GB2531344A

GB2531344A - Composite wound dressing

Info

Publication number: GB2531344A
Application number: GB1418453.5A
Authority: GB
Inventors: Stephen Cotton
Original assignee: Brightwake Ltd
Current assignee: Brightwake Ltd
Priority date: 2014-10-17
Filing date: 2014-10-17
Publication date: 2016-04-20
Also published as: GB201418453D0

Abstract

A composite wound dressing 1comprising an absorbent body 14 and an activated carbon cloth layer 13 that, in use, is in direct contact with the wound. The activated carbon cloth layer may be of a knitted form. The absorbent body may comprise foam, a gelling material, a superabsorbent material or a combination thereof, such foams optional formed of polyurethane. The wound dressing may further comprise antimicrobial, antifungal, antiseptic, anti-inflammatory agents, such as silver, polyhexamethylene biguanide or honey. The dressing may include a backing layer 11, which optionally forms a border on all sides around the carbon cloth, which may be formed of polyurethane film. A perforated wound contact layer 15 may also be included, which may extend beyond the edges of the carbon cloth on all sides to form a border. The perforations on the border section 22 may be smaller than those positioned over the activated carbon cloth layer 21. The wound contact layer may be formed of melt-blown polyurethane, and may further include an adhesive on the wound contacting face.

Description

Composite Wound Dressing This invention relates to a composite wound dressing, and in particular to a composite wound dressing comprising a layer of carbon cloth which is, in use, brought into direct contact with the wound.

Different types of wound dressing are required to meet different clinical needs, and no single wound dressing product is suitable for use in all wound types or at all stages of healing. There is therefore an ongoing need to provide improved wound dressings.

However, it is a common requirement for wound dressings that wound exudate is absorbed, and that bacteria and other sources of infection are efficiently removed from the wound. It is further important that, particularly in the treatment of chronic wounds, odour-causing molecules are removed in order to improve the comfort and confidence of the patient. Activated carbon cloth has been found to be effective in the removal of excess wound exudate and adsorption of odour-causing molecules, as well as displaying antimicrobial properties, and has been used in wound dressings for these reasons. Carbon cloth has the additional benefit that its durable, flexible structure means it flexes and moves easily with the patient, but can be worn for a number of days without structural deterioration. Activated carbon cloth is used particularly in the treatment of chronic wounds, eg those resulting from bed sores, pressure ulcers, leg ulcers, MRSA, skin grafts, burns, infected cuts and surgical wounds.

Zorflex® is a commercially available activated carbon cloth, known for use in wound dressings. It is a woven or knitted 100% activated carbon cloth with a surface area of 1000-2000 m2/g, which can be laminated to other materials or impregnated with chemical treatments.

Commercially available wound dressings incorporating activated carbon cloth are also available, and include Actisorb® plus (Johnson & Johnson Medical Ltd).

Actisorb® plus is a sterile dressing comprising an activated charcoal cloth, produced by carbonising and activating a knitted viscose rayon fabric, which is enclosed in a sealed, non-adherent nylon sleeve. This dressing has been found to trap odour and bind bacteria and toxins that impair the healing process. It is important that the dressing is not cut, otherwise particles of activated carbon may be released into the wound and cause discolouration.

Carboflex is a layered wound dressing. The wound contact layer is a layer of alginate and carboxymethylcellulose, and above this is a perforated plastic film, a layer of charcoal cloth and an absorbent layer. A second perforated plastic layer is sealed around the perimeter of the first.

Carbonet is also a multi-component dressing that combines both fluid-and odour-absorbing properties. It consists of a low adherence wound contact layer of knitted viscose backed with an absorbent layer of fibrous cellulose to which is bonded a layer of activated charcoal cloth, the whole of which is sandwiched between two layers of polyethylene net. An outer layer of polyester fleece completes the structure of the dressing.

Finally, KoCarbonAg® is an antimicrobial dressing consisting of a PET nonwoven, a silver coated activated carbon fibre cloth, and PE membrane. The PE membrane forms the wound contact layer, and is present to reduce dressing adherence and thereby reduce pain during dressing changes.

