Integra as a dermal replacement in a meshed composite skin graft in a rat model: a one-step operative procedure

Thermoresponsive and Injectable Hydrogel for Tissue Agnostic Regeneration

Injectable hydrogels can support the body's innate healing capability by providing a temporary matrix for host cell ingrowth and neovascularization. The clinical adoption of current injectable systems remains low due to their cumbersome preparation requirements, device malfunction, product dislodgment during administration, and uncontrolled biological responses at the treatment site. To address these challenges, a fully synthetic and ready-to-use injectable biomaterial is engineered that forms an adhesive hydrogel that remains at the administration site regardless of defect anatomy. The product elicits a negligible local inflammatory response and fully resorbs into nontoxic components with minimal impact on internal organs. Preclinical animal studies confirm that the engineered hydrogel upregulates the regeneration of both soft and hard tissues by providing a temporary matrix to support host cell ingrowth and neovascularization. In a pilot clinical trial, the engineered hydrogel is successfully administered to a socket site post tooth extraction and forms adhesive hydrogel that stabilizes blood clot and supports soft and hard tissue regeneration. Accordingly, this injectable hydrogel exhibits high therapeutic potential and can be adopted to address multiple unmet needs in different clinical settings.

Use of Composite Acellular Dermal Matrix-Ultrathin Split-Thickness Skin in Hand Hot-Crush Injuries: A One-Step Grafting Procedure

Background

Hot-crush injuries to the hands can be devastating, and early debridement and coverage with skin autograft remains the golden standard of wound treatment. However, this type of treatment is not feasible or unlikely to succeed due to limited donor sites and wound characteristics of hot-crush injuries on hands. Thus, the composite grafting of acellular dermal matrix (ADM) and split-thickness skin graft (STSG) as a novel alternative method has been attempted. In this series, the results are presented to demonstrate the feasibility and effectiveness of the use of one-stage procedure for early reconstruction in hand hot-crush injuries.

Methods

All consecutive patients with hand hot-crush injuries, who underwent one-stage procedure of ADM and ultrathin STSG for soft tissue coverage at our institution from December 2018 to November 2019, were retrospectively analyzed. Wound dressings were opened on 7 days after operation to examine graft survival and complications. Patients were followed up for at least 9 months to evaluate their hand profiles.

Results

Samples of 14 patients with a total of 23 wounds were involved in the study. Thirteen of the 23 third–fourth-degree wounds had varying degrees of tendon exposure. On 7 days postoperation, the composite grafts survived in 12 patients with minimal focal graft losses and liquefaction and necrosis in 2 patients, which achieved successful healing following new coverage of ultrathin STSG. All the wounds healed with hospital stays ranging from 9 days to 32 days (median: 24.5 days). At the final follow-up (from 9 months to 20 months), all patients achieved excellent or good total active motion grade and good scar quality (Vancouver scar scale scored 1–3) with no revision surgery.

Conclusions

One-stage composite grafting of ADM and ultrathin STSG is a reliable alternative for early reconstruction in hand hot-crush injuries, which delivers good functional outcomes and a good cosmetic appearance.

Characterization and Evaluation of Carboxymethyl Cellulose-Based Films for Healing of Full-Thickness Wounds in Normal and Diabetic Rats

Artificial skin substitute made of polymeric films are of great demand in the field of skin tissue engineering. We report here the fabrication of carboxymethyl cellulose (CMC) and poly(ethylene glycol) (PEG) blend films by solution casting method for wound healing applications. The physicochemical characteristics and the thermal stability of the films were analyzed. The surface morphology shows crystalline structures with large hexagonal-like platelet crystals of CMC on the surface of the films. Pure CMC films exhibited higher tensile strength than the CMC/PEG blend films. The swelling ratio (SR) of the films was influenced by the pH of Tris-HCL buffer (2.0, 5.0, and 7.0), which increased with increase in pH. The hemocompatibility assay and cytotoxicity test using NIH 3T3 fibroblast cells showed that the films were biocompatible. To evaluate the wound healing efficacy, the films were applied in full-thickness wounds created in normal and diabetic Wistar albino rats. The wounds healed faster with pure CMC film compared to blend films in both normal and diabetic rats, evidenced by intensive collagen formation in histopathological analysis. Thus, the films have potential application in skin regeneration, thereby to restore the structural and functional characteristics of the skin.

