New surfaces that mimic biological membranes will be created by covalent binding of phospholipid monolayers at high densities to a rigid, insoluble silica particle. A series of unique solid-phases denoted as "Immobilized Artificial Membranes" (IAM) will be synthesized and extensively characterized. These IAM will be evaluated for: 1. their usefulness as HPLC separation matrixes for biological macromolecules; and 2. as model biomembranes for the study of integral membrane protein function. Hydrophobicity of the IAM will be varied via three approaches: a. controlling the hydrophobic depth of the lipid monolayer; b. bonding lysolecithin containing one alkyl chain in contrast to bonding lecithin with two alkyl chains; c. covalently anchoring carboxyl groups attached to hydrocarbon spacers at the surface and at various depths within the IAM hydrocarbon core. Membrane fluidity and surface properties will be modified by inserting mobile lipids within the layer of immobile phospholipids anchored to the rigid core. IAM mimicking the lipid environment of the cell membrane are to provide separation media with a surface uniquely suitable for the purification of highly functional biomolecules which are difficult or impossible to purify by existing methods. The ability of IAM to purify several classes of molecules is likely, including integral membrane proteins (enzymes), peptides, receptors and oligonucleotides. IAM will further be evaluated as model systems to reconstitute and study the membrane-bound enzyme cytochrome P-450 monooxygenase. Ultimate goals include the design of improved models of functional biomembrane bilayers and highly specific membrane-bound peptide sequences for selective purification of recombinant proteins.
