Biomechanical Characterization of Engineered Dermal-Equivalent Tissue

Abstract

The purpose of this study is to probe and quantify the mechanical tension generated in the fibroblast-populated collagen lattices. In this study, we created tension-maintaining dermal equivalents by co-culturing human dermal fibroblasts with type-I collagens in relative low, medium and high concentrations. Polymerized collagen lattices were supported structurally by plastic mesh rings. TGF-?? was added to some lattices to study its effects on tension generation. The cultures were incubated in a CO2 incubator for 7 days to allow the lattices to develop. After incubation, the generated mechanical tension in these dermal equivalents was probed by removing a small circular section (2-mm in diameter) from the tissue with a biopsy punch. The expansions of these induced wounds were recorded and measured at various time points. We found that the circular wound area expanded more quickly the lower the collagen concentration in the lattices, and more slowly the higher the collagen concentration, suggesting that there is considerable level of mechanical tensions in the collagen lattices. In addition, the induced wounds in TGF-? treated lattices showed quicker and larger expansion than the control, which indicates more tension generated in the presence of TGF-?. The results would indicate that higher collagen concentration impedes the tension generation in the tissues.