Cultured Human Epidermis Combined With Meshed Skin Autografts Accelerates Epithelialization and Granulation Tissue Formation in a Rat Model

INTRODUCTION

As the take rate of cultured epidermal autografts in burn wound treatment is variable, widely expanded meshed auto skin grafts are often used in combination with cultured epidermal autograft to increase the take rate and achieve definitive wound coverage. However, a long time (3-4 weeks) required to prepare a cultured epidermis sheet is a disadvantage. Allogeneic cultured epidermis can be prepared in advance and cryopreserved to be used in combination with auto meshed skin grafts for treating third-degree burns. Nevertheless, the human cultured epidermis (hCE) has not been proved to accelerate wound healing after meshed skin grafting. Here, we investigated the effect of hCE on wound healing in a rat model of meshed skin grafting.

MATERIALS AND METHODS

Human cultured epidermis was prepared from human neonatal foreskin and assessed by the release of growth factors into the culture medium using enzyme-linked immunosorbent assay. Skin wounds were inflicted on male F344 rats and treated by the application of widely meshed (6:1 ratio) autogenous skin grafts with or without hCE (n = 8 rats per group). Wound area, neoepithelium length, granulation tissue formation, and neovascularization were evaluated on day 7 postgrafting.

RESULTS

Human cultured epidermis secreted IL-1α, Basic fibroblast growth factor, platelet-derived growth factor-AA, TGF-α, TGF-β1, and vascular endothelial growth factor in vitro. In rats, hCE accelerated wound closure (P = 0.003), neoepithelium growth (P = 0.019), and granulation tissue formation (P = 0.043), and increased the number of capillaries (P = 0.0003) and gross neovascularization area (P = 0.008) compared with the control group.

CONCLUSIONS

The application of hCE with meshed grafts promoted wound closure, possibly via secretion of growth factors critical for cell proliferation and migration, suggesting that hCE can enhance the healing effect of widely expanded skin autografts.

Retrospektive Analyse von56 Weichteildefekten nach einzeitiger Rekonstruktion unter Verwendung von Dermisersatzpräparaten

HINTERGRUND

Der Verschluss von Wunden mit ausgeprägtem Weichteilschaden stellt eine chirurgische Herausforderung dar und erfordert häufig umfangreiche plastische Operationen sowie freie Lappenplastiken. Die Kombination von Dermisersatzpräparaten und Spalthauttransplantationen ist eine innovative Methode die zur Versorgung von komplexen Verletzungen der Extremitäten angewandt werden kann. Wir haben diese Technik in das Standard-Handwerkszeug bei komplexen Verletzungen der Extremitäten aufgenommen. Die klinischen Ergebnisse von 56 behandelten Patienten werden vorgestellt.

PATIENTEN UND METHODEN

In 44 Fällen (78,6 %) wurde die beschriebene Methode an Defekten der unteren Extremitäten verwendet, einschließlich sieben Personen (12,5 %), die sich einer Stumpfdeckung nach Amputation unterzogen. Zwölf Defekte (21,4 %) befanden sich an den oberen Extremitäten. In zwei Fällen (3,6 %) wurde die Matriderm(®) -Matrix verwendet, um Nerven von unmittelbar angrenzenden chirurgischen Implantaten zu schützen.

ERGEBNISSE

Bei 41 Patienten (73,2 %) kam es zur Einheilung des Transplantats ohne Komplikationen. Fünfzehn Patienten (26,8 %) zeigten eine gestörte Wundheilung nach Defektverschluss, die unter konservativer Therapie zur Ausheilung gebracht werden konnte. Ein Patient (1,8 %) zeigte ein Transplantatversagen, was eine Revisionsoperation erforderlich machte. Umfangreiche plastische Rekonstruktionen mussten bei keinem Patienten angewandt werden.

SCHLUSSFOLGERUNGEN

Bei Fällen, in denen ausgedehnte plastische Operationen nicht möglich oder nicht erwünscht sind, ist die Verwendung von Dermisersatzpräparaten in Kombination mit Spalthauttransplantationen eine vielversprechende Alternative zum Wundverschluss bei ausgedehnten Weichteilschäden.

