CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/982,584, filed on February 27, 2020, which is incorporated herein by reference in its entirety.

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to systems, dressings, and fillers for negative- pressure tissue treatment, and methods of using systems, dressings, and fillers for negative-pressure tissue treatment.

BACKGROUND

[0003] 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.

[0004] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound can be washed out with a stream of liquid solution, or a cavity can be washed out using 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.

[0005] While the clinical benefits of negative-pressure therapy and instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. BRIEF SUMMARY

[0006] New and useful systems, apparatuses, and methods for cleansing a wound in a negative- pressure therapy environment 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.

[0007] For example, in some embodiments, a dressing for use with negative pressure therapy can be described. The dressing can have a first layer formed from a first polymer film having a plurality of fluid restrictions, a second layer formed from a second polymer film, and a manifold disposed between the first layer and the second layer. A plurality of bonds between the first layer and the second layer can define separable sections of the first layer, the second layer, and the manifold. A tissue cleansing interface formed from collagen and oxidized regenerated cellulose can be disposed adjacent to the plurality of fluid restrictions in at least one of the separable sections.

[0008] More generally, a dressing for treating a tissue site with negative pressure is described. The dressing can include a first layer having a plurality of fluid restrictions, a second layer, and a manifold disposed between the first layer and the second layer. An intermediate layer can be disposed between the manifold and the first layer, the intermediate layer comprising collagen and oxidized regenerated cellulose. A plurality of bonds can be formed between the first layer and the second layer, the plurality of bonds defining separable sections of the manifold.

[0009] Alternatively, other example embodiments may describe a wound dressing. The wound dressing can have a contact layer having a plurality of fluid restrictions, an outer layer, and a foam layer disposed between the contact layer and the outer layer. A plurality of tissue treatment structures, each tissue treatment structure forming a ring of collagen and oxidized regenerated cellulose disposed between the contact layer and the foam layer. A plurality of bonds can be formed between the contact layer and the outer layer, the plurality of bonds defining sections of the foam layer.

[0010] A tissue interface is also described herein. The tissue interface can include a foam layer and a plurality of rings formed from collagen and oxidized regenerated cellulose. The plurality of rings can be disposed on a side of the foam layer. A film can encapsulate the rings and the foam layer, the film having a plurality of bonds defining sections of the foam layer.

[0011] Still other embodiments described an apparatus for providing negative-pressure treatment to a tissue site. The apparatus can include a first layer having a plurality of fluid restrictions and a second layer. A manifold can be disposed between the first layer and the second layer. An intermediate layer can be formed from collagen and oxidized regenerated cellulose. The intermediate layer can be disposed between the manifold and the first layer. A plurality of bonds between the first layer and the second layer can define separable sections of the manifold. A negative-pressure source can be fluidly coupled to the manifold. [0012] 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

[0013] Figure 1 is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment in accordance with this specification.

[0014] Figure 2 is an exploded view of a dressing that may be associated with an example embodiment of the therapy system of Figure 1.

[0015] Figure 3 is a top view of a tissue interface of the dressing of Figure 2.

[0016] Figure 4 is a cross-sectional view of the tissue interface of Figure 3.

[0017] Figure 5 is an exploded view of a tissue interface that may be associated with an example embodiment of a dressing of the therapy system of Figure 1.

[0018] Figure 6 is a schematic view of an example configuration of fluid restrictions in a layer that may be associated with some embodiments of the dressing of Figure 2.

[0019] Figure 7 is a schematic view of the example layer of Figure 6 overlaid on the example layer of Figure 5.

[0020] Figure 8 is an assembly view of an example of a dressing, illustrating additional details that may be associated with some example embodiments of the therapy system of Figure 1.

[0021] Figure 9 is an assembly view of another example of a dressing, illustrating additional details that may be associated with some example embodiments of the therapy system of Figure 1.

[0022] Figures 10-16 are perspective views of examples of a cleanser of Figure 3 illustrating additional details that may be associated with some example embodiments of the therapy system of Figure 1.

DESCRIPTION OF EXAMPLE EMBODIMENTS [0023] 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 may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0024] 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. [0025] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including but not limited to, a surface wound, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. 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. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted. A surface wound, as used herein, is a wound on the surface of a body that is exposed to the outer surface of the body, such an injury or damage to the epidermis, dermis, and/or subcutaneous layers. Surface wounds may include ulcers or closed incisions, for example. A surface wound, as used herein, does not include wounds within an intra-abdominal cavity. 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.

[0026] Figure 1 is a simplified functional block diagram of an example embodiment of a therapy system 100 that can provide negative -pressure therapy with instillation of topical treatment solutions to a tissue site in accordance with this specification. The therapy system 100 may include a source or supply of negative pressure, such as a negative -pressure source 102, a dressing 104, a fluid container, such as a container 106, and a regulator or controller, such as a controller 108, for example. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 108 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a pressure sensor 110, an electric sensor 112, or both, coupled to the controller 108. As illustrated in the example of Figure 1, the dressing 104 may comprise or consist essentially of a tissue interface 114, a cover 116, or both in some embodiments.

[0027] The therapy system 100 may also include a source of instillation solution. For example, a solution source 118 may be fluidly coupled to the dressing 104, as illustrated in the example embodiment of Figure 1. The solution source 118 may be fluidly coupled to a positive-pressure source such as the positive-pressure source 120, a negative-pressure source such as the negative-pressure source 102, or both in some embodiments. A regulator, such as an instillation regulator 122, may also be fluidly coupled to the solution source 118 and the dressing 104 to ensure proper dosage of instillation solution (e.g. saline) to a tissue site. For example, the instillation regulator 122 may comprise a piston that can be pneumatically actuated by the negative-pressure source 102 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 108 may be coupled to the negative-pressure source 102, the positive-pressure source 120, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 122 may also be fluidly coupled to the negative-pressure source 102 through the dressing 104, as illustrated in the example of Figure 1. [0028] Some components of the therapy system 100 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 102 may be combined with the solution source 118, the controller 108, and other components into a therapy unit.

[0029] In general, components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 102 may be directly coupled to the container 106, and may be indirectly coupled to the dressing 104 through the container 106. 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 102 may be electrically coupled to the controller 108, 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. For example, the tissue interface 114 and the cover 116 may be discrete layers disposed adjacent to each other, and may be joined together in some embodiments.