There is now provided an improved wound dressing which overcomes and/or substantially mitigates problems associated with the prior art.

According to the invention, there is provided a composite wound dressing comprising an absorbent body and an activated carbon cloth layer that, in use, is in direct contact with the wound.

Carbon cloth has not previously been used in a composite wound dressing wherein the carbon cloth layer is, in use, brought into direct contact with the wound. This may be due to the risk of discolouration of the wound by the carbon cloth, the risk of particles of carbon cloth getting into the wound, and/or excessive adherence of the dressing to the wound. However, it has been surprisingly found that carbon cloth may be brought into direct contact with the wound as described in this invention, and this may not be susceptible to the above mentioned problems and may offer further benefits, such as increasing the rate of absorption of wound exudate and adsorption of odour-causing molecules, and hence facilitating treatment of the wound.

Activated carbon, also known as activated charcoal, is a form of graphite which has a highly porous, random structure, most commonly formed through heat treatment of a carbon-containing material. The porosity of the charcoal gives it a large surface area enabling it to adsorb a wide range of compounds, and activated carbon has the strongest physical adsorption forces of any known material. This makes it particularly suited for use in a wound dressing, where it is important that bacteria and odour-causing molecules adsorbed onto the surface are retained, and not released back into the wound environment.

Activated carbon can be made from any substance which has a high carbon content, such as coal, cellulose, coconut shells etc, and the nature of the raw material influences the properties of the activated carbon. It has long been known for use as an antidote to the ingestion of toxic substances, as it can adsorb toxic substances from the GI tract but is not itself digestible. However, granulated or powdered carbon can be difficult to use in wound dressings due to the need to retain it in place and the risk of particulate matter entering the wound.

Activated carbon fabric is activated charcoal in a flexible, microporous fabric form.

It is produced by carbonising a suitable cellulose fabric by heating it under carefully controlled conditions. During this process, the surface of the carbon breaks down to form small pores. The pores provide the dual benefit of greatly increased surface area (eg around 1000-2000 m2/g), which increases the ability of the cloth to adsorb odour-causing molecules, as well as facilitating the absorption of wound exudate. Activated carbon cloth is commercially available, and any suitable activated carbon cloth may be used in the present invention, and may contain from 95-100% activated carbon, or from 98-100% activated carbon, or 100% activated carbon. Most preferably, the activated carbon cloth is 100% activated carbon. A particularly preferred activated carbon cloth is sold under the tradename Zorflex® (Chemviron Carbon Corporation, 400 Calgon Carbon Drive, Pittsburgh, PAl 5205, USA).

The activated carbon cloth used in the present invention may be woven, knitted or nonwoven. Preferably, the activated carbon cloth is knitted. The knitting process produces a stretchable, elastic fabric which easily moves with and conforms to the patient, and which does not shed or fray, thus reducing the risk of particulate matter entering the wound.

The absorbent body is typically positioned directly adjacent to the distal face of the carbon cloth layer, ie the non-wound-facing side of the carbon cloth layer. The absorbent body may be bonded to, or in intimate contact with, the carbon cloth.

Suitable absorbent materials for use in wound dressings are known in the art, and the absorbent body of the present invention may be formed of any suitable material, or any suitable combination of materials.

For example, the absorbent body may comprise a foam, a gelling material, a superabsorbent material, or a combination of these components.

The foam may be any suitable foam known in the art. Usually, the foam is an open-celled foam. Preferably, the foam is a hydrophilic foam. More preferably, the hydrophilic foam is a polyurethane foam. Most preferably, the foam is an open-celled polyurethane foam. The open cellular structure of the foam allows exudate from a wound to pass through it as well as to be absorbed by it. The structure is sufficiently open to allow exudate to pass through it, but not sufficiently open to allow any part, eg a fibre or particle, of another material to pass through it to any substantial degree. The foam typically has a thickness of 0.5mm to 10mm, preferably from 1mm to 7mm, or from 2mm to 7mm, and the foam most preferably has a thickness of 2mm, 3mm, 4mm or 5mm.

