active agent is targeted to bone marrow cells in vivo. [00216] In certain embodiments, the composition comprising a conjugated lipomer of Formula (I); and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) are mixed with one or more agents and/or one or more other materials (e.g., polymers). In certain embodiments, the composition comprising a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II) is mixed with an agent, to provide inventive particles.

[00217] In certain embodiments, the biologically active agent is formulated in a composition with the conjugated lipomer of Formula (I) and lipid-polyethylene glycol (PEG) conjugate of Formula (II) by encapsulating the biologically active agent via microfluidic mixing. In certain embodiments, the microfluidic mixing is conducted in a microfluidic device. In certain embodiments, the biologically active agent is a therapeutic agent. In certain embodiments, the biologically active agent is a diagnostic agent. In certain embodiments, the biologically active agent is a small molecule. In certain embodiments, the biologically active agent is an

organometallic compound. In certain embodiments, the biologically active agent is a nucleic acid. In certain embodiments, the biologically active agent is a protein. In certain embodiments, the biologically active agent is a peptide. In certain embodiments, the biologically active agent is a polynucleotide, metal, targeting agent, an isotopically labeled chemical compound, drug, vaccine, or immunological agent. In certain embodiments, the biologically active agent is a polynucleotide (e.g., DNA or RNA). In certain embodiments, the biologically active agent is RNA. In certain embodiments, the RNA is RNA/ ^' , dsRNA, siRNA, shRNA, miRNA, or antisense RNA. In certain embodiments, the RNA is siRNA. In certain embodiments, the step of administering the biologically active agent to the subject comprises administering the

composition intravenously. In certain embodiments, the biologically active agent formulated as the composition is measured. In certain embodiments, the biologically active agent is measured in bone marrow cells. In certain embodiments, the biologically active agent formulated as the composition is measured by fluorescence-activated cell sorting followed by polymerase chain reaction (PCR) analysis of gene silencing. In certain embodiments, the fluorescence-activated cell sorting is fluorescence-activated cell sorting of marrow cell populations. In certain embodiments, the biologically active agent formulated as the composition is measured by a branched DNA assay to measure mRNA expression in target cells of interest.

[00218] The present disclosure also provides methods for the treatment of a wide range of diseases, such as proliferative diseases in a subject in need thereof. The present disclosure provides methods for the treatment and/or prevention of a proliferative disease (e.g., cancers (e.g., bone marrow cancer, leukemia, lymphoma, breast cancer metastasis, leukemia, lymphoma, multiple myeloma, prostate cancer metastasis), inflammatory diseases, autoinflammatory diseases, autoimmune diseases, immunological disorders, immunodeficiencies immunotherapy, hematological disorders, hematopoietic stem cell disorders, hematopoietic stem cell

transplantation, sickle cell anemia, environmentally-induced diseases (e.g., radiation poisoning), gene therapy, lysosomal storage disorders, metabolic disorders, single gene disorders, or viral diseases. In certain embodiments, the disease is a bone marrow disease. In certain embodiments, the bone marrow disease is anemia (e.g., aplastic anemia). In certain embodiments, the bone marrow disease is a myeloproliferative disorder. In certain embodiments, the disease is a proliferative disease. In certain embodiments, the proliferative disease is cancer. In certain embodiments, the cancer is bone marrow cancer. In certain embodiments, the cancer is leukemia. In certain embodiments, the cancer is lymphoma. In certain embodiments, the disease is an immunological disorder. In certain embodiments, the disease is a hematological disorder.

EXAMPLES

[00219] In order that the invention described herein may be more fully understood, the following examples are set forth. The synthetic and biological examples described in this application are offered to illustrate the compounds, compositions, pharmaceutical compositions, particles, and methods provided herein and are not to be construed in any way as limiting their scope.

Biological Applications

[00220] Patients which have metastasis in bone and bone marrow have poor prognosis.