[0030] A distribution component is preferably detachable, and may be disposable, reusable, or recyclable. The dressing 104 and the container 106 are illustrative of distribution components. 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 104.

[0031] A negative-pressure supply, such as the negative-pressure source 102, 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 applied to a tissue site 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).

[0032] The container 106 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.

[0033] A controller, such as the controller 108, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negative- pressure source 102. In some embodiments, for example, the controller 108 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 100. Operating parameters may include the power applied to the negative-pressure source 102, the pressure generated by the negative-pressure source 102, or the pressure distributed to the tissue interface 114, for example. The controller 108 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.

[0034] Sensors, such as the pressure sensor 110 or the electric sensor 112, 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 pressure sensor 110 and the electric sensor 112 may be configured to measure one or more operating parameters of the therapy system 100. In some embodiments, the pressure sensor 110 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 pressure sensor 110 may be a piezoresistive strain gauge. The electric sensor 112 may optionally measure operating parameters of the negative-pressure source 102, such as the voltage or current, in some embodiments. Preferably, the signals from the pressure sensor 110 and the electric sensor 112 are suitable as an input signal to the controller 108, 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 108. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0035] The tissue interface 114 can be generally adapted to partially or fully contact a tissue site. The tissue interface 114 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 114 may be adapted to the contours of deep and irregular shaped tissue sites. [0036] In some embodiments, the cover 116 may provide a bacterial barrier and protection from physical trauma. The cover 116 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 116 may be, 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 116 may have a high moisture- vapor transmission rate (MVTR) 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 cover 116 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.

[0037] The cover 116 may comprise, for example, one or more of the following materials: hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; hydrophilic silicone elastomers; an INSPIRE 2301 material from Coveris Advanced Coatings of Wrexham, United Kingdom having, for example, an MVTR (inverted cup technique) of 14400 g/m ² /24 hours and a thickness of about 30 microns; a thin, uncoated polymer drape; natural rubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; polyurethane (PU); EVA film; co-polyester; silicones; a silicone drape; a 3M Tegaderm® drape; a polyurethane (PU) drape such as one available from Avery Dennison Corporation of Glendale, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema, France; INSPIRE 2327; or other appropriate material.

[0038] An attachment device may be used to attach the cover 116 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 116 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 116 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight between about 25 grams to about 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.

[0039] The solution source 118 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.

[0040] 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.

[0041] In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies a position 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 a position 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.

[0042] Some dressings can be worn for a time period between about four days to about eight days, which can be referred to as an extended wear time . Dressings for extended wear time can provide cost-savings, time-efficiencies, and less trauma to a patient during dressing changes. Some tissue sites may need tissue removal or removal of infection during treatment. For example, a tissue site may not heal according to the normal medical protocol and may develop areas of necrotic tissue. Necrotic tissue may be dead tissue resulting from infection, toxins, or trauma that caused the tissue to die faster than the tissue can be removed by the normal body processes that regulate the removal of dead tissue. Sometimes, necrotic tissue may be in the form of slough, which may include a viscous liquid mass of tissue. Generally, slough is produced by bacterial and fungal infections that stimulate an inflammatory response in the tissue. Slough may be a creamy yellow color and may also be referred to as pus. Necrotic tissue may also include eschar. Eschar may be a portion of necrotic tissue that has become dehydrated and hardened. Eschar may be the result of a bum injury, gangrene, ulcers, fungal infections, spider bites, or anthrax. Eschar may be difficult to remove without the use of surgical cutting instruments. Necrotic tissue can also include thick exudate and fibrinous slough.

[0043] If a tissue site develops necrotic tissue, the tissue site may be treated with a process called debridement. Debridement may include the removal of dead, damaged, or infected material, such as thick exudate, fibrinous slough, slough, or eschar, from a tissue site. In some debridement processes, a mechanical process is used to remove necrotic tissue. Mechanical processes may include using scalpels or other cutting tools having a sharp edge to cut away the necrotic tissue from the tissue site. Typically, mechanical processes of debriding a tissue site may be painful and may require the application of local anesthetics.

[0044] Debridement may also be performed with an autolytic process. An autolytic process may involve using enzymes and moisture produced by a tissue site to soften and liquefy the necrotic tissue. Typically, a dressing may be placed over a tissue site having necrotic tissue so that fluid produced by the tissue site may remain in place, hydrating the necrotic tissue. Autolytic processes can be pain-free, but autolytic processes are a slow and can take many days. Because autolytic processes are slow, autolytic processes may also involve many dressing changes. Some autolytic processes may be paired with negative-pressure therapy so that, as necrotic tissue hydrates, negative pressure supplied to a tissue site may draw off the removed necrotic tissue. In some cases, a manifold positioned at a tissue site to distribute negative-pressure across the tissue site may become blocked or clogged with necrotic tissue broken down by an autolytic process. If a manifold becomes clogged, negative-pressure may not be able to draw off necrotic tissue, which can slow or stop the autolytic process.

[0045] Debridement may also be performed by adding enzymes or other agents to the tissue site. The enzymes digest tissue. Often, strict control of the placement of the enzymes and the length of time the enzymes are in contact with a tissue site must be maintained. If enzymes are left on the tissue site for longer than needed, the enzymes may remove too much tissue, contaminate the tissue site, or be carried to other areas of a patient. Once carried to other areas of a patient, the enzymes may break down undamaged tissue and cause other complications.

[0046] In a debridement process, the dressing covering a tissue site is generally removed to permit access to the tissue sit for debridement, preventing use of a dressing for an extended wear time. Thus, patient’s needing debridement may not receive the benefits of a dressing for an extended wear time. Furthermore, some patients may not be suitable candidates for surgical debridement due to the patient’s comorbidities or overall health condition.

[0047] Figure 2 is an assembly view of an example of the dressing 104 of Figure 1, illustrating additional details that may be associated with some embodiments in which the tissue interface 114 comprises separable sections. The dressing 104 may provide mechanical wound cleansing using collagen based structures and enhancement to wound healing due to the presence of collagen and oxidized regenerated cellulose (“ORC”), allowing for extended wear use. In the example of Figure 2, the tissue interface 114 comprises one or more interface sections 205, which may be bounded by seams 210. Each of the interface sections 205 may include a manifold section 215. In some examples, seams 210 may be formed between or may define the manifold sections 215.

