WO2021033078A1 - Wound dressing with selectable transparency materials for use with light-switching adhesive systems - Google Patents

Abstract

Selectable transparency wound dressings and methods intended for use with light switching adhesive systems are provided. The wound dressing may include at least a dressing layer, a drape comprising a flexible film layer for placement proximate a wound, a photosensitive adhesive layer with a release agent configured to weaken upon exposure to specific wavelengths of light, and a selectively transparent hydrochromic coating configured to switch between an opaque state and a transparent state upon application of a disclosing liquid. The method of use allows a user to apply a disclosing liquid on the hydrochromic coating thus making the coating reversibly transparent and allowing light to permeate the coating and deactivate or loosen the photosensitive adhesive. A negative pressure wound therapy system using a light-deactivatable adhesive is also provided.

Description

WOUND DRESSING WITH SELECTABLE TRANSPARENCY MATERIALS FOR USE WITH LIGHT-SWITCHING ADHESIVE SYSTEMS

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/889,810, filed on August 21, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] This application relates generally to wound therapy dressings, systems, and methods.

BACKGROUND

[0003] Wound dressings can be designed to be selectively adherent so that the dressing is tightly bound to a wound site upon application, but loosened significantly immediately before removal. Selective adherence is useful for, among other things, maintaining a stable wound healing environment until loosening is desired and decreasing the pain felt by a patient upon removal of the dressing. One type of selectively adherent wound dressing includes bonds that tightly adhere to a surface upon initial application around a wound site, but purposefully degrade when exposed to certain wavelengths of light (e.g., ultraviolet light, ambient light, etc.). In some instances, the bonds may be designed to degrade when exposed to light from a flashlight, for example. However, in order to function properly, these light-sensitive adhesives often require a removable light blocking layer so that light-sensitive adhesives do not improperly or prematurely loosen. There exists a need for a wound dressing that prevents light-sensitive adhesives from deactivating prematurely, while still remaining easy to loosen when desired.

SUMMARY

[0004] The present disclosure overcomes the drawbacks of previously known wound dressings by providing a wound dressing with a light-deactivatable adhesive on a drape layer configured to be coupled to tissue. The wound dressing may include at least: 1) a manifold layer having a suitable absorbent and/or manifolding material, 2) a drape having: (i) a flexible film layer, and (ii) a photosensitive adhesive layer disposed on at least a portion of an underside of this flexible film layer, and with at least one release agent disposed within the photosensitive adhesive layer, where the at least one release agent is configured to weaken a bond of the photosensitive adhesive layer to the tissue upon exposure to at least one of a plurality of light wavelengths; and 3) a selectively transparent hydrochromic coating disposed on a top side of the drape above the photo-sensitive adhesive layer and configured to change between a plurality of states, including (i) an opaque state configured to block at least one of the plurality of light wavelengths from passing through the hydrochromic coating; and (ii) a transparent state configured to allow at least one of the plurality of light wavelengths to pass through the hydrochromic coating. The hydrochromic coating may cover all of the drape or may overlay only the adhesive region.

[0005] In some embodiments, the hydrochromic coating may change from the opaque state to the transparent state when a disclosing liquid with a refractive index within a range of the refractive index of the selectively transparent hydrochromic coating is applied to the selectively transparent hydrochromic coating. In some embodiments, the refractive index of the disclosing liquid may be within about plus or minus five percent of the refractive index of the hydrochromic coating. In certain embodiments, the refractive index of the hydrochromic coating may be substantially within a range of about 1.0 to about 2.0. In some embodiments, the refractive index of the hydrochromic coating may be substantially within a range of about 1.2 to about 1.75. In certain embodiments, the refractive index of the hydrochromic coating may be substantially within a range of about 1.33 to about 1.6.

[0006] The selectively transparent hydrochromic coating may return to the opaque state as the disclosing liquid evaporates after application. In some embodiments, the disclosing liquid may be water or ethanol or any combination of water and ethanol. The disclosing liquid may also be a combination of ethanol and benzyl alcohol. Further, the disclosing liquid may be at least one of isopropyl alcohol or benzyl alcohol.

