CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/971,073, filed on February 6, 2020, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

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

BACKGROUND

[0003] Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negative- pressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0004] There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound or a cavity can be washed out with a liquid solution for therapeutic purposes. These practices are commonly referred to as "irrigation" and "lavage" respectively. "Instillation" is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative- pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed.

[0005] Additionally, there is widespread acceptance that covering a wound may protect from infection, and that making efforts to clean the wound prior to applying a dressing over the wound can prove beneficial for healing and recovery. [0006] While the clinical benefits of negative-pressure therapy and/or instillation therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients.

BRIEF SUMMARY

[0007] New and useful systems, apparatuses, and methods for treating tissue, for example in a negative-pressure therapy environment, are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0008] For example, in some embodiments, a dressing for application to a tissue site may be configured with one or more integral ultraviolet (UV) light sources directed to allow disinfection of the tissue site under the dressing without removal of the dressing. For example, the dressing may comprise a plurality of UV-C light sources, which may each be configured to emit UV-C 207-222 nm light. In some embodiments, each of the light sources may comprise a light emitting diode (LED). The light sources may be configured to provide one-time, continuous, or intermittent disinfection, sanitization, and/or sterilization of the tissue site, in order to kill infectious agents such as bacteria and/or viruses. By integrating the light sources within the dressing, active, on-going disinfection may take place underneath the dressing system (e.g. while the dressing is in place on the tissue site, without the need to remove the dressing).

[0009] Some dressing embodiments may comprise a tissue interface, which may comprise or consist essentially of a contact layer. In some embodiments, the contact layer may be substantially optically transparent and/or configured to diffuse light therethrough, and the light sources may be placed atop the contact layer and directed to emit UV light through the contact layer, which may allow diffusion of the UV light onto the tissue site. In some embodiments, the contact layer may be adhesive or tacky. For example, the contact layer may comprise silicone gel, which may be approximately 1/8 inch thick. In some embodiments, the dressing may also be configured for use in a negative-pressure therapy system. For example, the tissue interface may further comprise a manifold. In some embodiments, the light sources may be located between the manifold and the contact layer and may be directed to emit light towards a tissue site through the contact layer when the dressing is in place for treatment. In other embodiments, the manifold may be located between the light sources and the contact layer of the dressing, and the manifold may be substantially optically transparent and/or configured to diffuse light onto the tissue site. In some embodiments, the manifold may form the contact layer (e.g. the contact layer may be configured as a manifold). In some embodiments, UV light from the light sources may be diffused over the entire tissue site. In some embodiments, an occlusive cover, such as atop cap, may span the outer surface of the dressing. The cover may be configured to minimize the amount of light that is visible to the patient wearing the dressing.

[0010] In some embodiments, the light sources may be configured to ensure overlapping zones of UV-C, so that light from one of the light sources may overlap with light from at least one other of the light sources. In some embodiments, the light sources may be spaced apart. For example, the light sources may be spaced apart by about % inch. Some embodiments may also include safety features, for example to minimize the risk of unwanted UV exposure (for example, preventing UV light exposure to the patient’s eyes). Some dressing embodiments may power the light sources using a coin battery, and a tab may be initially and removably installed between the circuit for the light sources and the battery (for example, between the battery terminal contacts). The tab may be removed once the dressing is in place on the tissue site, to activate the light sources without risk of exposing the patient’s eyes to the UV light. Some embodiments may also be configured with a safety shutoff-strip, which may be a conductive strip that may attach to the patient’s skin when the dressing is in place on the tissue site, and may be temporarily left behind on the patient’s skin upon removal of the dressing, thereby deactivating the light sources to prevent exposure to the patient’s eyes.

[0011] More generally, some dressing embodiments may comprise: a tissue interface and a plurality of light sources configured to direct ultraviolet light through at least a portion of the tissue interface. In some embodiments, each of the light sources may comprise a light-emitting diode. In some embodiments, each of the light sources may be configured to emit UV-C light, for example light in a spectrum from 207 - 222 nm. In some embodiments, the tissue interface may comprise a contact surface, for example a surface of the contact layer configured to contact the tissue site, and all of the plurality of light sources may be located in a plane substantially parallel to and elevated off the contact surface. In some embodiments, the light sources may be configured so that light from each of the light sources overlaps with light from one or more other of the light sources (e.g. at least 2, or 3-6). In some embodiments, the light sources may be configured to be elevated at least approximately 1/8 inch above the tissue site when the dressing is in place on the tissue site (e.g. spaced above the contact surface). In some embodiments, the light sources may be spaced apart approximately % inch. In some embodiments the light sources may be aligned linearly, which may be particularly advantageous for treating incisions. In some embodiments, the plurality of light sources may be configured in an array. For example, the array may comprise at least three rows of light sources, with adjacent rows offset and alternating rows aligned.

[0012] In some embodiments, the plurality of light sources may be located on or within the contact layer. In some embodiments, the contact layer may comprise a ring of transparent adhesive with a central opening. In some embodiments, the contact layer may comprise a ring of adhesive, which may not be transparent, with a central opening, and the plurality of light sources may be oriented to direct light through the central opening. Some embodiments may further comprise a cover forming the outer surface. In some embodiments, the cover may be occlusive (e.g. block UV light). In some embodiments, the cover may be configured to provide a seal for negative-pressure therapy.

[0013] Some embodiments may further comprise a manifold which is substantially transparent to UV light and/or is configured to diffuse UV light therethrough. For example, the manifold may be located between the light sources and the contact layer. Some embodiments of the manifold may be non-transparent, non-diffusing, and/or non-translucent and may be located between the light sources and the cover. For example, the light sources may be located between the manifold and the contact layer. In some embodiments, the cover may comprise a cap that is coupled to the manifold. Some embodiments may further comprise a port (e.g. in the cover) configured to provide fluid communication into the cover. Some embodiments of the contact layer may further comprise a plurality of apertures configured to allow fluid communication between the manifold and the tissue site. In some embodiments, the light sources may not be located over any of the apertures in the contact layer.

[0014] Some embodiments may further comprise a battery configured to power the plurality of light sources. In some embodiments, the battery may be electrically coupled to the plurality of light sources by one or more electric pathway. In some embodiments, the one or more electric pathway may be at least partially located within the contact layer. Some embodiments may further comprise a safety shut-off strip configured to electrically couple the battery to the plurality of light sources while the dressing is in place on the tissue site, but to prevent the battery from powering the light sources upon removal of the dressing from the tissue site. For example, the safety shut-off strip may comprise: a bottom layer configured to adhere to tissue; a top layer coupled to the contact surface of the dressing and stacked atop and adhered to the bottom layer; wherein: the bottom layer comprises a first adhesive configured to adhere the bottom layer to the tissue site; the top layer is adhered to the bottom layer by a second adhesive; the first adhesive is stronger than the second adhesive; the coupling between the top layer and contact surface is stronger than the second adhesive; and the bottom layer and the top layer are configured so that the electric pathway is complete if the bottom layer and the top layer are stacked.

[0015] Some embodiments may further comprise a processor electrically coupled to the light sources and configured to operate the light sources. In some embodiments, the processor may be configured to activate the light sources for the same amount of time every day. In some embodiments, the processor may be configured to activate the light sources for less time each successive day. In some embodiments, the processor may be configured to activate the light sources for a first amount of time for each of the first 1-2 or 1-3 days, and then to activate the light sources for a second amount of time for the remaining days, wherein the first amount of time is greater than the second amount of time. In some embodiments, the dressing may be configured to allow use of the light sources for sterilization and/or disinfection of the tissue site without removing the dressing.

[0016] Alternatively, other example dressing embodiments may comprise: a contact surface; an outer surface; a plurality of light sources configured to direct UV-C light onto the tissue site when the dressing is in place on the tissue site (e.g. directing UV light through the contact surface); and a manifold configured to diffuse UV light and located between the plurality of light sources and the contact surface. Some embodiments may further comprise a cover configured to form the outer surface and to provide a seal for negative-pressure therapy. In some embodiments, the cover may comprise a port configured to provide fluid communication into the cover and/or to the manifold. Some embodiments may further comprise an adhesive layer configured to be substantially transparent to UV light and having a plurality of apertures configured to provide fluid communication between the manifold and the tissue site.

[0017] Alternatively, other example dressing embodiments may comprise: a plurality of light sources configured to direct UV-C light onto the tissue site when the dressing is in place on the tissue site; a cover configured to seal for negative-pressure therapy; and a manifold located between the plurality of light sources and the cover. In some embodiments, the light sources may be elevated at least about 1/8 inch from a contact surface. Some embodiments may further comprise an adhesive layer having a plurality of apertures configured to provide fluid communication between the manifold and the tissue site, wherein the plurality of light sources may be located between the adhesive layer and the manifold. Some embodiments may further comprise a protective layer, which may have a porous fabric or a film with slits, and which may be located between the light sources and the manifold.

