WO2021165826A1

WO2021165826A1 - Self-healing silicone drape

Info

Publication number: WO2021165826A1
Application number: PCT/IB2021/051291
Authority: WO
Inventors: Timothy Mark Robinson; Kyle TURTON
Original assignee: Kci Licensing, Inc.; Systagenix Wound Management, Limited
Priority date: 2020-02-18
Filing date: 2021-02-16
Publication date: 2021-08-26

Abstract

Some examples of a dressing may include a drape, a first layer disposed on a side of the drape, and a second layer disposed on a side of the first layer opposite the drape. The first layer may include an uncured silicone gel. Further, the second layer may include a cured silicone layer. A viscosity of the first layer may be greater than a viscosity of the second layer.

Description

SELF-HEALING SILICONE DRAPE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/978,038, filed on February 18, 2020, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The claimed subject matter relates generally to the treatment of tissue, and more particularly, but without limitation, to a dressings, systems, methods, compositions, and other apparatuses for application to a tissue site, such as a wound.

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, and/or otherwise promote healing and protect tissue from further damage, for example, when placed on a patient’s epidermis and substantially overlaying the wound.

[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 left untreated, can result in tissue loss, systemic infections, septic shock, and death. In some instances, the application of reduced pressure, such as negative pressure, to a dressing and a tissue site may enhance the treatment of the tissue site. [0005] Further, 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] While the clinical benefits of dressings and negative-pressure therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. BRIEF SUMMARY

[0007] New and useful systems, apparatuses, and methods for treating tissue 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.

[0008] For example, in some embodiments, a dressing may include a drape and a first layer disposed on a side of the drape. The first layer may comprise an uncured silicone gel. The dressing may comprise a second layer disposed on a side of the first layer opposite the drape. The second layer may comprise a cured silicone polymer. A viscosity of the first layer may be greater than a viscosity of the second layer. In illustrative embodiments, the second layer may be configured to form channels in response to a lateral force applied to the second layer. For example, the first layer may be configured to fill the channels. In some embodiments, the silicone gel may exhibit a viscosity in a range of about 100,000 cP to about 400,000 cP. In example embodiments, the silicone gel may exhibit a penetration depth of greater than or equal to about 11 mm. In illustrative embodiments, the silicone gel may include a bis- dimethylvinyl terminated polydimethylsiloxane. In example embodiments, the silicone gel may include a bis-hybrid terminated polydimethylsiloxane. In some embodiments, the silicone gel may include a polymerization inhibitor. In some dressing embodiments, the cured silicone polymer may exhibit a cone penetration depth of less than 11 mm. For example, the cured silicone polymer may exhibit a cone penetration depth of less than about 7 mm. In exemplary embodiments, the cured silicone polymer may exhibit a hardness between about 5 Shore OO and about 80 Shore OO.

[0009] Further, in some example embodiments, a method of applying a drape to tissue may include providing a dressing comprising a first layer disposed between a drape and a second layer. The first layer may include an uncured silicone gel layer. The second layer may include a cured silicone polymer. The first layer may exhibit a viscosity greater than a viscosity of the second layer. The method may include applying a lateral force to the second layer, forming a plurality of channels in the second layer in response to the lateral force, applying a side of the second layer to tissue, and filling at least one of the plurality of channels with the first layer. In some embodiments, the silicone gel may exhibit a viscosity in a range of about 100,000 cP to about 400,000 cP. In illustrative embodiments, the silicone gel may include a vinyl-substituted polydimethylsiloxane. In example embodiments, the silicone gel may include a hybrid-substituted polydimethylsiloxane. In some embodiments, the silicone gel may include a polymerization inhibitor.

[0010] A system for treating a tissue site with negative pressure is also described herein, wherein some example embodiments may include a manifold that may be configured to be positioned adjacent to the tissue site. Some examples of the system may include a drape that may be configured to be positioned over the tissue site and the manifold and seal to tissue adjacent to the tissue site to form a sealed space. The drape may include a cover layer, a first layer disposed on a side of the drape, and a second layer disposed on a side of the first layer opposite the drape. The first layer may include an uncured silicone gel. The second layer may include a cured silicone polymer. A viscosity of the first layer may be greater than a viscosity of the second layer. The second layer may be configured to form channels in response to a lateral force applied to the second layer. The first layer may be configured to fill the channels. A negative pressure source may be configured to provide negative pressure to the sealed space. In some embodiments, the silicone gel may exhibit a viscosity in a range of about 100,000 cP to about 400,000 cP. In illustrative embodiments, the silicone gel may include a polymerization inhibitor. In example embodiments, the silicone gel may be configured to fill the channels in response to negative pressure in the sealed space.