[0007] In some preferred embodiments, the hydrochromic coating may be an ink. The hydrochromic coating further may be perforated. In some embodiments, the hydrochromic coating may comprise a plurality of polymer particles. The polymer particles may include, but are not limited to, fluoropolymers, silicones, or acrylics. In other embodiments, the hydrochromic coating may be a plurality of mineral particles. The mineral particles may be at least one of silicas, silicates, fluorites, or fluorides.

[0008] The plurality of light wavelengths used to weaken a bond of the photosensitive adhesive layer may include ultraviolet (UV) light wavelengths. In some embodiments, the plurality of light wavelengths may be between about 280 nm and about 385 nm. In some embodiments, the plurality of light wavelengths may comprise a portion of the visible light spectrum. At least one of the plurality of light wavelengths may be a wavelength in a blue through violet portion of the visible light spectrum. In other embodiments, the plurality of light wavelengths may be ambient light.

[0009] The flexible film layer may be, in some embodiments, a polyurethane flexible film layer.

[0010] In some embodiments of the system, ultraviolet light may be blocked from passing through the hydrochromic coating in the opaque state. The at least one release agent configured to weaken a bond of the photosensitive adhesive layer may be a photopolymer, an oil particle, a gas particle, a solvent, a lipid, and/or one or more microstructures. The at least one release agent may be in an inert or inactive state in, on, or near an adhesive layer before release. [0011] In some embodiments, the hydrochromic coating may be disposed on a top side of the drape. A layer may also be disposed on top of the hydrochromic coating. In some embodiments, the layer disposed on top of the hydrochromic coating comprises polyurethane.

[0012] In certain alternative embodiments, the system includes the drape, the selectively transparent hydrochromic coating, and the layer disposed on top of the hydrochromic coating, and the hydrochromic coating is perforated.

[0013] The disclosing liquid may be maintained for administration, for example, on a disposable wipe or a moistened towelette. Moreover, the hydrochromic coating further may incorporate a color indicator configured to change color when light exposure has occurred.

[0014] A method for wound therapy is also provided herein. The method may include at least:

(1) coupling a wound dressing having a drape layer with a light-deactivatable adhesive in registry with a hydrochromic coating to a patient; (2) changing the hydrochromic coating from an opaque state to a transparent state; (3) exposing the light-deactivatable adhesive layer to at least one of a plurality of light wavelengths to weaken a bond of the light-deactivated adhesive layer; and (4) removing the wound dressing from the patient.

[0015] In some embodiments of the method, changing the hydrochromic coating from the opaque state to the transparent state may be done by applying the disclosing liquid to the coating. In certain embodiments of the method, exposing the adhesive layer to the plurality of light wavelengths may comprise exposing the adhesive layer to UV light. In some embodiments, the UV light may be of a wavelengths between about 280 nm and about 385 nm.

[0016] The hydrochromic coating may change from the opaque state to the transparent state upon application of the wipe to the hydrochromic coating.

[0017] A wound dressing is also provided herein. The wound dressing may include a selectively transparent light-deactivatable adhesive configured to bond the dressing to a patient, thereby preventing the unintended or premature removal of the light-deactivatable adhesive and eliminating the need for an additional removable opaque layer. The wound dressing may include at least: a manifold layer configured for placement proximate a wound; a drape disposed over the manifold layer; a hydrochromic coating disposed on at least a portion of the drape layer; a light sensitive adhesive material disposed at least partially on a bottom side of the drape layer, and at least partially beneath the hydrochromic coating.

[0018] In some embodiments, a light sensitive adhesive material may be further disposed at least partially on at least one of a top side of the manifold layer or a bottom side of the manifold layer. [0019] In some embodiments, the wound dressing may also have a negative pressure source coupled in fluid communication with the drape layer and configured to draw a negative pressure through the dressing layer.

BRIEF DESCRIPTION OF FIGURES

[0020] FIG. 1A shows an exemplary wound dressing with a light-deactivatable adhesive drape adhered to a patient before the selectively transparent hydrochromic coating has been wiped with a disclosing liquid.

[0021] FIG. IB illustrates a user applying a disposable wipe containing a disclosing liquid to the selectively transparent hydrochromic coating so as to allow light wavelengths to pass through the coating and drape to the photosensitive adhesive layer.

[0022] FIG. 1C an exemplary wound dressing with a light-deactivatable adhesive of the present disclosure where the hydrochromic coating is transparent after being wiped with a disclosing liquid.

