FIELD OF THE DISCLOSED SUBJECT MATTER

[0001] The subject matter pertains to a sealant for treating pulmonary air leaks.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to U.S. Provisional Application No. 62/404,991, filed October 6, 2016, the entirety of which is incorporated herein by reference.

BACKGROUND OF THE DISCLOSED SUBJECT MATTER

[0003] Patients with prolonged air leaks (greater than seven days duration), such as from septum rupture, following lung resection often suffer prolonged hospitalization (up to weeks) and are most commonly managed with tube thoracostomy (i.e., a chest tube placed into the thoracic cavity to drain air/fluid while the lung heals). Patients that fail this first-line therapy are often taken back to the operating room for further intervention. Another option in the treatment of prolonged air leaks are endobronchial valves; however they often have little effect and are prone to complications (e.g., dislodgment, inflammation, infection).

[0004] Air leaks occur in 15-18% of patients undergoing lung resection. There is a critical need in the field to prevent this complication, improve patient care, and decrease cost. Additionally, patients with underlying lung disease (e.g., COPD, emphysema) are more likely to suffer from air leaks following any intervention (e.g., surgery, IR biopsy) and other processes such as trauma can cause damage to the lung parenchyma, leading to air leaks. There is also a substantial need to treat these patients.

[0005] Physical adhesive patches over the air leak have been used as an alternative option. Such patches include synthetic self-adhesive sealant and barrier functions. Also known are two-part systems that form an adhesive patch over the air leak, including polyethylene glycol/human serum albumin, albumin/glutaraldehyde, or thrombin/fibrinogen combinations.

[0006] The solutions listed above are mainly fibrin-based products originally designed as adhesives for other applications in the body. Their adhesive and mechanical properties are not well-suited for the complex dynamics of the lung, and they are unable to accommodate mechanical changes in the lung during ventilation. They serve as very poor sealants and contain no organ- or tissue-specificity in properties or composition. Many rely on hemostatic mechanisms (e.g., activation in the presence of bleeding which is not present on the pleural surface of the lung). Metaanalysis data has shown little evidence that any of these products are effective in reducing air leaks, length of hospital stay, or cost. As a result, there is no routine use of any lung sealant today.

[0007] Thus, there is a continuing need for an effective lung sealant that can be used to treat pulmonary air leaks to avoid more costly surgical procedures.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

[0008] The present disclosure is directed to a biosealant composition.

[0009] In one embodiment, the biosealant composition comprises an extracellular matrix hydrogel and a thermogel. The extracellular matrix hydrogel comprises a first

extracellular matrix protein, an unbranched polysaccharide, and an elastic protein. The thermogel comprises gelatinous material and a cross-linking enzyme in an amount sufficient to result in gelation of the thermogel at a temperature from about 35°C to 37°C.

[0010] In another embodiment, the biosealant composition comprises an extracellular matrix hydrogel as a first layer and a thermogel as a second layer, with the second layer is atop the first layer. The extracellular matrix hydrogel layer comprises collagen, sulfated glycosaminoglycan, and elastin. The thermogel comprises gelatin and transglutaminase.

[0011] In another embodiment, the biosealant composition comprises a first extracellular matrix protein; an unbranched polysaccharide; and an elastic protein; a gelatinous material; and a cross-linking enzyme.

[0012] In another embodiment, the biosealant composition comprises collagen, sulfated glycosaminoglycan, elastin, gelatin and transglutaminase.

[0013] The present disclosure is also directed to a method for sealing a puncture.

[0014] In one embodiment, the method comprises the steps of applying an extracellular matrix hydrogel to a puncture, where the extracellular matrix comprises a first extracellular matrix protein, an unbranched polysaccharide, and an elastic protein. The method then comprises the step of applying a thermogel on top of the extracellular matrix hydrogel, where the thermogel comprises a gelatinous material and a cross-linking enzyme, wherein the cross-linking agent is in an amount sufficient to result in gelation of the thermogel at a temperature from about 35°C to 37°C.

[0015] In another embodiment, the method comprises the step of applying a composition to a puncture, where the composition comprises an extracellular matrix hydrogel and a thermogel. The extracellular matrix comprises a first extracellular matrix protein, an unbranched polysaccharide, and an elastic protein. The thermogel comprises a gelatinous material and a cross-linking enzyme in an amount sufficient to result in gelation of the thermogel at a temperature from about 35°C to 37°C.

