Biomimetic molecular assemblies on glass and mesoporous silica microbeads for biotechnology

This paper describes the use of glass and mesoporous silica microspheres (typically 1-50 mum) as supports for biomimetic lipid bilayer membrane architectures for use in biotechnological applications. We present methods and characterization of lipid bilayer membranes supported on commercially available glass beads and mesoporous silica beads formed by an aerosol process that takes advantage of self-assembly of surfactant template phases in sol-gel synthesis. Methods for controlling the concentration of fluorescent lipids, ligands, receptors, and transmembrane proteins in the bead-supported bilayer assemblies are discussed, along with methods for measuring the concentration of these species using flow cytometry. Diffusion of molecular species both within the lipid bilayer and within the mesoporous bead structure is probed using fluorescence recovery after photobleaching. Flow cytometry and confocal fluorescence microscopy are used to examine dye uptake of the porous beads and the stability of the encapsulating lipid bilayer membranes to proton and fluorophore leakage. The studies presented herein form the basis for the use of several new types of biomimetic bead-supported bilayer architectures in a variety of biotechnological applications including microimmunoassays and fluorescence-based high-throughput screening of biochemical recognition and protein function.