[0023] FIG. ID shows the photosensitive adhesive layer being peeled away from a patient’s skin after light exposure.

[0024] FIG. IE shows a negative pressure wound therapy system with a wound dressing having a light-deactivatable material disposed beneath a hydrochromic coating, according to an exemplary embodiment.

[0025] FIG. 2 shows an embodiment of the wound dressing with a light-deactivatable adhesive wherein the hydrochromic coating is disposed between two layers of polyurethane film or foam.

[0026] FIG. 3 shows an embodiment of the wound dressing with a light-deactivatable adhesive wherein the hydrochromic coating is disposed between two layers of polyurethane film or foam and the top layer of polyurethane is also perforated.

[0027] FIG. 4 illustrates an alternative wound dressing of the present disclosure adhered to a patient.

DETAIFED DESCRIPTION

Definitions

[0028] As used in the description of the invention and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0029] As used herein, the term “comprising” is intended to mean that the compositions and methods include the recited elements, but do not exclude others. As used herein, the transitional phrase consisting essentially of (and grammatical variants) is to be interpreted as encompassing the recited materials or steps and those that do not materially affect the basic and novel characteristic(s) of the recited embodiment. Thus, the term “consisting essentially of’ as used herein should not be interpreted as equivalent to “comprising.” “Consisting of’ shall mean excluding more than trace elements of other ingredients and substantial method steps for administering the compositions disclosed herein. Aspects defined by each of these transition terms are within the scope of the present disclosure.

[0030] The term “about,” as used herein when referring to a measurable value such as an amount or concentration and the like, is meant to encompass variations of 20%, 10%, 5%, 1 %, 0.5%, or even 0.1 % of the specified amount.

[0031] The terms or “acceptable,” “effective,” or “sufficient” when used to describe the selection of any components, ranges, dose forms, etc. disclosed herein intend that said component, range, dose form, etc. is suitable for the disclosed purpose.

[0032] Also as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).

[0033] As used herein, “Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0034] The term “light-deactivatable adhesive” is intended to mean an adhesive material that has certain photosensitive or light-sensitive properties that cause a bond by the adhesive material between a wound dressing and a patient to weaken upon exposure of the adhesive material to certain wavelengths of light (as more further described herein).

Modes of Carrying Out the Disclosure Wound Dressing:

[0035] A wound dressing with a light-deactivatable adhesive for wound management is provided herein. The light-deactivatable adhesive allows for easy removal when contacted by certain wavelengths of light and is otherwise adherent when not contacted by said wavelengths. Wound dressing 10 with light-deactivatable adhesive may be configured to couple to a patient over a wound bed (W) and to surrounding tissue (T). As shown in FIGS. 1A-1D, dressing 10 may include at least: 1) dressing layer 101; and 2) drape layer 100 having: (i) flexible film layer 103, and (ii) photosensitive adhesive layer 102 with at least one release agent 104 disposed within photosensitive adhesive layer 102, where the at least one release agent 104 is configured to weaken a bond of photosensitive adhesive layer 102 to the tissue (T) upon exposure to at least one of a plurality of light wavelengths (LW); and 3) selectively transparent hydrochromic 110 coating disposed on drape 100 and configured to change between a plurality of states, including (i) an opaque state 112 configured to block at least one of the plurality of light wavelengths (LW) from passing through hydrochromic coating 110; and (ii) a transparent state 111 configured to allow at least one of the plurality of light wavelengths (LW) to pass through hydrochromic coating 110. In some embodiments, hydrochromic coating 110 may cover all of drape 100 (as shown by way of example in FIG. 1A) or may overlay only a region corresponding to the adhesive layer 102 (i.e.. the hydrochromic coating may be provided in registry with the light-deactivatable adhesive).

[0036] Hydrochromic coating 110 comprises a material that changes from opaque state 112 to transparent state 111 when disclosing liquid 113 with a refractive index within a range of the refractive index of the selectively transparent hydrochromic coating 110 is applied to the coating. When dry, hydrochromic coating 110 appears opaque due to the scattering of light caused by the differential in refractive index between air in the pores of the particles and that of the particle itself.