[0016] The present disclosure is also directed to a kit for sealing of a puncture.

[0017] In one embodiment, the kit comprises a first, second, and third component. The first component is a first extracellular matrix protein, an unbranched polysaccharide, and an elastic protein. The second component is a gelatinous material. The third component is a cross- linking enzyme.

[0018] The present disclosure is also directed to a method of making a biosealant.

[0019] In one embodiment, the method comprises the steps of mixing a first extracellular matrix protein, an unbranched polysaccharide, an elastic protein, and a cross-linking enzyme to form an extracellular matrix hydrogel, mixing a gelatinous material in saline with the cross-linking enzyme to form a thermogel, heating the thermogel to about 52°C to 55°C; and making the thermogel porous.

[0020] In any of the above embodiments, the first extracellular matrix protein of the extracellular matrix hydrogel is present in an amount from about 25% by weight to about 75% by weight of the total weight of the first extracellular matrix protein, unbranched

polysaccharide, and elastic protein of the extracellular matrix hydrogel.

[0021] In any of the above embodiments, the unbranched polysaccharide of the extracellular matrix hydrogel is present in an amount from about 0.5% by weight to about 15% by weight of the total weight of the first extracellular matrix protein, unbranched polysaccharide, and elastic protein of the extracellular matrix hydrogel.

[0022] In any of the above embodiments, the elastic protein of the extracellular matrix hydrogel is present in an amount from about 25% to about 75% by weight of the total weight of the first extracellular matrix protein, unbranched polysaccharide, and elastic protein of the extracellular matrix hydrogel.

[0023] In any of the above embodiments, the first extracellular matrix protein of the extracellular matrix hydrogel is present in an amount from about 25% by weight to about 75%) by weight of the total weight of the first extracellular matrix protein, unbranched polysaccharide, and elastic protein of the extracellular matrix hydrogel, the unbranched polysaccharide of the extracellular matrix hydrogel is present in an amount from about 0.5% by weight to about 15%> by weight of the total weight of the first extracellular matrix protein, unbranched polysaccharide, and elastic protein of the extracellular matrix hydrogel, and the elastic protein of the extracellular matrix hydrogel is present in an amount from about 25% to about 75%) by weight of the total weight of the first extracellular matrix protein, unbranched polysaccharide, and elastic protein of the extracellular matrix hydrogel.

[0024] In any of the above embodiments, the first extracellular matrix protein is collagen.

[0025] In any of the above embodiments, the unbranched polysaccharide is sulfated glycosaminoglycan.

[0026] In any of the above embodiments, the elastic protein is elastin.

[0027] In any of the above embodiments, the first extracellular matrix protein, an unbranched polysaccharide, and an elastic protein of the extracellular matrix hydrogel are derived from lung extracellular matrix.

[0028] In any of the above embodiments, the extracellular matrix hydrogel also comprises a cross-linking enzyme.

[0029] In any of the above embodiments, the extracellular matrix hydrogel also comprises a cross-linking enzyme in a concentration of 0.5 units/mL to 5 units/mL.

[0030] In any of the above embodiments, the cross-linking enzyme is transglutaminase.

[0031] In any of the above embodiments, the extracellular matrix hydrogel also comprises additional therapeutics including cells, microsomes, peptides, or drugs. [0032] In any of the above embodiments, the gelatinous material of the thermogel is present in an amount from about 5% by weight to 10% by weight of the total weight of the thermogel.

[0033] In any of the above embodiments, the cross-linking enzyme of the thermogel is present in an amount from about 0.5 units/mL to 5 units/mL.

[0034] In any of the above embodiments, the gelatinous material is gelatin.

[0035] In any of the above embodiments, the thermogel further comprises one or more of the first extracellular matrix protein, the unbranched polysaccharide, and the elastic protein.

[0036] In any of the above embodiments, the first extracellular matrix protein of the thermogel is collagen.

[0037] In any of the above embodiments, the unbranched polysaccharide of the thermogel is sulfated glycosaminoglycan.

[0038] In any of the above embodiments, the elastic protein of the thermogel is elastin.

