JPH05192363A - Wound covering material - Google Patents

Abstract

PURPOSE:To protect a wound and promote the cure of the wound by applying to a skin wound surface when the skin is wound. CONSTITUTION:A wound covering material is formed of a highly water- containing gel layer and a steam transmission regulating layer 3 laminated thereon, and it has through holes 5 continued to the two layers. Thus, when the skin is wound, it is applied to the wound surface, whereby the wound surface is softly protected, the pain is eased, the contamination of bacteria is prevented, and the cure of the wound is promoted.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel wound dressing. More specifically, the present invention provides a wound,
When the skin is damaged due to a burn or the like, a wound dressing that is applied to the skin-damaged surface to protect the wound and promote the healing of the wound, and further to protect the wound and cells having a tissue repair function are provided. It relates to artificial skin that penetrates into it and promotes wound healing.

[0002]

2. Description of the Related Art Burns, barking wounds and traumatic skin defect wounds,
For the purpose of protecting the affected area due to diseases such as pressure ulcers or wounds and promoting healing, conventionally, gauze, absorbent cotton, etc. have been used as a wound dressing temporarily applied to the affected area, but these are bacteria. Since the infection-preventing property was low and the exudate was absorbed promptly, the wound surface became dry and accompanied by pain and bleeding when it was removed. Although an ointment or the like is also used in combination, in this case, on the contrary, the absorption of exudate is insufficient and the wound surface becomes excessively wet.

As an alternative to these, particularly when applied to a wide range of wound surfaces, artificial gauze made of silicone, synthetic rubber sheet made of silicone rubber and velor, synthetic fiber sheets such as Teflon, etc. are used. Coating films of materials and coating films of bio-derived materials such as freeze-dried pig skin, chitin non-woven fabric, collagen film, polyamino acid sponge and mucopolysaccharide complex collagen film are also known. However, among these, the coating film of the artificial material leaves various problems in terms of adhesion with the affected area, water vapor permeability, cracking, etc., while the coating film of the bio-derived material has biocompatibility, etc. However, many of them have antigenicity, and also have drawbacks such as bacterial infection and deterioration due to exudate, and there is a problem that raw materials are difficult to obtain.

More recently, as a method for solving the above problems, a composite membrane composed of a collagen-treated nylon mesh and a silicone membrane has been developed and partially put into practical use. The composite membrane adheres well to the wound surface and has an appropriate water permeability, but has the drawback that it adheres to the wound surface and granulation tissue penetrates into the coating film.

Similarly, artificial materials using collagen have been developed to solve the above problems. Generally, collagen itself is a biological material, so cells,
As described above, the material has a high affinity for tissues and is excellent in biocompatibility and is suitable, but on the other hand, collagen has a drawback that it is easily decomposed and absorbed in a living body. Therefore, when using collagen as an artificial material, a material that is devised to strengthen the physical properties by introducing crosslinks by an appropriate method is used. As the cross-linking method, those adopting dehydration cross-linking by heating, chemical cross-linking using chemicals, etc. have been developed. Of these, thermal dehydration cross-linking is safer than chemical treatment, but because physical resistance to collagenase and enzyme is physically lower than chemical cross-linking, chemical cross-linking is usually used in combination with heat cross-linking or chemical cross-linking alone. The method used in is selected. In the case of using an artificial material having such a cross-link introduced, in addition to the above, excellent effects such as remarkable improvement of properties in terms of physical properties are exhibited. For example, when thermal cross-linking is introduced under vacuum at a temperature of 110 ° C. for 24 hours, a specimen of the artificial material is left in a unit of collagenase 3 unit / ml at 37 ° C. for 1 day and the Whereas collagen is dissolved, collagenase 100 uni is obtained in the sample of the artificial material which is only chemically crosslinked using an isocyanate-based chemical.
No change in morphology is observed even after 7 days at 37 ° C. in t / ml. However, when the artificial material is used as an artificial skin, when a strong cross-linking is introduced, the affinity of collagen before the introduction for cells and tissues is significantly reduced, and macrophages and neutrophils are present in the collagen matrix. Inflammatory cells such as infiltrate, inflammatory granulation is formed, or even inflammatory cells do not enter,
There is a defect that the matrix is eliminated due to so-called down growth of the regenerated skin. On the other hand, an artificial material using the above collagen formed by forming a collagen-denatured collagen matrix having good cell-penetrating property has also been developed, and neutrophils and macrophages infiltrate early, and further, fibroblasts invade. You can
However, the artificial material has the drawback of causing wound contraction as in an open wound. In other words, in these artificial materials, it is a conflicting event that it is difficult to achieve compatibility between the enhancement of physical properties and the improvement of biological performance such as affinity for cells and tissues. The appearance was strongly desired.