Cancers (e.g., epithelial and blood cancers) that colonize in bone and bone marrow are difficult to treat due to inefficient delivery of drugs to these tissues. The compositions described in this disclosure are used to deliver nucleic acids to the tumor microenvironment. Furthermore, nucleic acids can now be delivered using these compositions silence "undruggable" targets within tumor cells within these tissues, enabling these tumors to now respond to chemo-, radio-, and immunotherapies. Applicable cancers for these compositions include: metastatic breast and prostate cancer, multiple myeloma, leukemia, and lymphoma. Example 1. Nanoparticle screen for in vivo siRNA delivery to the hematopoietic niche

[00221] Bone marrow endothelial cells (BMEC) are an integral component of the

hematopoietic niche and instruct stem cell and leukocyte behavior. Cell-specific deletion experiments revealed that both progenitor proliferation and migration are governed by BMEC- derived signals (/, 23). A polymer-lipid hybrid material was prepared by reacting CI 5 epoxide- terminated lipids with low molecular weight polyamines (PEI600) at a 14: 1 molar ratio (Figure 1 A). The resulting material was combined with small interfering RNA (siRNA) and a polyethylene glycol (PEG)-lipid conjugate in a high-throughput microfluidic mixing chamber (24) to formulate nanoparticles via electrostatic interactions between the cationic polymeric material and the negatively charged nucleic acid (Figure IB). This nanomaterial was used as a starting point for testing different PEG surface coatings that alter biodistribution and

pharmacokinetics of various nanoparticle types (25, 26). It is hypothesized that modulating nanoparticle PEG architecture enhances nanoparticle siRNA delivery to the bone marrow. By altering the PEG architecture, a library of 15 nanoparticle formulations was created, with three key parameters of the PEG-lipid conjugate modified in each candidate nanoparticle: i) molecular weight of the PEG surface coating (molecular weight range: 2000-5000), ii) PEG surface density, which was altered through varying the overall molar percentage of PEG within the formulation (molar percentage range: 2%-20%) and iii) the length of the lipid chain that anchors PEG within the nanoparticle membrane (Figure 1C). This mini-library was injected

intravenously into mice (1.0 mg/kg body weight) and then assessed Tie2 silencing in the bone marrow. Using a branched DNA assay, the best nanoparticle formulation (termed NicheEC-15) was indentified, which induced -80% Tie2 in vivo gene silencing in bone marrow (Figure ID). Cryoscanning electron microscopy and dynamic light scattering showed that NicheEC-15 formed multilamellar nanoparticles (Figure IE) with a 60-80 nm diameter (Figure IF). NicheEC-15 for Tie2 silencing in endothelial cells in vitro was next assessed. Nanoparticles containing 60 nM Tie2 siRNA induced potent gene silencing in the mouse endothelial cell line bEnd.3 and in primary murine BMEC (Figure 1G). Confocal microscopic imaging confirmed efficient in vitro uptake of nanoparticles containing fluorescent siRNA (Figure 1H). Example 2. In vivo behavior of the lead particle NicheEC-15

[00222] The in vivo blood half life of NicheEC-15, containing a fluorescent siRNA, was measured to be 13.8 minutes by fitting the decrease in blood fluorescence intensity over time after a single i.v. injection (Figure 2A). Using a range of 0.01 to 1.0 mg/kg siTie2, dose- dependent knock down of Tie2 mRNA expression by qPCR was observed (Figure 2B). At a dose of 1 mg/kg siTie2, the knock down achieved with NicheEC-15 was about 50% stronger than 7C1 nanoparticles (77), a previously described nanoparticle with excellent silencing in endothelial cells. A single injection of NicheEC-15 containing 1.0 mg/kg siTie2 induced long-lasting knock down for more than two weeks (Figure 2C). To better understand the uptake patterns of

NicheEC-15, the hematopoietic niche using intravital microscopy of the skull bone marrow was directly visualized. The vasculature was stained by intravenously injecting a cocktail of PE labeled CD31 and Seal antibodies, while Osteosense, a molecular imaging probe that enriches in osteoblasts, outlined the bone surface surrounding hematopoietic niches (27). Two hours after injecting NicheEC-15- containing fluorescently tagged siRNA, the siRNA associated imaging signal in the bone marrow vasculature was found (Figure 2D). Cellular distribution of NicheEC- 15 was measured by flow cytometric analysis of the bone marrow. While the highest

fluorescence intensity in CD45- CD31+ Sca-1+ endothelial cells, nanoparticle uptake into CD45+ leukocytes was minimal was observed (Figure 2E and 2F). NicheEC-15 to 7C117 in vivo was benchmarked next. Compared to 7C1, NicheEC-15 uptake into BMEC increased

significantly while uptake into lung endothelial cells decreased (Figure 2F). While 7C1 uptake was similar in both organs, NicheEC-15 exhibited a three-fold higher uptake into bone marrow endothelial cells (Figure 2G), a result that supports NicheEC-15's high avidity for the marrow over the lung. Furthermore, direct comparing Tie2 in lung and bone marrow showed that NicheEC-15 enhanced gene silencing in bone marrow while reducing such effects in lung, compared to 7C1 (Figure 2H). Such a predilection may allow for high silencing efficiency in the marrow at lower doses.