[0039] In any of the above embodiments, the first extracellular matrix protein, an unbranched polysaccharide, and an elastic protein of the thermogel are derived from lung extracellular matrix.

[0040] In any of the above embodiments, the thermogel comprises pores of diameter of about 0.025 mm to 90 mm.

[0041] In any of the above embodiments, the biosealant composition does not contain fibrin.

[0042] In any of the above embodiments, the first extracellular matrix protein is collagen, wherein the unbranched polysaccharide is sulfated glycosaminoglycan, and wherein the elastic protein is elastin.

[0043] In any of the above embodiments, the gelatinous material is gelatin, and wherein the cross-linking enzyme is transglutaminase.

[0044] In any of the above embodiments, the extracellular matrix hydrogel is applied directly to tissue. [0045] In any of the above embodiments, the extracellular matrix hydrogel is applied directly to the surface of the lung.

[0046] In any of the above embodiments, the extracellular matrix hydrogel is applied directly to the surface of the lung by chest tubes, drainage catheters, or injection when the thoracic cavity is closed.

[0047] In any of the above embodiments, the extracellular matrix hydrogel is applied at the time of bronchoscopy within the airways via catheter.

[0048] In any of the above embodiments, the extracellular matrix hydrogel is applied directly to the surface of an extracorporeal lung.

[0049] In any of the above embodiments, the thermogel is made porous by bubbling gas with a bubble generator through the thermogel material.

BRIEF DESCRIPTION OF THE DRAWINGS AND FIGURES

[0050] FIGURE 1 shows photographic images used to show schematically the layers of the biosealant system.

[0051] FIGURES 2A-2F show aspects of the extracellular matrix hydrogel layer.

[0052] FIGURES 3A-3D show aspects of the thermogel layer.

[0053] FIGURE 4A shows a photograph of a puncture wound in lung tissue and FIGURE 4B shows a photograph of the wound repaired with the biosealant described herein.

[0054] FIGURES 5A-5C show a parenchymal injury in lung tissue and the wound repaired with the biosealant described herein.

DETAILED DESCRIPTION OF THE DISCLOSED SUBJECT MATTER

[0055] There is a significant unmet clinical need and opportunity for the prevention and treatment of pulmonary air leaks. A biosealant product that could be applied at the time of surgery to prevent air leaks from occurring could result in decreased hospitalization, lower costs, less pain and fewer interventions on behalf of the patient. In addition to the prophylactic use of such a product, it could also be used to treat lung damage and air leaks occurring after surgery, trauma, or those known to occur spontaneously. [0056] In accordance with the disclosed subject matter, a biomechanically compliant, loadable lung biosealant for the prevention and treatment of pulmonary air leaks is described. The biosealant is multi-layered, with a tissue-specific (e.g., lung parenchymal- or pleural-derived) extracellular matrix hydrogel carrier loaded with therapeutic cells, microsomes (e.g., exosomes, liposomes), peptides (e.g., growth factors), or drugs applied directly to the lung surface.

[0057] The sealant adheres effectively to the surface of lung by natural peptide- peptide interactions (e.g., proteinaceous components of lung biosealant with proteinaceous components of lung pleural or exposed lung parenchyma. The novel, biomimetic design that underlies the biocompatibility, sealing function, and mechanics of this lung biosealant relies on both the presence of native lung matrix biomolecules (collagen, sulfated glycosaminoglycans, and elastin) and the spongey and porous structure. The extracellular matrix biomolecules function to mimic the natural tissue architecture and mechanical properties of the lung and also ensure a vehicle for natural, biological, cytocompatible therapeutic payloads including drugs, cells, or cellular products like growth factors or other paracrine signals. While the composition of the lung matrix biomolecules in the sealant closely mimics natural lung composition, the lung matrix biomolecules are not necessarily derived directly from lung tissue. The spongey and porous structure of the biosealant is biomimetic— it recapitulates the natural spongey and porous structure of pulmonary alveoli (air sacs). This rational design feature is novel and unlike any other lung sealant device or material, and is one key to the effective sealing action of the biosealant.

EXAMPLES

[0058] The present invention is demonstrated in the following examples, it being understood that these are for illustrative purposes only, and the invention is not intended to be limited thereto.