To maximize the transparency effect, the refractive index of disclosing liquid 113 and the particles of hydrochromic coating 110 should be reasonably close. In certain preferred embodiments, the refractive index of disclosing liquid 113 is within about plus or minus five percent of the refractive index of hydrochromic coating 110. In some embodiments, the refractive index of hydrochromic coating 110 is substantially within a range of about 1.0 to about 2.0. This may include, but is not limited to, refractive indices for hydrochromic coating 110 of about 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6,

1.7, 1.8, 1.9, and 2.0, or any values in between. In some embodiments, the refractive index of hydrochromic coating 110 is substantially within a range of about 1.2 to about 1.75. In some embodiments, the refractive index of the hydrochromic coating 110 is substantially within a range of about 1.33 to about 1.6.

[0037] Hydrochromic coating 110 is designed to return to opaque state 112 as disclosing liquid 113 evaporates after application. In some embodiments, disclosing liquid 113 may be made of water or ethanol or any combination of water and ethanol. Disclosing liquid 113 also may comprise ethanol and benzyl alcohol. In certain embodiments, disclosing liquid 113 may be at least one of isopropyl alcohol or benzyl alcohol.

[0038] Hydrochromic coating 110 is optionally perforated in some embodiments. Hydrochromic coating 110 further may be provided in the form an ink material. In some embodiments, hydrochromic coating 110 may comprise a plurality of polymer particles. Such polymer particles may be, but are not limited to, at least one of fluoropolymers, silicones, or acrylics. Hydrochromic coating 110 may also comprise a plurality of mineral particles. Such mineral particles may include, but are not limited to, silicas, silicates, fluorites, or fluorides.

[0039] The light-deactivatable adhesive as shown to be provided on the drape layer is a photosensitive adhesive material that is responsive to certain wavelengths of light and loosens (e.g., its bond weakens, degrades, etc.) upon exposure to those wavelengths. To that end, the plurality of light wavelengths (LW) may include ultraviolet (UV) light wavelengths (LW). In some embodiments, the plurality of light wavelengths (LW) should be between about 280 nm and about 385 nm. The plurality of light wavelengths (LW) may be a portion of the visible light spectrum. At least one of the plurality of light wavelengths (LW) may be a wavelength in a blue through violet portion of the visible light spectrum. The plurality of light wavelengths (LW) effective in loosening the bond of the photosensitive adhesive material may also include ambient light. Ultraviolet light may be blocked from passing through hydrochromic coating 110 in opaque state 112, in order to maintain the bond of the adhesive materials until removal of the dressing is desired.

[0040] In some embodiments, the flexible fdm layer 103 of drape 100 may be formed from a polyurethane material.

[0041] The release agent 104 within photosensitive adhesive layer 102 may be at least one of a photopolymer, an oil particle, a gas particle, a solvent, a lipid, and/or one or more microstructures. Release agent 104 may also be in an inert or inactive state in, on, or near the photosensitive adhesive layer 102 before release. In some embodiments, hydrochromic coating 110 may be disposed on a top side 120 of drape 100.

[0042] As shown in FIG. 2 and FIG. 3, in some embodiments, a layer 200 may be disposed on top of hydrochromic coating 110 as a protective layer for the hydrochromic layer. This protective layer may be used for example for “rub resistance” or other suitable resistance to abrasion, wear and tear, etc. In some embodiments, layer 200 may be formed from a polyurethane material. In some embodiments, dressing 10 comprises drape 100, selectively transparent hydrochromic coating 110, and protective layer 200 disposed on top of the hydrochromic coating 110, where hydrochromic coating 110 may be optionally perforated (as shown by way of example as perforations 114 in FIG.

3). In some embodiments, drape 100 may be formed from a polyurethane fdm coated with an adhesive. Drape 100 is typically manufactured with polyurethane fdm in one “pass” either through extrusion or casting. However, in some embodiments, it is possible to make the fdm in multiple passes where the polyurethane fdm is coated with one or more layers of polyurethane or other polymers. In some embodiments, a polyurethane fdm is first made, then coated with a hydrochromic ink, then perforated, then coated with another layer of polyurethane fdm, thus sandwiching the ink between two or more layers of polyurethane fdm. Referring to FIG. 2 and FIG. 3, layer 200 disposed on top of hydrochromic coating 110 is shown as an extra protective layer. In FIG. 3, layer 200 and hydrochromic coating 110 both are perforated, which allows the disclosing liquid 113 to enter the hydrochromic coating 110. One of the possible advantages of this extra layer is that it may provide rub resistance for the hydrochromic coating and photosensitive adhesive. [0043] As shown in FIG. IB, for ease of administration, disclosing liquid 113 may be maintained on disposable wipe 122 or a moistened towelette. Hydrochromic coating 110 further may include a color indicator material that changes color when light exposure has occurred.