Example 3. Sdf-l Mcp-1 target screening

[00223] Having identified NicheEC-15 as a promising delivery material, implementation of RNAi for modulating the hematopoietic bone marrow niche was advanced. Two target proteins that influence hematopoietic stem cell and leukocyte behavior were selected, specifically stromal derived factor 1 (Sdf-1, also known as Cxcl l2) and monocyte chemotactic protein 1 (Mcp-1, also known as Ccl-2). These well-studied proteins (/, 23, 28, and 29) were chosen because their known functional properties allowed for the use of specific functional in vivo assays;

additionally, because these proteins control cellular quiescence and migration, they are interesting drug targets. Viable siRNA sequences targeting Sdf-1 (Figures 7A to 7C) and Mcp-1 (Figures 8 A to 8C) were identified by in vitro screening of in silico— predicted candidates. The top four siRNA sequences silencing Sdf-1 (Figures 7 A and 7B) and Mcp-1 (Figures 8 A and 8B) were then screened in vitro with a dose response assay. The siRNAs with the lowest IC50 and IC80 were selected for scale-up, nanoparticle formulation and modification to minimize immunostimulation and off-target gene silencing (30). The lead siRNA candidates encapsulated in NicheEC-15 nanoparticles induced potent, dose-dependent gene silencing of Sdf-1 (Figure 7C) and Mcp-1 (Figure 8C) at low dosages in endothelial cells in vitro.

Example 4. siSdfl triggers bone marrow cell release

[00224] After tail vein inj ection of NicheEC-15 loaded with siRNA cargo targeting Sdf-1 (siSdfl), a >2-fold decrease in Sdf-1 expression was found (Figure 3A) and significantly decreased Sdf-1 protein in the femur (Figure 3B). To explore the cellular target responsible for this effect, bone marrow endothelial cells from mice after treatment with NicheEC-15 containing siSdfl was FACS-isolated. Indeed, compared to controls, Sdf-1 expression was strongly reduced in these cells (Figure 3C). Since Sdf-1 retains hematopoietic stem and progenitor cells (28) and leukocytes (29) in the bone marrow, HSPC migration was investigated to monitor functional consequences of RNAi. Indeed was investigated, and it was observed that there were higher lineage- scal+ ckit+ (LSK) cell numbers in blood of mice treated with siSdfl (Figure 3D), indicating release of these progenitor cells from the marrow. The increase in circulating HSPC was confirmed by colony forming unit (CFU) assays in blood (Figure 3E). Accordingly, siSdfl injection decreased bone marrow LSK cells (Figure 3F and 3G). Likewise, downstream myeloid progenitors, including common myeloid progenitors (CMP) and granulocyte macrophage progenitors (GMP), declined in numbers in the femur after siSdfl treatment (Figures 3H to 3 J).

[00225] In addition to progenitor release, it was further detected that siSdfl treatment leads to monocyte and neutrophil departure from the bone marrow (Figure 3K to 3M). As a consequence, neutrophils and monocytes may become more numerous in circulation. Since the level of circulating myeloid cells regulates their presence at sites of inflammation and closely associates with patient mortality, the early dynamics of this leukocyte release were studied. Two hours after siSdfl injection, myeloid cells became significantly more abundant compared to baseline, and increased even further at six hours (Figure 4A and 4B). Such a boost in circulating leukocytes may also be caused by redistribution from other cell pools, e.g. in the lung or spleen. Serial pre- and post-RNAi treatment intravital microscopy was used to survey the skull bone marrow. Bone marrow macrophages and monocytes in Cx3crl mice before and up to 2.5 hours after siSdfl injection was visualized. By monitoring specific bone marrow niches, individual cell behavior was tracked over time (Figure 4C). Treatment with siSdfl triggered departure of Cx3crl+ cells, while this was not observed after treatment with control siRNA (Figure 4D). A similar dynamic was observed for neutrophils that were labeled in vivo with an Ly6g-APC antibody (Figure 4E and 4F). In sum, these data demonstrate the ability to trigger stem cell and leukocyte release by silencing retention factors in the bone marrow vasculature.

