## 4 Discussion  
Full-thickness skin injuries, such as deep burn wounds, generally require surgical intervention in addition to sufficient debridement. In medical care, autologous skin grafting is still the gold standard of dermal replacement [15; 16; 17]. However, when harvesting a skin graft, a new wound surface will arise and might result in hypertrophic scarring, severe pain, unsatisfactory cosmetic and functional complications or even additional chronic wounds in patients with microcirculation disorders [18]. In burn patients, the harvesting of a graft leads to a larger wound area with an increased risk of fluid loss, infection and temperature loss. Moreover, in extensive burns, the donor region is limited, so the overall aim in plastic, reconstructive and burn surgery remains the use of skin analogues similar to natural skin. There are various manufactured skin substitutes, but at present, there is still no commercially available skin substitute that can restore all necessary characteristics of the native skin [19]. Beginning in the early 1980s, tissue engineering developed some skin replacement products with promising results with deep dermal burn wounds and for use in reconstructive surgery [20; 21; 22; 23], including the analyzed crosslinked and non-crosslinked biomatrices. Dermal substitutes such as these are mainly acellular 3-dimensional scaffolds and of allogenic, xenogenic or synthetic origin, which nourish the epidermal layer or an epidermal graft (i.e., skin grafts). Both analyzed products contain collagen, the key component of the human skin. Cell migration takes place along the collagen fibers in an organized manner. Figure 4: Neoepidermal cell density in untreated, the crosslinked and non-crosslinked biomatrices-derived neoepiderms within a section of 100 μm width taken repetitively in three different sections. Histologic examination demonstrated the densest colonization of neoepidermal cells in the non-crosslinked biomatrix-treated wounds. * Statistically significant results. The non-crosslinked biomatrix is used for dermal regeneration with promising results comparable to pure full-thickness grafts but with marginally slower regeneration compared with split-thickness skin grafting only [24]. Even in wet conditions it retains its stability and elasticity [25] and improves the biomechanical properties of the regenerating tissue due to the elastin component [26]. It reduces wound contraction and scar formation, so the reconstructed skin is stress-resistant sooner and patients' rehabilitation is faster, shortening their hospital stay and sophisticating long-term results [27; 28]. The crosslinked biomatrix also serves as a dermal regeneration template. The dermal matrix with its open pore structure promotes the ingrowth of fibroblasts and endothelial cells [29]. Its silicone layer functions as a temporary barrier preventing fluid loss and protects against mechanical influences and bacterial contamination [20; 25; 30; 31; 32; 33]. Usually, the silastic sheet may be removed 15 to 28 days after placement [29]. In our study, it was left on the wound for seven days because we already observed wound healing and did not want to integrate the silicone into the wound and compromise epithelialization. [PERSON] et al. already showed that deep facial burns tolerate the removal of the silicone layer after seven to ten days without difficulties [34]. By applying the crosslinked biomatrix complex, skin defects, even with exposed anatomical structures, can be managed and this process might even reduce the necessity for reconstructive techniques, such as local or free flap transplantation [35]. Nevertheless, artificial skin replacement products have disadvantages, including their relative expense, the risk of infection complications and, if the treatment is insufficient, patients will suffer fragile wounds and consequent surgical revisions [36]. The crosslinked and non-crosslinked biomatrices are usually applied together with split-thickness skin grafting, as [PERSON] et al. did in rats [5].