Tissue engineering for cutaneous wounds: selecting the proper time and space for growth factors, cells and the extracellular matrix.

Currently, autografts are the best treatment to any substantial cutaneous injury, and their success is well known as a burn therapy. However, autografts have been less successful in the treatment of chronic ulcers, and are usually a last-resort therapy because of infection at the injured site, high surgical expense, additional morbidity and engraftment failure. In addition, patients with burns covering more than 50% of their skin have limited donor sites for autograft harvest. Therefore, there is a great need for a cost-effective, user-friendly, tissue-engineered construct (TEC) that can provide successful treatments to both acute and chronic wounds in a wider repertoire of patients, including diabetics and the elderly. One approach to the challenge is to create a substitute for skin in vitro that can integrate into the engraftment site in vivo. An alternative is to engineer a biocompatible, resorbable matrix that can recruit the proper, native tissue cells to the injured site and induce them to heal the wound without scarring. This chapter reviews the 3 essential components of cutaneous wound healing, that is, cells, extracellular matrix molecules and bioactive molecules, that must be considered for designing TECs to potentially enhance the healing process. In nature, a 'dynamic reciprocity' exists amongst cells and extracellular matrix that is mediated by bioactive molecules at the site of injury. Thus, it is important to examine the interplay of all 3 components when engineering a TEC. This chapter also includes examples of commercially available products to highlight how researchers have already begun to find success in tissue engineering.