To date, as a solution to the above problems, an artificial skin having a three-layer structure consisting of a collagen matrix layer having a good cell-penetrating property, a collagen cross-linking support layer, and a water vapor permeation control layer. Has been developed by the present inventors (JP-A-2-34165). In animal experiments, when artificial skin is applied to the wound surface, fibroblasts infiltrate into the wound contact layer at an early stage to construct connective tissue like dermis, thereby promoting wound healing. When this artificial skin is applied to a wide range of burn wounds or a wide range of skin defects, it has a drawback that it takes a very long time to heal because of limitation of extension of the epidermis. However, regarding this drawback, it is possible to use a split-thickness skin graft that is generally performed clinically, and after transplanting the artificial skin described above for a certain period of time, sufficient cross-linking with a water vapor transmission control layer was performed. When the two layers of the support layer are peeled off and split-thickness skin grafting is performed, engraftment can be achieved, and the above defects can be compensated by this method, and application to a wide range of defect sites is also possible under certain conditions. However, although this method is less frequent, the supporting layer having a crosslinked structure could not be completely removed and remained on the collagen-denatured collagen matrix layer, which may adversely affect the survival of the split-thickness skin graft. ..

On the other hand, besides being mainly applied to the above-mentioned severe wounds, it is mainly used for a relatively mild wound such as a wide range of burns reaching a very shallow portion of the epidermis layer and the dermis layer or a cut wound. A two-layer wound dressing material has been developed by the present inventors (Japanese Patent Laid-Open No. 62-18376).
No. 0). In the experimental animal, the wound dressing protects and promotes early spreading of epidermal cells onto the injured dermis when applied to the wound surface, thereby promoting healing. However, in the actual clinical situation, when there is a large amount of bleeding, the blood cannot be processed, and in the initial stage the adhesion is poor due to blood retention, and after a certain period of time, fixation of the accumulated blood (hematoma formation) and delay of epidermal formation are delayed. May occur.

As has been seen above, conventional wound dressing materials and artificial skin cannot achieve perfect compatibility with living organisms, and wound dressing materials and artificial skin that sufficiently solve these problems. Is not obtained yet.

[0009]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to (1) properly adhere to the wound to prevent infection and pain, and (2) to provide appropriate moistening to the wound surface. A wound dressing material that has water vapor permeability and exudate absorbency, (3) prevents leakage of protein components in body fluids, and (4) easily obtains raw materials and is easy to manufacture. It is to provide, and in addition to (1) to (4) above, (5) to provide artificial skin such that good granulation tissue is regenerated.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned various objects, the present inventors have found that the site that can come into contact with a wound has a cell-permeable fibrotic collagen and a helix content of 0 to 0. The artificial skin is characterized by comprising a wound contact layer consisting of a matrix of 80% denatured collagen, a water vapor transmission control layer in close contact with the wound contact layer, and further having two continuous pores. Based on this finding, the present invention has been completed.

The present invention also provides a wound contact layer comprising a matrix of a fibrotic collagen having a good cell-penetrating property and a denatured collagen having a helix content of 0 to 80%, in addition to the wound contact layer. It is known that the above object is achieved by an artificial skin characterized by comprising a hydrophilized porous film laminated on the wound contact layer, and further the present invention based on this finding. It came to completion.

Further, in addition to the invention based on the above findings, the present invention also includes artificial skin in which the wound contact layer has collagen as a skeleton and denatured collagen is bonded by an appropriate ratio by thermal dehydration crosslinking. Knowing that the object has been achieved, the present invention has been completed based on this finding.

The present invention also comprises a layer composed of a matrix of a biocompatible water-absorbing polymer, for example, a cellulose derivative such as carboxymethyl cellulose, and a water vapor transmission control layer in close contact with the layer, and further comprises two layers. Based on this finding, the present invention has been completed based on the knowledge that the above object can be achieved by a wound dressing characterized by having continuous through holes.