[0044] Various disclosing liquid 113 mixtures may be used, including but not limited to, water, ethanol (RI 1.36) and benzyl alcohol (RI 1.54). In certain embodiments, the combination of components in disclosing liquid 113 may include water and ethanol with a refractive index of 1.34 to ethanol and benzyl alcohol with a refractive index of 1.45. In some embodiments, mixtures made be used with higher RI polymer fibers, such as polyvinylidene difluoride (PVdF) with an RI of about 1.42; polyamides with a refractive index between about 1.53 to about 1.56; and EVA’s and acrylics with a refractive index between about 1.48 to about 1.55.

[0045] According to any embodiment, dressing layer 101 may include any one or more of the following: a wound contact layer, a manifold layer, a wicking layer, and/or an absorbent layer. In some embodiments, wound dressing 10 may be adaptable for use on a patient as a standalone dressing and treatment option for wound care. In other embodiments, wound dressing 10 may be adaptable for use with a negative pressure wound therapy treatment (NPWT) option as shown by way of example in FIG. IE.

[0046] Negative pressure wound therapy refers to the application of negative pressure (relative to atmospheric pressure) to a wound bed to facilitate healing of the wound bed. Negative pressure may be applied in coordination with instillation therapy, in which instillation fluid (e.g., cleansing fluid, medicated fluid, antibiotic fluid, irrigation fluid) is applied to the wound bed. Negative pressure and instillation wound therapy (NPWTi) may facilitate removal of wound exudate and other debris from the wound bed and otherwise support healing.

[0047] Dressing 101 may be a manifold layer. The manifold layer may be configured to allow air and fluid to flow therethrough. In some embodiments, the manifold layer may be made of an open cell foam, for example a reticulated polyurethane open cell foam. In some embodiments, the manifold layer is made of an open-cell foam marketed as GRANUFOAM™ by ACELITY™. The manifold layer may have a thickness in a range between approximately 6mm and 10mm. Accordingly, the manifold layer may be thinner than in conventional bulky dressings. The reduced thickness of the manifold layer facilitates flexion of the dressing.

[0048] The manifold layer also allows for the communication of air pressure, for example negative pressure (relative to ambient air pressure), through the manifold layer and to the wound bed, in some embodiments via a fenestrated fdm layer. The dressing is configured such that air and fluid can flow between a first manifold layer and a second manifold layer. Negative pressure can thereby be communicated across the manifold layer. The dressing is configured to be coupled to a vacuum (negative pressure) tube and, in some embodiments, an instillation tube. For example, a hole may be cut in a firstbarrier layer and a connection pad may be coupled to the barrier layer over the hole. The connection pad is coupled to the vacuum tube and/or instillation tube. In some embodiments, multiple holes and/or connection pads are used. For example, the connection pad may be a SENSAT.R.A.C.™ connection pad marketed by ACELITY™. The manifold layer can thereby be put in fluid communication with a vacuum tube and/or an instillation tube. A negative pressure pump can also be controlled to remove air from the manifold layer, to establish a negative pressure at the manifold layer. The manifold layer is configured to allow air and fluid to flow therethrough.

[0049] Such application of dressing 10 for NPWT may include a connection interface pad 124 with a tube 125 coupled at a first end to the drape layer 100 (through a suitable hole or opening in the polyurethane film portion 118 of the drape layer) and at a second end to a NPWT therapy device 126. Therapy device 126 includes a negative pressure source and suitable controls and interfaces for applying a negative pressure to the dressing layer 101, as shown in FIG. IE.

