Bioactive Surface Gradients to Control Cell Adhesion

Matthew Becker

Abstract

Incorporating discrete cell adhesion motifs onto substrates in a defined orientation with variable spacing and increasing concentration offers a robust strategy for measuring ligand dependent cell-material interactions and encouraging specific cell adhesion. This approach provides a tool for the rapid and iterative fabrication of bioactive surfaces that elicit specific responses from cells through well-characterized receptor-ligand interactions and investigate density dependence on cell function. We quantified the number of adherent cells and cell spreading with increasing RGD peptide density on 40 mm gradients. The number of adherent cells remains at background levels before increasing upon reaching a threshold, while the projected cell area increases before reaching saturation. Images of cells stained for vinculin containing focal adhesions taken at intervals along the gradient also indicate possible surface dependent changes in cell shape and migratory behavior.Peptide functionalized gradient substrates have shown the ability to control cell adhesion and therefore provide a tool for screening surface directed cell function. Furthermore, this work extends the NIST combinatorial approach to materials characterization to an investigation of cell-material interactions.