A literature review of the military uses of silver-nylon dressings with emphasis on wartime operations

Medical support of military operations involves treatment of massive soft tissue wounds, thermal burns, open fractures, blast injuries and traumatic amputations under conditions that are often austere and far from supply lines. Military hospitals, as recently deployed in Iraq and Afghanistan, are designed and equipped for stabilization and rapid transfer of injured patients back to their home nation. These austere facilities are often tasked with the emergency or long-term treatment of local populations when injured or burned, further stressing the medical resupply system. Pathogens encountered in contemporary wartime practice are increasingly resistant to antibiotics. Ionic silver is bactericidal against a broad spectrum of bacteria, yeasts and fungi, has been utilized as a topical antiseptic for over 100 years, and has no known clinically-relevant resistance. Silver-nylon dressings, initially stocked in US military hospitals as a burn dressing, are now finding utility as a universal dressing for all types of combat wounds. Compared to conventional burn dressings, they are easier to transport and store, easier to use, and do not need to be changed as frequently, allowing for conservation of nursing resources. In this literature review, the recent military uses of silver-nylon dressings are examined. The stockpiling and use of silver-nylon as a universal military burn and wound dressing is advocated.

Silver in medicine: a brief history BC 335 to present

Silver is a naturally occurring element. Similar to other metals, the ionized form of silver (Ag(+1)) has known antimicrobial properties. A number of wound dressings incorporating silver ion or silver compounds have recently been developed and marketed. In addition, the antimicrobial effects of silver are currently being promoted in consumer products such as clothing and household appliances. The present use of silver in medical and consumer products has prompted concerns for potential toxicity and ecological effects, including induction of microbial resistance to antibiotics. These concerns ignore the fact that silver has been used for medicinal purposes for several thousand years. A historical review of the uses of silver in medicine is presented.

Silver in medicine: the basic science

Silver compounds are increasingly used in medical applications and consumer products. Confusion exists over the benefits and hazards associated with silver compounds. In this article, the biochemistry and physiology of silver are reviewed with emphasis on the use of silver for wound care.

[One-stage defect closure of deperiosted bone and exposed tendons with MATRIDERM® and skin transplantation. Possibilities and limitations]

BACKGROUND

Full-thickness skin defects over functional structures (tendons, vessels) or deperiosted bones of the extremities usually require extensive soft tissue reconstruction to cover the defect. A new option for coverage of the defect is the application of MATRIDERM®, a bovine matrix consisting of collagen and elastin, as a neodermis underneath skin transplants. Can this combined one-stage surgical intervention successfully cover deperiosted bone or tendon?

PATIENTS AND METHODS

We performed this one-stage procedure in ten patients instead of soft tissue reconstruction. The success of wound coverage with the one-stage method and in combination with skin transplantation for defects generally associated with considerable loss of transplants (deperiosted bones and tendons without paratenons) was determined.

RESULTS

In nine of ten patients, complete defect coverage could be achieved. A one-stage wound closure in extensive defects with exposed tendons in four of five locations could be achieved. In deperiosted bone defects the one-stage coverage was only successful in two of six patients. However, complete wound closure could be achieved with a second skin transplantation in a patient with exposed tendon and bone in three of the four locations.

CONCLUSION

As a one- or two-stage procedure, MATRIDERM® application with skin transplantation resulted in an effective defect closure without the need for a complex plastic reconstructive procedure. With regard to its functionality it cannot be considered as a substitute for skin flaps. In selected cases MATRIDERM® is an interesting and successful method in plastic reconstructive surgery.

Reconstruction of skin avulsion injuries of the upper extremity with integra(®) dermal regeneration template and skin grafts in a single-stage procedure

INTRODUCTION

Management of skin avulsion injuries of the upper extremity may require coverage with large flaps or skin autografts. Cutaneous grafting is frequently combined with artificial skin to optimize the final functional and cosmetic result. The conventional use of bilaminated dermal substitutes consists of a two-stage procedure and requires long immobilization of the operated area. The purpose of this retrospective study is to evaluate the impact of a dermal regeneration template immediately covered by skin grafts in a one-step procedure for reconstructing skin avulsion injuries of the hand and forearm.

MATERIALS AND METHODS

We performed this technique in eight patients who presented with extended skin defects of the hand and forearm following skin avulsion injuries. Dimensions of the defects ranged from 160 to 1,250 cm(2). After debridement, Integra(®) Single Layer was applied and covered with unmeshed thin skin autografts; compressive dressings were used for 1 week and mobilization started by the second postoperative week. Histological examination of the grafted areas was performed 2 weeks after surgery. Functional and cosmetic outcome was assessed 12 months postoperatively.