The gelling material may be any suitable gelling material known in the art, including pectin, alginate, materials made from alginate and another polysaccbaride, chitosan, byaluronic acid, other polysaccharide materials or materials derived from gums, or chemically-modified cellulosic materials, eg carboxymethyl cellulose (CMC). The gelling material may be a combination or blend of different gelling materials.

By "gelling" material is meant in relation to the invention materials that are capable of absorbing aqueous fluid, such as wound exudate, and which on absorbing liquid become gel-like, moist and slippery. The gelling material is preferably in the form of a non-woven pad. The gelling material may have an absorbency of at least 2 grams 0.9% saline solution per gram of material, as measured by the free swell absorbency test (ie dispersing a known dry weight of material in the test liquid (saline) for sufficient time for the material to absorb liquid, removing the excess liquid by vacuum filtration, and measuring the increase in weight of the fibre). The absorbency may be considerably higher, eg at least 5g/g, or at least 1 Og/g, or at least isgig, or at least 25g/g.

Currently preferred gelling fibres are alginate fibres and pectin fibres.

"Superabsorbent material" in the context of the present invention means a material that is capable of absorbing many times its own mass of water (eg up to 200, 300, 400, 500 or more times its own mass of water).

Although it should be appreciated that the wound dressing of the present invention may comprise any superabsorbent material, preferred superabsorbent materials are polymeric superabsorbent materials and include alginate, polyacrylate (ie a salt of polyacrylic acid), polyacrylamide copolymers, ethylene maleic anhydride copolymer, carboxymethylcellulose, polyvinylalcohol copolymers, polyethylene oxide and starch-grafted copolymers of polyacrylonitrile.

Many such superabsorbent materials may be used in particulate form. In such cases, the particles may be incorporated into a carrier material, for instance by being encapsulated between two layers of carrier material, eg tissue paper or the like.

Alginate superabsorbent may be sodium or calcium alginate. The alginate superabsorbent is preferably in the form of a non-woven mat, providing a superabsorbent layer suitable for the method of the present invention.

The most preferred superabsorbent material is sodium polyacrylate polymer.

Sodium polyacrylate polymer is a solid crystalline material, and is preferably incorporated into a layer in the form of particles encapsulated between two layers of carrier material, such as tissue paper. A specific example of a suitable material is Gelok® 14040S/S manufactured by Gelok International Corporation.

Additional agents known to assist or enhance wound healing may also be incorporated into the wound dressing. For example, the dressing may also include antimicrobial agents, antiseptic agents, antifungal agents and/or anti-inflammatory agents, and such agents may be incorporated either into the carbon cloth, or into the absorbent body.

The wound dressing of the present invention may comprise silver. Despite metallic silver being relatively unreactive, ionic silver has been shown to have antimicrobial activity and has been previously used in wound dressings. In use, positively charged silver ions bind to negatively charged sites on proteins and nucleic acids in bacteria. This causes a number of effects, including alteration of the protein structure, rupture of the cell wall and/or cell death. It is believed that silver ions have multiple attack sites, interacting with a number of different functional groups in bacteria, including thiol groups, carboxylates, phosphates, indoles and amines. This makes the development of bacterial resistance to silver unusual.

It is preferable that the incorporation of silver into the wound dressing results in the sustained release of low concentrations of silver ions over time. Such a slow release has been shown to stimulate healing and inhibit the growth of micro-organisms. Methods for incorporating silver into wound dressings are known in the art, as is the form in which silver may be used. Any suitable method or form known in the art may be used in the present invention. For example, the silver may be in the form of silver sulphadiazine. It has been found that the use of silver in combination with carbon cloth is particularly effective, as the carbon cloth draws in and traps bacteria, which is then killed by the silver.

Another antimicrobial that may be incorporated into the wound dressing of to the invention is polyhexamethylene biguanide (PHMB; also known as polyaminopropyl biguanide). PHMB is available as a 20% aqueous solution under the trade name COSMOCIL® CO from Arch Personal Care Products, 70 Tyler Place, South

Plainfield, NJ 07080, USA.