Materials & Methods

[0059] Extracellular Matrix Hydrogel. The extracellular matrix components can be prepared in a concentrated liquid solution according to the following ranges: collagen: 80-120 μg / mg biosealant; sulfated glycosaminoglycans: 2-20 μg / mg biosealant; elastin: 50- 250 μg / mg biosealant. The extracellular matrix hydrogel may also contain a cross-linking enzyme. This enzyme may be transglutaminase (0.5 - 5 units/mL), which is mixed with extracellular matrix components to obtain a extracellular matrix hydrogel.

[0060] Thermogel. The thermogel can be prepared by mixing 5-10 % wt gelatin in normal saline, adding 0.5-5 unit/mL transglutaminase, and heating to 52-55°C. The resulting viscous thermogel material can then be made porous by bubbling gas (air) with a bubble generator through the thermogel material at 52-55°C. The gas is introduced into the bubble generator at a flow rate resulting in thermogel pores with diameter range of 25-500 μπι, importantly approximately consistent with the range of diameters of ventilating pulmonary alveoli (air sacs), thus mimicking native lung structure and mechanics.

[0061] Application of Extracellular Matrix Hydrogel Layer and Thermogel Layer to Lung. Extracellular matrix hydrogel is applied to the surface of the lung. Then, porous thermogel is cooled to 37-42°C and then applied to the lung over the previously applied lung extracellular matrix hydrogel. The specified ranges of gelatin and transglutaminase enable natural gelation (setting) of the thermogel at a range of 35-37°C. Following application onto the surface of the lung, gelation of the hydrogel layers occurs within 10-120 seconds (depending on the precise ratios of the multiple components described above). The final size (i.e., surface area) of the lung biosealant must be applied to an area at least 50% larger than the injured or ruptured area of the lung pleura.

[0062] Method of Application of Biosealant to Lung. Biosealant can be applied onto the surface of the lung at the time of open surgery (direct visualization) or minimally invasive surgery (video assisted) via 12-20 gauge applicators. Alternatively, the biosealant can be applied onto the surface of the lung with the chest closed through chest tubes or drainage catheters within the thoracic cavity, or injected with the aid of image guidance (e.g., computed tomography or ultrasound) onto the surface of the lung (12-20 gauge needles). Alternatively, the biosealant can be injected at the time of bronchoscopy within the airways via a catheter 1.5-2mm in diameter. Alternatively, the biosealant can be applied directly onto the surface of an extracorporeal lung (i.e., lung supported outside the body with ex vivo lung perfusion) via 12-20 gauge applicators. EXAMPLE 1

[0063] FIGURE 1 depicts the thermogel and extracellular matrix hydrogel components of the biosealant system. The photographs are not necessarily to the same scale. The biosealant system 100 comprises an extracellular matrix hydrogel layer 102 applied directly to the lung surface 101. Proximate the extracellular matrix hydrogel layer 102 is the porous thermogel layer 103.

[0064] Referring to FIGURES 2A-2F aspects of the extracellular matrix hydrogel layer are depicted. As shown in FIGURE 2A, a loadable extracellular matrix hydrogel features natural, biological components (derived from lung extracellular matrix), providing a lung- specific composition. FIGURE 2B shows a schematic of the biomolecules 201 attached to a core-shell polymeric particle 202 to provide an extracellular matrix particle 203. FIGURE 2C shows the particles 203 in the hydrogel-forming suspension. FIGURE 2D is the same view as FIGURE 2C with additional imaging to show the hydrogel matrix 204 surrounding the particles 203. FIGURE 2E shows the particles in the hydrogel matrix layer 102. Also shown is the porous thermogel layer 103. FIGURE 2F shows a cross-sectional view of the hydrogel matrix layer 102 applied to the lung surface 101.

[0065] A collagen-based gelation process allows for pleural adhesion and cell/particle access into the site of injury. The matrix hydrogel is able to be loaded with therapeutics (e.g., cells, exosomes, growth factors, drugs). It can be delivered directly onto the lung surface at the site of injury, bronchoscopically for endobronchial injuries, or through interventional radiology biopsy needles.