[0011] Further, in some example embodiments, a dressing may include a first layer disposed between a drape and a second layer. The first layer may include an uncured silicone gel. The second layer may include a cured silicone polymer. A plurality of pillars may be formed on the second layer. The plurality of pillars may be formed from cured silicone polymer. A viscosity of the first layer may be greater than a viscosity of the second layer. In illustrative embodiments, the second layer may be configured to form a plurality of channels in the second layer in response to a lateral force applied to the second layer. For example, at least one of the plurality of channels may extend through the second layer. In example embodiments, the uncured silicone gel may be configured to fill at least one of the plurality of channels. In some embodiments, the drape may include an elastomeric film. For example, the drape may include a polyurethane film. In some embodiments, the drape may exhibit a thickness in a range of about 25 micrometers to about 50 micrometers. In illustrative embodiments, the drape may exhibit a moisture-vapor transmission rate (MVTR) in a range of about 250 g/m²/day to about 5,000 g/m²/24 hours.

[0012] In some embodiments, the first layer may include a vinyl-substituted polydimethylsiloxane. For example, the first layer may include a bis-dimethylvinyl terminated polydimethylsiloxane. In illustrative embodiments, the first layer may include a hybrid-substituted polydimethylsiloxane. For example, the first layer may include a bis-hybrid terminated polydimethylsiloxane. In some embodiments, the first layer may include a polymerization inhibitor. In example embodiments, the first layer may exhibit a viscosity in a range of about 100,000 cP to about 400,000 cP. In example embodiments, the first layer may exhibit a penetration depth of greater than or equal to about 11 mm. In some embodiments, the second layer may include a vinyl-substituted polydimethylsiloxane. For example, the second layer may include a bis-dimethylvinyl terminated polydimethylsiloxane. In illustrative embodiments, the second layer may include a hybrid-substituted polydimethylsiloxane. For example, the second layer may include a bis-hybrid terminated polydimethylsiloxane. In some embodiments, the second layer may exhibit a cone penetration depth of less than about 11 mm. For example, the second layer may exhibit a cone penetration depth of less than about 7 mm. In example embodiments, the second range may exhibit a thickness in a range of about 200 micrometers to about 1,000 micrometers. In some embodiments, the second layer may exhibit a hardness in a range of about 5 Shore 00 to about 80 Shore OO. In example embodiments, the first layer may be adhered to the drape. In illustrative embodiments, the second layer may be adhered to the first layer. In some embodiments, each of the pillars may be a circular column. For example, each circular column may exhibit a diameter in a range of about 0.5 mm to about 2.5 mm. In illustrative embodiments, each of the pillars may be a square column. For example, each square column may exhibit a width in a range of about 0.5 mm to about 2.5 mm. In example embodiments, each of the plurality of pillars may be spaced a distance in a range of about 1 mm to about 10 mm from any adjacent pillar.

[0013] Further, some example embodiments of a dressing may include a drape comprising a first side opposite a second side. A silicone gel layer may be disposed on the second side. A silicone polymer layer may be disposed on the silicone gel layer opposite the drape. The silicone gel layer may be an uncured silicone adhesive. The silicone polymer layer may be a partially cured silicone adhesive. The silicone polymer layer is configured to form channels through the silicone polymer layer in response to a lateral force applied to the silicone polymer layer. The silicone gel layer may be configured to fill the channels through the silicone polymer layer. In illustrative embodiments, the silicone gel layer may exhibit a viscosity in a range of about 100,000 cP to about 400,000 cP. Some example dressing embodiments may include a periphery around each of the drape, silicone gel layer, and silicone polymer layer. For example, the periphery may include a heat seal. In example embodiments, the periphery may include a heat-cured portion.

[0014] 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

[0015] Figure 1 is an exploded view of an example embodiment of a dressing in accordance with this specification;

[0016] Figure 2 is an isometric view of an assembled example of the dressing of Figure 1;

[0017] Figure 3 is a cross-sectional view of the example dressing of Figure 2, taken at line 3-3, applied to a tissue site in accordance with this specification;

[0018] Figure 4 is a detail view, taken at reference FIG. 4 in Figure 3, illustrating details that may be associated with some example embodiments of the example dressing of Figure 3;

[0019] Figure 5 illustrates additional details that may be associated with the detail view of Figure 4 in some embodiments of the dressing of Figure 3;

[0020] Figure 6 illustrates additional details that may be associated with the detail view of Figure 4 in some example embodiments of the dressing of Figure 3;

[0021] Figure 7 is a schematic view of another example dressing applied to a tissue site in accordance with this specification; [0022] Figure 8 is a schematic view of another example dressing applied to a tissue site in accordance with this specification; and

[0023] Figure 9 is a schematic diagram of an example embodiment of a therapy system in accordance with this specification.

DESCRIPTION OF EXAMPLE EMBODIMENTS [0024] 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.