RESULTS

The overall take rate of the dermal substitute and skin graft was 95-98 %. Histological results showed complete incorporation and vascular proliferation of the template, which allowed the neo-vascularization of the overlying autograft. The mean grip strength of the operated hands was at the 83 % of the normal contralateral hands. Pliability and overall appearance of the reconstructed areas was satisfactory (mean Vancouver Scar Scale Score 1.875).

CONCLUSIONS

The use of Integra(®) Single Layer dermal substitute and immediate skin overgrafting consists an alternative reconstructive option for managing extended skin avulsion injuries of the upper extremity; it reduces postoperative immobilization, minimizes donor site morbidity and provides good functional and esthetic results in a single surgical procedure.

Mathematical modeling and frequency gradient analysis of cellular and vascular invasion into integra and strattice: toward optimal design of tissue regeneration scaffolds

BACKGROUND

Rapid, effective host cell invasion and vascularization is essential for durable incorporation of avascular tissue-replacement scaffolds. In this study, the authors sought to qualitatively and quantitatively determine which of two commercially available products (i.e., Strattice and Integra) facilitates more rapid cellular and vascular invasion in a murine model of graft incorporation.

METHODS

Integra and Strattice were implanted subcutaneously into the dorsa of C57BL/6 mice; harvested after 3, 7, or 14 days; and stained with hematoxylin and eosin, 4',6-diamidino-2-phenylindole, and immunohistochemical stains for CD31 and α-smooth muscle actin. Exponential decay equations describing cellular invasion through each layer were fit to each material/time point. Mean cell density and cell frequency maps were created denoting extent of invasion by location within the scaffold.

RESULTS

Qualitative analysis demonstrated extensive cellular infiltration into Integra by 3 days and increasing over the remaining 14 days. Invasion of Strattice was sparse, even after 14 days. α-Smooth muscle actin immunohistochemistry revealed blood vessel formation within Integra by 14 days but no analogous neovascularization in Strattice. Mean decay equations for Integra and Strattice were y = 76.3(0.59) and y = 75.5(0.33), respectively. Both cell density measurements and frequency mapping demonstrated that, at all time points, Integra manifested a greater density/depth of cellular invasion when compared with Strattice.

CONCLUSIONS

These data confirm empiric clinical observations that Integra is more rapidly invaded than Strattice when placed in a suitable host bed. A remnant microvasculature template is not sufficient for effective cellular ingrowth into an artificial tissue construct. These findings provide insight into means for improving future dermal replacement products.

An historical perspective on advances in burn care over the past 100 years

The accelerated pace of clinical and laboratory research over the past century and application of the research findings to patient care have resulted in unprecedented survival of burned patients in all age groups. Resuscitation based on an understanding of the nature and magnitude of the multisystem response to injury now prevents burn shock; effective topical antimicrobial chemotherapy and early excision prevent wound toxemia and sepsis; biologic and bioengineered dressings compensate for the missing skin; and broad spectrum metabolic support regimens prevent exhaustion and accelerate convalescence. Rehabilitation programs have also been developed to restore physical function and permit the burn patient to reenter society as a productive individual.

Tissue engineering of skin

The engineering of skin substitutes and their application on human patients has become a reality. However, cell biologists, biochemists, technical engineers, and surgeons are still struggling with the generation of complex skin substitutes that can readily be transplanted in large quantities, possibly in only one surgical intervention and without significant scarring. Constructing a dermo-epidermal substitute that rapidly vascularizes, optimally supports a stratifying epidermal graft on a biodegradable matrix, and that can be conveniently handled by the surgeon, is now the ambitious goal. After all, this goal has to be reached coping with strict safety requirements and the harsh rules of the economic market.

