Abstract

Investigating how biomolecules behave in cell membranes gives us insight that can be used to create better assays, sensors, and devices that mimic the cell surface. Applications for these devices include rapid combinatorial analysis of drug targets, biosensors for toxin detection, and proteomics research. Solid-supported lipid bilayers (SLBs) are an excellent platform for mimicking the surface chemistry of cells. However, there are several drawbacks to these platforms. First, proteins can lose their mobility in these systems, impairing their function. Second, there is no good way to discriminate between analytes that bind to the same surface ligand within these platforms. Third, separation, purification, and formation of arrays of membrane species is difficult, impeding the progress of rapid combinatorial assaying of membrane proteins. Results will be presented on studies conducted to understand these issues and strategies to overcome them. By investigating the behavior of protein-protein interactions on SLBs, we found that protein-packing influences the point at which diffusion is arrested in these systems. To improve binding specificity, we devised a system for size-selective discrimination of protein analytes that bind to the same ligand, by incorporating poly(ethylene glycol) (PEG) lipopolymers into SLBs. Using our platform, we were able to achieve discrimination of several orders of magnitude. Finally, we developed a technique to separate membrane species within an SLB: bilayer chromatography. Results will be presented that show our separation method is sensitive enough to differentiate isomers of dye-labeled lipids and is currently being extended to the separation of membrane proteins.

URL:
http://www.cbe.cornell.edu/~sd386/webpage/susan.html