[0018] Alternatively, other example dressing embodiments may comprise: an adhesive tissue- contact layer configured to be substantially transparent to UV light; and a plurality of light sources configured to direct UV-C light through the adhesive tissue-contact layer. In some embodiments, the adhesive tissue-contact layer may comprise a contact surface and an exterior surface, wherein the plurality of light sources may be located on the exterior surface. Some embodiments may further comprise a non-adherent film located on the contact surface of the adhesive tissue-contact layer, wherein the non-adherent film may not span the entirety of the contact surface.

[0019] Alternatively, other example dressing embodiments may comprise: a contact surface; an outer surface; a battery; a plurality of light sources configured to direct UV-C light onto the tissue site when the dressing is in place on the tissue site; and a safety shut-off strip configured to electrically couple the battery to the light sources, as part of an electric pathway between the battery and the light sources, while the dressing is in place on the tissue site, but to prevent the battery from powering the light sources upon removal of the dressing from the tissue site. In some embodiments, the safety shut off strip may comprise: a tissue-adhering bottom layer; and a top layer coupled to the cover or the contact surface and stacked atop and adhered to the tissue-adhering bottom layer; wherein: the tissue adhering bottom layer may comprise a first adhesive configured to adhere to the tissue site; the top layer may be adhered to the tissue-adhering bottom layer by a second adhesive; the first adhesive may be stronger than the second adhesive; the coupling between the top layer and the contact surface may be stronger than the second adhesive; and the bottom layer and the top layer may be configured so that, when stacked in contact, the electric pathway is complete.

[0020] Alternatively, other example dressing embodiments may comprise: a contact surface; an outer surface; a plurality of light sources configured to direct UV-C light onto the tissue site when the dressing is in place on the tissue site; and a processor configured to operate the plurality of light sources for a plurality of days. In some embodiments, the processor may be configured to activate the light sources for the same amount of time each of the plurality of days. In some embodiments, the processor may be configured to activate the light sources for less time each successive one of the plurality of days. In some embodiments, the processor may be configured to activate the light sources for a first amount of time for each of the first 1-2 or 1-3 days, and then to activate the light sources for a second amount of time for the remaining days, wherein the first amount of time is greater than the second amount of time.

[0021] A system for providing negative-pressure therapy to a tissue site is also described herein, wherein some example embodiments may include: a negative-pressure source; and a UV disinfection dressing, such as the exemplary embodiments described herein, in fluid communication with the negative-pressure source. For example, in some embodiments the dressing may comprise: a contact surface, an outer surface, and a plurality of light sources configured to direct UV-C light onto the tissue site when the dressing is in place on the tissue site. Some system embodiments may further comprise a cover configured to form the outer surface and to provide a seal for negative-pressure therapy.

[0022] A method, for using a dressing having a plurality of UV light sources (for example, similar to those dressing embodiments described above) to treat a tissue site, is also described herein, wherein some example embodiments may include: applying the dressing to the tissue site so that the plurality of UV light sources are directed at the tissue site; and activating the plurality of UV light sources to sterilize the tissue site. In some embodiments, the plurality of UV light sources may be activated while the dressing is in place on the tissue site. In some embodiments, the plurality of UV light sources may be activated without removing the dressing from the tissue site. In some embodiments, the tissue site may be located on a patient, and the plurality of UV light sources may be activated while the patient is ambulatory. In some embodiments, applying the dressing may comprise adhering the dressing to the tissue site. In some embodiments, the dressing may comprise an adhesive layer configured to be substantially transparent to UV light, and activating the plurality of UV light sources may comprise directing UV light through at least a portion of the adhesive layer and onto the tissue site. In some embodiments, the dressing may further comprise a manifold and a cover, and the method may further comprise: fluidly coupling a negative-pressure source to the manifold through the cover; and providing negative-pressure therapy to the tissue site.

[0023] In some embodiments, the dressing may further comprise a processor configured to operate the plurality of light sources for a plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for the same amount of time each of the plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for less time each successive one of the plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for a first amount of time for each of the first 1-2 or 1-3 days, and then activating the plurality of UV light sources for a second amount of time for the remaining days, wherein the first amount of time is greater than the second amount of time. Some embodiments may further comprise removing the dressing from the tissue site; and automatically deactivating the plurality of UV light sources upon removal. Some embodiments may further comprise attaching a safety strip to the tissue site, wherein the safety strip is configured to deactivate the plurality of UV light sources upon removal of the dressing from the tissue site.

[0024] A method, for manufacturing a UV disinfection dressing (for example, similar to those dressing embodiments disclosed herein), is also described, wherein some example embodiments may include: providing a plurality of UV light sources; and configuring the plurality of UV light sources to be elevated off a contact surface of the dressing. In some embodiments, the step of providing the plurality of UV light sources may comprise providing a plurality of UV-C light sources. In some embodiments, the step of configuring the plurality of UV light sources to be elevated off a contact surface may comprise configuring the plurality of UV light sources to be elevated at least about 1/8 inch off the contact surface and to direct UV light towards and/or through the contact surface. Some embodiments may further comprise configuring the plurality of UV light sources so that the light from each of the light sources overlaps with light from another of the light sources. In some embodiments, the step of configuring the plurality of UV light sources so that the light from each of the light sources overlaps with light from another of the light sources may comprise spacing apart the plurality of UV light sources approximately % inch.

[0025] Some embodiments may further comprise: providing an adhesive layer configured to be transparent to UV light; and configuring the plurality of UV light sources with respect to the adhesive layer so that UV light passes through at least a portion of the adhesive layer. In some embodiments, the UV light from the plurality of UV light sources may pass entirely through the adhesive layer. In some embodiments, the plurality of UV light sources may be located or disposed within the adhesive layer. For example, the step of providing an adhesive layer may comprise forming the adhesive layer with the plurality of UV light sources located therein, in some embodiments. In some embodiments, the adhesive layer may comprise a plurality of apertures therethrough, and the step of configuring the plurality of UV light sources with respect to the adhesive layer may comprise configuring the plurality of UV light sources to not be located over any of the apertures. Some embodiments may further comprise providing a battery for the plurality of UV light sources, wherein an electric pathway between the battery and the plurality of UV light sources may be at least partially located within the adhesive layer. Some embodiments may further comprise electrically coupling a safety shut-off strip between a battery and the plurality of UV light sources, wherein the safety shut-off strip may be configured to automatically deactivate the plurality of UV light sources upon removal of the dressing from a tissue site.

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

[0027] Figure 1 is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment and instillation treatment in accordance with this specification;

[0028] Figure 2 is a graph illustrating additional details of example pressure control modes that may be associated with some embodiments of the therapy system of Figure 1;

[0029] Figure 3 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system of Figure 1 ;

[0030] Figure 4 is a chart illustrating details that may be associated with an example method of operating the therapy system of Figure 1; and

[0031] Figure 5 is an isometric view of an exemplary dressing illustrating additional details that may be associated with the therapy system of Figure 1;

[0032] Figure 6 is a schematic cross-section view of the dressing of Figure 5;

[0033] Figure 7 is a schematic exploded or assembly view of the dressing of Figure 6;

[0034] Figure 8 is a schematic plan view of an exemplary array of light sources for the dressing of Figure 5;

[0035] Figure 9 is a schematic plan view of another exemplary array of light sources for the dressing of Figure 5;

[0036] Figure 10 is a schematic cross-section view of an alternate dressing;

[0037] Figure 11 is a schematic cross-section view of another alternate dressing;

[0038] Figure 12 is a schematic cross-section view of yet another alternate dressing;

[0039] Figure 13 is a schematic cross-section view of still another alternate dressing;

[0040] Figure 14 is a schematic cross-section view of yet another alternate dressing;

[0041] Figure 15 is an isometric view of an alternate exemplary dressing illustrating additional details that may be associated with some embodiments;

[0042] Figure 16 is a schematic cross-section view of the dressing of Figure 15;

[0043] Figure 17 is a schematic cross-section view of an alternate dressing;

[0044] Figure 18 is a schematic cross-section view of another alternate dressing;

[0045] Figure 19 is a schematic cross-section view of yet another alternate dressing;

[0046] Figure 20 is a schematic cross-section view of still another alternate dressing;

[0047] Figure 21 is a schematic cross-section view of yet another alternate dressing;

[0048] Figure 22A is an isometric view of an exemplary dressing in place on a tissue site, illustrating additional details that may be associated with some embodiments;

[0049] Figure 22B is an isometric view of the dressing of Figure 22A upon removal from the tissue site, illustrating additional details that may be associated with some embodiments; [0050] Figure 23 is a schematic isometric view of the safety shut-off strip which is part of the dressing of Figure 22A, illustrating additional details that may be associated with some embodiments; and

[0051] Figure 24 is a chart illustrating exemplary operation options of the light sources of the dressing of Figure 5 for sterilization of the tissue site.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0052] 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.