[0048] The manifold sections 215 may comprise or consist of foam in some embodiments. For example, the foam may be open-cell foam, such as reticulated foam. The foam may also be relatively thin and hydrophobic to reduce the fluid holding capacity of the dressing, which can encourage exudate and other fluids to pass quickly to external storage. The foam layer may also be thin to reduce the dressing profile and increase flexibility, which can enable it to conform to wound beds and other tissue sites under negative pressure. In some embodiments, the manifold sections 215 may be formed of 3- dimensional textiles, non-woven wicking material, vacuum-formed texture surfaces, and composites thereof. A hydrophobic manifold having a thickness of less than 7 millimeters and a free volume of at least 90% may be suitable for many therapeutic applications. In some embodiments, the manifold sections 215 may be formed of colored material. Each of the manifold sections 215 may be a same color or a different color.

[0049] As illustrated in the example of Figure 2, the tissue interface 114 may have one or more fluid restrictions 220, which can be distributed uniformly or randomly across the tissue interface 114. The fluid restrictions 220 may be bi-directional and pressure-responsive. For example, each of the fluid restrictions 220 generally may comprise or consist essentially of an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient. The fluid restrictions 220 may be coextensive with the manifold sections 215.

[0050] For example, some embodiments of the fluid restrictions 220 may comprise or consist essentially of one or more slits, slots or combinations of slits and slots. In some examples, the fluid restrictions 220 may comprise or consist of linear slots having a length less than 4 millimeters and a width less than 1 millimeter. The length may be at least 2 millimeters, and the width may be at least 0.4 millimeters in some embodiments. A length of about 3 millimeters and a width of about 0.7 millimeters may be particularly suitable for many applications, and a tolerance of about 0.3 millimeter may also be acceptable. Such dimensions and tolerances may be achieved with a laser cutter, for example. In some embodiments, the fluid restrictions 220 may be formed by ultrasonics or other heat means. Slots of such configurations may function as imperfect valves that substantially reduce liquid flow in a normally closed or resting state. For example, such slots may form a flow restriction without being completely closed or sealed. The slots can expand or open wider in response to a pressure gradient to allow increased liquid flow.

[0051] As illustrated in the example of Figure 2, the dressing 104 may include a release liner 245 to protect an optional adhesive on a portion of the cover 116 prior to use. The release liner 245 may also provide stiffness to assist with, for example, deployment of the dressing 104. The release liner 245 may be, for example, a casting paper, a fdm, or polyethylene. Further, in some embodiments, the release liner 245 may be a polyester material such as polyethylene terephthalate (PET), or similar polar semi-crystalline polymer. The use of a polar semi-crystalline polymer for the release liner 245 may substantially preclude wrinkling or other deformation of the dressing 104. For example, the polar semi-crystalline polymer may be highly orientated and resistant to softening, swelling, or other deformation that may occur when brought into contact with components of the dressing 104, or when subjected to temperature or environmental variations, or sterilization. Further, a release agent may be disposed on a side of the release liner 245 that is configured to contact the tissue interface 114. For example, the release agent may be a silicone coating and may have a release factor suitable to facilitate removal of the release liner 245 by hand and without damaging or deforming the dressing 104. In some embodiments, the release agent may be a fluorocarbon or a fluorosilicone, for example. In other embodiments, the release liner 245 may be uncoated or otherwise used without a release agent.

[0052] Figure 2 also illustrates one example of a fluid conductor 250 and a dressing interface 255. As shown in the example of Figure 2, the fluid conductor 250 may be a flexible tube, which can be fluidly coupled on one end to the dressing interface 255. The dressing interface 255 may be an elbow connector, as shown in the example of Figure 2, which can be placed over an aperture 260 in the cover 116 to provide a fluid path between the fluid conductor 250 and the tissue interface 114.

[0053] Figure 3 is a bottom view of the tissue interface 114 of Figure 2, illustrating additional details that may be associated with some examples. The manifold sections 215 in each of the interface sections 205 may have a same shape or a different shape. As shown in the example of Figure 3, the interface sections 205 and the manifold sections 215 may have similar shapes. In some embodiments, each of the interface sections 205 and the manifold sections 215 may have a tessellate shape, such as the generally square shape in the example of Figure 3, with sides having a length ranging from about 10 mm to about 30 mm (e.g., about 15 mm to about 25 mm or about 18 mm to about 22 mm) with a tolerance of about 0.5 mm. For example, the manifold sections 215 may be squares having dimensions of about 20 mm by about 20 mm.

[0054] Each of the seams 210 may have a width W ranging from about 2 mm to about 5 mm with a tolerance of about 0.5 mm, and may be wide enough to allow for the interface sections 205 to be separated along the seams 210 without exposing any portion of the manifold sections 215. In some embodiments, the seams 210 may be sacrificial bonds. The sacrificial bonds can aid in the separation of the interface sections 205.

[0055] In some embodiments, the tissue interface 114 can include one or more tissue cleansing interfaces or tissue treatment structures, such as cleansers 222. For example, a cleanser 222 can be disposed in each interface section 205. In other embodiments a cleanser 222 can be disposed in less than each interface section 205. Each cleanser 222 may be formed from a mixture of collagen and ORC. For example, the cleanser 222 can be formed from a mixture of 55% collagen and 45% ORC. In other embodiments, biologically-derived polymers, such as gelatin, hyaluronic acid, chitosan, cellulose, cellulose derivatives, alginate, fibrin, silk, carrageenan, chondroitin sulfate, agarose, keratin, dextran, or combinations thereof can be added to the cleanser 222. The cleanser 222 can also include synthetically derived polymers such as polyglycolic acid, polylactic acid, polycaprolactone, poly(lactic- co-glycolic acid), poly(glycolide-co-caprolactone), poly (glycolide-co-trimethylene carbonate), and combinations thereof. In other embodiments, functional additives can be included in the cleanser 222. For example, antimicrobial agents, growth factors, and peptides can be added to the cleansers 222. Non- functional additives can also be included in the cleansers 222. For example, pigments and fragrances can be added to the cleansers 222.

