Epidermal substitutes are used for treating lesions that have affected the dermis

The procedure is relatively complicated, but the desired and effective results are usually achieved. Both epidermal and dermal tissues of the skin are used in the materials and methods part of the procedure. Epidermal substitutes are used for treating lesions that have affected the dermis. They contain autologous keratinocytes that are obtained and cultured in cell cultures in the laboratory and in the presence of murine fibroblasts (Horch 599). First, a skin biopsy extending some 2 to 5 cm²Â is obtained. Secondly, the dermis and epidermis tissues sections are separated from each other. Third, the keratinocytes are isolated and cultured, which takes about 3 weeks to culture in an appropriate medium (Bartholomew et al. 45). Since this time is relatively long, the patient must be treated with a temporary dressing to protect the wounds and the tissues involved and stimulate their healing process. However, current technologies allow for direct spraying of the biopsy cells directly into the wound, which makes it possible for local delivery of the cells. However, this technique is not recommended for third-degree burn wounds. Recent techniques have made it possible to treat third-degree wounds within a short time through application of cultured keratinocytes. For instance, surface-functionalized polymer discs make it possible for the delivery of cultured autologous keratinocytes directly into chronic and third-degree wounds (Pham, Sharma and Mikos 1198).

Another method of isolation involves dermal substitutes as compared to epidermal substitutes. To treat full-thickness lesions that affect both the dermis and the epidermis. The use of an allograft or dermal constructs is necessary for these situations. Dermal substitutes are developed through natural or synthetic techniques. They tend to prevent the contraction of the wound and provide mechanical stability. For instance, the process involves engineering tissues using such procedures as loading dermal substitutes with complexes of plasmid DNA that encodes for VEGF-165/N,N,N-trimethyl chotisan chloride (Cancedda et al. 83). Testing for regeneration of the full-thickness wounds in animal models as well as in humans has shown that the process is faster and more effective, making it an important approach to healing these wounds (MacNeil 876).