[0053] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

[0054] Figure 1 is a simplified functional block diagram of an example embodiment of a therapy system 100 that can provide negative-pressure therapy with optional instillation of topical treatment solutions to a tissue site in accordance with this specification.

[0055] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target located on or within tissue, including, but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted.

[0056] The therapy system 100 may include a source or supply of negative pressure, such as a negative-pressure source 105, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 110, and a fluid container, such as a container 115, are examples of distribution components that may be associated with some examples of the therapy system 100. As illustrated in the example of Figure 1, the dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments.

[0057] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface may facilitate coupling a fluid conductor to the dressing 110. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0058] The therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0059] The therapy system 100 may also include a source of instillation solution. For example, a solution source 145 may be fluidly coupled to the dressing 110, as illustrated in the example embodiment of Figure 1. The solution source 145 may be fluidly coupled to a positive-pressure source, such as a positive-pressure source 150, a negative-pressure source such as the negative-pressure source 105, or both, in some embodiments. A regulator, such as an instillation regulator 155, may also be fluidly coupled to the solution source 145 and the dressing 110 to ensure proper dosage of instillation solution (e.g. saline) to a tissue site. For example, the instillation regulator 155 may comprise a piston that can be pneumatically actuated by the negative-pressure source 105 to draw instillation solution from the solution source during a negative-pressure interval and to instill the solution to a dressing during a venting interval. Additionally or alternatively, the controller 130 may be coupled to the negative-pressure source 105, the positive-pressure source 150, or both, to control dosage of instillation solution to a tissue site. In some embodiments, the instillation regulator 155 may also be fluidly coupled to the negative-pressure source 105 through the dressing 110, as illustrated in the example of Figure 1.

[0060] Some components of the therapy system 100 may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate therapy. For example, in some embodiments, the negative-pressure source 105 may be combined with the controller 130, the solution source 145, and other components into a therapy unit.

[0061] In general, components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 105 may be directly coupled to the container 115 and may be indirectly coupled to the dressing 110 through the container 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. For example, the negative-pressure source 105 may be electrically coupled to the controller 130 and may be fluidly coupled to one or more distribution components to provide a fluid path to a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0062] A negative-pressure supply, such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro pump, for example. “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. References to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0063] The container 115 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.

[0064] A controller, such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negative- pressure source 105. In some embodiments, for example, the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example. The controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters based on the input signals.

[0065] Sensors, such as the first sensor 135 and the second sensor 140, are generally known in the art as any apparatus operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is detected or measured. For example, the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the therapy system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 135 may be a piezo-resistive strain gauge. The second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 130. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0066] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. The tissue interface 120 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 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.

[0067] In some embodiments, the tissue interface 120 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid, such as fluid from a source of instillation solution, across a tissue site.

[0068] In some illustrative embodiments, a manifold may comprise a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

[0069] In some embodiments, the tissue interface 120 may comprise or consist essentially of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and foam having an average pore size in a range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compression load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the tissue interface 120 may be at least 10 pounds per square inch. The tissue interface 120 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the tissue interface may be foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the tissue interface 120 may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0070] The thickness of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the thickness of the tissue interface may be decreased to reduce tension on peripheral tissue. The thickness of the tissue interface 120 can also affect the conformability of the tissue interface 120. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0071] The tissue interface 120 may be either hydrophobic or hydrophilic. In an example in which the tissue interface 120 may be hydrophilic, the tissue interface 120 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 120 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open-cell foam such as V.A.C. WHITEFOAM™ dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0072] In some embodiments, the tissue interface 120 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 120 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 120 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.

[0073] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 125 may comprise or consist of, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties.

[0074] In some example embodiments, the cover 125 may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 125 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 polymide copolymers. Such materials are commercially available as, for example, Tegaderm® drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane films, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m ² /24 hours and a thickness of about 30 microns.

[0075] An attachment device may be used to attach the cover 125 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure -sensitive adhesive configured to bond the cover 125 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[0076] The solution source 145 may also be representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0077] In operation, the tissue interface 120 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound. The cover 125 may be placed over the tissue interface 120 and sealed to an attachment surface near a tissue site. For example, the cover 125 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment.

[0078] The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example.

[0079] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies something relatively further away from a source of negative pressure or closer to a source of positive pressure. Similarly, it may be convenient to describe certain features in terms of fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components herein. However, the fluid path may also be reversed in some applications, such as by substituting a positive-pressure source for a negative-pressure source, and this descriptive convention should not be construed as a limiting convention.

[0080] Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in container 115.

[0081] In some embodiments, the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the therapy system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, controller 130 may include an input for receiving a desired target pressure and may be programmed for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 130 can operate the negative -pressure source 105 in one or more control modes based on the target pressure and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0082] Figure 2 is a graph illustrating additional details of an example control mode that may be associated with some embodiments of the controller 130. In some embodiments, the controller 130 may have a continuous pressure mode, in which the negative-pressure source 105 is operated to provide a constant target negative pressure, as indicated by line 205 and line 210, for the duration of treatment or until manually deactivated. Additionally or alternatively, the controller may have an intermittent pressure mode, as illustrated in the example of Figure 2. In Figure 2, the x-axis represents time and the y-axis represents negative pressure generated by the negative-pressure source 105 over time. In the example of Figure 2, the controller 130 can operate the negative-pressure source 105 to cycle between a target pressure and atmospheric pressure. For example, the target pressure may be set at a value of 135 mmHg, as indicated by line 205, for a specified period of time (e.g., 5 min), followed by a specified period of time (e.g., 2 min) of deactivation, as indicated by the gap between the solid lines 215 and 220. The cycle can be repeated by activating the negative-pressure source 105, as indicated by line 220, which can form a square wave pattern between the target pressure and atmospheric pressure.

[0083] In some example embodiments, the increase in negative-pressure from ambient pressure to the target pressure may not be instantaneous. For example, the negative-pressure source 105 and the dressing 110 may have an initial rise time, as indicated by the dashed line 225. The initial rise time may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in a range of about 20-30 mmHg/second and in a range of about 5-10 mmHg/second for another therapy system. If the therapy system 100 is operating in an intermittent mode, the repeating rise time, as indicated by the solid line 220, may be a value substantially equal to the initial rise time as indicated by the dashed line 225.

[0084] Figure 3 is a graph illustrating additional details that may be associated with another example pressure control mode in some embodiments of the therapy system 100. In Figure 3, the x- axis represents time and the y-axis represents negative pressure generated by the negative-pressure source 105. The target pressure in the example of Figure 3 can vary with time in a dynamic pressure mode . For example, the target pressure may vary in the form of a triangular waveform, varying between a negative pressure of 50 and 135 mmHg with a rise time 305 set at a rate of +25 mmHg/min. and a descent time 310 set at -25 mmHg/min. In other embodiments of the therapy system 100, the triangular waveform may vary between negative pressure of 25 and 135 mmHg with a rise time 305 set at a rate of +30 mmHg/min and a descent time 310 set at -30 mmHg/min.

[0085] In some embodiments, the controller 130 may control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure may vary between a maximum and minimum pressure value that may be set as an input prescribed by an operator as the range of desired negative pressure. The variable target pressure may also be processed and controlled by the controller 130, which can vary the target pressure according to a predetermined waveform, such as a triangular waveform, a sine waveform, or a saw-tooth waveform. In some embodiments, the waveform may be set by an operator as the predetermined or time-varying negative pressure desired for therapy.

[0086] Figure 4 is a chart illustrating details that may be associated with an example method 400 of operating the therapy system 100 to provide negative-pressure treatment and instillation treatment to the tissue interface 120. In some embodiments, the controller 130 may receive and process data, such as data related to instillation solution provided to the tissue interface 120. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to a tissue site (“fill volume”), and the amount of time prescribed for leaving solution at a tissue site (“dwell time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the dwell time may be between one second to 30 minutes. The controller 130 may also control the operation of one or more components of the therapy system 100 to instill solution, as indicated at 405. For example, the controller 130 may manage fluid distributed from the solution source 145 to the tissue interface 120. In some embodiments, fluid may be instilled to a tissue site by applying a negative pressure from the negative-pressure source 105 to reduce the pressure at the tissue site, drawing solution into the tissue interface 120, as indicated at 410. In some embodiments, solution may be instilled to a tissue site by applying a positive pressure from the positive- pressure source 160 to move solution from the solution source 145 to the tissue interface 120, as indicated at 415. Additionally or alternatively, the solution source 145 may be elevated to a height sufficient to allow gravity to move solution into the tissue interface 120, as indicated at 420.