Example 5. siMcpl inhibits bone marrow cell release

[00226] While Sdf-1 silencing increased cell migration from the marrow, a gene target was next chosen to explore the opposite functionality, i.e. to use RNAi to dampen leukocyte traffic. Such an intervention could be a therapeutic avenue to reducing systemic leukocyte supply in the setting of inflammation. Monocyte bone marrow departure is triggered by secretion of the chemokine Mcp-1 into the sinusoidal space, for instance after infection, injection of

lipopolysaccharide, a building block of the bacterial wall that binds toll like receptors, or myocardial infarction (16, 31). Because monocytes express the cognate chemokine receptor Ccr2, they follow the Mcp-1 chemokine gradient and extravasate from the niche into the bone marrow sinusoids. The effect of Mcp-1 silencing in the setting of LPS-induced inflammation was tested (Figure 5 A). As expected, LPS injection dramatically increased Mcpl expression in the marrow, and such expression was significantly reduced by siMcpl treatment (Figure 5B). Mcpl protein levels were similarly elevated by LPS, which was abrogated by siMcpl treatment (Figure 5C). As a consequence, monocyte numbers in the bone marrow were higher in siMcpl -treated mice (Figure 5D to 5F), whereas blood monocyte numbers decreased (Figure 5G to 51).

[00227] Mcp-1/Ccr2 signaling also regulates monocyte migration in sterile inflammation, including during cardiovascular disease. In particular, acute myocardial infarction (MI) triggers blood monocytosis, followed by cell recruitment into the ischemic myocardium (32). After MI, systemic oversupply of inflammatory monocytes may lead to heart failure and subsequent ischemic events (8). Therefore it was tested if silencing Mcp l in mice with acute MI may reduce inflammatory Ly6c ^Mgl1 monocyte numbers in circulation and the heart. Treating mice with siMcpl led to a lower bone marrow Mcpl expression (Figure 6 A) and protein level (Figure 6B). Consequently, monocyte bone marrow numbers rose (Figure 6C and 6D) while circulating monocyte numbers remained lower (Figure 6F to 6H), results that indicated attenuated cell release from the marrow. Ultimately, fewer monocytes, including the inflammatory Ly6c ^Mgl1 subset, were recruited to the infarcted heart in mice treated with siMcpl (Figure 61 to 6K).

Methods

[00228] For compositions with the nanoparticle comprising a conjugated lipomer of Formula

(I) and a lipid-polyethylene glycol (PEG) conjugate of Formula (II), these compositions of both components were made via microfluidics-based synthesis, where these two materials complex with nucleic acids via electrostatic interactions to form nanoparticles. For a particle comprising a conjugated lipomer of Formula (I) and a lipid-polyethylene glycol (PEG) conjugate of Formula

(II) , this particle is synthesized using microfluidic devices to utilize chaotic mixing to form nanoparticles via electrostatic interactions.

Example 6. Polymer-lipid hybrid synthesis

[00229] Polymer-lipid hybrids were synthesized by reacting CI 5 alkyl epoxides (Tokyo Chemical Industry and Sigma) with PEI600 at 90 °C in 100% ethanol for 48-72 hours at a 14: 1 molar ratio. Due to the polydispersity of PEI600 (Mn=600, PDI = 0.33), polymer-lipids were purified via high performance liquid chromatography (UPLC) on a silica column with DCM. MeOH and NH ₄ OH were added to the solvent over a 45 minute period to decrease polarity, which enabled UPLC separation of the polymer-lipid into fractions related to the hydrophobic C 15 : hydrophilic PEI ratio. Mixtures were split into five fractions and individually assessed for their ability to induce gene silencing in mice. Example 7. siRNA Nanoparticle Synthesis

