Cell Adhesion to Peptide-Functionalized Surfaces

The goal of this project is to explore ways to functionalize surfaces using peptide ligands as a means of creating efficient biomaterials.  It is known that specific receptor-ligand interactions that mimic the interactions of mammalian cells in vivo can be engineered to create biomimetic surfaces.  For example, incorporating the RGD peptide sequence on surfaces has been shown to promote the adhesion and proliferation of fibroblast cells.  We explore ways to display peptide ligands on surfaces to create the most optimal environment for cell adhesion.

We use the peptide-amphiphile as a vehicle to deposit peptide ligands on surfaces in a controlled way.  Peptide-amphiphiles are molecules with a peptide head-group (e.g. GRGDSP) conjugated to a hydrophobic lipid-like tail segment.  The amphiphilic character of these molecules enables their self-assembly into various aggregates in solution and on surfaces.   We use these amphiphiles incorporated in lipid vesicles to create solid-supported bilayers that can be visualized by fluorescence microscopy.

Our research is focused on optimizing the concentration of a peptide-amphiphile (containing the peptide ligand RGD) in a lipid bilayer, so we can regulate cell adhesion.   The optimal concentration of RGD ligands is the one which results in the highest fraction of cells adhered to the surface. Further, we hope to use these methods to display multiple peptide ligands and thus mimic the native extra-cellular matrix to a greater extent, which might allow the surface to function more efficiently as a biomaterial.