[0087] The controller 130 may also control the fluid dynamics of instillation at 425 by providing a continuous flow of solution at 430 or an intermittent flow of solution at 435. Negative pressure may be applied to provide either continuous flow or intermittent flow of solution at 440. The application of negative pressure may be implemented to provide a continuous pressure mode of operation at 445 to achieve a continuous flow rate of instillation solution through the tissue interface 120, or it may be implemented to provide a dynamic pressure mode of operation at 450 to vary the flow rate of instillation solution through the tissue interface 120. Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation at 455 to allow instillation solution to dwell at the tissue interface 120. In an intermittent mode, a specific fill volume and dwell time may be provided depending, for example, on the type of tissue site being treated and the type of dressing being utilized. After or during instillation of solution, negative-pressure treatment may be applied at 460. The controller 130 may be utilized to select a mode of operation and the duration of the negative pressure treatment before commencing another instillation cycle at 465 by instilling more solution at 405. [0088] Figure 5 is an isometric view of an example of the dressing 110 illustrating additional details that may be associated with the therapy system of Figure 1. In some embodiments, the dressing 110 may comprise a first surface (e.g. a contact surface 505) and a second surface (e.g. an outer surface 510). The contact surface 505 may be configured to contact the tissue site, and the outer surface 510 may be located opposite the contact surface 505. Some embodiments of the dressing 110 may also comprise a port 515, which can be configured to couple the dressing 110 to a negative-pressure source.

[0089] Figure 6 is a schematic cross-section view of the dressing 110 of Figure 5, illustrating additional details that may be associated with some embodiments. In Figure 6, the tissue interface may comprise a contact layer 605, a plurality of UV light sources 610, and a manifold layer 615, which may be stacked with the cover 125 and coupled together. In some embodiments, the contact layer 605 may be configured to form the contact surface 505 and/or to adhere the dressing 110 in place on the tissue site (e.g. as the attachment device). For example, the contact layer 605 may form an adhesive layer. In some embodiments, the contact layer 605 may comprise a plurality of apertures 620 therethrough. In some embodiments, the plurality of UV light sources 610 may be disposed between the contact layer 605 and the manifold layer 615. In some embodiments, the plurality of UV light sources 610 may be set off from the apertures 620 in the adhesive layer 605 and/or not aligned or located over the apertures 620. The manifold layer 615 may be disposed between the plurality of UV light sources 610 and the cover 125, in some embodiments. The cover 125 may form the outer surface 510 of the dressing 110, in some embodiments, and/or may comprise the port 515, which may be configured to fluidly couple the manifold layer 615 to the negative-pressure source. In some embodiments, the cover 125 may be configured to seal the dressing 110 for negative-pressure therapy. For example, the cover 125 may be configured to maintain negative pressure within the dressing 110 (e.g. the cover 125 may be formed of material operable to maintain a seal against negative pressure) and/or to provide a seal adequate to maintain negative-pressure within the dressing 110 for a given (e.g. therapeutic) negative-pressure source. In some embodiments, the cover 125 may be occlusive, for example being substantially opaque.

[0090] In some embodiments, the apertures 620 in the contact layer 605 may be configured to provide fluid communication between the manifold layer 615 and the tissue site. The apertures 620 may have a uniform distribution pattern, or may be randomly distributed on the contact layer 605. In some embodiments, the apertures 620 may be distributed approximately evenly across and/or be co-extensive with the contact layer 605. The apertures 620 may have many shapes, including circles, squares, stars, ovals, polygons, slits, complex curves, rectilinear shapes, triangles, for example, or may have some combination of such shapes. Each of the apertures 620 may have uniform or similar geometric properties. For example, in some embodiments, each of the apertures 620 may be circular apertures, having substantially the same diameter. In some embodiments, the diameter of each of the apertures 620 may be between about 1 millimeter and about 50 millimeters. In other embodiments, the diameter of each of the apertures 620 may be between about 1 millimeter and about 20 millimeters. In some embodiments, the apertures 620 may be generally circular and may have a diameter of about 2 millimeters. In some embodiments, geometric properties of the apertures 620 may vary. For example, the diameter of the apertures 620 may vary depending on the position of the apertures 620 in the contact layer 605. The apertures 620 may be spaced substantially equidistant over the contact layer 605, in some embodiments. Alternatively, the spacing of the apertures 620 may be irregular. In some embodiments, the apertures 620 may be distributed across the contact layer 605 in a grid of parallel rows and columns. Within each row and column, the apertures 620 may be equidistant from each other. In some embodiments, the apertures 620 may be spaced about 6 millimeters apart along each row and column, with a 3 millimeter offset. The apertures 620 may be formed by cutting or by application of local RF or ultrasonic energy, for example, or by other suitable techniques for forming an opening in the contact layer 605.

[0091] In some embodiments, the dressing 110 may comprise a battery 625, such as a coin battery, which may be configured to power the plurality of UV light sources 610. Some embodiments may also (optionally) comprise a protective layer 630, for example between the contact surface 505 and/or the plurality of UV light sources 610 and the manifold layer 615. In some embodiments, the protective layer 630 may act as a comfort layer, configured to improve comfort and/or to protect the tissue site from chaffing at the tissue site (for example, in embodiments, when the manifold is in close proximity to the tissue site). In some embodiments, the protective layer 630 may act as a fluid control layer, configured to minimize maceration, backflow of exudate out of the dressing to the tissue site, and/or tissue in-growth from the tissue site into the dressing 110.

[0092] In some embodiments, the contact layer 605 may be formed of a material which is configured to not substantially interfere with transmission of UV light (e.g. UV-C light) and/or configured to diffuse light from the UV light sources 610 over the entirety of the contact surface 505 and/or the tissue site. In some embodiments, the contact layer 605 may be substantially transparent or translucent. The contact layer 605 may also comprise or consist essentially of an adhesive or tacky material in some embodiments, for example forming an adhesive layer. For example, the contact layer 605 may comprise or consist essentially of silicone gel. The silicone gel may be substantially transparent or translucent in some examples. A thickness of at least approximately 1/8 inch thick (e.g. about 1/8 inch thick) may be suitable for some embodiments. In some embodiments, the contact layer 605 may have a hardness between about 5 Shore OO and about 80 Shore OO. In some embodiments, the plurality of UV light sources 610 may contact the contact layer 605 opposite the contact surface 505, so that the plurality of UV light sources 610 may be elevated off the contact surface 505 at least approximately 1/8 inch (e.g. the thickness ofthe contact layer 605). In some embodiments, the plurality of UV light sources 610 may be located in a plane configured to be substantially parallel to the contact surface 505, and/or may be configured to direct their light through the contact layer 605 and/or through the contact surface 505 to the tissue site (e.g. to provide sterilization/disinfection of the tissue site). In some embodiments, the UV light sources 610 may each be configured to emit UV-C light. In some embodiments, each of the plurality of UV light sources 610 may be configured to emit light in a spectrum from about 207-222 nm (e.g. wavelength). In some embodiments, each of the UV light sources 610 may comprise an LED.

[0093] The protective layer 630 may be configured to allow fluid transport from the tissue site into the dressing 110 and/or manifold layer 615 during negative-pressure therapy. In some embodiments, the protective layer 630 may comprise a porous fabric, a porous film, or a polymeric film (e.g. which may be liquid impermeable) with a plurality of fluid passages (e.g. slits, slots, or fluid valves). In some embodiments, the protective layer 630 may comprise or consist essentially of a woven, elastic material or a polyester knit textile substrate. In some embodiments, the protective layer 630 may comprise or consist essentially of a liquid-impermeable, elastomeric material. For example, the protective layer 630 may comprise or consist essentially of a polymer fdm. In some embodiments, for example, the protective layer 630 may comprise or consist essentially of a hydrophobic polymer, such as a polyethylene fdm. The simple and inert structure of polyethylene can provide a surface that interacts little, if any, with biological tissues and fluids, providing a surface that may encourage the free flow of liquids and low adherence, which can be particularly advantageous for many applications. Other suitable polymeric fdms include polyurethanes, acrylics, polyolefin (such as cyclic olefin copolymers), polyacetates, polyamides, polyesters, copolyesters, PEBAX block copolymers, thermoplastic elastomers, thermoplastic vulcanizates, polyethers, polyvinyl alcohols, polypropylene, polymethylpentene, polycarbonate, styreneics, silicones, fluoropolymers, and acetates. A thickness between 20 microns and 100 microns may be suitable for many applications. In some embodiments, the protective layer 630 may be hydrophobic. In some embodiments, the protective layer 630 may be hydrophilic. In some embodiments, the protective layer 630 may be suitable for welding to other layers, such as the manifold layer 615.