[0025] Figure 1 is an exploded view of an example embodiment of a dressing 100 for application to a tissue site. In some embodiments, dressing 100 may comprise a cover layer, such as a drape 105, a first layer 110, and a second layer 115. The drape 105 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 Inspire 2327 polyurethane films, commercially available from Transcontinental Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the drape 105 may comprise Inspire 2301 having an MVTR (upright cup technique) of 2600 g/m²/24 hours and a thickness of about 30 microns. In illustrative embodiments, drape 105 may have a high MVTR, for example, at least 250 g/m²/24 hours. For example, drape 105 may have an MVTR in a range of about 250 g/m²/24 hours to about 5,000 g/m²/24 hours. In some embodiments, the drape 105 may comprise a first side 120 opposite a second side 125. Drape 105 may comprise a periphery 130 at an outer perimeter of the drape 105. The drape 105 may be in a substantially sheet form. For example, the first side 120 may be a substantially planar surface. In some embodiments, the second side 125 may be a substantially planar surface.

[0026] In illustrative embodiments, the first layer 110 may comprise a non-cured or partially-cured silicone gel adhesive. In example embodiments, the first layer 110 may comprise a vinyl-substituted polydimethylsiloxane. For example, the first layer 110 may comprise a bis-dimethylvinyl terminated polydimethylsiloxane. In some embodiments, the first layer 110 may comprise a hybrid-substituted polydimethylsiloxane. For example, the first layer 110 may comprise a bis-hybrid terminated polydimethlsiloxane. The first layer 110 may comprise a polymerization inhibitor, for example, a reagent added to the first layer 110 in order to prevent polymerization by electromagnetic radiation or thermal polymerization. For example, the polymerization inhibitor can delay or prevent the first layer 110 from curing. In illustrative embodiments, the non-cured or partially-cured silicone gel adhesive of the first layer 110 may be viscous or flowable. For example, the first layer 110 may exhibit a viscosity from about 100,000 cP to about 400,00 cP. The viscosity of the first layer 110 may be measured by methods such as by using a cone and plate viscometer, for example, as supplied by AMETEK Brookfield. In some embodiments, the silicone gel may exhibit a cone penetration depth (according to ISO 2137) of greater than or equal to 11 nm. The cone penetration depth of the first layer 110 may be measured using a Penetrometer: PNR 12 apparatus supplied by Anton Paar GmbH, for example, in a test performed at 25° C by measuring the penetration of the cone penetrometer (where a total weight of the rod and cone attached is 62.5 grams) into the sample by releasing the cone penetrometer and allowing the cone penetrometer to act for five seconds. In some embodiments, the first layer 110 may comprise a first side 135 opposite a second side 140. The first layer 110 may additionally comprise a periphery 145 at an outer perimeter of the first layer 110. In illustrative embodiments, the first layer 110 may be in a substantially sheet form. For example, first side 135 may be a substantially planar surface. In some embodiments, second side 140 may be a substantially planar surface.

[0027] In some embodiments, the second layer 115 may be a sealing layer formed from a soft, pliable material suitable for providing a fluid seal with a tissue site, such as a suitable gel material or polymer material, and may have a substantially flat surface. For example, the second layer 115 may comprise 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. In illustrative embodiments, the second layer 115 may be a fully-cured silicone adhesive. In some embodiments, the second layer 115 may comprise a vinyl-substituted polydimethylsiloxane. For example, the second layer 115 may comprise a bis-dimethylvinyl terminated polydimethylsiloxane. In example embodiments, the second layer 115 may comprise a hybrid-substituted polydimethylsiloxane. For example, the second layer 115 may comprise a bis-hybrid terminated polydimethylsiloxane. The second layer 115 may be adherent or tacking in some example embodiments. In illustrative embodiments, the second layer 115 may be non-adherent or non-tacky. In example embodiments, the second layer 115 may exhibit a cone penetration depth of less than 11 mm. For example, the second layer 115 may exhibit a cone penetration depth of less than 7 mm. In some embodiments, the second layer 115 may have a thickness between about 200 micrometers and about 1,000 micrometers. In illustrative embodiments, the second layer 115 may exhibit a Shore hardness between about 5 Shore OO and 80 Shore OO. The second layer 115 may comprise hydrophobic or hydrophilic materials. In example embodiments, the second layer 115 may comprise a first side 150 opposite a second side 155. In illustrative embodiments, the second layer 115 may comprise a periphery 160 at an outer perimeter of the second layer 115. In some embodiments, the second layer 115 may be in a substantially sheet form. For example, the first side 150 may be a substantially planar surface. For example, the second side 155 may be a substantially planar surface.

[0028] Figure 2 shows an isometric view of some embodiments of the dressing 100 with the drape 105, the first layer 110, and the second layer 115 in assembled form. In illustrative embodiments, the periphery 130 of the drape 105 may be substantially coextensive with the periphery 145 of the first layer 110. In example embodiments, the periphery 145 of the first layer 110 may be substantially coextensive with the periphery of the second layer 115. Assembled, the first side 120 of the drape 105 may be opposite the dressing 100 from the second side 155 of the second layer 115. In some embodiments, the first side 120 of the drape 105 and the second side 155 of the second layer 115 may be outward facing sides of the dressing 100.