The present invention also comprises a layer composed of a matrix of a biocompatible water-absorbing polymer, for example, a cellulose derivative such as carboxymethyl cellulose, and a hydrophilized porous membrane laminated on the matrix. Based on this finding, the present invention has been completed based on the knowledge that the above object can be achieved by at least the wound contact layer having a through hole.

That is, the present invention comprises a highly hydrous gel layer,
It is achieved by a wound dressing characterized by comprising a water vapor transmission control layer laminated thereon, and further having continuous through holes in two layers.

The present invention also comprises a highly hydrous gel layer and a hydrophilized porous membrane laminated thereon, and at least the highly hydrous gel layer has through holes. Achieved by the dressing.

[0017]

The operation will be described in detail based on the embodiments of the present invention.

The wound dressing of the present invention comprises a highly water-containing gel layer on one side of which a water vapor permeation control layer or a hydrophilized porous membrane is laminated. In the former case, two layers are continuously formed. The latter has a hole penetrating therethrough, and the latter has a hole penetrating at least the highly hydrous gel layer. These through-holes facilitate the drainage of exudate and blood of biological origin, and in artificial skin, facilitate the invasion of biologically-derived substances and dermis-derived cells from the side surface of the through-holes to improve biocompatibility of the matrix part. To facilitate the engraftment by supplementing nutrients to the split-layer skin that was difficult to engraft, and to enhance the adherence to the wound surface by the above-mentioned drainage effect even in a shallow wound dressing. At the same time, hematoma can be prevented from remaining and sticking to the wound surface can be finally prevented.

The highly hydrous gel layer is made of a highly biocompatible polymer. For example, when a matrix made of a bioabsorbable material such as collagen is used, cells with a wound repairing action can be invaded therein, and reconstruction by cells invading a dermis defect that could not be conventionally compensated. It can be replaced with the tissue of the living body and is preferably used for a wound invading the dermis. In addition, when the matrix is formed of a material that is not absorbed by the living body, such as a silicone-coated carboxymethyl cellulose nonwoven fabric,
Since the matrix itself has a function of protecting the living body without being taken up by the living body, healing by the living body itself can be promoted in a shallow wound or the like that does not require reconstruction with a filling material, and the epidermal layer and dermis layer can be promoted. It is suitable for use in wounds that have reached a very shallow site.

The through-hole has a function of facilitating drainage of exudate and blood of biological origin, and in a deep wound invading the dermis, invasion of biologically-derived substance and dermis-derived cells from the side of the through-hole. To improve the biocompatibility of the matrix part and facilitate engraftment at the same time, and even in wounds that reach a very shallow part of the epidermal layer and dermis layer, due to the above-mentioned drainage effect, the wound surface is more At the same time, the adherence to the wound surface can be finally prevented by preventing the hematoma from remaining and improving the adhesion of

FIG. 1 is an enlarged sectional view showing the fine structure of one embodiment of the artificial skin of the present invention. As shown in FIG. 1, the artificial skin 1 of the present invention is adjacent to the wound contact layer 2 and the wound contact layer 2 in which the site that can contact the wound is a collagen-modified collagen matrix layer having good cell-penetrating property. The water vapor permeation control layer 3 or the hydrophilized porous membrane 4 and the through holes 5 are formed.

Here, the wound contact layer 2 having the cell-penetrating property means that when the artificial skin 1 is applied to a wound site,
It is the infiltration of inflammatory cells in macrophages and neutrophils, and early invasion of fibroblasts, resulting in the reconstruction of dermal-like connective tissue.

