The donor site for STSGs provides a consistent model of superficial wounds that offers the opportunity to study both mechanisms of wound healing and potential mechanisms of action of NPWT. In patients undergoing both standard dressings and NPWT, the investigators will sample the wound exudate and perform microbiopsies of the healing wound at fixed intervals and perform histologic and molecular analysis in order to quantify the degree of re-epithelization and the trophic and inflammatory profile of the healing wound.