The wound dressing of the present invention may comprise honey. Honey has long been known to be effective in treating wounds, with records of such use dating from at least 2000 years ago. More recently, research has shown it to have potent antimicrobial, antifungal and anti-inflammatory properties, and to be able to stimulate lymphocytic and phagocytic activity within the body. Further, honey has been demonstrated to assist in the debridement of necrotic tissue, and to stimulate the growth of new tissue. In terms of its antibacterial activity, honey has been reported to have an antibacterial effect on more than 60 species of bacteria, including aerobes, anaerobes, Gram-positive and Gram-negative bacteria. In particular, honey has been shown to be effective against antibiotic resistant strains of bacteria including MRSA.

Without wishing to be bound by theory, it is believed that the antibacterial activity of honey is partly due to the release of low levels of hydrogen peroxide, a well known antimicrobial agent. As the production of hydrogen peroxide is stimulated by dilution of the honey (eg by wound exudate), honey has the distinctive property of becoming more active on dilution, rather than less.

Many studies have shown that the maintenance of a moist wound environment aids in wound healing. However, a moist environment also promotes the growth of bacteria, and the prevention of infection is therefore a serious concern. The addition of honey to a wound dressing thus enables the wound to be kept moist whilst inhibiting bacterial growth and reducing the likelihood of infection.

In the present invention, the wound dressing may be supplied impregnated with honey, in the absorbent body and/or in the carbon cloth layer, or with honey on the surface. Alternatively, honey may be applied to the dressing or directly to the wound prior to application of the dressing. Preferably, honey is impregnated into the absorbent body.

Honey is produced worldwide from many different floral sources, and its antibacterial activity varies with the source of the honey and the processing it has undergone. For example, lotus honey in India is reputed to be good for eye diseases, whereas manuka honey, a monofloral honey produced from pollen from the manuka bush, is known for its antiseptic properties. The manuka plant is part of the genus leptospermum, and honeys produced from plants of this genus, such as manuka or jelly bush honey, are known for their particularly strong anti-bacterial properties. Preferably, the honey used in the present invention is produced from plants of the genus Ieptospermum. More preferably, the honey is manuka honey or jelly bush honey.

The wound dressing may further comprise a backing layer, which forms a barrier between the wound and the surrounding atmosphere, and any suitable material known in the art may be used for the backing layer.

The backing layer will generally be impermeable to wound exudate and other liquids, but is preferably permeable to air and moisture vapour. In particular, the backing layer preferably exhibits a relatively high moisture vapour transmission rate (MVTR). The MVTR of the backing layer may be at least 300g/m2/24h, more suitably at least 500g/m2/24h and preferably at least 700g/m2/24h at 37°C and 100% to 10% relative humidity difference.

The backing layer is most preferably a plastics film having the desired characteristics. The backing layer may be a polyurethane film.

The backing layer may be larger in size than the carbon cloth, such that it extends beyond the edge of the carbon cloth on one or more sides. Preferably, the backing layer extends beyond the edge of the carbon cloth on all sides, forming a border around the carbon cloth.

The wound dressing of the invention may further comprise a perforated wound contact layer, which enables the layer of carbon cloth to come into direct contact with the wound. The perforated wound contact layer will typically be formed of or coated in a material which adheres to the skin, whilst still permitting easy removal of the wound dressing without damage to the wound or surrounding skin.

The perforations in the wound contact layer allow the transfer of wound exudate through the contact layer, as well as allowing the wound facing activated carbon cloth layer to come into direct contact with the wound. The perforations are typically circular, and have a diameter of from 3mm to 20mm, preferably 3mm to 15mm, or 4mm to 10mm.

Where the perforated wound contact layer extends beyond the carbon cloth layer, it may comprise a second set of perforations which are smaller than the perforations described above. The smaller set of perforations are typically positioned around the edge of the wound dressing in order to ensure sufficient adherence of the dressing to the skin.

The second set of perforations are smaller than the first set and are located such that they extend across the border of the dressing on the sections of the dressing that are intended to contact the healthy skin around the wound and not the wound itself. Typically, these perforations are also circular and have a diameter of from 0.5mm to 4mm, preferably from 0.5 to 2mm, eg about 1mm to 2mm.

