FOR USE AS A TISSUE DRESSING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/934,886, filed on November 13, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention set forth in the appended claims relates generally to treatment of tissue, including without limitation to devices for delivering a flowable material to a tissue site, such as a wound, as well as systems, kits and methods for treating a tissue site.

BACKGROUND

[0003] A wide variety of materials and devices, generally characterized as “dressings,” are generally known in the art for use in treating an injury, defect, or other disruption of tissue. Such disruptions of tissue may be the result of trauma, surgery, or disease, and may affect skin or other tissues. In general, dressings may control bleeding, absorb exudate, ease pain, assist in debriding tissue, protect tissue from infection, or otherwise promote healing and protect tissue from further damage.

[0004] Some dressings may protect tissue from, or even assist in the treatment of, infections associated with wounds. Infections can retard wound healing and, if untreated, can result in tissue loss, systemic infections, septic shock and death.

[0005] Additionally, clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negative-pressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro-deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0006] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound or a cavity can be washed out with a liquid solution for therapeutic purposes. These practices are commonly referred to as "irrigation" and "lavage" respectively. "Instillation" is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative- pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

[0007] While the benefits of dressings are widely accepted, improvements to dressings may benefit healthcare providers and patients. Furthermore, while the clinical benefits of negative-pressure therapy and/or instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients.

BRIEF SUMMARY

[0008] New and useful devices, methods, and kits for treating a tissue site are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0009] For example, in some embodiments, a delivery device for delivering a flowable material for forming a tissue dressing material and a cover is provided. The delivery device includes the flowable material, for example, a photopolymer present in a carrier. The carrier is a low boiling point liquid, water, a compressed gas, or a combination thereof. The delivery device further includes a first delivery means and a second delivery means. The first delivery means has a first aperture defined therein having a first cross-sectional diameter. The second delivery means has a second aperture defined therein having a second cross-sectional diameter. The first cross-sectional diameter is greater than the second cross-sectional diameter. In some embodiments, the photopolymer can be polyurethane acrylate, polyurethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate or a combination thereof.

[0010] In some embodiments, the first cross-sectional diameter is about 1.5 mm to about 5 mm, and the second cross-sectional diameter is about 0.1 mm to about 1 mm.

[0011] In some embodiments, the delivery device can further include a photoinitiator.

[0012] In some embodiments, the delivery device can further include an ultraviolet (UV) light source, water, or a combination thereof for solidifying the flowable material.

[0013] In some embodiments, the flowable material can be present in a single container. The first delivery means and the second delivery means each can be detachably connected to the single container.

[0014] In some alternative embodiments, the flowable material can be present in a first container and a second container. The first delivery means can be detachably or integrally connected to the first container and the second delivery means can be detachably or integrally connected to the second container.

[0015] Alternatively, other example embodiments may include a kit including the delivery device described herein.

[0016] Alternatively, other example embodiments may include a therapy system including the delivery device described herein and a negative pressure source.

[0017] In some embodiments, the therapy system can further include an open cell foam manifold having a plurality of flow channels adjacent to a tissue site and a cover adjacent to the open cell foam manifold and the tissue site. The open cell foam manifold can be formed by solidifying the flowable material delivered as a first fiber via the first delivery means to a tissue site. The cover can be formed by solidifying the flowable material delivered as a second fiber via the second delivery means to the tissue site.

[0018] In some embodiments, the delivery device can be physically separate from the negative-pressure source or the delivery device can be in fluid communication with the negative- pressure source.

[0019] Alternatively, other example embodiments may include a method for treating a tissue site. The method includes delivering a flowable material as a first fiber having a first cross-sectional diameter via a first delivery means from a delivery device to a tissue site. The method further includes delivering the flowable material as a second fiber having a second cross-sectional diameter via a second delivery means from the delivery device to the tissue site. The first cross-sectional diameter can be greater than the second cross-sectional diameter. The method further includes solidifying the first fiber to form an open cell foam manifold having a plurality of flow channels in fluid communication with the tissue site and/or solidifying the second fiber to form a cover adjacent to the open cell foam manifold and the tissue site. The delivery device can include the flowable material, for example, a photopolymer, present in a carrier. The carrier is a low boiling point liquid, water, a compressed gas, or a combination thereof.

[0020] In some embodiments, the first cross-sectional diameter is about 1.5 mm to about 5 mm, and the second cross-sectional diameter is about 0.1 mm to about 1 mm.

[0021] In some embodiments, the delivery device can further include a photoinitiator.

[0022] In some embodiments, the delivery device can further include an ultraviolet (UV) light source, water, or a combination thereof for solidifying the flowable material.

[0023] In some embodiments, the method can further include applying a negative-pressure to the tissue site through the plurality of flow channels via a manifold delivery tube.

[0024] In some embodiments, solidifying the first fiber and/or the second fibers includes contacting the first fiber and/or the second fiber with water. [0025] In some embodiments, the first fiber is formed by exposing the flowable material delivered via the first delivery means to a UV light source and/or the second fiber is formed by exposing the flowable material delivered via the second delivery means to the UV light source.

[0026] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A is a cross-sectional view, illustrating details that may be associated with some embodiments of a delivery device;

[0028] Figure IB is a cross-sectional view, illustrating details that may be associated with some embodiments of a first delivery means and a second deliver means of the delivery device of Figure i;

[0029] Figure 1C is a cross-sectional view, illustrating details that may be associated with some alternative embodiments of a delivery device having a first container and a second container;

[0030] Figures 1D-1H are cross-sectional views of alternative cross-sectional diameter shapes of a first delivery means;

[0031] Figure II is a cross-sectional view, illustrating details that may be associated with some alternative embodiments of a delivery device having an ultraviolet (UV) light source.