[00230] To formulate nanoparticles, polymer-lipid materials were combined with

polyethylene (PEG)-lipid conjugates (Avanti Polar Lipids) and mixed with siRNA in a microfluidic device. Polymer-lipids and PEG-lipid conjugates were dissolved in 200 proof ethanol and loaded into a gas-tight Hamilton glass syringe, while siRNA were in an 10 mM citrate buffer (pH 3.0; Teknova). Syringes were connected to inlets of a microfluidic device containing static mixers, and contents were perfused through the device to formulate

nanoparticles. Nanoparticle formulations were sterile filtered against PBS using a MW 20,000 cutoff dialysis cassette (Thermo Scientific) to remove citrate and ethanol. Nanoparticle size and structure were determined by both dynamic light scattering (DLS) using a Zetasizer Nano ZS machine (Malvern Instruments) and cryo- transmission electron microscopy (TEM) using a Tecnai 12 G2 TEM (FEI). Nanoparticle samples were prepared in a vitrification system (25 °C, -100% humidity), and images of samples were recorded on an UltraScan 1000 CCD camera (Gatan) in low dose conditions. For zeta potential measurements, nanoparticles (25 μΐ.) at a polymer-lipid concentration of 1 mg/mL were added to PBS (1 mL) and measured using a Malvern Zetasizer Nano ZS machine. The concentration of siRNA used for in vitro and in vivo treatment was quantified using both a QuaRibogreen assay (Invitrogen) and NanoDrop measurement (Thermo Scientific).

Example 8. Cell culture experiments

[00231] The endothelial cell line bEnd.3 (CRL-2299, ATCC) was cultured in Dulbecco's modified Eagle's medium, supplemented with 10% (vol/vol) fetal bovine serum and 1%

(vol/vol) penicillin/ streptomycin under humidified conditions at 37°C and 5% C0 ₂ until cell confluence. To investigate knock down efficiency, bEnd.3 cells were plated in 24 well plates (150,000 cells per well) and incubated for 24 hours prior to treatment with nanoparticles formulated with siRNA targeting one of the following genes: luciferase (LUC), monocyte chemoattractant protein- 1 (MCP-1) or stromal-derived factor- 1 (SDF-1). A serial dilution of each siRNA nanoparticle formulation in PBS was prepared at concentrations of 1-60 nM of siRNA. Samples were then incubated for 24 hours prior to gene expression analysis. Cells were washed with PBS and harvested using 0.25% trypsin. RNA was extracted from cells using a Arcturus PicoPure RNA Isolation Kit (Thermo Scientific). To study the in vitro uptake of NicheEC-15 by microscopy, bEnd.3 cells were plated in 6 well plates (500,000 cells per well) and grown until confluence. NicheEC-15 containing Alexa Fluor 647 coupled luciferase siRNA was then added at a concentration of 200 nM RNA 2 hours before imaging. 15 minutes before imaging 5 μΜ Syto 13 Green (Life Technologies) and 5 μg/ml wheat germ agglutinin Alexa Fluor 555 (WGA, Life Technologies) were added. During the last 5 minutes the cell cultures were washed repeatedly with PBS. The controls were treated identically, except that NicheEC-15 containing unlabelled luciferase siRNA was used. All steps except washing were done under humidified conditions at 37 °C and 5% C0 ₂ .

Example 9. Mice

[00232] All animal procedures conducted at MGH and MIT were approved by the Institutional Animal Care and Use Committees (IACUC) and were in accordance with local, state and federal regulations. C57BL/6J and hemizygous Cx3crlGFP/+ mice were used at 1 1 to 13 weeks of age. C57BL/6J (stock # 000664) mice were purchased and for hemizygous Cx3crl mice, homozygous B6.129P-Cx3crl ^tmlLitt/J (stock # 005582) mice were crossed with C57BL/6J mice, both from Jackson Laboratory. Nanoparticles were administered by tail vein injection.

Myocardial infarction was induced by permanent coronary ligation as previously described (27). Briefly, mice were anaesthetised, given buprenorphin subcutaneously for analgesia, intubated and ventilated with 2% isoflurane supplemented with oxygen. After thoracotomy, the heart was exposed, and the left coronary artery was identified, and permanently ligated with a

monofilament nylon 8-0 suture. For the LPS model, after nanoparticle treatment, 10 μΐ normal saline containing 2 ng LPS (Sigma) was injected i.v. and mice harvested 4 hours after LPS injection.