[0029] In some embodiments, the drape 105 may be coupled to or adhered to the first layer 110. Coupling may also include mechanical, thermal, electrical, or chemical coupling (such as a chemical bond) in some contexts. For example, substantially all of the first side 135 of the first layer 110 may be coupled to or adhered to substantially all of the second side 125 of the drape 105. In illustrative embodiments, the periphery 130 of the drape 105 may be substantially coextensive with the periphery 145 of the first layer 110. For example, the second side 125 of the drape 105 may be coated with the first layer 110. In illustrative embodiments, the first layer 110 may be coupled to or adhered to the second layer 115. Substantially all of the first side 150 of the second layer 115 may be coupled to or adhered to substantially all of the second side 140 of the first layer 110. The periphery 145 of the first layer 110 may be substantially coextensive with the periphery 160 of the second layer 115. For example, the second side 140 of the first layer may be coated with the second layer 115.

[0030] Figure 3 is a cross-sectional view of the example dressing 100 of Figure 3, taken at line 3- 3, applied to a tissue site 305. The dressing 100 may be applied to an exemplary tissue site 305. In some embodiments, the dressing 100 may be configured to interface with the tissue site 305. For example, the dressing 100 may be generally configured to be positioned adjacent to the tissue site 305 and/or in contact with a portion of the tissue site 305, substantially all of the tissue site 305, or the tissue site 305 in its entirety. If the tissue site 305 comprises a wound 310, for example, the dressing 100 may partially or completely fill the wound 310, or be placed over the wound 310. In various embodiments, the dressing 100 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 the tissue site 305. For example, the size and shape of the dressing 100 may be adapted to the contours of deep and irregular shaped tissue sites and/or may be configured to be adapted to a given shape or contour. Moreover, in some embodiments, any or all of the surfaces of the dressing 100 may comprise projections, or an uneven, coarse, or jagged profile that can, for example, induce strains and stresses on the tissue site 305, which may be effective to promote granulation at the tissue site 305. [0031] The terms “tissue site” in this context broadly refers to a wound or 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 terms “tissue site” and/or “surface tissue site” in this context may also refer to areas of 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 used in certain tissue areas to grow additional tissue that may be harvested and transplanted to another tissue location. In some embodiments, the tissue site 305 may comprise a surface wound 310 that extends through the epidermis 315 and into a dermis 320. In some examples, the tissue site 305 may comprise a wound 310 which extends through the epidermis 315 and dermis 320 and into a subcutaneous tissue 325.

[0032] In some embodiments, the dressing 100 may be applied to the tissue site 305. For example, the second side 155 of the second layer 115 may be configured to face the tissue site 305. In illustrative embodiments, the second side 155 of the second layer 115 may be in contact with and adhered to a portion of the epidermis 315 surrounding the wound 310. In some embodiments, the second side 155 of the second layer 115 may be in contact with and adhered to a portion of the epidermis 315 surrounding the wound 310, and a portion of the wound 310. In illustrative embodiments, for example, where the second layer 115 comprises a partially-cured or cured silicone adhesive, the portion of the second layer 115 in contact with a moist wound 310 may not be adhered to a moist wound 310, or may be adhered to a moist wound 310 with reduced tack relative to the level of adhesion to a dry epidermis 315. For example, the partially-cured or cured silicone adhesive of the second layer 115 may exhibit a reduced tack against a moist or wet surface. In some embodiments, the partially-cured or cured silicone adhesive of the second layer 115 may facilitate a user lifting a portion of the dressing 100 from the tissue site 305, for example, to inspect the wound 310 or the periwound area, and re-adhering the lifted portion to the tissue site 305. In some embodiments, the dressing 100 may be removed from and reapplied to the tissue site 305, for example, to facilitate a user repositioning the dressing 100.