[0056] A cleanser 222 can be a circular structure, a disc structure, ring-shaped structure, a square structure, a triangular structure, a hexagonal structure, or can have an amorphous shape. An outer diameter of each cleanser 222 can be between about 0.5 cm and about 0.8 cm. In some embodiments, the cleanser 222 can be a ring and have an inner diameter between about 10 cm and about 15 cm. In some embodiments, each cleanser 222 may have athickness between about 0.2 cm and about 0.4 cm. In other embodiments, the cleansers 222 adjacent to each other may have different thicknesses. For example, cleansers 222 adjacent to each other may vary in thickness between about 1mm and about 4 mm. In some embodiments, a cleanser 222 can be manufactured by mixing the collagen and ORC material. The mixed collagen and ORC material can be disposed in a sheet of material having the desired thickness of the cleansers 222 and prepared by freeze-drying the sheet. The freeze-dried sheet can be laser cut to form each cleanser 222 having the desired shape. In some embodiments, a slurry of collagen and ORC can be poured directly into a mold to obtain the structures. For example, the slurry could be poured into a circular-shaped mold, a disc-shaped mold, a ring-shaped mold, a square-shaped mold, a triangular-shaped mold, a hexagonal-shaped mold, a polygonal-shaped mold, or an amorphous shaped-mold. The slurry fdled molds can be allowed to cure or crosslink to solidify. In some embodiments, the cleansers 222 can be crosslinked. Crosslinking the cleansers 222 during manufacturing can increase the hardness of each cleanser 222. Crosslinking occurs by chemically joining two or more molecules by a covalent bond linking one polymer chain to another polymer chain. Materials, such as the collagen/ORC mixture can be crosslinked using a chemically-activated process, a thermally-activated process, or a light-activated process. For example, the collagen/ORC mixture can be heated to crosslink the material while preserving the collagen material within the mixture. In some embodiments, the cleansers 222 can be crosslinked to have a modulus of elasticity between about 20 kilopascal (“kPa”) to about 150 kPa and, preferably, between about 55 kPa and about 85 kPa.

[0057] Figure 4 is a section view of the tissue interface 114 of Figure 3 taken along line 4-4, illustrating additional details that may be associated with some embodiments. In the example of Figure 4, the tissue interface 114 comprises a first layer 405, a second layer 410, and the manifold sections 215 disposed between the first layer 405 and the second layer 410. In some embodiments, the first layer 405 may be disposed adjacent to the manifold sections 215 as shown in the example of Figure 4. The second layer 410 may be disposed on an opposite side of the manifold sections 215 and can be a contact layer. In some embodiments, the cleanser 222 can be positioned between the second layer 410 and the manifold section 215. Each cleanser 222 can be symmetrically aligned with a respective manifold section 215. In other embodiments, each cleanser 222 may not be symmetrically aligned with a respective manifold section 215. Also as shown in the example of Figure 4, the seams 210 may be formed by one or more bonds between the first layer 405 and the second layer 410. The bonds may be continuous or discrete. [0058] The first layer 405 and the second layer 410 may comprise or consist essentially of a means for controlling or managing fluid flow. In some embodiments, the first layer 405 and the second layer 410 may comprise or consist essentially of an elastomeric material that is impermeable to liquid. For example, the first layer 405 and the second layer 410 may comprise or consist essentially of a polymer film. The first layer 405 and the second layer 410 may also have a smooth or matte surface texture in some embodiments. A glossy or shiny finish better or equal to a grade B3 according to the SPI (Society of the Plastics Industry) standards may be particularly advantageous for some applications. In some embodiments, variations in surface height may be limited to acceptable tolerances. For example, the surface of the second layer may have a substantially flat surface, with height variations limited to 0.2 millimeters over a centimeter.

[0059] In some embodiments, the first layer 405 and the second layer 410 may comprise or consist essentially of a hydrophobic material. The hydrophobicity may vary, but may have a contact angle with water of at least ninety degrees in some embodiments. In some embodiments the hydrophobic material may have a contact angle with water of no more than 150 degrees. For example, in some embodiments, the contact angle may be in a range of at least 90 degrees to about 120 degrees, or in a range of at least 120 degrees to 150 degrees. Water contact angles can be measured using any standard apparatus. Although manual goniometers can be used to visually approximate contact angles, contact angle measuring instruments can often include an integrated system involving a level stage, liquid dropper such as a syringe, camera, and software designed to calculate contact angles more accurately and precisely, among other things. Non-limiting examples of such integrated systems may include the FTA125, FTA200, FTA2000, and FTA4000 systems, all commercially available from First Ten Angstroms, Inc., of Portsmouth, VA, and the DTA25, DTA30, and DTA100 systems, all commercially available from Kruss GmbH of Hamburg, Germany. Unless otherwise specified, water contact angles herein are measured using deionized and distilled water on a level sample surface for a sessile drop added from a height of no more than 5 cm in air at 20-25°C and 20-50% relative humidity. Contact angles reported herein represent averages of 5-9 measured values, discarding both the highest and lowest measured values. The hydrophobicity of the first layer 405, the second layer 410, or both may be further enhanced with a hydrophobic coating of other materials, such as silicones and fluorocarbons, either as coated from a liquid, or plasma coated.

[0060] The first layer 405 and the second layer 410 may also be suitable for bonding to other layers, including each other. For example, the first layer 405, the second layer 410, or both may be adapted for welding to polyurethane foams using heat, radio frequency (RF) welding, or other methods to generate heat such as ultrasonic welding. RF welding may be particularly suitable for more polar materials, such as polyurethane, polyamides, polyesters and acrylates. Sacrificial polar interfaces may be used to facilitate RF welding of less polar film materials, such as polyethylene. The first layer 405 and the second layer 410 may include hot melt films. [0061] The area density of the first layer 405 and the second layer 410 may vary according to a prescribed therapy or application. In some embodiments, an area density of less than 40 grams per square meter may be suitable, and an area density of about 20-30 grams per square meter may be particularly advantageous for some applications.