Example 10. Tie2 gene silencing

[00233] Gene silencing in femoral bone marrow was assessed up to 18 days post injection of NicheEC-15 containing a dose of 1.0 mg/kg Tie2 siRNA. For dose response studies, ice were treated with a single dosage of Tie2 siRNA nanoparticles ranging from 0.01-1.0 mg/kg, and femurs were harvested 48 h post-injection. Mice were sacrificed by C0 ₂ asphyxiation, and femurs were harvested and immediately snap-frozen in liquid nitrogen. Frozen tissues were pulverized to form a powder using a SPEX 2010 Geno/Grinder (SPEX SamplePrep). Tissue lysates were prepared in Tissue and Cell Lysis Buffer (Epicentre) supplemented with 0.5 mg/mL Proteinase K (Epicentre). Tissue samples were mixed at 1400 RPM for 2 h at 65 °C and centrifuged at 16,000 RCF to remove bone debris. mRNA levels in the supernatant were quantified using the QuantiGene 2.0 luminescent-based branched DNA (bDNA) assay kit and the QuantiGene 2.0 probes against Tie2 and GAPDH (Thermo Fisher Scientific) according to the manufacturer's protocol. Luminescent signals were measured using a Tecan Infinite 200 PRO plate reader (Tecan). Standard curves for femur tissues and each target gene were constructed using samples from untreated mice to ensure optimal dilutions for assay samples that avoid luminescent signal saturation. Tie2 silencing in treated mice was quantified by calculating the ratio of Tie2 gene luminescence to Gapdh gene luminescence, with all values normalized to Tie2:Gapdh gene ratios from untreated mice.

Example 11. mRNA Extraction and qPCR

[00234] Messenger RNA (mRNA) was extracted from cells using a Arcturus PicoPure RNA Isolation Kit (Thermo Scientific) for cultured and sorted endothelial cells, and the RNeasy Mini Kit (Qiagen) was used for whole bone marrow samples, both according to the manufacturers' protocols. mRNA concentration was measured using a NanoDrop 2000c Spectrophotometer (Thermo Scientific) or using a 2100 Bioanalyzer (Agilent) for low mRNA concentration. After adjusting for yield mRNA was transcribed to complementary DNA (cDNA) with the high capacity RNA to cDNA kit (Applied Biosystems). Taqman primers (Applied Biosystems) were used. Results were expressed by Ct values normalized to the housekeeping gene Gapdh.

Example 12. Flow Cytometry and Cell Sorting

[00235] Single-cell suspensions were obtained from peripheral blood, bone marrow, aorta and lung. Briefly, blood was collected by eye bleeding using heparinised capillaries or, if larger volumes were needed, by cardiac puncture and addition of 50 mmol/L EDTA. Red blood cells lysis was achieved by adding lx red blood cell lysis buffer (Biolegend) for 2 minutes. After blood collection, mice were perfused through the left ventricle with 30 mL ice-cold PBS. Bone marrow was harvested by flushing femurs in PBS with 0.5% bovine serum albumin (BSA) for leukocyte and HSPC staining or with HBSS containing 2% FBS, 2 mg/ml disease 2 and 1 mg/ml collagenase IV and incubated with gentle agitation for 30 minutes at 37 °C for endothelial cells. Lungs were excised and minced with a fine scissor before digestion in DMEM w/o phenol red containing 2% FBS, 2 mg/ml dispase 2, 5 mg/ml collagenase I (Worthington) and 1 mg/ml DNase I (Sigma) at 37°C and 125 revolutions for 20 minutes. Tissues were then plunged thorough 40-μιη nylon mesh (BD Falcon), washed and centrifuged (8 minutes; 300g; 4°C). The obtained single cell suspensions were stained at 4 °C for 30 minutes and afterwards washed, centrifuged and resuspended. Fluorochrome- and biotin-conjugated antibodies specific to mouse B220 (clone RA3-6B2), CD3e (clone 145-2C11), CD4 (clone GK1.5), CD8a (clone 53-6.7), CD1 lb (clone Ml/70), CD1 lc (clone HL3), CD16/32 (clone 93 and 2.4G2), CD19 (clone 1D3), CD31 (clone MEC13.3), CD34 (clone RAM34), CD41 (clone MWReg30), CD45.2 (clone 104), CD48 (HM48-1), CD90.2 (clone 53-2.1), CD115 (clone AFS98), CD150 (clone TC15-12F12.2), c-kit (clone 2B8), F4/80 (clone BM8), GRl (clone RB6-8C5), IL7Ra (clone A7R34), Ly6C (clone AL-21), Ly-6G (clone 1A8), NKl . l (clone PK136), Sca-1 (clone D7) and Ter-119 (clone TER-119) were used. Antibodies were purchased from Biolegend, BD Biosciences or eBioscience. Monocytes were identified as CD90- CD19- NKl . l- Ly-6G- D45.2+