Methods of Use:

[0050] A method of wound therapy is also provided herein. As shown in FIG. 1A-1D, the method may include at least: (1) coupling a wound dressing 10 having a light-deactivatable adhesive material to a patient’s tissue (T) surrounding a wound bed (W), where dressing 10 includes: (i) a drape or cover layer 100 comprising: (a) flexible film layer 103, and (b) photosensitive adhesive layer 102 having at least one release agent 104 disposed within photosensitive adhesive layer 102, where the at least one release agent 104 is configured to weaken a bond of the photosensitive adhesive layer 102 between the drape layer and tissue (T) upon exposure to at least one of a plurality of light wavelengths (LW), and (ii) a selectively transparent hydrochromic coating 110 disposed on drape 100 and configured to change between a plurality of states, wherein the plurality of states comprise: (a) opaque state 112 configured to block at least one of the plurality of light wavelengths (LW) from passing through hydrochromic coating 110; and (b) transparent state 111 configured to allow at least one of the plurality of light wavelengths (LW) to pass through hydrochromic coating 110; (2) changing selectively transparent hydrochromic coating 110 from opaque state 112 to transparent state 111; (3) exposing the photosensitive adhesive layer to at least one of the plurality of light wavelengths to weaken the bond of photosensitive adhesive layer 102; and (4) removing drape 100 from tissue (T).

[0051] As shown in FIG. IB, in some embodiments of the method, changing hydrochromic coating 110 from opaque state 112 to transparent state 111 includes applying disclosing liquid 113 to coating 110. As further shown in FIG. 1C, after application of disclosing liquid 113 to hydrochromic coating 110, coating 110 switches to transparent state 111. In some embodiments, exposing adhesive layer 102 to the plurality of light wavelengths (LW) may include exposing adhesive layer 102 to UV light. In some embodiments, UV light can include wavelengths, for example, between about 280 nm and about 385 nm. [0052] Hydrochromic coating 110 may change from opaque state 112 to the transparent state 111 upon application of wipe 122 to hydrochromic coating 100.

[0053] Referring to FIG. ID, when photosensitive adhesive layer 102 is exposed to the plurality of light wavelengths (LW), release agent 104 is activated and the bond created in the photosensitive layer 102 between the drape and tissue (T) loosens. Thus, the drape can be removed from tissue (T) with greater ease and less pain for the patients.

[0054] A negative pressure wound therapy system with a light-deactivatable adhesive is also provided herein. The system may comprise at least: 1) a dressing layer; 2) a drape layer disposed atop the dressing layer, the dressing layer comprising: i) a flexible fdm, and ii) a photosensitive adhesive material disposed on at least a portion of an underside of the flexible fdm layer, and a release agent disposed within the photosensitive adhesive material, wherein the release agent is configured to weaken a bond of the photosensitive adhesive material upon exposure to at least one of a plurality of light wavelengths; 3) a selectively transparent coating disposed on a top side of the drape above the photosensitive adhesive material and configured to change between: a) an opaque state configured to block at least one of the plurality of light wavelengths from passing through the coating; and b)a transparent state configured to allow at least one of the plurality of light wavelengths to pass through the coating to the photosensitive adhesive material; 4) a manifold configured to overlay the drape layer and adhere to periwound or skin tissue; 5) a negative pressure source; 6) a canister; and 7) a conduit in fluid communication between both the manifold and the canister and the manifold and the negative pressure source. When the negative pressure source is activated, the dressing adheres to a wound bed and or a periwound PW, whereby exudate and wound fluids are withdrawn through the dressing, selectively transparent coating, the manifold and the conduit to the canister

Alternative Embodiments:

[0055] In some embodiments, a color indicator may be added to hydrochromic coating 110 to show a user when the required light exposure to loosen photosensitive adhesive layer 102 has occurred.

[0056] In all embodiments described above, the gas-porous hydrochromic coating 110 should not affect or hinder the moisture vapor transmission rate of the entire system or any of its constituent parts.

[0057] If a user changes their mind during removal of drape 100 after application of disclosing liquid 113, they may leave the system exposed to ambient air, which will reverse the process whereby the coating is made translucent. Hydrochromic coating 110 will revert to opaque within a few minutes. [0058] A wound dressing with selectively transparent materials for use with light switching adhesive systems is disclosed herein. Referring to FIG. 4, wound dressing 20 may include dressing layer 400 configured for placement proximate a wound; drape layer 402 disposed over dressing layer 400; hydrochromic coating 404 disposed at least partially on top side 406 of drape layer 402; and light sensitive adhesive material 408 disposed at least partially on bottom side 410 of drape layer 402, and at least partially beneath hydrochromic coating 404.

[0059] In some embodiments, light sensitive adhesive material 408 may be further disposed at least partially on at least one of top side 412 of the dressing layer 400 or bottom side 410 of the dressing layer 400.