[0032] Figure 1 J is a cross-sectional view, illustrating details that may be associated with some alternative embodiments of a delivery device.

[0033] Figure 2 is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0034] Figure 3 is a graph illustrating additional details of example pressure control modes that may be associated with some embodiments of the therapy system of Figure 2;

[0035] Figure 4 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system of Figure 2;

[0036] Figure 5 is a chart illustrating details that may be associated with an example method of operating the therapy system of Figure 2;

[0037] Figure 6 is a front view, illustrating details of a therapy system that can provide negative-pressure treatment in accordance with this specification;

[0038] Figure 6 is a front view, illustrating details that may be associated with some alternative embodiments of a therapy system that can provide negative-pressure treatment in accordance with this specification;

[0039] Figure 7A is a reaction scheme that may be associated with some embodiments of solidifying a flowable material delivered to a tissue site to treat the tissue site; [0040] Figure 7B is another reaction scheme that may be associated with some embodiments of solidifying a flowable material delivered to a tissue site to treat the tissue site.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0041] The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but it may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0042] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

I. Devices and Kits for Delivering a Flowable Material to Form a Tissue Dressing and a Cover

[0043] Devices for delivering a flowable material for treating a tissue site, for example, for closing and/or fdling an opening on a tissue site, such as a wound, and covering the opening are described herein. As used herein, the term “flowable” refers to an ability of a substance to be transported by gravity or under pressure from a storage vessel to a tissue site. Examples of a “flowable” substance include, but are not limited to a liquid, a gel, a slurry, a suspension, an aerosol, and any combination thereof. As used herein, the term “tissue site” broadly refers to a wound or a defect located on or within tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. The devices described herein can deliver a flowable material, which can readily conform to the size and shape of the tissue site. Thus, the devices, methods and kits described herein can form tissue dressings in various configurations.

[0044] Figure 1A illustrates details that may be associated with some embodiments of a delivery device 100 for delivering a flowable material. In some embodiments, the delivery device 100 may be a single container 105 including a photopolymer present in a carrier. As used herein, a “photopolymer” refers to a polymer that can be solidified, for example, crosslinked by exposure to radiation, often using radiation in the ultraviolet (UV) region of the spectrum, or other types of radiation. Examples of a suitable photopolymer include, but are not limited to a polyurethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate and combinations and/or copolymers thereof. The photopolymer may be dissolved or dispersed in a suitable carrier, such as, but not limited to a low boiling point liquid, water, a compressed gas, and combinations thereof. The reacted polymer and carrier may be in the form of a dispersion, solution or emulsion. Examples of a low boiling point liquid include, but are not limited to a fluorocarbon, a chlorofluorocarbon, a hydrofluorocarbon (e.g., tetrafluoropropene, Solkane®) a hydrochlorofluorocarbon, and combinations thereof. Examples of a compressed gas include but are not limited to compressed carbon dioxide, compressed nitrogen, a compressed alkane (e.g., methane, ethane, propane, and the like), and combinations thereof.

[0045] The delivery device 100 further includes a first delivery means 185 having a first aperture 110 and a second delivery means 187 having a second aperture 120. The first delivery means 185 and the second delivery means 187 may be in fluid communication with an optional delivery tube 170 for delivering the flowable material to a tissue site. An example of a suitable delivery means 185, 187 includes, but is not limited to a nozzle, such as a spray nozzle. At least one extension tube (not shown) may also be included, which can be in fluid communication with the first delivery means 185 and/or the second delivery means 187 for providing more precise delivery of the flowable material.

[0046] As illustrated in Figure IB, the first aperture 110 has a first cross-sectional diameter (di) such that the flowable material may be delivered as a first fiber having a cross-sectional diameter corresponding to the first cross-sectional diameter (di). The second aperture 120 has a second cross- sectional diameter (d2) such that the flowable material may also be delivered as a second fiber having a cross-sectional diameter corresponding to the second cross-sectional diameter (d2). In any embodiment, the first cross-sectional diameter can be greater than the second cross-sectional diameter (di > d2). In such instances, a first fiber and a second fiber may be delivered from the delivery device 100, where the first fiber is larger or has a greater thickness than the second fiber. The first fiber may be delivered to a tissue site to fill a wound space as a tissue dressing material and the second fiber may be delivered to the site to form a cover over the tissue dressing material. Thus, the delivery device 100 is advantageously capable of delivering both the tissue dressing material and the cover. In some embodiments, only the first delivery means 185 may be present for delivering only the first fiber to a tissue site or only the second delivery means 187 may be present for delivering only the second fiber to a tissue site. In any embodiment, the first cross-sectional diameter may be greater than or equal to about 1 mm, greater than or equal to about 1.5 mm, greater than or equal to about 2 mm, greater than or equal to about 2.5 mm, greater than or equal to about 3 mm, greater than or equal to about 3.5 mm, greater than or equal to about 4 mm, greater than or equal to about 4.5 mm, greater than or equal to about 5 mm, greater than or equal to about 5.5 mm, or about 6 mm; or from about 1 mm to about 6 mm, about 1.5 mm to about 5 mm, about 1.5 mm to about 4 mm, or about 2 mm to about 3 mm. In any embodiment, the second cross-sectional diameter may be greater than or equal to about 0.1 mm, greater than or equal to about 0.25 mm, greater than or equal to about 0.5 mm, greater than or equal to about 0.75 mm, greater than or equal to about 1 mm, greater than or equal to about 1.25 mm, greater than or equal to about 1.5 mm, or about 2.0 mm; or from about 0.1 mm to about 2 mm, about 0.1 mm to about 1 mm, or about 0.1 mm to about 0.5 mm.

