Surface-directed assembly of fibrillar extracellular matrices

Abstract

Biologically-inspired materials have emerged as promising substrates for enhanced repair in various therapeutic and regenerative medicine applications, including nervous and vascular tissues, bone, and cartilage. These strategies focus on the development of materials that integrate well-characterized domains from biomacromolecules to mimic individual functions of the extracellular matrix (ECM), including cell adhesive motifs, growth factor binding sites, and protease sensitivity. A vital property of the ECM is the fibrillar architecture arising from supramolecular assembly. For example, the fibrillar structure of fibronectin (FN) matrices modulates cell cycle progression, migration, gene expression, cell differentiation, and the assembly of other matrix proteins. Current biomaterials do not actively promote deposition and assembly of ECM. In this research, we describe the rational design and investigation of non-fouling biomimetic surfaces in which an oligopeptide sequence (FN13) from the self-assembly domain of FN is tethered to non-fouling substrates. This surface modification directs cell-mediated co-assembly of robust fibrillar FN and type I collagen (COL) matrices reminiscent of ECM, and increases in cell proliferation rates. Furthermore, the effect of this peptide is surface-directed, as addition of the soluble peptide has no effect on matrix assembly. We have also identified a critical surface density of the immobilized peptide to elicit the full activity. These results contribute to the development and design of biomimetic surface modifications that direct cell function for biomedical and biotechnology applications.