[0062] In some embodiments, for example, the first layer 405, the second layer 410, or both may comprise or consist essentially of a hydrophobic polymer, such as a polyethylene film. The simple and inert structure of polyethylene can provide a surface that interacts little, if any, with biological tissues and fluids, providing a surface that may encourage the free flow of liquids and low adherence, which can be particularly advantageous for many applications. Other suitable polymeric films include polyurethanes, acrylics, polyolefin (such as cyclic olefin copolymers), polyacetates, polyamides, polyesters, copolyesters, PEBAX block copolymers, thermoplastic elastomers, thermoplastic vulcanizates, polyethers, polyvinyl alcohols, polypropylene, polymethylpentene, polycarbonate, styreneics, silicones, fluoropolymers, and acetates. A thickness between 20 microns and 100 microns may be suitable for many applications. Films may be clear, colored, or printed. More polar films suitable for laminating to a polyethylene film include polyamide, co-polyesters, ionomers, and acrylics. To aid in the bond between a polyethylene and polar film, tie layers may be used, such as ethylene vinyl acetate, or modified polyurethanes. An ethyl methyl acrylate (EMA) film may also have suitable hydrophobic and welding properties for some configurations.

[0063] In some embodiments, the fluid restrictions 220 may comprise or consist essentially of perforations in at least one of the first layer 405 and the second layer 410. Perforations may be formed by removing material from the first layer 405, the second layer 410, or both. For example, perforations may be formed by cutting through the material, which may also deform the edges of the perforations in some embodiments. In the absence of a pressure gradient across the perforations, the passages may be sufficiently small to form a seal or fluid restriction, which can substantially reduce or prevent liquid flow. Additionally or alternatively, one or more of the fluid restrictions 220 may be an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient. A fenestration in the material may be a suitable valve for some applications. Fenestrations may also be formed by removing material, but the amount of material removed and the resulting dimensions of the fenestrations may be an order of magnitude less than perforations, and may not deform the edges. In some embodiments, the fluid restrictions 220 extend through both the first layer 405 and the second layer 410, and the fluid restrictions 220 are coextensive with at least one of the first layer 405 and the second layer 410.

[0064] Each of the manifold sections 215 has a length El, which can be in a range from about 10 mm to about 30 mm (e.g., about 15 mm to about 25 mm or about 18 mm to about 22 mm). For example, each of the manifold sections 215 may have a length of about 20 mm. In some embodiments, the manifold sections 215 may be spaced apart by a distance D1 of about 5 mm to about 15 mm. For example, a distance D1 of about 10 mm may be particularly advantageous for some embodiments.

[0065] In some embodiments, each of the manifold sections 215 in the tissue interface 114 may be the same size. In other embodiments, one or more of the manifold sections 215 in the tissue interface 114 may have a different size.

[0066] In some embodiments, the tissue interface 114 has a thickness T1 ranging from about 5 mm to about 20 mm (e.g., about 8 mm to about 18 mm, or about 10 mm to about 15 mm). For example, the tissue interface 114 may have a thickness T1 of about 8 mm. The thickness T1 of the tissue interface 114 may vary depending upon a thickness of the manifold sections 215 and the cleansers 222 used to form the tissue interface 114. For example, each of the manifold sections 215 may have a thickness ranging from about 5 mm to about 15 mm (e.g., about 8 mm to about 12 mm). In some embodiments, the first layer 405 and the second layer 410 may be formed of a transparent polymer to aid in cutting the interface sections 205 apart along the seams 210.

[0067] In some embodiments, the tissue interface 114 can be formed by spacing the manifold sections 215 apart, placing a cleanser 222 over each manifold section 215, placing the second layer 410 of polymer film over the manifold sections 215, placing the first layer 405 under the manifold sections 215, and bonding the first layer 405 to the second layer 410, forming the seams 210 between the manifold sections 215. Suitable means for bonding the first layer 405 to the second layer 410 may include, for example, an adhesive such as an acrylic, and welding, such as heat, radio frequency (RF), or ultrasonic welding. In some embodiments, sacrificial materials may be disposed between the first layer 405 and the second layer 410 to facilitate welding. Suitable sacrificial materials may include, for example, hot melt films supplied by Bayer (such as H2, HU2, and H5 films), Cornelius (Collano film), or Prochimir (such as TC203 or TC206 film).

[0068] In some embodiments, a cleanser 222 can be positioned on a manifold section 215 and the first layer 405 and the second layer 410 can be welded to each other to enclose the cleanser 222 and the manifold section 215. In other embodiments, the first layer 405 and the second layer 410 can be coupled to each other by bonding, adhering, or other securing processes such as flame bonding, hot air gun bonding, induction/impact coupling, dielectric coupling, ultrasonic coupling, and/or solvent bonding can be used. Manufacturing in this manner can secure the cleanser 222 with the manifold section 215 within the space formed by the first layer 405 and the second layer 410. In some embodiments, the cleanser 222 can be coupled to the manifold section 215 or the second layer 410. For example, a biocompatible adhesive can be used to adhere the cleanser 222 to the manifold section 215, the second layer 410, or both. In some embodiments, such as large scale manufacturing operations, a large sheet of manifold sections 215 each having an associated cleanser 222 can be encapsulated in the first layer 405 and the second layer 410 and sized at the point-of-use. [0069] In some embodiments, the manifold sections may be formed from an integral manifold material, such as foam. In some embodiments, for example, bonds between the first layer 405 and the second layer 410 may extend through a layer of manifold material to define the manifold sections 215. For example, some embodiments of a manifold layer may have a thickness ranging from about 5 mm to about 8 mm, and at least one of the first layer 405 and the second layer 410 may melt through the manifold layer during welding to form the seams 210.

[0070] Additionally or alternatively, a unitary manifold material can be perforated and cut to define the manifold sections 215 in a variety of suitable shapes and patterns. In some embodiments, the seams 210 may align with perforations between the manifold sections 215. In some examples, sacrificial joints may be left between the manifold sections 215 to maintain the manifold sections 215 together as a single unit. Maintaining the manifold sections 215 as a single unit can allow for easier assembly of the tissue interface 114. In some embodiments, any or all of the first layer 405, the second layer 410, and the cleansers 222 may also be bonded to the manifold sections 215 for additional stability.

[0071] In other embodiments, the tissue interface 114 may include more or fewer of the interface sections 205. Each of the interface sections 205 may have a different size or a same size. Each of the interface sections 205 may have a same shape or a different shape . For example, the interface sections 205 may be in the form of equilateral polygons, which may have sides not exceeding about 20 millimeters and having an area less than about 400 square millimeters.