[0047] As illustrated in Figure 1 A, the first delivery means 185 and the second delivery means 187 may be detachably connected to single container 105. In other words, a user may attach first delivery means 185 to single container 105 to deliver flowable material to a tissue site, for example, to form a tissue dressing material which can fill a wound space. Then, the user may detach the first delivery means 185 and attach the second delivery means 186 to single container 105 to deliver flowable material to the tissue, for example, to form a cover over the tissue dressing material. Alternatively, as illustrated in Figure 1C, a delivery device 101 can include a first container 130 comprising flowable material as described herein with a first delivery means 185 detachably or integrally connected with the first container 130. The delivery device 101 also includes a second container 140 comprising flowable material as described herein with a second delivery means 187 detachably or integrally connected with the second container 130. Although not shown, it is also contemplated herein that the first delivery means 185 and the second delivery means 187 may be present in a single delivery means, for example, a rotatable single nozzle having a first aperture 110 and second aperture 120 defined therein. A user can rotate the rotatable single nozzle to engage and use the first aperture 110 to deliver flowable material, and the user can further rotate the rotatable single nozzle to engage and use the second aperture 120 to deliver flowable material. Optionally, the first delivery means 185 and/or the second delivery means 187 each may further include a throttle function, such as a needle valve (not shown), which can control the flow of flowable material and the diameter of the first and/or second fiber.

[0048] The first aperture 110 and the second aperture 120 each may have any suitable cross- sectional shape. For example, as illustrated in Figures 1D-1H, suitable cross-sectional shapes for the first aperture 110 and/or the second aperture 120 include, but are not limited to a substantially round cross-section (Figure ID, aperture 110), a substantially rectangular cross-section (Figure IE, aperture 110a), a polygon cross-section (Figure IF, aperture 110b), a star cross-section (Figure 1G, aperture 110c), a multi-lobed cross-section (Figure 1H, aperture l lOd). As understood herein, “substantially round” may include circular and oval cross-sections and the dimensions of the cross-section may deviate in some aspects. As understood herein, “substantially rectangular” may include square cross-sections and the dimensions of the cross-section may deviate in some aspects. As understood herein, “polygon” may include triangular, pentagonal, hexagonal, octagonal, and so on cross-sections and the dimensions of the cross-section may deviate in some aspects. As understood herein, “star” may include from five points to twelve points, for example, a five-pointed start, a six-pointed star, a seven-pointed star and so on. As used herein, the term “multi-lobe” refers to a cross-sectional shape having a point (not necessarily in the center of the cross-section) from which at least two lobes extend (not necessarily evenly spaced or evenly sized), for example a bi-lobe, tri-lobe, and so on. The first fiber and/or a second fiber formed from the flowable material can thereby have a shape corresponding to the cross-sectional shape of the first aperture 110 and/or the second aperture 120 from which they are delivered. While the cross-sectional shapes illustrated in Figures 1D-1H can form a substantially solid first fiber and/or a substantially solid second fiber, it is contemplated herein that the cross-sectional shape of the first aperture 110 and/or the second aperture 120 may form a hollow first fiber and/or a hollow second fiber, for example, a tube-shaped first fiber and/or a tube-shaped second fiber.

[0049] Optionally, as illustrated in Figure II, an UV light source 165 may be included with the delivery device 102, for example, for at least partially solidifying a flowable material. It is contemplated herein, that the UV light source 165 may solidify flowable material substantially concurrently with the flowable material’s exit (or delivery) from: the first delivery means 185 to form the first fiber; the second delivery means 187 to form the second fiber, or both. This use of the UV light source 165 to solidify flowable material to form the first fiber and/or the second fiber can be considered a first solidification step, also referred to as a rapid solidification step. While Figure II illustrates a UV light source 165 as integral to the delivery device 102, for example, present on a surface of the first delivery means 185, it is contemplated herein that the UV light source 165 may be removable from the device 101 and/or may be separate from the delivery device 102. Additionally or alternatively, the UV light source 165 may also be present on a surface of the second delivery means 187. It is also contemplated herein that the UV light source 165 can be present on an interior surface of the first delivery means 185 and/or the second delivery means 187. Although not shown, the UV light source 165 can be present in any of the device embodiments described herein. In some embodiments, it is also contemplated herein that the UV light source 165 may also be connected to an interior surface of an extension tube described above, for example, along an inner bore of the extension tube, to provide further solidification of the flowable material.

[0050] Additionally or alternatively, the delivery devices described herein can further include water, which can be used to further solidify the flowable material (e.g., first fiber, second fiber) once applied to a tissue site. This addition of water can be considered a second solidification step. The water can be present in a separate container or syringe to add to the flowable material.

[0051] Optionally, as illustrated in Figure 1 J, a canister 160 may be in fluid communication with a single container 105 of a delivery device 103. The canister 160 can contain a propellant, as further described below, for further enabling delivery of a flowable material from the delivery device 103. For example, the propellant may expand to force the flowable material out of the device 103, for example, through aperture 110 and/or aperture 120 (not shown) as an aerosol. Although not shown, it is contemplated herein that canister 160 can be present in any of the device embodiments described herein. Additionally, the canister 160 may be removable or irremovable. Optionally, a mixer 190 for mixing the flowable material may be included in the device, for example, as illustrated in Figure 1A in the delivery device 100. Examples of a suitable mixer 190 include but are not limited to a ball (e.g., metal, glass, or plastic ball), a mechanical reciprocating plunger, magnetically coupled impeller or beads, for example, where an external magnetic source rotates the impellor or agitates the beads. Although not shown, it is contemplated herein that the mixer 190 can be present in any of the device embodiments described herein.