The presence of different sizes of perforation allows the adhesive dressing to adhere effectively to the healthy skin around the wound whilst also allowing transfer of exudate from the wound through the contact layer into the carbon cloth, and facilitating direct contact between the activated carbon cloth and the wound. If small perforations were present across the full extent of the dressing, transfer of wound exudate may be restricted; if large perforations were present across the full extent of the dressing, adherence of the dressing to the surrounding skin may be reduced.

Other shapes of perforation may alternatively be used, eg square perforations or elongated slits. Some such arrangements of perforations may enhance the extensibility of the dressing in one or more directions, and so improve its conformability to the body.

The surface of the contact layer that, in use, is applied to the wound and pen-wound skin may be coated with an adhesive that extends across the entire extent of the wound dressing. The adhesive layer overlies and contacts the wound itself, rather than just the surrounding healthy skin, and so it is generally preferable that the adhesive that is used is one that is non-adherent and permits the wound dressing to be removed relatively easily and without causing trauma to the wound.

Thus, the adhesive may be, for instance, a hydrocolloid adhesive, a polyurethane adhesive, a hydrogel or, most preferably, a silicone adhesive, particularly a silicone gel.

Silicone adhesives offer numerous advantages. Most preferably, the silicone adhesive is in the form of a silicone gel of the type generally referred to as a "soft silicone".

Soft silicone adhesives are particularly suited for use as skin contact layers in wound dressings. They are soft, tactile and conformable, and exhibit good adhesion to dry skin but low adherence to an underlying wound. Thus, the dressing can be applied to a wound and subsequently removed without causing trauma to the wound. Silicone gels are adhesive but do not leave fibres or residue on a surface/substrate when removed.

Silicone gels suitable for use as skin contact materials in the present invention may be carried on a layer of melt-blown non-woven material, eg a sheet of melt-blown polyurethane (MBFLJ), as described in W02007/1 13597. The reverse side of the MBPU may be coated with an adhesive, eg an acrylic adhesive, to affix the silicone gel/MBPU laminate to overlying components of the dressing, eg a carbon cloth and/or a backing layer, such as a breathable film of plastics material, for instance polyurethane.

Where the wound dressing of the invention comprises a perforated wound contact layer and a backing layer, the edges of the carbon cloth may be wholly or partially encapsulated between the wound contact layer and the backing layer, or between the wound contact layer or backing layer and the absorbent body. For example, the wound contact layer and the backing layer may be bonded together about their periphery with the carbon cloth layer and the absorbent body sandwiched between. The edges of the carbon cloth may be captured between the two exterior layers where they are bonded together about their periphery, or may be captured between one exterior layer (eg the wound contact layer) and the absorbent body. This reduces or eliminates the risk that particles of carbon cloth may be transferred from the dressing into the wound.

The dressing will generally be supplied with a releasable liner on its underside.

The releasable liner may cover the adhesive portions of the wound dressing prior to use, and be removed from the dressing immediately before application of the dressing to the wound. This reduces the risk of contamination of the wound dressing and facilitates handling of the dressing.

Such releasable liners are commonly used on wound dressings known in the art, and suitable materials which can be employed in the present invention will be familiar to the skilled worker. For example, the releasable liner may be of a suitable plastics sheet or a siliconised paper or the like.

The releasable liner may be a single sheet which covers the underside of the wound dressing, or may be formed of two or more sheets. The releasable liner may further comprise a tab to enable the liner to be easily removed from the dressing before use. In particular, where the releasable liner is formed of two or more parts, the parts may either overlap or abut and extend outwards from the wound dressing, thus providing an easy method for removal of the releasable liner.

The wound dressing according to the invention may be used alone or in conjunction with a secondary dressing. It may be affixed to the patient by means of an adhesive eg a soft silicone adhesive as described above, or may be fixed to the patient by other suitable means, such as tape or a bandage.

The invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a plan view of a first embodiment of a wound dressing according to the invention; Figure 2 is cross-sectional view of the wound dressing of Figure 1, on the line Il-Il and not to scale; and Figure 3 is an underside view of the wound dressing of Figures 1 and 2, after removal of a releasable liner.

Figure 4 is a cross-sectional view of a second embodiment of a wound dressing according to the invention.

Referring first to Figures 1 and 2, there is shown a wound dressing 1 according to the invention. The dressing 1 is generally square in form and comprises a backing layer of microporous, gas-and vapour-permeable polyurethane film 11, to a central portion of the underside of which is affixed an absorbent body comprising a layer of absorbent polyurethane foam 14 bonded to a layer of activated carbon cloth 13 (see Figure 2).

In other embodiments, the foam 14 may be replaced by other forms of absorbent material, eg an alginate nonwoven material, or a composite, for instance of foam and a superabsorbent material.

A perforated skin contact layer 15 extends across the whole extent of the underside of the dressing 1, and is covered by a protective release liner 1 6a,1 6b.

The skin contact layer 15 comprises a sheet of melt-blown polyurethane that carries a coating of silicone gel. The reverse side of the melt-blown polyurethane is coated with acrylic adhesive by which it is affixed to the border of the backing layer 11 and to the absorbent foam 14.

As can be seen in the underside plan view of Figure 3, the contact layer 15 is formed with two different arrays of perforations: larger perforations 21 and smaller perforations 22. The larger perforations 21 are formed in the central portion of the dressing 1 and coincide with the carbon cloth layer 13. These perforations 21 have approximate diameter 8mm, to permit wound exudate to pass from the wound, through the carbon cloth layer 13 and into the absorbent foam 14. The smaller perforations 22 are formed in the border of the contact layer 15, ie the portion surrounding, but not extending over, the carbon cloth 13 and absorbent foam 14. These perforations have adiameterof 1-2mm and permit the passage of water vapour and gas from the surface of the skin surrounding a wound, through the backing layer 11. Maceration of the pen-wound skin is thereby avoided, but the smaller perforations 22 do not substantially impair secure retention of the dressing 1 on the skin. The silicone gel layer 15 contacts not only the healthy skin around the wound, but also the wound itself, with the carbon cloth layer 13 exposed to the wound through the large perforations 21. The non-adherent properties of the silicone gel skin contact layer 15 permit the dressing 1 to be removed from the wound without trauma or pain, whilst the larger perforations 21 permit the carbon cloth layer 13 to directly contact the wound.

The wound dressing is supplied with a two-part release liner 16a,16b (shown in Figure 2, but not in Figure 3), which is removed from the dressing 1 immediately prior to use.

When the dressing 1 is applied to a wound, wound exudate passes through the larger perforations 21 and the carbon cloth layer 13, into the absorbent foam 14.

The dressing may be manufactured by the following general method.

First, a pre-laminate comprising the silicone gel layer is produced in the manner described in W02007/113597. In general terms, this involves applying silicone gel precursors to a sheet of melt-blown polyurethane (MBPU), the underside of which carries a coating of acrylic adhesive and a temporary protective backing, eg of plastics film or paper. Once the silicone gel precursors have cured, to produce a hydrophobic silicone gel, a temporary cover, again of plastics film or paper material, is applied to the gel. Fertorations corresponding to the larger and smaller perforations 21,22 are then formed in the pre-laminate.

In a separate operation, a carbon cloth/absorbent foam laminate is produced by bonding sheets of foam and carbon cloth together. Bonding may be achieved by interposing a fusible dry web material between the foam and carbon cloth, and applying heat and pressure. Individual squares, or other appropriate shapes, are then cut out.

The temporary protective backing is then removed from the underside of the MBPU to expose the acrylic adhesive. The squares of the carbon cloth/foam laminate are applied to the acrylic adhesive, before a sheet of breathable polyurethane film (which constitutes the backing layer 11 of the finished dressing 1) is applied over the squares of carbon cloth/foam laminate, adhering to the acrylic adhesive about the periphery of the squares of carbon cloth/foam laminate.