[0094] Some embodiments of the protective layer 630 may have one or more fluid passages (such as a plurality of slits or slots - not shown here), which can be distributed uniformly or randomly across the protective layer 630. The fluid passages may be bi-directional and pressure-responsive. For example, each of the fluid passages generally may comprise or consist essentially of an elastic passage that is normally unstrained to substantially reduce liquid flow, and can expand or open in response to a pressure gradient. In some embodiments, the fluid passage may comprise or consist essentially of perforations in the protective layer 630. Perforations may be formed by removing material from the protective layer 630. For example, perforations may be formed by cutting through the protective layer 630, which may also deform the edges of the perforations in some embodiments. In the absence of a pressure gradient across the perforations, the passages may be sufficiently small to form a seal or fluid restriction, which can substantially reduce or prevent liquid flow. Additionally or alternatively, one or more of the fluid passages may be an elastomeric valve that is normally closed when unstrained to substantially prevent liquid flow, and can open in response to a pressure gradient. A fenestration may be a suitable valve for some applications. Fenestrations may also be formed by removing material from the protective layer 630, but the amount of material removed and the resulting dimensions of the fenestrations may be up to an order of magnitude less than perforations, and may not deform the edges.

[0095] For example, some embodiments of the fluid passages may comprise or consist essentially of one or more slits, slots or combinations of slits and slots in the protective layer 630. In some examples, the fluid passages may comprise or consist of linear slots having a length less than 4 millimeters and a width less than 1 millimeter. The length may be at least 2 millimeters, and the width may be at least 0.4 millimeters in some embodiments. A length of about 3 millimeters and a width of about 0.8 millimeters may be particularly suitable for many applications, and a tolerance of about 0.1 millimeter may also be acceptable. Such dimensions and tolerances may be achieved with a laser cutter, for example. Slots of such configurations may function as imperfect valves that substantially reduce liquid flow in a normally closed or resting state. For example, such slots may form a flow restriction without being completely closed or sealed. The slots can expand or open wider in response to a pressure gradient to allow increased liquid flow. In some embodiments, some or all of the slits may be aligned with apertures 620 in the contact layer 605.

[0096] In some embodiments, the contact layer 605 may not be adhesive, but may be a substantially transparent or translucent spacer layer. In such embodiments, an attachment device (not shown here) may be configured to couple the cover 125 (and thereby the dressing) to the tissue site. For example, the attachment device may be integral to the cover 125 (such as a ring of adhesive about the perimeter of the cover) or separately applied (such as tape used to affix the cover 125 to the tissue site).

[0097] Figure 7 is a schematic exploded or assembly view of the dressing 110 of Figure 6, illustrating additional details that may be associated with some embodiments. In addition to further demonstrating the layers of the dressing 110 of Figure 6, Figure 7 also illustrates the one or more electric pathway 705 that may couple the battery 625 to the plurality of UV light sources 610. In some embodiments, at least a portion of the electric pathway 705 may be located within the contact layer 605, which may provide electric insulation and/or protect the electric pathway 705 from direct contact with liquids such as exudate. In the embodiment shown in Figure 7, the protective layer 630 may have a plurality of fluid passages 710. In some embodiments, at least some, and in some variants all, of the fluid passages 710 may align with the apertures 620 in the contact layer 605. As discussed above, not all embodiments of the protective layer 630 may require or have such fluid passages, for example if the material is porous.

[0098] Figure 8 is a schematic bottom plan view (e.g. looking at the tissue-contact surface) of an exemplary layout of UV light sources 610 for the dressing 110 of Figure 5, illustrating additional details that may be associated with some embodiments. In some embodiments, the plurality of UV light sources 610 may be aligned linearly (e.g. into a single line), which may be configured for placement directly over an incision at the tissue site. [0099] Figure 9 is a schematic plan view of an alternate exemplary layout of UV light sources 610 for the dressing 110, illustrating additional details that may be associated with some embodiments. In some embodiments, the plurality of UV light sources 610 may be configured in an array, for example a two dimensional array (e.g. with light sources distributed across a plane). In some embodiments, the array may comprise a plurality of rows of UV light sources 610, for example with three to four rows. In some embodiments, adjacent rows may be offset, and alternating rows may be aligned. The array may be configured so that light from the plurality of UV light sources 610 may be dispersed or diffused substantially over the entire tissue site (e.g. over the entire tissue-contact surface). In some embodiments, the UV light sources 610 may be spaced apart approximately % inch. For example, adjacent UV light sources 610 may be spaced apart about % inch, with each UV light source 610 no more than about % inch from at least one other UV light source 610. In some embodiments, the plurality of UV light sources 610 may be configured so that light from each of the UV light sources 610 overlaps with light from at least one (e.g. at least two, at least three, 2-5, or 3-5) other of the UV light sources 610. In some embodiments, the plurality of UV light sources 610 may be configured so that any portion of the tissue site (e.g. contact surface) receives UV light from at least two, at least three, 2-6, or 3-6 of the UV light sources 610.

[00100] Figure 10 is a schematic cross-section view of an alternate dressing 110, illustrating additional details that may be associated with the therapy system of Figure 1. The exemplary dressing 110 of Figure 10 may be similar to that of Figure 6, except that instead of a full, sheet-like adhesive (e.g. contact) layer, the dressing 110 of Figure 10 may have an adhesive ring 1005. The adhesive ring 1005 may be similar to the adhesive layer of Figure 6, but instead of a plurality of apertures it may have a central opening 1010 (e.g. a single large opening in the center of the adhesive ring 1005). In some embodiments, the adhesive ring 1005 may not be circular in shape, so long as it comprises a perimeter wall and a central opening 1010. In some embodiments, the adhesive ring 1005 may form the contact surface 505. In some embodiments, the plurality of UV lights 610 may be located between the adhesive ring 1005 (e.g. between the central opening of the adhesive ring) and the manifold layer 615. Some embodiments may optionally comprise the protective layer 630.

[00101] In some embodiments, the adhesive ring 1005 may be substantially optically transparent or translucent, for example being formed of silicone gel. In other embodiments, the adhesive ring 1005 may be formed of a non-transparent (e.g. opaque) adhesive material, and the plurality of UV light sources 610 may be disposed over and/or may direct their light through the central opening 1010 in the adhesive ring 1005. In some embodiments, the ring may not be adhesive, but may simply act as a spacer to elevate the plurality of UV light source 610 off the contact surface 505 (for example, at least about 1/8 inch from the contact surface 505). In such embodiments, some other attachment device, for example associated with the cover 125, may secure the dressing in place. For example, surgical tape may be used to adhere the cover 125 in place on the tissue site, thereby securing the dressing 110 to the tissue site. [00102] Figure 11 is a schematic cross-section view of another alternate dressing 110, illustrating additional details that may be associated with the therapy system of Figure 1. The exemplary dressing 110 of Figure 11 may be similar to that of Figure 6, except that the plurality of UV light sources 610 may be located within the contact layer 605. The contact layer 605 may be substantially transparent, and the plurality of UV light sources 610 may be disposed (e.g. embedded) within the contact layer 605 (for example, at least about 1/8 inch from the contact surface 505) and oriented to direct their light through the remainder of the contact layer 605 and the contact surface 505. In some embodiments, the UV light sources 610 may be horizontally separated or spaced from the apertures 620 in the contact layer 605 (e.g. not aligned with or positioned over the apertures 620). In some embodiments, the plurality of UV light sources 610 and at least some portion of the electrical pathway 705 may be embedded within the contact layer 605, which may protect the electrical components from liquid, such as exudate during negative-pressure therapy and/or instillation solution during instillation. In some embodiments, the contact layer 605 may be an adhesive layer, configured to be adhesive or tacky, while in other embodiments the contact layer 605 may be a non-adhesive separator layer.