[0052] The flowable material is capable of solidifying, for example, via the first solidification step and/or the second solidification step, to form a foam when applied to a tissue site. The foam formed may be an open cell foam or a closed cell foam. In any embodiment, the foam may have a higher molecular weight (M _n ), for example, greater than or equal to about 100,000, greater than or equal to about 500,000 or about 1,000,000; or from about 100,000 to about 1,000,000, about 250,000 to about 1,000,000 or about 500,000 to about 1,000,000. Additionally or alternatively, the foam may have a moisture vapor transmission rate (MVTR) of about 250 g/m ² /24 hours to about 1500 g/m ² /24 hours, or about 500 g/m ² /24 hours to about 1500 g/m ² /24 hours, or about 1000 g/m ² /24 hours to about 1500 g/m ² /24 hours. For example, in some embodiments, upon delivery via the first delivery means 185, the flowable material may form a first fiber having a first cross-sectional diameter as described herein. The first fiber may be formed of foam as described above and be applied to a tissue site as a tissue dressing material, for example, to fill a wound space. In some embodiments, an open cell foam tissue dressing material may be delivered via the first delivery means 185. Additionally or alternatively, upon delivery via the second delivery means 187, the flowable material may form a second fiber having a second cross-sectional diameter as described herein. The second fiber may be formed of foam as described above and be applied to a tissue site as a cover, for example, as a thin film, for a tissue dressing.

[0053] In any embodiment, the delivery devices described herein may be made of any suitable material, such as, but not limited to metal, plastic, or a combination thereof. Suitable metals include, but are not limited to aluminum and coated steels. Suitable plastics include, but are not limited to polycarbonates, polyesters, and polyolefins. In any embodiment, an interior of the devices described herein is sterile and the contents of the device may be sterile. Sterilization can be achieved by any known methods in the art, for example, via gamma sterilization or electron beam (e-beam) sterilization. In the case of e-beam sterilization, the devices described herein may include a window, for example, a plastic window, to permit transmission of the e-beam.

[0054] The delivery devices described herein can include one or more additional agents for incorporation into a flowable material and/or for use in the formation of a flowable material. In any embodiment, a cell opener can be included in the delivery devices described herein to promote opening or rupturing of cell walls and to enhance an open cell structure as a polymer foam is produced. Examples of a suitable cell opener include, but are not limited to a silicone, a polyether siloxane, a mineral (e.g., clays, silicas, calcium carbonate and the like), and combinations thereof.

[0055] Additionally or alternatively, the delivery devices described herein can further include a foaming agent, a propellant, or a combination thereof to assist with foam formation and delivery. As used herein, a foaming agent includes any suitable surfactants and blowing agents as known in the art for producing a flowable material, e.g., a polymer foam. Examples of suitable foaming agents include, but are not limited to a low boiling point liquid, water, a compressed gas, hydrocarbons (e.g. pentane, isopentane, cyclopentane), liquid carbon dioxide, and combinations thereof. Examples of a low boiling point liquid include, but are not limited to a fluorocarbon, a chlorofluorocarbon, a hydrofluorocarbon (e.g., tetrafluoropropene, Solkane®) a hydrochlorofluorocarbon, and combinations thereof. Examples of a compressed gas include but are not limited to compressed carbon dioxide, compressed nitrogen, a compressed alkane (e.g., methane, ethane, propane, and the like), and combinations thereof. Examples of a suitable propellant include, but are not limited to low boiling point liquids as described herein. The propellant may be present within the devices described herein, for example, in the single container 105. Alternatively, with reference to Figure 1 J, the propellant may be present in a separate canister 160 in fluid communication with the devices described herein. In addition to aiding in delivery of a flowable material, the propellant may also aid in mixing of the photopolymer.

[0056] Additionally or alternatively, the delivery devices described herein and/or the flowable material can further include a softener, such as water soluble particles, to encourage a certain degree of porosity at the tissue site interface, which upon contact with water present in the wound can soften and/or dissolve to leave pores or fissures in foam. Examples of suitable water soluble particles include, but are not limited to a salt, a water soluble polymer, and combinations thereof. Examples of a salt include, but are not limited to sodium chloride, magnesium chloride, calcium chloride, sodium carbonate, potassium carbonate, and combinations thereof. Examples of water soluble polymers include, but are not limited to polyvinylpyrrolidone (PVP), a polyvinyl alcohol, polyethylene oxide (PEO), carboxy modified polyurethane, hydroxy modified polyurethane, and combinations thereof.

[0057] Additionally or alternatively, the devices described herein and/or the flowable material can further include an antimicrobial agent. Examples of suitable antimicrobial agents include, but are not limited to organic acids such as carboxylic acids, silver, gold, zinc, copper, polyhexamethylene biguanide (PHMB), iodine and combinations thereof. Exemplary carboxylic acids include, but are not limited to ascorbic acid (e.g., (R)-3,4-dihydroxy-5-((S)- l,2-dihydroxyethyl)furan-2(5H)-one or Vitamin C), formic acid, gluconic acid, lactic acid, oxalic acid, tartaric acid, peroxy-pyruvic acid, and combinations thereof. Examples of carboxylic acids include, but are not limited to citric acid and acetic acid (i.e., ethanoic acid). The metal (e.g., silver) may be present in metallic form, in ionic form (e.g., a silver salt), or both.