[0072] During negative-pressure therapy, the dressing 104 can be positioned over a tissue site so that the cleansers 222 of the tissue interface 114 are proximate to the tissue site. Placing the cleansers 222 proximate to the tissue site provides a modulating agent to the tissue site. For example, during healing of a tissue site, matrix metalloproteinase (MMP) is produced. MMPs are an enzyme that aids the process of remodeling a tissue site. MMPs may be classified as zinc -dependent endopeptidases that belong to a larger family of proteases that may be known as the metzincin superfamily. MMPs may be associated with both physiological and pathological processes, including morphogenesis, angiogenesis, tissue repair, cirrhosis, arthritis, and metastasis. Generally, MMPs degrade extracellular matrix proteins. Extracellular matrix proteins are extracellular components of a multicellular structure. Extracellular matrix proteins can support tissue, separate tissues, regulate communication between the cells of tissues, and regulate the dynamic behavior of cells. Extracellular matrix proteins can also store cellular growth factors that can be released when tissue is damaged. Extracellular matrix proteins aid in regrowth and healing of tissue by preventing the immune system response at the injury to prevent inflammation. Extracellular matrix proteins can also aid the surrounding tissue to repair the damaged tissue rather than form scar tissue. MMPs assist the extracellular matrix proteins in tissue healing by breaking down damaged extracellular matrix proteins when tissue is injured. Breaking down damaged extracellular matrix proteins allows undamaged extracellular matrix proteins to integrate with newly formed components. MMPs also remove bioflims that can cause infection, help establish new blood vessels in damaged tissue, aid in the migration of epithelial cells, and remodel scarred tissue. However, MMPs can inhibit healing of damaged tissue. For example, MMPs in the wrong locations in a tissue site or too many MMPs in a tissue site can degrade extracellular matrix proteins that are needed for healing. Typically, tissue sites that exhibit an increased inflammatory response may be producing MMPs at rates that can lead to inhibition of healing. Inflammation can also cause an increased production of fluid from the tissue site, leading to maceration and other degenerative conditions that may prolong healing time.

[0073] Excess MMPs may be modulated by adding modulating agents to the tissue site. A modulating agent may be an agent, such as a structural protein, that is added to the tissue site. Modulating agents may include scavenging or sacrificial structures formed from a protein material. If the sacrificial structure is placed adjacent a tissue site, the excess MMPs degrade the sacrificial structure rather than newly formed tissue, reducing existing inflammation and the likelihood of additional inflammation. Some sacrificial structures may include sheets of a collagen material that form a collagen substrate. The collagen substrate may be placed on a surface of a tissue site or coated onto another substrate, such as a tissue interface or manifold. Generally, a modulating agent should be placed in close contact to areas of a tissue site where the MMPs are active and deleterious to healing.

[0074] Some tissues sites may stall during healing. A stalled tissue site may be a tissue site that does not follow the desired healing progression within the desired time frame. A stalled tissue site may be caused by excess MMPs as well as excess elastases and bacterial proteases. Elastase and bacterial proteases are types of proteases that may aid in breaking down proteins. Excess elastase and bacterial proteases may inhibit healing by breaking down the new tissue as it develops, preventing the tissue site from healing. Similar to MMPs, elastases and bacterial proteases may be modulated by adding modulating agents, such as oxidized regenerated cellulose (ORC), to the tissue site. The ORC may be stable below a pH of about 4.4 and negatively charged. If the ORC is placed in the tissue site, the tissue site may react to raise the pH of the ORC to the natural pH of the body, producing glucuronic acid that may aid in the removal of undesired products from the tissue site. The ORC, being negatively charged, may also attract and bind with elastase and bacterial proteases, which are positively charged.

[0075] In some embodiments, the positioning of the dressing 104 may open the fluid restriction 220, permitting the MMPs to move into the dressing and degrading the cleansers 222. During the application of negative pressure, proximity to the heat and moisture at the tissue site may also cause the cleansers 222 to desolidify and flow through the fluid restrictions 220 into the tissue site. The desolidification of the cleansers 222 can cause the collagen/ORC mixture to come into contact with the necrotic tissue at the tissue site, for example, the slough or eschar. The collagen/ORC can interact with the necrotic tissue to soften the necrotic tissue, allowing the necrotic tissue to be separated and removed from the tissue site by the application of negative -pressure. In other embodiments, fluid may be applied to the tissue site through the dressing 104 in an instillation process. The application of fluid can provide further softening of the necrotic tissue, further aiding removal of the necrotic tissue.

[0076] Figure 5 is a bottom assembly view of another example of the tissue interface 114 of Figure 1. In the example of Figure 5, the tissue interface 114 includes the first layer 405, the second layer 410, the manifold sections 215, the cleansers 222 (not shown), athird layer 502, and a fourth layer 504. In some embodiments, the fourth layer 504 may be a contact layer configured to contact tissue.

[0077] The third layer 502, the fourth layer 504, or both may comprise or consist essentially of a soft, pliable material suitable for providing a fluid seal with a tissue site, and may have a substantially flat surface. The third layer 502, the fourth layer 504, or both may be a sealing layer. In some embodiments, the third layer 502, the fourth layer 504, or both may also be adhesive. For example, the third layer 502 may comprise, without limitation, a silicone gel, a soft silicone, hydrocolloid, hydrogel, polyurethane gel, polyolefin gel, hydrogenated styrenic copolymer gel, a foamed gel, a soft closed cell foam such as polyurethanes and polyolefins coated with an adhesive, polyurethane, polyolefin, or hydrogenated styrenic copolymers. A silicone gel having a coating weight of about 100 g.s.m. to about 150 g.s.m. may be suitable for some applications. In some embodiments, the third layer 502, the fourth layer 504, or both may have a thickness between about 200 microns (pm) and about 1000 microns (pm). In some embodiments, the third layer 502, the fourth layer 504, or both may have a hardness between about 5 Shore OO and about 80 Shore OO. Further, the third layer 502, the fourth layer 504, or both may be comprised of hydrophobic or hydrophilic materials.

[0078] In some embodiments, the third layer 502, the fourth layer 504, or both may be a hydrophobic-coated material. For example, either or both may be formed by coating a spaced material, such as, for example, woven, nonwoven, molded, or extruded mesh with a hydrophobic material. The hydrophobic material for the coating may be a soft silicone, for example.