Real-time analysis of the kinetics of angiogenesis and vascular permeability in an animal model of wound healing

The use of engineered tissue for the treatment of a variety of acute to chronic wounds has become a clinical standard, and a better understanding of the cellular mechanisms of re-vascularization and barrier integrity could enhance clinical outcomes. Here, we focus on the characterization of the re-vascularization of acellular grafts such as Integra in an animal model to better understand the physiological properties of blood vessels growing in the collagen-glycosaminoglycan matrix vs. wound margins. While Integra has been extensively studied in pre-clinical models, the re-modeling mechanisms of the capillary bed under these matrices are not well understood. Therefore, our first objective was to quantify the kinetics of re-vascularization. The second objective was to assess changes in vascular permeability (VP) of the wound bed compared to normal adjacent skin. The third objective was to establish a non-invasive and quantitative assay for the measurement of VP to facilitate the rapid and reproducible characterization of vascular integrity. Using an excisional wound model in mice, we characterize the appearance, growth, and maturation of blood vessels in an Integra graft over 28 days after surgery. Initial appearance of blood vessels in the graft was observed at 7 days, with angiogenesis peaking between 7 and 14 days. The onset of VP coincided with the increase in re-vascularization of the wound bed and there was a sustained elevation of VP that declined to baseline by 28 days. We propose a non-invasive strategy to assess VP of the wound capillary bed will facilitate a better understanding of the cell and molecular basis of angiogenesis in wound healing.

Hyalomatrix: a temporary epidermal barrier, hyaluronan delivery, and neodermis induction system for keratinocyte stem cell therapy

Keratinocyte stem cell technology provides at least an adjuvant therapy to clinically close large cutaneous wounds (e.g., burn wounds). Here, the performance of keratinocyte cultures depends primarily on the quality of the bed to which they are applied. Clinical take rates for cultured keratinocyte grafts are optimal when applied to a vascularized dermal bed with minimal bacterial colonization. In the absence of autologous dermis, staged reconstruction with a dermal equivalent or dermal regeneration template is required. A novel product, Hyalomatrix, is a bilayer of an esterified hyaluronan scaffold beneath a silicone membrane. The scaffold delivers hyaluronan to the wound bed, and the silicone membrane acts as a temporary epidermal barrier. The product has been investigated in a controlled, porcine, acute full-thickness excisional wound model. Cultured autologous keratinocytes (CAKs) were delivered on Laserskin to acute full-thickness wounds treated with Hyalomatrix within chambers, and graft take rates were assessed longitudinally using image analysis. In the absence of chambers, wound contraction was assessed. Clinical CAK take rates fall sequentially with delay in application post-Hyalomatrix pre-treatment, but repeated pre-treatment removed this, with maximal take of 57.2% at 5 weeks post-wounding. In the absence of chambers, more-complete wound closure resulted from edge re-epithelialization and contraction, by a factor of 5 at 1 month, and was achieved at least 2 weeks sooner in the gold standard controls of split-thickness autograft to an acute or pre-treated wound bed. Wound contraction and late neodermal morphology (1 year) were similar in pre-treated CAKs and split-thickness autograft wounds. In this model, the Hyalomatrix wound bed pre-treatment increase in CAK take appeared to be dose dependent. The product appeared to act as a hyaluronan delivery system rather than a dermal regeneration template. The silicone membrane may limit wound bed colonization, and the combination of this temporary barrier with hyaluronan delivery and neodermis induction has been termed a barrier-delivery-induction system. The development of similar systems for serial application offers an alternative to a dermal regeneration template when CAKs are engrafted in the hostile, colonized environment of large burn wounds.

The use of a non-cultured autologous cell suspension and Integra® dermal regeneration template to repair full-thickness skin wounds in a porcine model: A one-step process

Integra is a skin substitute used for dermal reconstruction. Current clinical practice consists of two procedures, first applying Integra to the wound and then replacing the silicone pseudo-epidermis with an epidermal autograft 3 weeks later. This two-step repair limits the clinical use of the product. An effective one-step procedure could reduce the time taken to repair and decrease the number of procedures for use of Integra. This study examined the effects of simultaneous application of a non-cultured autologous suspension of cells, isolated using the ReCell autologous cell harvesting device, in combination with Integra, to achieve a one-step skin repair. In two female Yorkshire swine, 10 full-thickness wounds were created. Wounds were treated with Integra seeded with cell suspension and compared to controls of Integra alone and cell suspension alone. Weekly macroscopic and histological assessment demonstrated that the wounds treated simultaneously with Integra and non-cultured autologous cells had enhanced epithelialization at an early time-point compared to controls. Wounds treated simultaneously with Integra and cell suspension demonstrate that cells remain viable, migrate through the Integra template and self-organize into differentiated epidermis. The results indicate that combining Integra with autologous cells facilitates one-step skin reconstruction of a full-thickness skin wound.