[0058] Additionally or alternatively, the delivery devices described herein and/or the flowable material can further include a polysaccharide, such as chitosan and/or an anionic polysaccharide. The anionic polysaccharide may be substantially insoluble in water at pH 7. Additionally or alternatively, the anionic polysaccharide may have a molecular weight greater than about 20,000, more preferably greater than about 50,000. The anionic polysaccharide may be in the form of a fdm, or fibers having a length greater than 1 mm. Suitable anionic polysaccharides include, but are not limited to, polycarboxylates, alginates, hyaluronates, pectins, carrageenans, xanthan gums, sulfated dextrans, cellulose derivatives, such as carboxymethyl celluloses, and oxidized celluloses. The term “oxidized cellulose” refers to any material produced by the oxidation of cellulose, for example with dinitrogen tetroxide. Such oxidation converts primary alcohol groups on the saccharide residues to carboxylic acid groups, forming uronic acid residues within the cellulose chain. The oxidation generally does not proceed with complete selectivity, and as a result hydroxyl groups on carbons 2 and 3 are occasionally converted to the keto form. These keto units introduce an alkali-labile link, which at pH 7 or higher initiates the decomposition of the polymer via formation of a lactone and sugar ring cleavage. In some embodiments, oxidized cellulose may be oxidized regenerated cellulose (ORC), which may be prepared by oxidation of a regenerated cellulose, such as rayon. It has been known that ORC has haemostatic properties. ORC has been available as a haemostatic fabric called SURGICEL ^® (Johnson & Johnson Medical, Inc.) since 1950. This product may be produced by the oxidation of a knitted rayon material.

[0059] Additionally or alternatively, the delivery devices described herein and/or the flowable material can further include an alcohol, a colorant (e.g., a pigment, a dye), a release agent (e.g., wax, fluorocarbon), and a combination thereof. For example, an alcohol can be included as a further solvent and/or suspending agent along with the reacted polymer. Examples of a suitable alcohol include, but are not limited to ethanol, isopropyl alcohol, and a combination thereof.

[0060] Additionally or alternatively, the devices described herein and/or the material can further include a photoinitiator that is capable of undergoing photopolymerization or radiation curing, i.e., producing a free radical when exposed to radiation, e.g., UV light, which can react, for example, with the first reactant and/or the second reactant, to initiate polymer chain growth. Examples of a suitable photoinitiator include, but are not limited to, 2,2-dimethoxy-l,2,-diphenylethan-l-one,l- hydroxy-cyclohexyl-phenyl-ketone (IRGACURE® 184); l-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy- 2-methyl-l -propane- 1 -one (IRGACURE® 2959); and 2-benzyl-2-(dimethylamino)-l-[4- (4- morpholinyl) phenyl] -1-butanone (IRGACURE® 369),

[0061] Additionally or alternatively, the delivery devices described herein and/or the flowable material can further include one or more super absorbent polymers, for example in particle form. Examples of suitable super absorbent polymers include, but are not limited to polyacrylic acid, a salt of polyacrylic acid (e.g, sodium polyacrylate (Luquasorb® 1160, Luquasorb® 1161; BASF)), polyacrylamide, cellulosic polymer, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), polyethylene oxide (PEO), and a combination thereof.

[0062] Kits including the delivery devices described herein are also provided. The kits may further include a separate cover, for example, if the flowable material in the delivery device is not used to form a cover. In some embodiments, the separate cover may provide a bacterial barrier and protection from physical trauma. The separate cover may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The separate cover may be, for example, an elastomeric film or membrane. The separate cover may have a high moisture-vapor transmission rate in some applications. For example, the MVTR may be at least 300 g/m ² per twenty- four hours in some embodiments. In some example embodiments, the separate cover may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of about 25 microns to about 50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained.

II. Therapy Systems and Methods for Administering Negative-Pressure Therapy

[0063] Figure 2 is a simplified functional block diagram of an example embodiment of a therapy system 10 that can provide negative-pressure therapy, optionally with instillation of topical treatment solutions to a tissue site in accordance with this specification.

[0064] The therapy system 10 may include a source or supply of negative pressure, such as a negative-pressure source 18, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 5, and a fluid container, such as a container 11, are examples of distribution components that may be associated with some examples of the therapy system 10. As illustrated in the example of Figure 2, the dressing 5 may comprise or consist essentially of a tissue interface 7, a cover 9, or both in some embodiments.

[0065] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface may facilitate coupling a fluid conductor to the dressing 5. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0066] The therapy system 10 may also include a regulator or controller, such as a controller 13. Additionally, the therapy system 10 may include sensors to measure operating parameters and provide feedback signals to the controller 13 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 10 may include a first sensor 12 and a second sensor 14 coupled to the controller 13.

[0067] The therapy system 10 may also include a source of instillation solution. For example, a solution source 16 may be fluidly coupled to the dressing 5, as illustrated in the example embodiment of Figure 2. The solution source 16 may be fluidly coupled to a positive-pressure source, such as a positive-pressure source 15, a negative-pressure source such as the negative-pressure source 18, or both in some embodiments. A regulator, such as an instillation regulator 17, may also be fluidly coupled to the solution source 16 and the dressing 5 to ensure proper dosage of instillation solution (e.g. saline) to a tissue site . For example, the instillation regulator 17 may comprise a piston that can be pneumatically actuated by the negative-pressure source 18 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval. Additionally or alternatively, the controller 13 may be coupled to the negative-pressure source 18, the positive-pressure source 15, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 17 may also be fluidly coupled to the negative -pressure source 18 through the dressing 5, as illustrated in the example of Figure 2.

[0068] Some components of the therapy system 10 may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy. For example, in some embodiments, the negative-pressure source 18 may be combined with the controller 13, the solution source 16, and other components into a therapy unit.

[0069] In general, components of the therapy system 10 may be coupled directly or indirectly. For example, the negative-pressure source 18 may be directly coupled to the container 11 and may be indirectly coupled to the dressing 5 through the container 11. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. For example, the negative-pressure source 18 may be electrically coupled to the controller 13 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0070] A negative-pressure supply, such as the negative-pressure source 18, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump, for example. “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. References to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative -pressure source 18 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between - 50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0071] The container 11 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.