[0033] Figure 4 is a detail view, taken at reference FIG. 4 in Figure 3, illustrating additional details that may be associated with some embodiments of the example dressing 100 of Figure 3. For example, the second side 155 of the second layer 115 may be in contact with and/or adhered to the epidermis 315. The first side 150 of the second layer 115 may be in contact with and/or adhered to the second side 140 of the first layer 110. The first side 135 of the first layer 110 may be in contact with and/or adhered to the second side 125 of the drape 105. In illustrative embodiments, the first layer 110 may be substantially intact, for example, voids or channels may not be present in the first layer 110. In some embodiments, the second layer 115 may be substantially intact, for example, voids or channels may not be present in the second layer 115. [0034] Figure 5 illustrates additional details that may be associated with the detail view of Figure 4 in some embodiments of the dressing 100 of Figure 3. For example, the second layer 115 may be subjected to a force 505, or a force 505 may be applied to the second layer 115. In some embodiments, the second layer 115 may experience a force 505 in a lateral direction substantially parallel to the first side 150 of the second layer 115 and/or the second side of the second layer 115. For example, a lateral force 505 may be applied to the second layer 115. In illustrative embodiments, the force 505 may be applied directly to the second layer 115. In some embodiments, the force 505 may be transmitted to the second layer 115 at least partially through the drape 105 and/or the first layer 110. In example embodiments where the force 505 overcomes the internal bond strength of the second layer 115 or overcomes the bond strength of the adhesive of the second layer 115 to the first layer 110 and/or to the drape 105, one or more voices, spaces, openings, or channels 510 may form in the second layer 115. For example, Figure 5 shows the dressing 100 at a first point in time ti after a plurality of channels 510 have been formed. In example embodiments, the viscous and flowable adhesive of the first layer 110 will begin to flow into at least one of the plurality of channels 510. For example, the viscous and flowable adhesive of the first layer 110 may begin to flow into each of the plurality of channels 510. [0035] Figure 6 illustrates additional details that may be associated with the detail view of Figure 4 in some example embodiments of the dressing 100 of Figure 3. For example, Figure 6 illustrates the dressing 100 at a second point in time h after the first point in time ti. For example, at h. the viscous and flowable adhesive of the first layer 110 may have flown into and substantially filled at least one of the channels 510. In illustrative embodiments, at h. the viscous and flowable adhesive of the first layer 110 will have flow into and substantially filled each of the plurality of channels 510. By substantially filling channel 510, the viscous and flowable adhesive of the first layer 110 may prevent fluid flow and/or leaks through channel 510, improving the seal and/or barrier provided by the dressing 100 for the tissue site 305 against the environment.

[0036] Figure 7 is a schematic view of an exemplary dressing 100 applied to tissue site 305. In some embodiments, the dressing 100 may be sealed around a periphery 705. For example, the dressing 100 may be heat sealed around the periphery 705. In some embodiments, heat sealing may compress and cure the portion of the first layer 110 and the second layer 115 at the periphery 705 of the dressing to form a heat-cured portion 710. In example embodiments, the after heat sealing or heat curing, the portion of the first layer 110 at the periphery 705 or the heat-cured portion 710 may exhibit a substantially reduced viscosity when compared with the portion of the first layer 110 not at the periphery 705 or the heat-cured portion 710. For example, the periphery 705 may substantially contain the non heat sealed or non-heat-cured portions of the first layer 110 and the second layer 115. In illustrative embodiments, the periphery 705 or the heat-cured portion 710 may substantially contain the non-heat sealed or non-heat-cured portions of the first layer 110 and the second layer 115 within a volume defined by the drape 105, the periphery 705 or the heat-cured portion 710, and the tissue site 305. [0037] Figure 8 is a schematic view of an exemplary dressing 100 applied to tissue site 305. In some embodiments, the second layer 115 may include pillars 805. For example, pillars 805 may comprise fully-cured silicone adhesive material. In illustrative embodiments, pillars 805 may comprise the same material as the second layer 115. For example, pillars 805 may be integral with the second layer 115. In some embodiments, each pillar 805 may comprise a circular column. For example, each circular column may comprise a diameter in a range of about 0.5 mm to about 2.5 mm. In illustrative embodiments, each pillar 805 may be square columns. For example, each square column may comprise a width in a range of about 0.5 mm to about 2.5 mm. In example embodiments, each pillar 805 may be spaced a distance in a range of about 1 mm to about 10 mm from any adjacent pillar. In illustrative embodiments, pillars 805 may be circular columns, triangular columns, square columns, pentagonal columns, hexagonal columns, heptagonal columns, octagonal columns, nonagonal columns, decagonal columns, or columns with a polygonal or non-polygonal cross-section, or a combination of regularly and/or irregularly shaped columns. The addition of pillars 805 may reinforce the dressing 100 from collapse when force is applied to the dressing 100. For example, when force is applied substantially normal to the first side 120 of the drape 105 and towards the second layer 115, the drape 105 may be displaced towards the second layer 115, but portions of the drape 105 may be stopped from further displacement upon coming into contact with a pillar 805. In example embodiments, the pillars 805 may prevent or reduce the displacement of the first layer 110 by preventing the drape 105 from contacting the second layer 115 in at least the regions between the pillars 805, preserving a region for the first layer 110 to occupy.