Claims

WE CLAIM:

1. A wound dressing with a light-deactivatable adhesive, comprising: a dressing layer; and a drape layer disposed atop the dressing layer, comprising: a flexible film, and a photosensitive adhesive material disposed on at least a portion of an underside of the flexible film layer, and a release agent disposed within the photosensitive adhesive material, wherein the release agent is configured to weaken a bond of the photosensitive adhesive material upon exposure to at least one of a plurality of light wavelengths; and a selectively transparent coating disposed on a top side of the drape above the photosensitive adhesive material and configured to change between: an opaque state configured to block at least one of the plurality of light wavelengths from passing through the coating; and a transparent state configured to allow at least one of the plurality of light wavelengths to pass through the coating to the photosensitive adhesive material.

2. The wound dressing of claim 1, wherein the coating is a hydrochromic coating that changes from the opaque state to the transparent state when a disclosing liquid with a refractive index within a range of the refractive index of the selectively transparent hydrochromic coating is applied to the selectively transparent hydrochromic coating.

3. The wound dressing of claim 2, wherein the refractive index of the disclosing liquid is within about plus or minus five percent of the refractive index of the hydrochromic coating.

4. The wound dressing of claim 2, wherein the refractive index of the hydrochromic coating is substantially within a range of about 1.0 to about 2.0.

5. The wound dressing of claim 2, wherein the refractive index of the hydrochromic coating is substantially within a range of about 1.2 to about 1.75.

6. The wound dressing of claim 2, wherein the refractive index of the hydrochromic coating is substantially within a range of about 1.33 to about 1.6.

7. The wound dressing of claim 2, wherein the hydrochromic coating returns to the opaque state as the disclosing liquid evaporates after application.

8. The wound dressing of claim 2, wherein the disclosing liquid comprises water or ethanol or any combination of water and ethanol.

9. The wound dressing of claim 2, wherein the disclosing liquid comprises ethanol and benzyl alcohol.

10. The wound dressing of claim 2, wherein the disclosing liquid comprises at least one of isopropyl alcohol or benzyl alcohol.

11. The wound dressing of claim 2, wherein the hydrochromic coating comprises an ink.

12. The wound dressing of claim 2, wherein the hydrochromic coating is perforated.

13. The wound dressing of claim 2, wherein the hydrochromic coating comprises a plurality of polymer particles.

14. The wound dressing of claim 13, wherein the polymer particles comprise fluoropolymers, silicones, or acrylics.

15. The wound dressing of claim 2, wherein the hydrochromic coating comprises a plurality of mineral particles.

16. The wound dressing of claim 15, wherein the mineral particles comprise silicas, silicates, fluorites, or fluorides.

17. The wound dressing of claim 1, wherein the plurality of light wavelengths include ultraviolet (UV) light wavelengths.

18. The wound dressing of claim 1, wherein the plurality of light wavelengths are between about 280 nm and about 385 nm.

19. The wound dressing of claim 1, wherein the plurality of light wavelengths comprise a portion of the visible light spectrum.

20. The wound dressing of claim 1, wherein at least one of the plurality of light wavelengths is a wavelength in a blue through violet portion of the visible light spectrum.

21. The wound dressing of claim 1, wherein the plurality of light wavelengths comprise ambient light.

22. The wound dressing of claim 1, wherein the flexible fdm comprises polyurethane.

23. The wound dressing of claim 1, wherein ultraviolet light is blocked from passing through a hydrochromic coating in the opaque state.

24. The wound dressing of claim 1, wherein the release agent comprises a photopolymer, an oil particle, a gas particle, a solvent, a lipid, and/or one or more microstructures.

25. The wound dressing of claim 1, wherein the release agent comprises an inert or inactive state in, on, or near an adhesive layer before release.

26. The wound dressing of claim 2, wherein the hydrochromic coating is disposed on a top side of the drape.

27. The wound dressing of claim 2, further comprising a layer disposed on top of the hydrochromic coating.

28. The wound dressing of claim 27, wherein the layer disposed on top of the hydrochromic coating comprises polyurethane.

29. The wound dressing of claim 28, wherein the hydrochromic coating is perforated.

30. The wound dressing of claim 2, wherein the disclosing liquid is maintained for administration on a disposable wipe or a moistened towelette.