Finally, the temporary protective cover is removed from the silicone gel and replaced with appropriately formed release liners 1 6a, 1 6b, and individual dressings 1 are punched out and sterile packaged.

Figure 4 shows a second embodiment of a wound dressing according to the invention. The wound dressing is generally designated 40 and comprises an absorbent foam 41 bonded to a carbon cloth layer 42. A vapour-permeable polyurethane film 45 is bonded to the reverse face of the foam 41. In use, the carbon cloth layer 42 is brought into contact with the wound. Such a wound dressing may be used in combination with a secondary wound dressing, or may simply be held in place on the patient by means of adhesive tape, or secured with a bandage.

Claims

Claims 1. A composite wound dressing comprising an absorbent body and an activated carbon cloth layer that, in use, is in direct contact with the wound.
2. The composite wound dressing of Claim 1, wherein the activated carbon cloth contains from 95-100% activated carbon.
3. The composite wound dressing of Claim 1 or Claim 2, wherein the activated carbon cloth contains from 98-100% activated carbon.
4. The composite wound dressing of any preceding claim, wherein the activated carbon cloth is knitted.
5. The composite wound dressing of any preceding claim, wherein the absorbent body is positioned directly adjacent to the distal face of the carbon cloth layer.
6. The composite wound dressing of any preceding claim, wherein the absorbent body comprises a foam, a gelling material, a superabsorbent material, or a combination of these components.
7. The composite wound dressing of Claim 6, wherein the absorbent body comprises a foam.
8. The composite wound dressing of Claim 7, wherein the absorbent body comprises a polyurethane foam.
9. The composite wound dressing of Claim 7 or Claim 8, wherein the foam has a thickness of from 0.5mm to 10mm.
10. The composite wound dressing of any preceding claim, which further comprises one or more agents selected from antimicrobial agents, antiseptic agents, antifungal agents and/or anti-inflammatory agents.
11. The composite wound dressing of Claim 10, wherein the one or more agents comprise silver.
12. The composite wound dressing of Claim 10 or Claim 11, wherein the one or more agents comprise PHMB.
13. The composite wound dressing of any of Claims 10 to 12, wherein the one or more agents comprise honey.
14. The composite wound dressing of any preceding claim, which further comprises a backing layer.
15. The composite wound dressing of Claim 14, wherein the backing layer has an MVTR of at least 300g/m2/24b at 37°C and 100% to 10% relative humidity difference.
16. The composite wound dressing of Claim 14 or Claim 15, wherein the backing layer is a polyurethane film.
17. The composite wound dressing of Claim 15 or Claim 16, wherein the backing layer extends beyond the edge of the carbon cloth on all sides, forming a border around the carbon cloth.
18. The composite wound dressing of any preceding claim, which further comprises a perforated wound contact layer.
19. The composite wound dressing of Claim 18, wherein the perforations are circular, and have a diameter of from 3mm to 20mm.
20. The composite wound dressing of Claim 18 or Claim 19, wherein the perforated wound contact layer extends beyond the edges of the carbon cloth layer to form a border.
21. The composite wound dressing of Claim 20, wherein the perforated wound contact layer comprises a first set of perforations and a second set of perforations, the second set of perforations being smaller than the first set of perforations and extending across the border of the wound dressing.
22. The composite wound dressing of Claim 21, wherein the first set of perforations are circular and have a diameter of from 3mm to 20mm, and the second set of perforations are circular and have a diameter of from 0.5mm to 4mm.
23. The composite wound dressing of any of Claims 18 to 22, wherein the wound contact layer is a melt-blown non-woven material.
24. The composite wound dressing of Claim 23, wherein the melt-blown non-woven material is MBFLJ.
25. The composite wound dressing of any of Claims 18 to 24, wherein the wound contact layer is coated with an adhesive on the wound contacting face.
26. The composite wound dressing of Claim 25, wherein the adhesive is a silicone gel.
27. The composite wound dressing of any preceding claim, which further comprises a releasable liner.
28. A composite wound dressing, substantially as described herein and as depicted in Figures 1 to 3.
29. A composite wound dressing, substantially as described herein and as depicted in Figure 4.