Using self-assembled monolayers that present arg-gly -ASP peptide ligands to study adhesion of fibroblasts

Methods for controlling the attachment of cells to man-made materials are important in the design of substrates for cell biology and biotechnology. Our research program uses self-assembled monolayers ol alkanethiolates on gold that present Arg-Gly-Asp peptide ligands to study cell adhesion. Since the properties of the monolayer depend on the terminal functional group of the precursor alkanethiol, virtually any surface can be engineered using organic synthesis. This methodology permits control of the structure, density, and environment of attached ligands. Optical microscopy showed that the morphology of attached cells depends on the density of peptide ligand. At low densities, cells remained rounded, while at higher density of ligand, cell-spreading on the substrate increased. Morphology also depended on the steric environment of the peptide. Decreasing accessability of the ligand significantly reduced the number ol cells able to adhere to the substrate and forced attached cells to adopt a more rounded morphology. Environmental effects on the peptide became more marked at lower densities, and immunostaining of these substrates showed significant differences in cytoskeletal architecture at the interface. This experimental system will be important for understanding the relationship between the affinity of attached ligands for integrin receptors and cell adhesion.