[0066] The tissue specific hydrogel comprises extracellular matrix components such that it may respond to the natural signaling and regulatory function from biophysical and biochemical cues. It may provide immunomodulatory effects from paracrine actions, episomal or microsomal particles. It may comprise antigen-presenting cells and allow for the transfer of mitochondria. Mesenchymal stem cells (MSCs) may facilitate tissue regeneration at the site of the leak.

[0067] FIGURE 3 shows various aspects of the thermogel layer. A porous thermogel is subsequently applied to contain the therapeutic cargo at the site of air leaks and seal the damaged lung. As shown schematically in FIGURE 3 A, the porous thermogel comprises a mixture of three (3) components: (i) gelatin 301, (/ ^' /) transglutaminase 302, and (Hi) extracellular matrix 303 components derived from lung, visceral pleura, and/or other connective tissues. Transglutaminase (TG) 302 crosslinks the gelatin particles desirably at a temperature at about human body temperature.

[0068] The porous thermogel patch features a porous structure that mimics native lung alveolar architecture. Its porosity is adjustable, and can be applied with a microfluidic bubble generator, as shown in FIGURE 3B. FIGURE 3C shows an enlarged view of the porous thermogel where the pores have an average diameter of 0.851 mm (std 0.2 mm). As shown in FIGURE 3D, it flexible and elastic to allow it to biomechanically compliant to lung contraction and expansion during respiration, with elastic and tensile strength that allows for uniform surface load and minimizes potential for tearing and tissue damage (a problem with conventional sealants). The three-part composition provides rapid bonding, and the kinetics may be adjusted for a gelation set point at body temperature. The thermogel exhibits no antigenicity, and may treated to be bacteriostatic.

[0069] The biosealant system described herein provides improved ability to effectively seal pulmonary air leaks and superior biomechanics over prior sealant products. It also provides tissue healing facilitated by the therapeutic agents incorporated into the hydrogel matrix layer. Other advantages include little or no systemic toxicity and minimal local irritation.

EXAMPLE 2

[0070] The therapeutic lung biosealant system can be applied as a prophylactic treatment during surgical lung resection or as a treatment for prolonged alveolar air leaks. For example, it may be applied to the external surface of the lung, e.g. on the visceral pleura, or through the airway for application to bronchial disruptions, e.g. bronchopleural fistulas.

Alternatively, it may be applied as surface strips to stapling devices that would incorporate the bio-sealant directly along the staple line.

[0071] Referring to FIGURE 4A, shown is a 16 gauge puncture wound 401 in lung tissue caused by a 16 gauge (1.65 mm diameter) needle outlined by the dashed line.

FIGURE 4B shows the wound repaired using the biosealant system described herein. EXAMPLE 3

[0072] FIGURE 5A shows a parenchymal injury (highlighted by arrow) in lung tissue and FIGURE 5B shows the air leak resulting from the injury. FIGURE 5C shows the wound repaired using the biosealant system (outlined by the dashed line) described herein.

[0073] The biosealant may also be used for ex-vivo lung repair, regeneration, bioengineering, and wound and burn healing.

[0074] Although described herein primarily for use in treating pulmonary air leaks, the biosealant system may be adapted for treatment of other organs by modification using cellular or extracellular components from other organs. For example, the biosealant with suitable modifications may be used for skin repair, treatment of alimentary tract leaks, and prophylactic sealing of other organs during surgical intervention.

[0075] While methods, systems and devices are described herein by way of examples and embodiments, those skilled in the art recognize that the methods, systems and devices for culturing tissue constructs are not limited to the embodiments or drawings described. It should be understood that the drawings and description are not intended to be limited to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the appended claims. Any headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims. As used herein, the word "may" is used in a permissive sense (i.e., meaning having the potential to) rather than the mandatory sense (i.e., meaning must). Similarly, the words

"include," "including," and "includes" mean including, but not limited to.

[0076] Having described and illustrated the principles of the disclosed subject matter with reference to the described embodiments, it will be recognized that the described embodiments can be modified in arrangement and detail without departing from such principles. It should be understood that the systems, devices, processes, or methods described herein are not related or limited to any particular type of environment, unless indicated otherwise.

[0077] In view of the many possible embodiments to which the principles of the disclosed subject matter can be applied, we claim as our disclosed subject matter all such embodiments as can come within the scope and spirit of the following claims and equivalents thereto.