RESUMEN
Tissue engineering seeks to produce living, three-dimensional cellular constructs that can be used as clinical replacements of damaged tissues and organs as well as research tools to study cell and matrix interactions that occur in higher-order systems. To organize the cells into a three-dimensional structure in vitro, a provisional extracellular matrix support is required. The two main methods to achieve this are (a) to culture the stromal cells on a three-dimensional synthetic meshwork, or else (b) embed the cells within a three-dimensional lattice, for example type I collagen. The contracted collagen lattice can be used for a variety of practical applications including the support of epithelial growth and differentiation to produce a skin replacement (Toxic In vitro 5:591-596, 1991; J. Biomech. Eng. 113:113-119, 1991; Parenteau, 1994, Keratinocyte Methods, 1994, Cambridge University Press, Cambridge, pp.45-55; Dermatol. Surg. 21:839-843, 1995; Biomaterials 17:311-320, 1996). This has been used successfully to treat patients with chronic ulcers. However, this model system can also be exploited for experiments to study cell-matrix interactions such as the influence of tension on cell phenotype (Exp. Cell Res. 193:198-207, 1991).