The denatured collagen used in the wound contact layer 2 can be obtained by heat treatment, chemical treatment, physical treatment or the like of collagen, and heat treatment is most preferable. The degree of denaturation of collagen is indicated by the content of helix structure. Here, the helix (structure) content refers to the content of a triple-chain helix structure that is molecularly unique to collagen, and denatured collagen has a helix content of denatured collagen because the helix is randomly coiled. It corresponds to the degree. This helix content can be measured by circular dichroism or an infrared spectrophotometer (PLGordon, IVYannas, et al. Macr.
omolecules, 7 (6) 954 (1974), Nakakura, Hashimoto et al., Polymers Collection 41 (8) 473 (1984)). The index of denaturation of collagen used here, that is, the helix content is 0.
-80%, preferably 0-50%, more preferably 30
~ 50%. For example, collagen solution at 60 ℃, 3
When heat treated for 0 minutes, the helix content is about 40%,
Helix content is 0% after heat treatment at 100 ℃ for 24 hours
Becomes From this, it can be seen that a part of the collagen molecule is cleaved by electrophoresis. The composition of denatured collagen is 5 to 80%, more preferably 10 to 50%. The collagen used is preferably atelocollagen in which an antigenic determinant is enzymatically removed from the viewpoint of suppressing the expression of antigenicity, and if the atelocollagen is used as it is in a dispersed state, the physical properties are not significantly improved even if crosslinking is introduced,
Atelocollagen is more preferably subjected to a neutralization treatment (using a phosphate buffer) at 37 ° C. to form a fibrotic atelocollagen having a periodic fibrous structure as in vivo.

Further, by providing the water vapor permeation control layer 3 or the hydrophilized porous membrane 4, proper water permeation is performed, and by providing the through holes 5, the exudate is not stored on the wound surface and the wound surface is wet. The protein component in the exudate is prevented from leaking to the outside,
It will provide a very favorable environment for tissue repair.

The density of collagen-denatured collagen, which is a constituent member of the wound contact layer 2 used in the present invention, is
Although not particularly limited, it is preferably 0.01 to
0.1 g / cm ³ , more preferably 0.02 to 0.06
A range of g / cm ³ is good. Under this condition, even if there is no supporting layer as an intermediate layer composed of a fibrillated collagen matrix having a crosslinked structure as disclosed in JP-A-2-34165, which is structurally similar to the present invention. It is excellent in having sufficient strength.

When the wound contact layer 2 or the water vapor transmission control layer 3 has through holes 5, the exudate is not accumulated at the interface between the wound surface and the wound contact layer 2, and the wound contact layer 2 is well connected to the wound surface. They are in close contact with each other, and good granulation formation can be expected at an early stage. The hole diameter of the through hole 5 is not particularly limited, but is preferably 0.1 to 5.0.
mm, more preferably 1.0 to 3.0 mm. Under these conditions, granulation occurs at an early stage, so that the split-thickness skin graft can be transplanted at an early stage. Further, the hole diameter of the through hole is similar in the wound dressing.

The material of the water vapor transmission control layer 3 used in the present invention may be, for example, a silicone elastomer thin film or a polyurethane elastomer thin film.

Further, as the material used for the porous membrane of the hydrophilized porous membrane 4 of the present invention, polyolefin such as polyethylene and polypropylene, polyvinylidene fluoride, polyvinylidene chloride and halogenated polyolefin such as chlorinated polyethylene are used. Is mentioned. Hydrophilization of the porous membrane is performed by coating the surface of the membrane with a hydrophilic polymer by chemical bonding. The material of the polymer is not particularly limited as long as it is a hydrophilic polymer,
Preferred examples include polymethoxyethyl acrylate, polydimethylacrylamide, and methoxyacrylic acid ester copolymer. For use as artificial skin, the pore size of the porous membrane is usually 0.01 to
The range is 1.0 μm, preferably 0.1 to 0.4 μm.

On the other hand, as the matrix which is a biocompatible water-containing polymer having no water absorption property, a cellulose derivative, poly (meth) acrylamide type, poly (meth) acrylic acid type, polyoxyethylene-polyoxy is used. A matrix in which a propylene block copolymer system, more preferably a carboxymethyl cellulose-based nonwoven fabric or the like is coated with silicone or the like is used. The thickness of this matrix is preferably 50 to 200 μm, more preferably about 100 μm.

A wound dressing material comprising a matrix which is a biocompatible hydrous polymer having no bioabsorbability and a hydrophilized porous membrane, and which has a through-hole penetrating two layers, is either of these materials. This layer can also be a wound contact layer depending on the situation.

