Developing Peptide Concentrations in a Membrane Environment

Most biomaterials interact with cells at interfaces. Because of this, much attention has been focused on studying cell behavior on such surfaces. My project involves the creation of membrane bound peptide gradients using microfluidic channels and solid substrates. Starting with substrates having a pattern of barriers to lateral diffusion a bilayer composed of different peptide concentrations can be deposited along the substrate width using vesicle fusion. A microfluidic device was constructed on a silicon wafer and was transfered on to a mold made of PDMS. Inlets and outlets for our flow solutions were then made on our PDMS mold. The peptides used in this experiment are the fibronectin originated GRGDSP amino acid sequence, known to promote cell adhesion. The vesicle solutions contain Texas Red, a fluorescent compound that makes the gradient observable under fluorescent light. The bilayer formed, an extracellular matrix-like material, consists of different peptide amphiphiles concentrations along the surface that can come to serve as an important tool to study cell behavior. Cell migration and optimum substrate concentration for cell spreading are two examples of how a peptide concentration gradient can be useful.