[00103] Figure 12 is a schematic cross-section view of yet another alternate dressing 110, illustrating additional details that may be associated with the therapy system of Figure 1. The exemplary dressing 110 of Figure 12 may be similar to that of Figure 6, but may not have a contact layer. Instead, the UV light sources 610 may be suspended over a gap 1200 and configured to be elevated off the tissue site when the dressing 110 is in place on the tissue site. In some embodiments, the cover 125 may be substantially shape-retaining and/or self-supporting, for example retaining its shape (e.g. forming the gap 1200) even when the dressing 110 is under negative-pressure. For example, the cover 125 may comprise a substantially rigid cap. The manifold layer 615 may be located between the plurality of UV light source 610 and the cover 125, and the plurality of UV light sources 610 may be positioned between the manifold and the tissue site when the dressing is in place on the tissue site. Some embodiments may have the optional protective layer 630, for example located between the manifold layer 615 and the UV light sources 610. In some embodiments, the plurality of UV light sources 610 may be suspended in place within the cover, for example by being attached to the bottom surface of the manifold layer 615 or the protective layer 630 (which may be attached to the cover 125). The cover 125 may span and/or retain the manifold layer 615 and the plurality of UV light sources 610, for example to form a unitary dressing 110. In some embodiments, the manifold may be adhered in place on the cover 125. In some embodiments, an attachment device 1205 may be configured to couple the cover 125 to the tissue site. For example, the attachment device 1205 may be integral to the cover 125 (such as a ring of adhesive about the perimeter of the cover) or separately applied (such as tape used to affix the cover to the tissue site). In some embodiments without a rigid cover, a spacer ring (not shown) or substantially transparent spacer layer (not shown) may be located between the plurality of UV light sources 610 and the tissue site, to elevate the UV light sources 610 and help retain the shape and/or configuration of the dressing 110. [00104] Figure 13 is a schematic cross-section view of still another alternate dressing 110, illustrating additional details that may be associated with the therapy system of Figure 1. In some embodiments, the manifold layer 615 may be substantially transparent, substantially translucent, and/or may be configured to diffuse light from the plurality of UV light sources 610 over the entirety of the contact surface 505 and/or the tissue site. For example, the manifold layer 615 may be configured to be substantially transparent or translucent to UV light (e.g. to at least UV-C light). In some embodiments, the manifold layer 615 may be located between the plurality of UV light sources 610 and the contact surface 505. In some embodiments, as shown in Figure 13, the protective layer 630 may form the contact surface 505, and the manifold layer 615 may be located between the protective layer 630 and the plurality of UV light sources 610. In some such embodiments, the protective layer 630 may be substantially transparent and/or may diffuse the UV light to allow the UV light to pass through to the tissue site (e.g. without negatively impacting transmission of the UV light through the contact surface 505). In some embodiments, for example without a protective layer, the manifold layer 615 may form the contact layer and/or the contact surface 505. In some embodiments, the plurality of UV light sources 610 may be disposed between the manifold layer 615 and the cover 125, for example with the cover 125 spanning and/or enclosing the plurality of UV light sources 610, the manifold layer 615, and the protective layer 630. In some embodiments, the cover 125 may form the outer surface 510 of the dressing 110. In some embodiments, the cover 125 may be configured to seal the dressing 110 for negative-pressure therapy. In some embodiments, an attachment device 1205 may be configured to couple the cover 125 to the tissue site, with the cover 125 retaining the manifold layer 615, protective layer 630, and/or plurality of UV light sources 610 to the tissue site . For example, the attachment device 1205 may be integral to the cover 125 (such as a ring of adhesive about the perimeter of the cover) or separately applied (such as tape used to affix the cover to the tissue site). The cover 125 may comprise the port 515, in some embodiments, configured to fluidly couple the tmanifold layer 615 to a negative- pressure source.

[00105] Figure 14 is a schematic cross-section view of yet another alternate dressing 110, illustrating additional details that may be associated with the therapy system of Figure 1. The exemplary dressing 110 of Figure 14 may be similar to that of Figure 13, but may further comprise a contact layer 605 located between the contact surface 505 and the UV light sources 610 and/or the transparent manifold layer 615. For example, the contact layer 605 may form the contact surface 505. In some embodiments, the contact layer 605 may comprise a substantially transparent or translucent adhesive material, such as silicone gel. In some embodiments, the contact layer 605 may comprise a plurality of apertures 620 therethrough, configured to provide fluid communication between the manifold layer 615 and the tissue site. In some embodiments, the UV light sources 610 may be disposed so as to not align with or be located over the apertures 620. Some embodiments may comprise a protective layer 630 between the contact layer 605 and the manifold layer 615 (e.g. with the protective layer 630 and the manifold layer 615 being substantially transparent or translucent), but other embodiments may not have a protective layer (e.g. with the contact layer 605 being sufficient to protect the manifold layer 615). The plurality of UV light sources 610 may be located between the cover 125 and the manifold layer 615, and may be configured to direct light through the manifold layer 615 and the contact layer 605. In some embodiments, the manifold layer 615 and the contact layer 605 may be configured to diffuse light from the plurality of UV light sources 610 over the entirety of the contact surface 505 and/or the tissue site.

[00106] While the dressing embodiments of Figures 5-14 illustrate exemplary dressings which may be used with negative-pressure wound therapy, some embodiments of the dressing may be configured for use without negative-pressure wound therapy. For example, some such dressings may not include a manifold, a cover configured to seal for negative-pressure wound therapy, a protective layer, and/or a port through the cover configured to supply negative pressure to the tissue site. The following figures may illustrate exemplary embodiments of such dressings, which may be used to cover a tissue site to protect the tissue site from exposure to infectious agents, dirt, etc., but may not be configured for use within a negative-pressure wound therapy system.

[00107] Figure 15 is an isometric view of an alternate exemplary dressing 110 (e.g. not configured for use with a negative-pressure therapy system), illustrating additional details that may be associated with some embodiments. In Figure 15, the dressing 110 may be configured as a pad or patch, which may not include a manifold in some embodiments. In the embodiment of Figure 15, the dressing 110 may comprise or consist essentially of the contact layer 605 and the plurality of UV light sources 610. Some embodiments may include a battery and electric pathway (not shown), while in other embodiments, each UV light source 610 may include its own internal power supply (e.g. battery). In some embodiments, the contact layer 605 may be substantially transparent or translucent (e.g. to UV light, or at least to UV-C light) and/or may be configured to diffuse light from the plurality of UV light sources 610 over the entirety of the contact surface 505 and/or the tissue site. In some embodiments, the contact layer 605 may be an adhesive layer. For example, the contact layer 605 may comprise or consist essentially of a tacky or adhesive material, such as silicone gel. In more particular examples, the contact layer 605 may comprise or consist essentially of a solid sheet of silicone gel. In some embodiments, the contact layer 605 may comprise a solid sheet of adhesive material, substantially without any apertures, openings, holes, or perforations. In some embodiments, the plurality of UV light sources 610 may be configured with respect to the contact layer 605 to direct UV light through at least some portion of the thickness of the contact layer 605, for example through the entire thickness of the contact layer 605. In some embodiments, the plurality of UV light sources 610 may be configured as an array. In some embodiments, the plurality of UV light sources 610 may be spaced apart about % inch.

[00108] Figure 16 is a schematic cross-section view of the dressing HO ofFigure 15, illustrating additional details that may be associated with some embodiments. In some embodiments, the contact layer 605 may form the contact surface 505. In some embodiments, the plurality of UV light sources 610 may be disposed opposite the contact surface 505 (e.g. mounted on the outer surface 510 of the contact layer 605). In some embodiments, the contact layer 605 may be configured to diffuse UV light from the plurality of UV light sources 610 for delivery onto the tissue site through the contact surface 505. For example, the contact layer 605 may be configured to diffuse light from the UV light sources 610 through the contact layer 605 and over the entirety of the contact surface 505 and/or tissue site. In some embodiments, the contact layer 605 may be configured to effectively cover and/or seal the tissue site, for example to protect the tissue site from infectious agents, dirt, etc. In some embodiments, the UV light sources 610 may be elevated off the contact surface 505 by the thickness of the contact layer 605, which may be about 1/8 inch thick, so that when the dressing is in place on the tissue site, the UV light sources 610 may be elevated off the tissue site.

[00109] Figure 17 is a schematic cross-section view of another example of the dressing 110, illustrating additional details that may be associated with some embodiments. The dressing 110 of Figure 17 may be similar to that of Figure 16, except that the plurality of UV light sources 610 may be located within (e.g. embedded in) the contact layer 605. For example, the plurality of UV light sources 610 may be disposed within the contact layer 605 in proximity to the outer surface 510. The plurality of UV light sources 610 may be configured to direct light through a portion of the thickness of the contact layer 605. In some embodiments, the plurality of UV light sources 610 may be located in a plane at least approximately 1/8 inch from the contact surface 505.