[0072] A controller, such as the controller 13, may be a microprocessor or computer programmed to operate one or more components of the therapy system 10, such as the negative -pressure source 18. In some embodiments, for example, the controller 13 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 10. Operating parameters may include the power applied to the negative-pressure source 18, the pressure generated by the negative-pressure source 18, or the pressure distributed to the tissue interface 7, for example. The controller 13 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

[0073] Sensors, such as the first sensor 12 and the second sensor 14, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, the first sensor 12 and the second sensor 14 may be configured to measure one or more operating parameters of the therapy system 10. In some embodiments, the first sensor 12 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 12 may be a piezo-resistive strain gauge. The second sensor 14 may optionally measure operating parameters of the negative-pressure source 18, such as a voltage or current, in some embodiments. Preferably, the signals from the first sensor 12 and the second sensor 14 are suitable as an input signal to the controller 13, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 13. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0074] The tissue interface 7 can be generally adapted to partially or fully contact a tissue site. The tissue interface 7 may take many forms, and may have many sizes, shapes, or thicknesses, depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of the tissue interface 7 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 7 may have an uneven, coarse, or jagged profile.

[0075] In some embodiments, the tissue interface 7 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 7 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 7, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.

[0076] In some illustrative embodiments, a manifold may comprise a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

[0077] In some embodiments, the tissue interface 7 may comprise or consist essentially of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and foam having an average pore size in a range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the tissue interface 7 may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the tissue interface 7 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the tissue interface 120 may be at least 10 pounds per square inch. The tissue interface 7 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the tissue interface may be foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the tissue interface 7 may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0078] The thickness of the tissue interface 7 may also vary according to needs of a prescribed therapy. For example, the thickness of the tissue interface may be decreased to reduce tension on peripheral tissue. The thickness of the tissue interface 7 can also affect the conformability of the tissue interface 7. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0079] The tissue interface 7 may be either hydrophobic or hydrophilic. In an example in which the tissue interface 7 may be hydrophilic, the tissue interface 7 may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 7 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open- cell foam such as V.A.C. WHITEFOAM™ dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0080] In some embodiments, the tissue interface 7 may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include, without limitation, polycarbonates, polyfumarates, and capralactones. The tissue interface 7 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 7 to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

[0081] In some embodiments, the tissue interface 7 may be formed from a tissue dressing material as described herein and delivered from the first delivery means 185 as described above.

[0082] In some embodiments, the cover 9 may provide a bacterial barrier and protection from physical trauma. The cover 9 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 9 may comprise or consist of, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 9 may have a high MVTR in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty- four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties.

[0083] In some example embodiments, the cover 9 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 9 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene vinyl acetate (EVA); co-polyester; and polyether block polyamide copolymers. Such materials are commercially available as, for example, Tegaderm® drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane fdms, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 9 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m ² /24 hours and a thickness of about 30 microns. In various aspects, the cover 9 may be formed of the flowable material as described above and delivered via the second delivery means 187 as described above.

[0084] An attachment device may be used to attach the cover 9 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive configured to bond the cover 9 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 9 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel. In some embodiments, the cover 9 may not include an adhesive and the flowable material as described herein may provide a seal or adhesion to a tissue site.

[0085] The solution source 16 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0086] In operation, the tissue interface 7 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 7 may partially or completely fill the wound, or it may be placed over the wound. The cover 9 may be placed over the tissue interface 7 and sealed to an attachment surface near a tissue site. For example, the cover 9 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 5 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 18 can reduce pressure in the sealed therapeutic environment.

[0087] The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example. [0088] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies something relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.

[0089] Negative pressure applied across the tissue site through the tissue interface 7 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in container 11

[0090] In some embodiments, the controller 13 may receive and process data from one or more sensors, such as the first sensor 12. The controller 13 may also control the operation of one or more components of the therapy system 10 to manage the pressure delivered to the tissue interface 7. In some embodiments, controller 13 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 7. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 13. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 13 can operate the negative-pressure source 18 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 7.

[0091] Figure 3 is a graph illustrating additional details of an example control mode that may be associated with some embodiments of the controller 13. In some embodiments, the controller 13 may have a continuous pressure mode, in which the negative-pressure source 18 is operated to provide a constant target negative pressure, as indicated by line 205 and line 208, for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode, as illustrated in the example of Figure 3. In Figure 3, the x-axis represents time and the y-axis represents negative pressure generated by the negative-pressure source 18 over time. In the example of Figure 3, the controller 13 can operate the negative-pressure source 18 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg, as indicated by line 205, for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation, as indicated by the gap between the solid lines 215 and 218. The cycle can be repeated by activating the negative-pressure source 18, as indicated by line 218, which can form a square wave pattern between the target pressure and atmospheric pressure.

[0092] In some example embodiments, the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous. For example, the negative-pressure source 18 and the dressing 5 may have an initial rise time, as indicated by the dashed line 225. The initial rise time may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in a range of about 20-30 mmHg/second and in a range of about 5-10 mmHg/second for another therapy system. If the therapy system 10 is operating in an intermittent mode, the repeating rise time, as indicated by the solid line 218, may be a value substantially equal to the initial rise time as indicated by the dashed line 225.

[0093] Figure 4 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system 10. In Figure 4, the x-axis represents time and the y-axis represents negative pressure generated by the negative-pressure source 18. The target pressure in the example of Figure 4 can vary with time in a dynamic pressure mode. For example, the target pressure may vary in the form of a triangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise time 308 set at a rate of +25 mmHg/min. and a descent time 310 set at -25 mmHg/min. In other embodiments of the therapy system 10, the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a rise time 308 set at a rate of +30 mmHg/min and a descent time 310 set at -30 mmHg/min.

[0094] In some embodiments, the controller 13 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure. The variable target pressure may also be processed and controlled by the controller 13, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform. In some embodiments, the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.