[0031]

[Examples] Collagen solution preparation Atelocollagen (manufactured by Koken Co., Ltd.) was dissolved in dilute hydrochloric acid having a pH of 3.0 at a temperature of 4 ° C to 0.2 to 0.4 w /.
It was adjusted to v%. Add this solution to 0.8 μm and 0.2 μm
After being sterilized by filtration through two kinds of filters having pores with a diameter of m, the pH is 7.
4 phosphate buffer was added to give a final concentration of 0.1-0.15.
The collagen solution was w / v% atelocollagen (30 mM sodium phosphate, 100 mM sodium chloride). Then, it was left in a constant temperature bath at 37 ° C. for 4 hours to prepare a fibrotic atelocollagen (hereinafter referred to as FC) solution. Then, the FC solution was concentrated under aseptic conditions by centrifugation to adjust the concentration to 4 w / v%. On the other hand, a 0.2-0.4 w / v% atelocollagen solution that has been passed through a filter is freeze-dried and redissolved again in sterile distilled water to a concentration of 6.6 w / v%. The solution was left for 30 minutes in a constant temperature bath to cause heat denaturation to obtain a denatured atelocollagen (hereinafter referred to as HAC) solution. The HA
The solution C was sterilized by filtration through a filter having pores with a diameter of 0.45 μm at a temperature of 37 ° C.
HAC / (FC + HAC) for w / v% FC solution
= 0.1 (HAC about 67% by volume with respect to 1000% by volume of FC) and stirred to obtain a mixed solution of fibrotic atelocollagen-denatured atelocollagen (hereinafter referred to as FC-HAC).

Example 1 The mixed solution of FC-HAC obtained by the above-mentioned solution preparation was poured into a stainless steel pad, rapidly cooled to -30 ° C or lower and sufficiently frozen, and then at -40 ° C less than 0.1 Torr. The matrix of FC-HAC was obtained by freeze-drying under vacuum. Next, 66 on a Teflon plate.
% Medical grade silastics silicone (Adhesive Silicone Type A manufactured by Dow Corning Co., Ltd.) precision coating tool (applicator)
Immediately after coating, the above FC-HAC matrix is placed on the wet layer, and the mixture is applied at room temperature for 1 hour.
After standing for 0 minutes, it was cured in an oven at 60 ° C. for at least 1 hour. In addition, a commercially available disposable punch (hole diameter 3
mm, manufactured by Maruho Co., Ltd.).

Example 2 400 parts by weight of liquid paraffin (average molecular weight 3) per 100 parts by weight of a polypropylene mixture having a melt flow index of 30 and 0.3 (mixing weight ratio 100: 40).
24) and 0.3 part by weight of 1, as a crystal nucleating agent
2,3,4-Bis (p-ethylbenzylidene) sorbitol was melt-kneaded by a twin-screw extruder and pelletized. The pellets are heated to 150-
It is melted at 200 ° C and extruded into air from a T-die with a slit of 0.6 mm to form a film. This film-like material is introduced into a cooling immobilization solution by a guide roller placed directly below the T-die, and then cooled and immobilized, and then wound. take. This wound film-like material is cut into a certain size, fixed in both vertical and horizontal directions,
The liquid paraffin in the film was extracted by immersing the film in 1,1,2-trichloro-1,2,2-trifluoroethane for a total of 4 times for 10 minutes. Then, heat treatment was performed in air at 135 ° C. for 2 minutes to obtain a polypropylene porous film (hereinafter referred to as a PP film) having a pore size of 0.2 μm and a film thickness of 100 μm. Further, after irradiating the PP film with argon plasma at 0.1 Torr for 15 seconds, in a methoxyethyl acrylate atmosphere (25 ° C., 4 Torr), 3
Plasma initiated polymerization was carried out for 0 minutes.

On the other hand, FC obtained by the above-mentioned solution preparation
-Injecting a mixed solution of HAC into a stainless steel pad, and slowly placing the hydrophilized PP film thereon, it floats upward.
After further rapid cooling to -30 ° C or lower and sufficient freezing,
By freeze-drying at −40 ° C. under a vacuum of less than 0.1 Torr, artificial skin having FC-HAC as the lower layer and hydrophilic PP film as the upper layer was prepared. Further, the FC-HAC layer portion was punched out from several places on the silicone film with a commercially available disposable punch (hole diameter: 3 mm, manufactured by Maruho Co., Ltd.).