31. The wound dressing of claim 2, wherein the hydrochromic coating further comprises a color indicator that changes color when light exposure has occurred.

32. The wound dressing of claim 1, wherein the dressing layer comprises any one or more of a wound contact layer, a manifold layer, or an absorbent layer.

33. The wound dressing of claim 1, further comprising a negative pressure wound therapy source coupled in fluid communication with the drape layer and configured to draw a negative pressure at the dressing layer.

34. A method, comprising: applying a wound dressing having a drape layer with a light-deactivatable adhesive in registry with a hydrochromic coating; changing the hydrochromic coating from an opaque state to a transparent state; exposing the light-deactivatable adhesive to at least one of a plurality of light wavelengths to weaken a bond of the light-deactivatable adhesive; and removing the wound dressing.

35. The method of claim 34, wherein changing the hydrochromic coating from the opaque state to the transparent state comprises applying a disclosing liquid to the hydrochromic coating.

36. The method of claim 34, wherein exposing the light-deactivatable adhesive layer to the plurality of light wavelengths comprises exposing the light-deactivatable adhesive layer to UV light.

37. The method of claim 36, wherein the UV light comprises wavelengths between about 280 nm and about 385 nm.

38. The method of claim 34, wherein the hydrochromic coating changes from the opaque state to the transparent state upon application of a wipe containing disclosing liquid to the hydrochromic coating.

39. A wound dressing, comprising: a dressing layer configured for placement proximate a wound; a drape layer disposed over the dressing layer; a hydrochromic coating disposed at least partially on a top side of the drape layer; a light-sensitive adhesive material disposed at least partially on a bottom side of the dressing layer, and at least partially beneath the hydrochromic coating.

40. The wound dressing of claim 39, further comprising a negative pressure source coupled in fluid communication with the drape layer and configured to draw a negative pressure at the dressing layer.

41. The wound dressing of claim 39, wherein the dressing layer comprises a manifold layer.

42. The wound dressing of claim 40, wherein the manifold layer is configured to allow air and fluid to flow therethrough.

43. The wound dressing of claim 40, wherein the manifold layer may be made of an open-cell foam, optionally a reticulated polyurethane open cell foam.

44. The wound dressing of claim 40, wherein the manifold layer may have a thickness in a range between approximately 6mm and 10mm.

45. The wound dressing of claim 40, wherein the coating is a hydrochromic coating that changes from the opaque state to the transparent state when a disclosing liquid with a refractive index within a range of the refractive index of the selectively transparent hydrochromic coating is applied to the selectively transparent hydrochromic coating.

46. The wound dressing of claim 40, wherein the refractive index of the disclosing liquid is within about plus or minus five percent of the refractive index of the hydrochromic coating.

47. The wound dressing of claim 40, wherein the hydrochromic coating returns to the opaque state as the disclosing liquid evaporates after application.

48. The wound dressing of claim 40, wherein the hydrochromic coating comprises an ink.

49. The wound dressing of claim 40, wherein the hydrochromic coating is perforated.

50. The wound dressing of claim 40, wherein the hydrochromic coating comprises a plurality of mineral particles.

51. The wound dressing of claim 40, wherein the hydrochromic coating comprises a plurality of polymer particles.

52. A negative pressure wound therapy system with a light-deactivatable adhesive, comprising: a dressing having: a manifold layer configured for placement proximate a wound bed; a drape layer disposed atop the manifold layer, comprising: a flexible film, and a photosensitive adhesive material disposed on at least a portion of an underside of the flexible film layer, and a release agent disposed within the photosensitive adhesive material, wherein the release agent is configured to weaken a bond of the photosensitive adhesive material upon exposure to at least one of a plurality of light wavelengths; and a selectively transparent coating disposed on a top side of the drape above the photosensitive adhesive material and configured to change between: an opaque state configured to block at least one of the plurality of light wavelengths from passing through the coating; and a transparent state configured to allow at least one of the plurality of light wavelengths to pass through the coating to the photosensitive adhesive material; a negative pressure source; and a conduit in fluid communication between the manifold and the negative pressure source.

53. The negative pressure wound therapy system of claim 52, wherein the negative pressure source is disposed within a therapy unit, and further comprising a canister removably coupled to the therapy unit and in fluid communication with the negative pressure source and the conduit.