[0038] Figure 9 is a schematic view of an example embodiment of a negative-pressure therapy system 900 illustrating details that may be associated with some embodiments of the dressing 100 configured to treat the tissue site 905 with negative pressure. As shown in the illustrative embodiment of Figure 9, the negative-pressure therapy system 900 may include the dressing 100 fluidly coupled to a negative-pressure source 910. In some embodiments, the negative-pressure source 910 may be coupled to the dressing 100 by a conduit, such as a tube 915, and a connector, such as a connector 920. The system 900 may comprise a tissue interface, such as a tissue interface 925. The dressing 100 may serve as a cover or sealing member, and may be attached to the epidermis 315. The dressing 100 may substantially prevent the leakage of fluids while allowing vapor to egress through the drape 105. [0039] In general, components of the negative-pressure therapy system 900 may be coupled directly or indirectly to each other. For example, the negative-pressure source 910 may be directly coupled to the connector 920 and indirectly coupled to the tissue interface 925 through the connector 920. Components may be fluidly coupled to each other to provide a path for transferring fluids, for example, liquids and/or gases, between the components. In some embodiments, components may be fluidly coupled with a tube, such as the tube 915, for example. A “tube,” as used herein, broadly refers to a tube, pipe, hose, conduit, or other structure with one or more lumina adapted to convey fluids between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. In some embodiments, components may additionally or alternatively be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0040] In operation, a tissue interface, such as the tissue interface 925, may be placed within, over, on, against, or otherwise proximate to a tissue site. The drape 108 may be sealed to undamaged epidermis 315 peripheral to the tissue site 905 by the first layer 110 and the second layer 115, which may form an adhesive bond with the tissue site 905. Thus, the dressing may provide a sealed therapeutic environment 930 proximate to the tissue site 905. The sealed therapeutic environment 930 may be substantially isolated from the external environment, and the reduced-pressure source 910 may be fluidly coupled to the sealed therapeutic environment 930. For example, the connector 920 may be received through aperture 935 formed in drape 105, aperture 940 formed in first layer 110, and aperture 945 formed in second layer 115. The aperture 935, aperture 940, and the aperture 945 may form a fluid seal against the connector 920, and the connector 920 may be in fluid communication with the sealed therapeutic environment 930. Negative pressure applied across the tissue site 905 through the tissue interface 925 disposed in the sealed therapeutic environment 930 can induce macrostrain and microstrain at the tissue site 905, and reduce exudates and other fluids from the tissue site. The removed exudates and other fluids can be collected in a container and disposed of properly.

[0041] In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term “downstream” may refer to a position in a fluid path relatively closer to a negative-pressure source, and conversely, the term “upstream” may refer to a position relatively further away from a negative-pressure source. 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 of negative-pressure therapy systems herein. However, a 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] “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to the sealed therapeutic environment 930 provided by the dressing 100. 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. Similarly, 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. [0043] A negative-pressure source, such as the negative-pressure source 910, may be a reservoir of air at a negative pressure, or may be a manual or electrically-powered device that can reduce the pressure in a sealed volume, such as a vacuum pump, a suction pump, a wall-suction port available at many healthcare facilities, or a micro-pump, for example. A negative-pressure source may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or operator interfaces that further facilitate negative-pressure therapy. 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 -75 mm Hg (-9.9 kPa) and -300 mm Hg (-39.9 kPa).

[0044] The tissue interface 925 can be generally adapted to contact the tissue site 905. The tissue interface 925 may be partially or fully in contact with the tissue site 905. If the tissue site 905 is a wound, for example, the tissue interface 925 may partially or completely fill the wound, or may be placed over the wound. The tissue interface 925 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 925 may be adapted to the contours of deep and irregular shaped tissue sites. In some embodiments, the tissue interface 925 may be a manifold. A “manifold” in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under negative pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute the negative pressure through multiple apertures across a tissue site, 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 across a tissue site. In some illustrative embodiments, the pathways of a manifold may be channels interconnected to improve distribution or collection of fluids across a tissue site. For example, cellular foam, 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 pathways. Liquids, gels, and other foams may also include or be cured to include apertures and flow channels. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores adapted to distribute negative pressure across a tissue site. The foam material may be either hydrophobic or hydrophilic. In one non-limiting example, a manifold may be an open-cell, reticulated polyurethane foam such as GranuFoam^® dressing available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0045] In an example in which the tissue interface 925 may be made from a hydrophilic material, the tissue interface 925 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 925 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam 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. The tissue interface 925 may further promote granulation at a tissue site when pressure within the sealed therapeutic environment 930 is reduced. For example, any or all of the surfaces of the tissue interface 925 may have an uneven, coarse, or jagged profde that can induce microstrains and stresses at the tissue site 905 if negative pressure is applied through the tissue interface 925. In some embodiments, the tissue interface 925 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 925 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 925 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.