[0095] Figure 5 is a chart illustrating details that may be associated with an example method 400 of operating the therapy system 10 to provide negative-pressure treatment and instillation treatment to the tissue interface 7. In some embodiments, the controller 13 may receive and process data, such as data related to instillation solution provided to the tissue interface 7. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes. The controller 13 may also control the operation of one or more components of the therapy system 10 to instill solution, as indicated at 405. For example, the controller 13 may manage fluid distributed from the solution source 16 to the tissue interface 7. In some embodiments, fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 18 to reduce the pressure at the tissue site, drawing solution into the tissue interface 7, as indicated at 410. In some embodiments, solution may be instilled to a tissue site by applying a positive pressure from the positive-pressure source 15 to move solution from the solution source 16 to the tissue interface 7, as indicated at 415. Additionally or alternatively, the solution source 16 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 7, as indicated at 420.

[0096] The controller 13 may also control the fluid dynamics of instillation at 425 by providing a continuous flow of solution at 430 or an intermittent flow of solution at 435. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution at 440. The application of negative pressure may be implemented to provide a continuous pressure mode of operation at 445 to achieve a continuous flow rate of instillation solution through the tissue interface 7, or it may be implemented to provide a dynamic pressure mode of operation at 450 to vary the flow rate of instillation solution through the tissue interface 7. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation at 455 to allow instillation solution to dwell at the tissue interface 7. In an intermittent mode, a specific fill volume and dwell time may be provided depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative-pressure treatment may be applied at 460. The controller 13 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle at 465 by instilling more solution at 405.

[0097] In various aspects, the therapy system 10 may include a delivery device as described herein, which can deliver a flowable material, which can readily conform to the size and shape of the tissue site to form the tissue interface 7 and the cover 9. For example, as illustrated in Figure 6, a delivery device as described herein (e.g. , delivery device 100) can deliver flowable material as described herein as a first fiber to a tissue site 50, for example, into a void space, such as a wound space. The first fiber may undergo further solidification to form tissue dressing material 85, for example, an open cell foam manifold having a plurality of flow channels adj acent to the tissue site 50. The delivery device can also deliver flowable material as described herein as a second fiber to the tissue site 50, for example, adjacent to the tissue dressing material 85 and the tissue site 50. The second fiber may undergo further solidification to form cover 9, for example, a thin polymer film. In some embodiments, the tissue site 50 can include an internal site (e.g., void space) and the flowable tissue dressing material may be delivered percutaneously.

[0098] As further illustrated in Figure 6, the therapy system can include a negative-pressure source 18 in fluid communication with cover 9 and the tissue dressing material 85 and a negative- pressure may be applied to the tissue site 50 through the plurality of flow channels (not shown) of the tissue dressing material 85. For example, negative-pressure may be delivered via a manifold delivery tube 70. In some embodiments, the manifold delivery tube 70 may be integral with a connector pad 75. In some embodiments, the connector pad 75 may include a pressure valve (e.g., positive pressure valve) (not shown) for releasing gas formed during solidification of the flowable tissue dressing material. The negative-pressure source 18 for applying the negative-pressure can be in fluid communication with the manifold delivery tube 70, the connector pad 75, the cover 9, or a combination thereof, for example via fluid conductor 80 for applying the negative-pressure. In some embodiments, the connector pad 75 may include a water soluble component, such as a baffle, which can degrade or break down after the foam has been formed. For example, instillation fluid can cause at least a portion of the connector pad 75 to degrade or breakdown in order to prevent foam from entering fluid conductor 80. Examples of suitable material for the water soluble component of the connector pad 75 include, but are not limited to a sugar, polyvinylpyrrolidone (PVP), a polyvinyl alcohol, polyethylene oxide (PEO), and cellulose. As illustrated in Figure 6, the delivery device 100 is not in fluid communication with the negative- pressure source 18, i.e., the delivery device 100 is physically separate from the negative-pressure source 18. Although not shown, it is contemplated herein, that the delivery device 100 can be in fluid communication with the negative-pressure source 18, for example, via one or more flowable material fluid conductors. In such instances, it is contemplated herein, that the flowable material may be delivered to tissue site 50 via the one or more flowable material fluid conductors and delivery of the flowable material may be automatic. For example, the therapy system may further comprise a delivery actuator or a pump (e.g. , peristaltic pump) in fluid communication with the negative-pressure source 18 and the tissue site 50 for delivering the flowable material. The delivery actuator or pump can actuate a pressurized container to deliver the flowable material to the tissue site 50, for example. The therapy system may measure the pressure at the tissue site 50 while the flowable material is being delivered, for example, via a controller 13, in order to calculate when the wound is full. For example, as the air in a wound is displaced it can enter the fluid conductor 80, in effect pressuring the container 11, and this wound fill pressure can be logged in the system. Once this wound fill pressure has reached a plateau, the wound can be deemed to be full and delivery of the flowable material can be ceased, for example, via a first delivery means 185. The rate of change of wound fill pressure can be relatively constant while filling the wound but can sharply increase once the wound is full. Then, delivery of flowable material via a second delivery means 187 can commence to form the cover 9. In addition to controlling the delivery of the flowable material, the controller 13 may also control the means (e.g. , the transmission of UV light) for solidifying the flowable material.

[0099] Methods for treating a tissue site, for example, administering negative-pressure therapy to a tissue site, for example, via the therapy system 10 are also provided herein. The method may include delivering a flowable material from a delivery device as described herein. For example, flowable material may be delivered as described herein via a first delivery means 185 as described herein from a delivery device as described herein to a tissue site 50, for example, into a wound space as tissue dressing material 85 (also referred to as a wound filler material). When utilizing the first delivery means 185, the flowable material may be delivered as a first fiber as described herein having a first cross-sectional diameter as described herein. The method further includes delivering flowable material via a second delivery means 187 as described from a delivery device as described herein to a tissue site 50, for example, adjacent to the first fiber, to form a cover 9. When utilizing the second delivery means 187, the flowable material may be delivered as a second fiber as described herein having a second cross-sectional diameter as described herein. In any embodiment, the first cross-sectional diameter is greater than the second cross-sectional diameter. In some aspects, the first fiber may be delivered at a lower pressure, for example, less than about 2 bar, and the second fiber may be delivered at a higher pressure, for example, greater than or equal to about 2 bar to less than or equal to about 5 bar.