CD1 lbhighCDl 15+ F4/801ow and separated into Ly-6C ^low and a Ly-6C ^Mgh populations.

Neutrophils were identified as CD90- CD19- NK1.1- D45.2+ CD1 lbhigh Ly-6G+. Blood and bone marrow LSK were identified as (B220 CD3e CD4 CD8a CD1 lb CD1 lc CD19 CD90.2 GRl IL7Ra NKl . l Terl l9)- c-kit+ Sca-1+, LKs as (B220 CD3e CD4 CD8a CDl lb CDl lc CD19 CD90.2 GRl NKl . l Terl l9)- c-kit+ Sca-1- and subdivided into CMP, MEP and GMP by their CD16/32 and CD34 expression. Bone marrow and lung endothelial cells were gated as CD45.2- CD41- Terl l9- CD31+ Sca-1+ and Terl l9- CD45+ CD31+, respectively. To define positivity for AF647-siRNA uptake, cells from uninjected mice were used as a negative control. Data were acquired on an LSRII (BD Biosciences) and analysed with FlowJo software (Tree Star). For cell sorting the populations were defined as described and sorted using a F ACS Aria II cell sorter. The cells were directly sorted into lysis buffer, and the samples were vortexed, quick frozen on dry ice and stored at -80°C until RNA extraction. Example 13. Colony-forming unit assay

[00236] Colony-forming unit (CFU) assays were performed using a semisolid cell culture medium (Methocult M3434, Stem Cell Technology) following the manufacturer's protocol. 100 μΐ whole blood were processed following the protocol, plated on 35-mm plates in duplicates and incubated for 10 days. Colonies were counted using a low-magnification inverted microscope.

Example 14. Intravital microscopy

[00237] To visualize in vivo uptake of NicheEC-15 in bone marrow endothelial cells, the skull bone marrow was imaged as previously described (27). Osteosense was injected i.v. 24 hours, NicheEC-15 AF647-siRNA 2 hours and PE labeled CD31 and Seal antibodies 1 hour before imaging.

Example 15. ELISA

[00238] ELISAs for SDF1 and MCP1 (both R&D) in the bone marrow were performed by spinning (1 1.000 g, 2 min, 4°C) the bone marrow out of one femur and taking the supernatant for ELISAs, which were performed according to the manufacturers' instructions.

Example 16. Statistics

[00239] Data are expressed as mean±SEM. Analyses were performed using Prism 7

(GraphPad Software Inc). For a 2-group comparison, a Student t test was applied if the pretest for normality (D'Agostino-Pearson normality test) was not rej ected at 0.05 significance level; otherwise, a Mann-Whitney test for nonparametric data was used. ANOVA tests followed by Bonferroni post- tests were applied for comparison of >2 groups. P values <0.05 indicate statistical significance.