[0079] The third layer 502, the fourth layer 504, or both may have a periphery 506 surrounding or around an interior portion 508, and apertures 510 disposed through the periphery 506 and/or the interior portion 508. The interior portion 508 may correspond to a surface area of the first layer 405 or the second layer 410 in some examples. An interior border 512 may be disposed around the interior portion 508, between the interior portion 508 and the periphery 506. The interior border 512 may be substantially free of the apertures 510, as illustrated in the example of Figure 5. In some examples, as illustrated in Figure 5, the interior portion 508 may be symmetrical and centrally disposed.

[0080] The apertures 510 may be formed by cutting or by application of local RF or ultrasonic energy, for example, or by other suitable techniques for forming an opening. The apertures 510 may have a uniform distribution pattern, or may be randomly distributed on the third layer 502, the fourth layer 504, or both. The apertures 510 may have many shapes, including circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, for example, or may have some combination of such shapes. [0081] Each of the apertures 510 may have uniform or similar geometric properties. For example, in some embodiments, each of the apertures 510 may be circular apertures, having substantially the same diameter. In some embodiments, the diameter of each of the apertures 510 may range from about 1 millimeter to about 50 millimeters. In other embodiments, the diameter of each of the apertures 510 may range from about 1 millimeter to about 20 millimeters.

[0082] In other embodiments, geometric properties of the apertures 510 may vary. For example, the diameter of the apertures 510 may vary depending on the position of the apertures 510. In some embodiments, the diameter of the apertures 510 in the periphery 506 may be larger than the diameter of the apertures 510 in the interior portion 508. For example, in some embodiments, the apertures 510 disposed in the periphery 506 may have a diameter ranging from about 9.8 millimeters to about 10.2 millimeters. In some embodiments, the apertures 510 disposed in the comers may have a diameter ranging from about 7.75 millimeters to about 5.75 millimeters. In some embodiments, the apertures 510 disposed in the interior portion 508 may have a diameter ranging from about 1.8 millimeters to about 2.2 millimeters.

[0083] At least one of the apertures 510 in the periphery 506 may be positioned at an edge of the periphery 506, and may have an interior cut open or exposed at the edge that is in fluid communication in a lateral direction with the edge. As shown in the example of Figure 5, the apertures 510 in the periphery 506 may be positioned proximate to or at the edges and in fluid communication in a lateral direction with the edges. The apertures 510 positioned proximate to or at the edges may be spaced substantially equidistant around the periphery 506 as shown in the example of Figure 5. Alternatively, the spacing of the apertures 510 proximate to or at the edges may be irregular.

[0084] Figure 6 is a schematic view of an example configuration of the apertures 510, illustrating additional details that may be associated with some embodiments of the third layer 502, the fourth layer 504, or both.

[0085] In some embodiments, the apertures 510 may be arranged in rows, columns, or a grid of rows and columns. The apertures 510 may be offset in some embodiments. For example, as illustrated in Figure 6, the apertures 510 in one row may be offset from the apertures 510 in adjacent rows, and the apertures in one column may be offset from the apertures in adjacent columns. In other embodiments, the apertures 510 in adjacent rows or columns may be aligned. A pattern of the apertures 510 may be substantially uniform in some configurations. Within each row and column, for example, the apertures 510 may be equidistant from each other. Figure 6 illustrates one example configuration that may be particularly suitable for many applications, in which the apertures 510 are spaced about 6 millimeters apart along each row and column, with a 3 millimeter offset. The apertures 510 in the interior portion 508 of Figure 6 have a diameter of about 2.0 mm. In some embodiments, the pattern of apertures 510 is non-uniform. [0086] Figure 7 is a schematic view of the example configuration of the apertures 510 of Figure 6 overlaid on an example configuration of the fluid restrictions 220, illustrating additional details that may be associated with some example embodiments of the tissue interface 114. For example, as illustrated in Figure 7, the fluid restrictions 220 may be aligned, overlapping, in registration with, or otherwise fluidly coupled to at least some of the apertures 510 in some embodiments. In some embodiments, one or more of the fluid restrictions 220 may be registered with the apertures 510 only in the interior portion 508, or only partially registered with the apertures 510. The fluid restrictions 220 in the example of Figure 7 are generally configured so that each of the fluid restrictions 220 is registered with only one of the apertures 510. In other examples, one or more of the fluid restrictions 220 may be registered with more than one of the apertures 510. For example, any one or more of the fluid restrictions 220 may be a perforation or a fenestration that extends across two or more of the apertures 510. Additionally or alternatively, one or more of the fluid restrictions 220 may not be registered with any of the apertures 510.

[0087] Figure 8 is an assembly view of an example ofthe dressing 104 of Figure 1, illustrating additional details that may be associated with some embodiments of another tissue interface 114. In the example of Figure 8, the tissue interface 114 comprises a substrate layer 605 and the second layer 410. In some embodiments, the substrate layer 605 may be disposed adjacent to the second layer 410. For example, the substrate layer 605 and the second layer 410 may be stacked so that the substrate layer 605 is in contact with the second layer 410. The substrate layer 605 may also be bonded to the second layer 410. In some embodiments, a plurality of cleansers 222 may be disposed between the substrate layer 605 and the second layer 410. For example, the plurality of cleansers 222 can be stacked so that the substrate layer 605 is in contact with the cleansers 222 and the second layer 410. The substrate layer 605 can be bonded to the second layer 410 to enclose the cleansers 222.

[0088] The substrate layer 605 generally comprises or consists essentially of a manifold or a manifold layer, which provides a means for collecting or distributing fluid across the tissue interface 114 under pressure. For example, the substrate layer 605 may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 114, 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 from a source of instillation solution, across the tissue interface 114.

[0089] In some illustrative embodiments, the pathways of the substrate layer 605 may be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, the substrate layer 605 may comprise or consist essentially of a porous material having interconnected fluid pathways. For example, open-cell foam, reticulated foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid channels. Other suitable materials may include a 3D textile (Baltex, Muller, Heathcoates), non-woven (Libeltex, Freudenberg), a 3D polymeric structure (molded polymers, embossed and formed fdms, and fusion bonded films [Supracore]), and mesh, for example. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, the substrate layer 605 may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, the substrate layer 605 may be molded to provide surface projections that define interconnected fluid pathways. Any or all of the surfaces of the substrate layer 605 may have an uneven, coarse, or jagged profile

[0090] In some embodiments, the substrate layer 605 may comprise or consist essentially of a reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, a reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and a foam having an average pore size in a range of 400-600 microns may be particularly suitable for some types of therapy. The tensile strength of the substrate layer 605 may also vary according to needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the substrate layer 605 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 substrate layer 605 may be at least 10 pounds per square inch. The substrate layer 605 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the substrate layer 605 may be a foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In one non-limiting example, the substrate layer 605 may be a reticulated polyurethane foam such as used in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from KCI of San Antonio, Texas.