[00100] As described above, the flowable material comprises a photopolymer present in a carrier as described herein. Thus, a UV light source 165 as described above, may solidify flowable material substantially concurrently with the flowable material’s exit (or delivery) from: the first delivery means 185 to form the first fiber; the second delivery means 187 to form the second fiber; or both. It is also contemplated herein that the first fiber, the second fiber, or both optionally may be further exposed to UV light at the tissue site 50 to achieve additional solidification. As described above, this use of the UV light source 165 to solidify flowable material to form the first fiber and/or the second fiber can be considered a first solidification step, also referred to as a rapid solidification step. An example illustrating this first solidification step is shown in Figure 7A wherein the photopolymer is a polyurethane acrylate. As shown in Figure 7A, acrylate group(s) present in the polyurethane acrylate polymerize when exposed to UV light and optionally, a photoinitiator, thereby solidifying the flowable material into the first fiber, the second fiber, or both. Advantageously, a first fiber delivered to the tissue site can fill and/or cover a wound space and form a tissue dressing material 85 as a loosely packed scaffolding having a porosity defined therein. The porosity may be defined as having a free volume of about 50% to about 98%. Following delivering of the first fiber, the second fiber may be delivered to the tissue site, and form a cover 9, for example, as a thin film, adjacent to the first fiber and the tissue site (e.g., skin surrounding a wound). The cover 9 may have a thickness of greater than or equal to about 5 pm, greater than or equal to about 25 pm, greater than or equal to about 50 pm, greater than or equal to about 75 pm, or about 100 pm; or from about 5 pm to about 100 pm, about 5 pm to about 75 pm, about 5 pm to about 50 pm, or about 5 pm to about 25 pm.

[00101] In any embodiment, the method includes further solidifying the first fiber and the second fiber to further form a foam, for example, an open cell foam or a closed cell foam adjacent to the tissue site 50. In any embodiment, the foam may have a higher molecular weight (M _n ), for example, greater than or equal to about 100,000, greater than or equal to about 500,000 or about 1,000,000; or from about 100,000 to about 1,000,000, about 250,000 to about 1,000,000 or about 500,000 to about 1,000,000. Additionally or alternatively, the foam may have a MVTR of about 250 g/m ² /24 hours to about 1500 g/m ² /24 hours, or about 500 g/m ² /24 hours to about 1500 g/m ² /24 hours, or about 1000 g/m ² /24 hours to about 1500 g/m ² /24 hours. In some embodiments, the foam may be radio-opaque so that is capable of detection by X-ray. In any embodiment, the first fiber can be solidified to form an open cell foam manifold having a plurality of flow channels in fluid communication with the tissue site 50. Additionally or alternatively, the second fiber can be further solidified to form a foam cover 9. As described above, this further solidification of the first fiber, the second fiber, or both can be considered a second solidification step. This second solidification step can be achieved by any known means in the art, for example, via cooling, reacting, heating, curing, cross-linking, exposure to ultraviolet light, and combinations thereof. An example of reacting can include reacting the first fiber, the second fiber, or both with water, e.g., contacting the first fiber, the second fiber, or both with water. Any suitable source of water may be used. For example, sources of water include, but are not limited to a user injecting or adding water to the first fiber and/or second fiber at the tissue site, water present in the atmosphere, water present in the wound, and combinations thereof. An example illustrating this second solidification step is shown in Figure 7B where water reacts with an isocyanate group of a polyurethane acrylate to form polyurea. Advantageously, this second solidification step can result in a more rigid tissue dressing with increased mechanical strength allowing for the tissue dressing to remain substantially intact upon removal from a tissue site.

[00102] In some embodiments, the flowable material is allowed to react completely, e.g., foaming has stopped and the majority of heat is released, before applying the flowable material to a tissue site. In other embodiments, the flowable material, for example, as the first fiber and/or the second fiber, is applied to a tissue site while still reacting, e.g., foaming. In such instances, a cooler temperature of the tissue site can slow and/or stop the foaming.

[00103] The method may further include applying a negative-pressure to the tissue site through the plurality of flow channels of the open cell foam. For example, negative-pressure may be delivered via a manifold delivery tube 70. In some embodiments, the manifold delivery tube 70 may be integral with a connector pad 75. In some embodiments, the connector pad 75 may include a pressure valve (e.g., positive pressure valve) (not shown) for releasing gas formed during solidification of the flowable tissue dressing material. In some embodiments, the user may have to cut a hole into cover 9 before application of a connector pad 75 to deliver negative-pressure. The negative-pressure source 18 for applying the negative-pressure can be in fluid communication with, the manifold delivery tube 70, the connector pad 75, the cover 9, or a combination thereof, for example via fluid conductor 80 for applying the negative-pressure.

[00104] The systems, delivery devices, and methods described herein may provide significant advantages. For example, the delivery devices described herein can provide a tissue dressing material, cover, or both that can be readily applied to wounds of varying sizes without needing timely customization. The nature of the flowable material can also allow for better adhesion between the tissue dressing material and/or cover and skin of a tissue site. Additionally, the delivery devices can eliminate the need for additional traditional dressing material components, such as support and release layers. Furthermore, the delivery devices are portable and can be used in many environments and settings to produce tissue dressings in various configurations. [00105] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing 5, the container 11, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller 13 may also be manufactured, configured, assembled, or sold independently of other components.

[00106] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.