[0046] The drape 105 of the dressing 100 may be an example of a sealing member. A sealing member may be constructed from a material that can provide a fluid seal between two environments or components, such as between a therapeutic environment and a local external environment. A sealing member may be, for example, an impermeable or semi-permeable, elastomeric fdm or barrier that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. For semi-permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. Generally, a drape 105 suitable for covering a tissue site for negative-pressure therapy may comprise a fdm having a thickness between about 25 microns and about 50 microns that is water- vapor permeable and formed of a polymer. The fdm, often formed of polyurethane, may be coated with an adhesive having a coating weight between about 25 gsm and about 65 gsm. The adhesive may often be acrylic-based and pressure sensitive. A pressure-sensitive adhesive increases in bond strength when pressed against the surface to which the adhesive is being bonded. In some applications, a pressure-sensitive adhesive may undergo a physical change when compressed against a surface. In other applications, a pressure-sensitive adhesive may flow into crevices of a surface when compressed, increasing the bond strength without undergoing a physical change. An attachment device may be used to attach a sealing member to an attachment surface, such as undamaged epidermis, a gasket, or another sealing member. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or an entire sealing member. In some embodiments, the attachment device may be an acrylic-based pressure sensitive adhesive having a coating weight between about 25 grams/m² (gsm) and about 60 gsm. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, organogel, or an acrylic adhesive.

[0047] A “container” broadly includes a canister, pouch, bottle, vial, or other fluid collection apparatus. A container, for example, 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.

[0048] A connector 920 may be used to fluidly couple the tube 915 to the sealed therapeutic environment 930. The negative pressure developed by the negative-pressure source 910 may be delivered through the tube 915 to the connector 920. In one illustrative embodiment, the connector 920 may be a T.R.A.C.^® Pad or Sensa T.R.A.C.^® Pad available from KCI of San Antonio, Texas. The connector 920 allows the negative pressure to be delivered to the sealed therapeutic environment 930. In other exemplary embodiments, the connector 920 may also be a tube inserted through the dressing 100. The negative pressure may also be generated by a device directly coupled to the dressing 100, such as a micropump.

[0049] While shown in several 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 100 and other components of the negative-pressure therapy system 900 may be eliminated or separated from other components for manufacture or sale.

Claims

CLAIMS What is claimed is:

1. A dressing comprising: a drape; a first layer disposed on a side of the drape, the first layer comprising an uncured silicone gel; and a second layer disposed on a side of the first layer opposite the drape, the second layer comprising a cured silicone polymer; wherein a viscosity of the first layer is greater than a viscosity of the second layer.

2. The dressing of claim 1, wherein the second layer is configured to form one or more channels in response to a lateral force applied to the second layer.

3. The dressing of claim 2, wherein the first layer is configured to fill at least one of the one or more channels.

4. The dressing of claim 1, wherein the silicone gel comprises a viscosity in a range of about 100,000 cP to about 400,000 cP.

5. The dressing of claim 1, wherein the silicone gel exhibits a cone penetration depth greater than or equal to about 11 mm.

6. The dressing of claim 1, wherein the silicone gel comprises a bis-dimethylvinyl terminated polydimethylsiloxane .

7. The dressing of claim 1, wherein the silicone gel comprises a bis-hybrid terminated polydimethylsiloxane .

8. The dressing of claim 1, wherein the silicone gel comprises a polymerization inhibitor.

9. The dressing of claim 1, wherein the cured silicone polymer exhibits a cone penetration depth of less than about 11 mm.

10. The dressing of claim 1, wherein the cured silicone polymer exhibits a cone penetration depth of less than about 7 mm.

11. The dressing of claim 1, wherein the cured silicone polymer comprises a hardness between about 5 Shore OO and about 80 Shore OO.

12. A method of applying a drape to tissue, comprising: providing a dressing comprising a first layer disposed between a drape and a second layer, the first layer comprising an uncured silicone gel, the second layer comprising a cured silicone polymer, the first layer exhibiting a viscosity greater than a viscosity of the second layer; applying a lateral force to the second layer; forming a plurality of channels in the second layer in response to the lateral force; applying a side of the second layer to tissue; and filling at least one of the plurality of channels with the first layer.

13. The method of claim 12, wherein the silicone gel exhibits a viscosity in a range of about 100,000 cP to about 400,000 cP.

14. The method of claim 12, wherein the silicone gel comprises a vinyl-substituted polydimethylsiloxane .

15. The method of claim 12, wherein the silicone gel comprises a hybrid-substituted polydimethylsiloxane .

16. The method of claim 12, wherein the silicone gel comprises a polymerization inhibitor.

17. A system for treating a tissue site with negative-pressure, comprising: a manifold configured to be positioned adjacent to the tissue site; a drape configured to be positioned over the tissue site and the manifold and seal to tissue adjacent to the tissue site to form a sealed space, the drape comprising: a cover layer, a first layer disposed on a side of the drape, the first layer comprising an uncured silicone gel, and a second layer disposed on a side of the first layer opposite the drape, the second layer comprising a cured silicone polymer, wherein a viscosity of the first layer is greater than a viscosity of the second layer, wherein the second layer is configured to form channels in response to a lateral force applied to the second layer, wherein the first layer is configured to fill the channels; a negative-pressure source configured to provide negative pressure to the sealed space.