[0091] The substrate layer 605 generally has a first planar surface and a second planar surface opposite the first planar surface. The thickness of the substrate layer 605 between the first planar surface and the second planar surface may also vary according to needs of a prescribed therapy. For example, the thickness of the substrate layer 605 may be decreased to relieve stress on other layers and to reduce tension on peripheral tissue. The thickness of the substrate layer 605 can also affect the conformability of the substrate layer 605. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0092] As illustrated in the example of Figure 8, the second layer 410 may have the one or more fluid restrictions 220, which can be distributed uniformly or randomly across the second layer 410. In the example of Figure 8, the dressing 104 may further include an attachment device, such as an adhesive 640. The adhesive 640 may be, for example, a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or the entire cover 116. In some embodiments, for example, the adhesive 640 may be an acrylic adhesive having a coating weight between 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. In some embodiments, such a layer of the adhesive 640 may be continuous or discontinuous. Discontinuities in the adhesive 640 may be provided by apertures or holes (not shown) in the adhesive 640. The apertures or holes in the adhesive 640 may be formed after application of the adhesive 640 or by coating the adhesive 640 in patterns on a carrier layer, such as, for example, a side of the cover 116. Apertures or holes in the adhesive 640 may also be sized to enhance the MVTR of the dressing 104 in some example embodiments.

[0093] As illustrated in the example of Figure 8, in some embodiments, the dressing 104 may include the release liner 245 to protect the adhesive 640 prior to use. Figure 8 also illustrates the fluid conductor 250 and the dressing interface 255, which can be placed over the aperture 260 in the cover 116 to provide a fluid path between the fluid conductor 250 and the tissue interface 114.

[0094] Figure 9 is an assembly view of another example of the dressing 104 of Figure 1, illustrating additional details that may be associated with some embodiments in which the tissue interface 114 may comprise additional layers. In the example of Figure 9, the tissue interface 114 comprises the fourth layer 504 in addition to the substrate layer 605 and the second layer 410. In some embodiments, the fourth layer 504 may be adjacent to the second layer 410 opposite the substrate layer 605. The fourth layer 504 may also be bonded to the second layer 410 in some embodiments. In some embodiments, the plurality of cleansers 222 may be an intermediate layer disposed between the substrate layer 605 and the second layer 410. For example, the plurality of cleansers 222 can be stacked so that the substrate layer 605 is in contact with the cleansers 222 and the second layer 410. The substrate layer 605 can be bonded to the second layer 410 to enclose the cleansers 222. In some embodiments, the cleanser 222 can have an ovular ring-shape.

[0095] As illustrated in the example of Figure 9, in some embodiments, the release liner 245 may be attached to or positioned adjacent to the fourth layer 504 to protect the adhesive 640 prior to use. In some embodiments, the release liner 245 may have a surface texture that may be imprinted on an adjacent layer, such as the fourth layer 504. Further, a release agent may be disposed on a side of the release liner 245 that is configured to contact the fourth layer 504.

[0096] Figure 10 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 10, the cleanser 222 can have a disc-shape. Figure 11 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 11, the cleanser 222 can have a rectangular-shape. Figure 12 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 12, the cleanser 222 can have a triangular-shape. Figure 13 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 13, the cleanser 222 can have a hexagonal-shape. Figure 14 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 14, the cleanser 222 can have a disc-shape and a plurality of openings 702. The openings 702 can comprise or consist essentially of perforation, slots, or slits. The perforations, slots, or slits can extend through the cleanser 222, permitting fluid flow through the cleanser 222. In some embodiments, the openings 702 can be circumferentially disposed around the cleanser 222. In other embodiments, the openings 702 can be preferentially located in the cleanser 222 to provide varying fluid flow characteristics across the cleanser 222. In each variation of a shape of a cleanser 222, a mass and density of the cleansers 222 may be substantially the same regardless of shape.

[0097] Figure 15 is a perspective view of another example of the cleanser 222 of Figure 3 illustrating additional details that may be associated with some embodiments. As shown in Figure 15 the cleanser 222 comprises or consists essentially of a plurality of threads 802 formed from collagen and ORC. The threads 802 can have a linear pattern, a crisscross pattern, or an abstract pattern. In some embodiments, the threads 802 can have a diameter of about 0.5 mm to about 3 mm. The threads 802 may be reinforced by a supporting material wherein the collagen/ORC content of the collagen fibers may be about 30% of the total content of the collagen fibers. In other embodiments, the total collagen/ORC content of the threads 802 may be between about 10% and about 50% of the total content of the threads 802. In some embodiments, the supporting material may be polyethylene oxide, and the polyethylene oxide may be between about 90% and about 50% of the total material content of the threads 802. The supporting material may be water soluble. The supporting material may also be biodegradable. In some embodiments, the supporting material may take the form of supporting fibers formed from the supporting material and twisted together with the collagen/ORC to further reinforce the threads 802.

[0098] Figure 16 is a perspective view of another example of the threads 802 of Figure 15 illustrating additional details that may be associated with some embodiments. As shown in Figure 16, the plurality of threads 802 can be disposed in a non-woven arrangement.

[0099] The systems, apparatuses, and methods described herein may provide significant advantages. For example, in some embodiments, the seams 210 may be wide enough to allow the interface sections 205 to be cut apart or otherwise separated so as to obtain a tissue interface 114 having a desired size and shape. For example, tissue interface 114 can be sized and shaped to fill deep and/or irregular wounds by separating the interface sections 205. Moreover, some embodiments of the dressing 104 may be worn for about 3 to about 10 days (e.g., about 7 days). Furthermore, the cleansers 222 can provide mechanical wound cleansing of devitalized tissue in long -wear time dressing. The cleansers 222 can also enhance wound healing due to the presence of collagen and ORC.

[00100] 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 102, the container 112, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller 108 may also be manufactured, configured, assembled, or sold independently of other components.

[00101] 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.