Discussion

[00240] Bone marrow niche cells regulate hematopoietic and leukocyte activity in numerous ways, including cell transit into the circulation (7, 23, and 33). A nanoformulation capable of delivering siRNA to bone marrow niche cells was developed. These new nanoparticles are derivatives of prior materials with avidity for lung endothelial cells (77). Nanoparticle siRNA delivery to the bone marrow by modulating nanoparticle PEG architecture was enhanced, including i) the molecular weight of the PEG surface coating, ii) the length of the lipid chain that anchors PEG within the nanoparticle membrane and iii) PEG surface density. By screening polymer-lipid hybrid materials, combined with modulating PEG nanoparticle surface coatings, a nanoparticle, termed NicheEC-15, was developed with superior avidity for and efficient silencing in bone marrow endothelial cells. To test NicheEC-15, two prototypical hematopoietic niche factors were silenced. One of them, Sdf-1, promotes stem cell quiescence and bone marrow retention of leukocytes via interaction with its cognate receptor Cxcr4. This pathway is currently targeted clinically using G-CSF and AMD3100, which trigger stem cell liberation into the blood (34). Silencing HSPC retention factors using nanoparticle enabled RNAi may improve the cell yield in stem cell transplantation, especially in patients that are poor stem cell mobilizers due to comorbidities such as diabetes (35). The second target, Mcp-1, has the opposite effect, as this chemokine triggers bone marrow monocyte release. It was found that silencing those proteins, using NicheEC-15 enabled RNAi, altered migration of HSPC and leukocytes from bone marrow niches into the systemic blood pool. The data provides first proof-of-principle that bone marrow HSPC and leukocyte behavior may be addressed using RNAi therapeutics with avidity for the hematopoietic niche.

[00241] Due to RNAi' s modular character, this approach can be adapted for silencing any other endothelial cell derived bone marrow niche factor, including growth hormones, cytokines and adhesion molecules that influence HSPC or leukocyte biology. Furthermore, silencing receptors may modulate endothelial cells' ability to sense and relay information they receive from the circulation. The function of bone marrow niche cells in steady state and disease is the subject of vibrant research, and large unbiased data-sets, for instance obtained by RNA sequencing of bone marrow endothelial cells, are increasingly becoming available (36). The technology described herein is ideally suited to rapidly testing the function of highly exressed genes and newly arising drug candidates in vivo.

[00242] Endothelial cells separate bone marrow niches from the blood pool. Their barrier function, which ultimately regulates cell release, make them a particularly attractive target for modulating cell migration. However, there are other niche cells that regulate hematopoiesis. Future materials may deliver siRNA to bone marrow macrophages, mesenchymal stromal cells or osteoblasts, thereby targeting other niche components. Such additions to the target cell portfolio may also facilitate RNAi for niche-driven malignancies. [00243] Stem cell quiescence and lineage bias are of particular interest as they decisively influence the size and function of any systemic blood cell pool. As demonstrated by silencing Mcp-1, reducing the release of short-lived leukocytes from their site of production may dampen inflammation at any inflammatory site, including the ischemic heart. Thus, reducing the oversupply of innate immune cells may curtail exuberant inflammatory actiuvity in

cardiovascular disease (5), the leading cause of death worldwide.

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EQUIVALENTS AND SCOPE

[00244] In the claims articles such as "a," "an," and "the" may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that include "or" between one or more members of a group are considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. The invention includes embodiments in which exactly one member of the group is present in, employed in, or otherwise relevant to a given product or process. The invention includes embodiments in which more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process.

[00245] Furthermore, the invention encompasses all variations, combinations, and

permutations in which one or more limitations, elements, clauses, and descriptive terms from one or more of the listed claims is introduced into another claim. For example, any claim that is dependent on another claim can be modified to include one or more limitations found in any other claim that is dependent on the same base claim. Where elements are presented as lists, e.g., in Markush group format, each subgroup of the elements is also disclosed, and any element(s) can be removed from the group. It should it be understood that, in general, where the invention, or aspects of the invention, is/are referred to as comprising particular elements and/or features, certain embodiments of the invention or aspects of the invention consist, or consist essentially of, such elements and/or features. For purposes of simplicity, those embodiments have not been specifically set forth in haec verba herein. It is also noted that the terms "comprising" and "containing" are intended to be open and permits the inclusion of additional elements or steps. Where ranges are given, endpoints are included. Furthermore, unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or sub-range within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise.

[00246] This application refers to various issued patents, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference. If there is a conflict between any of the incorporated references and the instant specification, the

specification shall control. In addition, any particular embodiment of the present invention that falls within the prior art may be explicitly excluded from any one or more of the claims. Because such embodiments are deemed to be known to one of ordinary skill in the art, they may be excluded even if the exclusion is not set forth explicitly herein. Any particular embodiment of the invention can be excluded from any claim, for any reason, whether or not related to the existence of prior art.

[00247] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments described herein. The scope of the present embodiments described herein is not intended to be limited to the above Description, but rather is as set forth in the appended claims. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the present invention, as defined in the following claims.