[00110] Figure 18 is a schematic cross-section view of another example of the dressing 110, illustrating additional details that may be associated with some embodiments. The dressing 110 of Figure 18 may be similar to that of Figure 16, and may further comprise a non-adherent layer 1805, which may be a polymer fdm, stacked adjacent to the contact layer 605 opposite the plurality of UV light sources 610. In some embodiments, the non-adherent layer 1805 may be substantially transparent or translucent to UV light. In some embodiments, the non-adherent layer 1805 may be sized smaller in surface area than the contact layer 605. In some embodiments, the non-adherent layer 1805 may be configured to contact at least a portion of a tissue site, and may be configured to prevent a portion of the contact layer 605 from adhering to the tissue site. In some embodiments, the contact layer 605 may be stacked between and coupled to the plurality of UV light sources 610 and the non-adherent layer 1805. For example, the non-adherent layer 1805 may be located to contact a central portion of the contact layer 605 (e.g. of the surface of the adhesive layer configured to face the tissue site), forming an adherent border around the perimeter of the dressing 110 with a non-adherent center. Uight from the plurality of UV light sources 610 may be directed to pass through the contact layer 605 and the non adherent layer 1805.

[00111] Figure 19 is a schematic cross-section view of yet another example of the dressing 110, illustrating additional details that may be associated with some embodiments. The dressing 110 of Figure 19 may be similar to that of Figure 16, but may further comprise the cover layer 125. In some embodiments, the contact layer 605 may be configured to contact at least a portion of a tissue site, and the plurality of UV light sources 610 may be disposed between the contact layer 605 and the cover 125. The cover 125 may form an outer surface 510 of the dressing 110 and may be configured to protect the tissue site from direct exposure to infectious agents, dirt, etc.

[00112] Figure 20 is a schematic cross-section view of still another example of the dressing 110, illustrating additional details that may be associated with some embodiments. The dressing 110 of Figure 20 may be similar to that of Figure 19, but may comprise a non-adhesive separator layer 2005 instead of an adhesive layer (e.g. in place of the adhesive contact layer in Figure 19). In some embodiments, the separator layer 2005 may be substantially transparent or translucent to UV light, and may be configured to contact at least a portion of a tissue site. In some embodiments, the plurality of UV light sources 610 may be located between the separator layer 2005 and the cover 125, and may be oriented to direct light through the separator layer 2005 onto the tissue site. In some embodiments, the separator layer 2005 may be configured to diffuse light over the entire tissue site . In some embodiments, the cover 125 may be secured to a tissue site by an attachment device 1205, which may be integral to the cover 125 (such as a ring of adhesive about the perimeter of the cover) or separately applied (such as tape used to affix the cover to the tissue site) . In some embodiments, the cover 125 may be configured so that, when coupled to the tissue site, it spans and retains the plurality of UV light sources 610 and separator layer 2005 in place with respect to the tissue site.

[00113] Figure 21 is a schematic cross-section view of yet another alternate example of the dressing 110, illustrating additional details that may be associated with some embodiments. The dressing 110 of Figure 21 may be similar to that of Figure 20, except that the separator layer may be in the form of a ring with a central opening (e.g. instead of a solid sheet separator layer, Figure 21 may have a separator ring 2105). In some embodiments, the separator ring 2105 may give form to the dressing 110, for example acting as a frame about which the cover 125 may fit and/or attach. The plurality of UV light sources 610 may be configured to be elevated above a tissue site when the dressing 110 is located in place on the tissue site, for example being coupled to and/or suspended from the cover 125 within the central opening 2110 of the separator ring 2105. In some embodiments, the UV light sources may be configured to direct light through the central opening 2110 and onto the tissue site, when the dressing 110 is in place on the tissue site. In some embodiments, the separator ring 2105 may not be transparent or translucent, while in other embodiments, the separator ring 2105 may be transparent or translucent. In some embodiments, the separator ring 2105 may comprise an adhesive. In some embodiments, the separator ring 2105 (and its central opening) may form the contact surface. In some embodiments, the cover 125 may form the outer surface 510 of the dressing 110. The cover 125 may span the separator ring 2105 and the plurality of UV light sources 610, and when affixed to the tissue site by the attachment device 1205, may retain the UV light sources 610 and the separator ring 2105 to the tissue site . In some embodiments, the separator ring 2105 may not be circular in shape, so long as it comprises a perimeter wall and the central opening 2110. [00114] Figure 22A is an isometric view of an exemplary dressing 110, similar to that shown in Figure 5, in place on a tissue site 2205, illustrating additional details that may be associated with some embodiments. In some embodiments, the dressing 110 may comprise a removable, non- conductive tab 2210 between the battery 625 and the electric pathway (e.g. between the battery and the battery terminal or contact). In some embodiments, the tab 2210 may be configured to initially prevent the battery from powering the UV light sources while in place, and to electrically couple the battery 625 to the UV light sources upon removal. In other embodiments, there may be no battery, and the plurality of UV light sources may instead be configured to be electrically coupled to the negative- pressure therapy unit for power.

[00115] In some embodiments, the dressing 110 of Figure 22A may comprise a safety shut-off strip 2215 configured to electrically couple the battery 625 (e.g. the battery terminal) to the light sources (e.g. as part of the electric pathway) while the dressing 110 is in place on the tissue site 2205, but to prevent the battery 625 from powering the light sources upon removal of the dressing 110 (e.g. UV light sources) from the tissue site 2205. In some embodiments, the safety shut-off strip 2215 may be configured to provide a safety measure that automatically deactivates the UV light sources upon removal of the dressing 110 from the tissue site 2205.

[00116] Figure 22B is an isometric view of the dressing 110 of Figure 22A upon removal from the tissue site 2205, illustrating additional details that may be associated with some embodiments. As shown in Figure 22B, the safety shut-off strip 2215 may comprise two initially stacked layers, a top layer 2220 and a bottom layer 2225, which may be configured to separate (e.g. so as to no longer be stacked) upon removal of the dressing 110 from the tissue site 2205. Upon removal, the bottom layer 2225 may stay attached to the patient’s skin, while the top layer 2220 may remain attached to the dressing 110. In some embodiments, the top layer 2220 and bottom layer 2225 may be configured so that, when stacked, the safety shut-off strip 2215 allows power to flow to the UV light sources, and when separated, the gap between the top layer 2220 and the bottom layer 2225 breaks electrical connection between the battery 625 and the UV light sources to automatically deactivate the UV light sources.

[00117] Figure 23 is a schematic isometric view of the safety shut-off strip 2215 which is part of the dressing of Figures 22A-22B, illustrating additional details that may be associated with some embodiments. In some embodiments, the safety shut-off strip 2215 may comprise the tissue-adhering bottom layer 2225 and the top layer 2220, which may be configured to be coupled to the dressing (e.g. coupled to the cover, the adhesive layer, and/or the tissue-contact surface) and initially stacked atop and adhered to the bottom layer 2225. In some embodiments, the tissue-adhering bottom layer 2225 may comprises a first adhesive 2305 configured to adhere the bottom layer 2225 to the tissue site (for example located on the bottom surface of the bottom layer 2225); the top layer 2220 may be adhered to the bottom layer 2225 by a second adhesive 2310; the first adhesive 2305 may be stronger than the second adhesive 2310 (e.g. significantly stronger); the coupling between the top layer 2220 and the dressing may be stronger than the second adhesive 2310 (e.g. significantly stronger); and the bottom layer 2225 and the top layer 2220 may be configured so that, when stacked in contact, the electric pathway between the battery and the UV light sources is complete, allowing the battery to power the UV light sources. In some embodiments, one layer (e.g. the bottom layer 2225) may comprise a first contact 2315, a second contact 2320, and an electrically conductive pathway 2325 therebetween; and the other layer (e.g. the top layer 2220) may comprise athird contact 2330 (e.g. configured to electrically couple to the battery terminal) and a fourth contact 2335 (e.g. configured to electrically couple to the UV light sources), with the third contact 2330 and the fourth contact 2335 being separated on the top layer 2220 by non-conductive material. When the layers are stacked, the contacts in the layers may be electrically coupled (e.g. the second contact 2320 to the third contact 2330, and the first contact 2315 to the fourth contact 2335), completing the circuit and electrically connecting the battery to the plurality of UV light sources.

[00118] Some dressing embodiments may further comprise a processor (not shown) electrically coupled to the battery and/or UV light sources and configured to operate the light sources. In some embodiments, the processor may comprise a timer. In some embodiments, the processor may be located within a common housing with the battery. Some embodiments may use the controller of the negative- pressure therapy unit to serve as the processor for the dressing. In some embodiments, the processor may comprise a wireless receiver (e.g. configured for Bluetooth® standards) and may be configured to receive instructions wirelessly (e.g. from a mobile computing device, such as a smartphone). The processor may be used to set intermittent timing of activation and/or deactivation of the UV light sources, or to allow manual activation of the UV light sources (e.g. by the patient). In some embodiments, all of the UV light sources may be activated simultaneously (e.g. when one light source is activated, they all are activated). In other embodiments, the light sources may be activated individually or as sub-groups. For example, each light source may be activated in succession for a specified duration of time each day, so that less power is needed at any given time.

