Skin substitutes composed of cultured cells and biopolymers provide alternative materials
for study of skin biology and pathology, treatment of skin wounds, safety testing of consumer
products, and therapeutic delivery of gene products. Most frequently, substitutes for
epidermis consist of cultured keratinocytes and dermal substitutes consist of resorbable
biopolymers populated with cultured fibroblasts. Preclinical models characterize cellular
morphogenesis, antigen expression, and barrier properties in vitro, and recovery of tissue
function after grafting. Clinical considerations include time required to prepare cultured
autografts, time required for graft vascularization, management of microbial contamination
in wounds, mechanical fragility of cultured grafts, and high cost. Safety in graft preparation
generally requires the use of materials and procedures that comply with standards for
quality assurance. Efficacy of engineered skin substitutes has been evaluated predominantly
by subjective criteria, but evaluation may become more objective and quantitative by application
of noninvasive biophysical instrumentation. Future directions with engineered skin
substitutes are expected to include gene therapy by addition or deletion of selected gene
products and establishment of international standards for fabrication and assessment of engineered
skin.