Transplantation Test The matrices obtained in Examples 1 and 2 above were transplanted and tested on the dorsal skin of minipigs. Cocatan micro pigs, which are miniature pigs, were hair-removed under anesthesia with Nembutal, and a total wound skin defect of 40 × 40 mm on the wound surface with a fat layer completely exposed on the skin of the minipigs disinfected with isodine was prepared, and after bleeding and drying, The samples containing raw food were attached to each. Merolin (manufactured by S & N) and Opsite (manufactured by S & N) were overlaid thereon, and further fixed by compression with an elastic bandage made of elasticon (manufactured by J & J). 1 week after transplantation,
Peel off the upper layer of silicone or porous film, and remove FC-
Autologous split-thickness skin grafts were transplanted onto the HAC layer and observed for a further 4 weeks. Macroscopically, there was not much contraction, and the grafted split-thickness graft did not detach. Histopathologically, the dermis-like tissue regenerated by using artificial skin and the engrafted split-thickness skin graft were in close contact with each other, and the capillaries in the split-thickness skin graft were blood vessels that entered the artificial skin. Blood flow had resumed through.

Carboxymethyl cellulose high water content gel layer
Fabrication of commercially available carboxymethylcellulose sodium salt (hereinafter referred to as CMC) non-woven fabric (Tokai Senko Co., Ltd., degree of etherification 0.40) was made with 5% medical grade silastics (registered trademark) silicone (adhesive type). A, manufactured by Dow Corning Co., Ltd.) was immersed in a hexane solution for 10 seconds to obtain a highly hydrous gel layer having a thickness of about 100 μm.

Example 3 The high water content gel layer produced as described above was allowed to stand still on a medical grade silastics (registered trademark) silicone (MDX4-4210, manufactured by Dow Corning) and heated. Then, it was slowly placed on the hydrophilized polypropylene (hereinafter referred to as PP) film obtained in Example 2 and adhered thereto, and heated again to prepare a wound dressing composed of two layers of CMC nonwoven fabric and PP film. .. In addition, several points were punched out from the CMC non-woven fabric with a commercially available disposable punch (hole diameter: 2 mm).

Transplantation test 2 The dressing obtained in Example 3 above was transplanted to the back skin of a rat and tested. Wistar rats were hair-removed under Nembutal anesthesia.
A skin wound having a wound surface of 20 × 20 mm with a depth of / 1000 inch was mechanically prepared, and the specimen was applied as it was without stopping bleeding.
The gauze specified by the local law was placed on it. The bleeding blood was immediately drained from the through hole and stopped when it came into contact with gauze. Furthermore, it was easy to change the gauze after several days, and the epidermalization was completed only after the healing, which normally took 2 weeks or more, took 3 to 7 days.

[0039]

EFFECTS OF THE INVENTION The wound dressing of the present invention is applied to a damaged surface when the skin is damaged by a wound, a heat wound, a pressure ulcer, etc. to softly protect the wound surface, relieve pain, and prevent bacterial infection. To prevent.

Further, the wound dressing of the present invention has a fibrotic collagen and helix content of 0 to 80% as a wound contact layer.
When using a matrix with denatured collagen that is
Since the wound contact surface has cell invasion properties, when applied to the wound surface, fibroblasts early invade the wound adhesion layer and build up dermal-like connective tissue, thus promoting wound healing.
After transplanting and holding for a certain period of time, the upper layer water vapor permeation control layer is peeled off, and an autologous split-thickness skin graft can be transplanted for survival.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a fine structure of an embodiment of the artificial skin of the present invention.

[Explanation of symbols]

 1 ... Artificial skin 2 ... Cell-penetrating support layer 3 ... Water vapor permeation control layer 4 ... Hydrophilized porous membrane layer 5 ... Through hole

Front page continued (72) Inventor Takeo Katakura 1500 Inoguchi, Nakai-cho, Ashigarakami-gun, Kanagawa Terumo Corporation (72) Inventor Yuyuki Nakamura 403-1 Tomitsuka-cho, Hamamatsu-shi, Shizuoka

Claims (2)

[Claims] 1. A wound dressing material comprising a highly hydrous gel and a water vapor transmission control layer laminated on the gel, and further having continuous through holes in two layers. 2. A wound dressing material comprising a highly water-containing gel and a hydrophilized porous membrane laminated on the gel, and the wound contact layer having through holes.