Novel application method of artificial dermis: One-step grafting procedure of artificial dermis and skin, rat experimental study

BACKGROUND

Currently, to treat skin defects with artificial dermis (AD), two surgical procedures where the artificial dermis grafting and another secondary skin grafting are required. The purpose of this study was to achieve simultaneous grafting of the artificial dermis and the split-skin. To enhance the wound angiogenesis, cultured endothelial cells, fibroblasts and PDWHF (platelet derived wound healing factor) were employed.

METHODS

The experiment consists of following two parts: (1) Investigation to obtain faster angiogenesis into the bilayer artificial dermis: full-thickness wounds created on the back of the rats were treated with the artificial dermis (Terudermis, with silicone sheet, TERUMO Co., Japan). Prior to the artificial dermis grafting, following four groups were established; control group (AD alone, n=6), PDWHF group (AD treated with PDWHF, n=6), cultured cells group (AD treated with cultured endothelial cells and fibroblasts, n=6), combination group (AD treated with PDWHF and cultured cells, n=6). (2) Trial of one-stage grafting of the AD and the skin: simultaneous grafting of the artificial dermis and skin was performed using the same rat model. Before making skin defects, split thickness skin were harvested. Then the skin grafting was carried out immediately after the AD grafting. To allow grafting of the skin onto the artificial dermis, the AD without silicone sheet (Terudermis without silicone sheet, TERUMO Co., Japan) were used. Two groups, control group (AD alone, n=3) and treatment group (AD with PDWF and cultures, n=3) were established.

RESULTS

(1) When the artificial dermis were treated with PDWHF, cultured endothelial cells and fibroblasts, vascular invasion into the artificial dermis was observed 5 days after the surgery. (2) In the treatment group, the skin grafted immediately after the artificial dermis grafting was completely taken.

CONCLUSIONS

The present study revealed that treatment with PDWHF, combined with cultured endothelial cells and fibroblasts, accelerated wound angiogenesis. By this method, one-step grafting procedure of the artificial dermis and the skin is possible.

The application of new biosynthetic artificial skin for long-term temporary wound coverage

Temporary dressings protect wounds from desiccation and infection. In our previous study, we used meshed acellular porcine dermis (APD) to enhance wound healing and decrease wound contraction; however, the wounds showed meshed scar. In this study, we produced an artificial skin composed of a cross-linked silicon sheet on the surface of APD which we have called silicone acellular porcine dermis (SAPD). This new artificial skin can protect the wound long enough to promote wound healing either by second intention or covered long enough until cultured epithelium autograft (CEA) or autologous skin graft can be harvested for permanent coverage. We delivered 4 cm x 5 cm full-thickness wound on the back of 350 g Sprague-Dawley rats. Thirty-six rats were divided into two groups. Eighteen rats had SAPD and the other 18 were covered with Biobrane. The wounds were first examined 2 weeks after grafting and followed weekly for an additional 4 weeks to evaluate the wound and study pathological changes by using H.E. and Masson's stains. Wound size was calculated by ruler and analyzed by Student's t-test. At the 2-week inspection, both SAPD and Biobrane showed tight adherence to the wound with no change of wound size. Both the SAPD and Biobrane dermal templates were pink. In the Biobrane-covered group, the wounds contracted soon after the tie-over dressing was removed. Its dermal layer is a layer of thin porcine dermal substance, which was promptly digested by tissue hyaluronidase and provides no real dermal template. In the SAPD-covered group however, the wound size was maintained significantly from third to sixth week after grafting (p<0.001). SAPD was designed with thick epidermal silicone and a well-organized porcine dermis so that it incorporates into the recipient wound. Clinically the silicone layer of SAPD dislodged from APD about 6-7 weeks after grafting and was followed by dermal matrix exposure and infection. In pathological examination, much like a human skin graft, new vessels were found in APD about 1 week after grafting with minimal inflammatory cells infiltrated in the graft and wound. Six weeks after grafting, the collagen of APD incorporated into the wound, showing palisade arrangement and no sign of rejection. In the Biobrane group however, the wounds showed severe inflammation, the porcine dermal matrix was digested and disappeared 3 weeks after coverage. In conclusion, SAPD is a thick biosynthetic artificial skin, which protects the rat wound significantly longer than Biobrane and prevents contraction. We expect that using of SAPD for temporary wound coverage will provide enough time to grow autologous-cultured epithelium or to reharvest skin grafts.