[00119] Figure 24 is a chart illustrating exemplary operation options of the UV light sources of the dressings of Figures 5-21 for disinfection and/or sterilization of the tissue site. The chart demonstrates three examples illustrating options for operating the UV light sources by the processor. In some embodiments, the processor may be configured to activate the UV light sources for less time each successive day (see Example 1 on the chart of Figure 24). For example, the first day, the UV light sources may be activated for the greatest duration of time, and the duration of activation for the light sources may drop each successive day thereafter. The drop in duration for each successive day may be linear, exponential, or logarithmic, in some embodiments.

[00120] In some embodiments, the processor may be configured to activate the UV light sources for the same amount of time every day, as shown in Example 2 of the chart of Figure 24. For example, each day, the UV light sources may all be illuminated continuously for a period of time, and that period of time may be the same duration each day of treatment (at least until the battery’s life is reached). Alternatively, the processor may activate the light sources intermittently (e.g. each day, the UV light sources may be illuminated for a plurality of distinct time periods intermittently spaced throughout the day) as cycles throughout the day, but regardless each day the total duration of illumination may stay the same.

[00121] In some embodiments, the processor may be configured to activate the light sources for a first amount of time for each of the first block of days (e.g. for days 1-2 or, as shown in the chart of Figure 24 as Example 3, days 1-3), and then to activate the light sources for a second amount of time for the remaining (e.g. second block of) days of the treatment, for example days 4-7 as shown in Example 3 of the chart of Figure 24 (or until the battery’s life is reached). In some embodiments, the first amount of time may be greater than the second amount of time. Higher intensity usage (e.g. due to longer exposure of the tissue site to UV light) initially may help to reduce the chance of infection, since most infectious exposure occurs before the dressing is applied to the tissue site. The lower intensity usage for the second block of days may provide some additional protection against lingering infection risk after the initial danger has passed, and may also minimize unnecessary exposure of the tissue site to UV light and/or allow for a smaller battery to power the light sources for the entirety of the treatment.

[00122] The dressings described above may be used to treat a tissue site. For example, method of use embodiments may include: applying the dressing to the tissue site so that the plurality of UV light sources are directed at the tissue site; and activating the plurality of UV light sources to sterilize the tissue site. In some embodiments, the plurality of UV light sources may be activated while the dressing is in place on the tissue site. In some embodiments, the plurality of UV light sources may be activated without removing the dressing from the tissue site. In some embodiments, the tissue site may be located on a patient, and the plurality of UV light sources may be activated while the patient is ambulatory. In some embodiments, applying the dressing may comprise adhering the dressing to the tissue site. In some embodiments, the dressing may comprise an adhesive layer configured to be substantially transparent to UV light, and activating the plurality of UV light sources may comprise directing UV light through at least a portion of the adhesive layer and onto the tissue site. In some embodiments, the dressing may further comprise a manifold and a cover, and the method may further comprise: fluidly coupling a negative-pressure source to the manifold through the cover; and providing negative-pressure therapy to the tissue site. In some embodiments, the manifold may be substantially transparent to UV light, and activating the plurality of UV light sources may comprise directing UV light through the manifold. In some embodiments, the UV light from the light sources may be diffused through the manifold and/or the adhesive layer to substantially span the entirety of the tissue-contact surface.

[00123] In some embodiments, the dressing may further comprise a processor configured to operate the plurality of light sources for a plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for the same amount of time each of the plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for less time each successive one of the plurality of days. Some embodiments may further comprise activating, by the processor, the plurality of UV light sources for a first amount of time for each of the first 1-2 or 1-3 days, and then activating the plurality of UV light sources for a second amount of time for the remaining days of therapy, wherein the first amount of time is greater than the second amount of time. In some embodiments, each day of therapy the UV light sources may be activated for a single, continuous block of time. In other embodiments, each day of therapy the UV light sources may be activated for several distinct sessions, which may be spaced throughout the day. In some embodiments, the UV light sources may be activated for sufficient continuous time or duration to effectively disinfect the tissue site. Some embodiments may further comprise removing the dressing from the tissue site; and automatically deactivating the plurality of UV light sources upon removal. Some embodiments may further comprise attaching a safety strip to the tissue site (e.g. upon applying the dressing to the tissue site), wherein the safety strip is configured to deactivate the plurality of UV light sources upon removal of the dressing from the tissue site.

[00124] Methods for manufacturing a UV sterilization dressing (for example, similar to those dressing embodiments disclosed above), are also described herein. Some example method embodiments may include: providing a plurality of UV light sources; and configuring the plurality of UV light sources to be elevated off a contact surface of the dressing. In some embodiments, the step of providing the plurality of UV light sources may comprise providing a plurality of UV-C light sources. In some embodiments, the step of configuring the plurality of UV light sources to be elevated off a contact surface may comprise configuring the plurality of UV light sources to be elevated at least about 1/8 inch off the contact surface and to direct UV light towards and/or through the contact surface . Some embodiments may further comprise configuring the plurality of UV light sources so that the light from each of the light sources overlaps with light from another of the light sources. In some embodiments, the step of configuring the plurality of UV light sources so that the light from each of the light sources overlaps with light from another of the light sources may comprise spacing apart the plurality of UV light sources approximately % inch.

[00125] Some embodiments may further comprise: providing an adhesive layer configured to be transparent to UV light; and configuring the plurality of UV light sources with respect to the adhesive layer so that UV light passes through at least a portion of the adhesive layer. In some embodiments, the UV light sources may be mounted on the outer surface of the adhesive layer. In some embodiments, the adhesive layer may form the contact surface. In some embodiments, the UV light from the plurality of UV light sources may pass entirely through the adhesive layer. In some embodiments, the plurality of UV light sources may be located or disposed (e.g. embedded) within the adhesive layer. For example, the step of providing an adhesive layer may comprise forming the adhesive layer with the plurality of UV light sources located therein, in some embodiments. In some embodiments, the adhesive layer may comprise a plurality of apertures therethrough, and the step of configuring the plurality of UV light sources with respect to the adhesive layer may comprise configuring the plurality of UV light sources to not be located over any of the apertures.

[00126] Some embodiments may further comprise providing a manifold layer and a cover with a port configured for fluidly coupling to a negative-pressure source. In some embodiments, the UV light sources may be positioned between the manifold and the contact surface (e.g. the manifold may be positioned between the UV light sources and the cover). In some embodiments, providing the manifold may comprise providing a transparent manifold, which may be configured to diffuse UV light, and the manifold may be positioned between the UV light sources and the contact surface (e.g. the UV light sources may be positioned between the transparent manifold and the cover, and may direct UV light through the transparent manifold). Some embodiments may further comprise providing a battery for the plurality of UV light sources, wherein an electric pathway between the battery and the plurality of UV light sources may be at least partially located within the adhesive layer. Some embodiments may further comprise electrically coupling a safety shut-off strip between a battery and the plurality of UV light sources, wherein the safety shut-off strip may be configured to automatically deactivate the plurality of UV light sources upon removal of the dressing from a tissue site.

[00127] The systems, apparatuses, and methods described herein may provide significant advantages. For example, UV lights directed at a wound site may aid in sterilization and/or disinfection of the wound site. Using UV lights may provide a non-chemical method for disinfection. UV-C light may effectively disinfect the wound site without negatively impacting the tissue, for example without significant mutations of the skin. The integral nature of the UV light sources in dressing embodiments may allow disinfection to take place under the dressing, while the dressing is in place. This may allow the dressing to be left in place for extended periods, minimizing exposure of the wound site to further infectious agents. Some embodiments of the dressing may also allow for negative-pressure wound therapy, so that the benefits of sterilization/disinfection of the wound site may occur in conjunction with the benefits of negative-pressure wound therapy. The dressing may be configured to diffuse UV light across the entire protected area under the dressing. The integral nature of the dressing may also allow for sterilization/disinfection to occur on ambulatory patients, for example continuously or intermittently, without the need for the patient to be at a medical facility. Some embodiments of the dressing may also have one or more safety features configured to protect the patient from unwanted exposure to the UV light, for example protecting the user’s eyes by deactivating the UV lights when the dressing is removed from the wound site.

[00128] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context. Components may be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing 110, the container 115, or both may be separated from other components for manufacture or sale. In other example configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components. [00129] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.