18. The system of claim 17, wherein the silicone gel exhibits a viscosity in a range of about 100,000 cP to about 400,000 cP.

19. The system of claim 17, wherein the silicone gel comprises a polymerization inhibitor.

20. The system of claim 17, wherein the silicone gel is configured to fill the channels in response to negative pressure in the sealed space.

21. A dressing comprising: a first layer disposed between a drape and a second layer, the first layer comprising an uncured silicone gel, the second layer comprising a cured silicone polymer; a plurality of pillars formed on the second layer, the plurality of pillars comprising cured silicone polymer; wherein a viscosity of the first layer is greater than a viscosity of the second layer.

22. The dressing of claim 21, wherein the second layer is configured to form a plurality of channels in the second layer in response to a lateral force applied to the second layer.

23. The dressing of claim 22, wherein at least one of the plurality of channels extends through the second layer.

24. The dressing of claim 22, wherein the uncured silicone gel is configured to fill at least one of the plurality of channels.

25. The dressing of claim 21, wherein the drape comprises an elastomeric film.

26. The dressing of claim 21, wherein the drape comprises a polyurethane fdm.

27. The dressing of claim 21, wherein the drape comprises a thickness in a range of about 25 micrometers to about 50 micrometers.

28. The dressing of claim 21, wherein the drape comprises an MVTR in a range of about 250 g/m²/24 hours to about 5,000 g/m²/24 hours.

29. The dressing of claim 21, wherein the first layer comprises a vinyl-substituted polydimethylsiloxane .

30. The dressing of claim 21, wherein the first layer comprises a bis-dimethylvinyl terminated polydimethylsiloxane .

31. The dressing of claim 21, wherein the first layer comprises a hybrid-substituted polydimethylsiloxane .

32. The dressing of claim 21, wherein the first layer comprises a bis-hybrid terminated polydimethylsiloxane .

33. The dressing of claim 21, wherein the first layer comprises a polymerization inhibitor.

34. The dressing of claim 21, wherein the first layer exhibits a viscosity in a range of about 100,000 cP to about 400,000 cP.

35. The dressing of claim 21, wherein the first layer exhibits a penetration depth greater than or equal to about 11 mm.

36. The dressing of claim 21, wherein the second layer comprises a vinyl-substituted polydimethylsiloxane .

37. The dressing of claim 21, wherein the second layer comprises a bis-dimethylvinyl terminated polydimethylsiloxane .

38. The dressing of claim 21, wherein the second layer comprises a hybrid-substituted polydimethylsiloxane .

39. The dressing of claim 21, wherein the second layer comprises a bis-hybrid terminated polydimethylsiloxane .

40. The dressing of claim 21, wherein the second layer exhibits a cone penetration depth of less than about 11 mm.

41. The dressing of claim 21, wherein the second layer exhibits a cone penetration depth of less than about 7 mm.

42. The dressing of claim 21, wherein the second layer comprises a thickness in a range of about 200 micrometers to about 1,000 micrometers.

43. The dressing of claim 21, wherein the second layer exhibit a hardness in a range of about 5 Shore OO to about 80 Shore OO.

44. The dressing of claim 21, wherein the first layer is adhered to the drape.

45. The dressing of claim 21, wherein the second layer is adhered to the first layer.

46. The dressing of claim 21, wherein each of the plurality of pillars is a circular column.

47. The dressing of claim 46, wherein each circular column comprises a diameter in a range of about 0.5 mm to about 2.5 mm.

48. The dressing of claim 21, wherein each of the plurality of pillars is a square column.

49. The dressing of claim 47, wherein each square column comprises a width in a range of about 0.5 mm to about 2.5 mm.

50. The dressing of claim 21, wherein each of the plurality of pillars is spaced a distance in a range of about 1 mm to about 10 mm from any adjacent pillar.

51. A dressing comprising: a drape comprising a first side opposite a second side; a silicone gel layer disposed on the second side; and a silicone polymer layer disposed on the silicone gel layer opposite the drape; wherein the silicone gel layer is an uncured silicone adhesive, wherein the silicone polymer layer is a partially cured silicone adhesive, wherein the silicone polymer layer is configured to form channels through the silicone polymer layer in response to a lateral force applied to the silicone polymer layer, and wherein the silicone gel layer is configured to fill the channels through the silicone polymer layer.

52. The dressing of claim 51, wherein the silicone gel layer exhibits a viscosity in a range of about 100,000 cP to about 400,000 cP.

53. The dressing of claim 51, further comprising a periphery around each of the drape, silicone gel layer, and silicone polymer layer.

54. The dressing of claim 53, wherein the periphery comprises a heat seal.

55. The dressing of claim 53, wherein the periphery comprises a heat-cured portion.

56. The systems, apparatuses, and methods substantially as described herein.