- Surface chemistry monomolecular model membranes
sterol / lipid interactions, and branched-chain lipids - Langmuir-Blodgett multilayers of polymers
- B. S., St. Andrews University, Scotland (1954)
- Ph.D., Bristol University, England (1957)
- Alexander von Humbold Senior U.S. Scientist Award (1983)
Current studies include film characteristic determinations of glycerides, vitamin related and carotenoid films with a particular regard being paid to pressure and oxidation stability. A new technique is being employed in examining a wide variety of systems. This involves locating a biphasic monomolecular film in the objective stage of an optical microscope and observing both fluid and microcrystalline condensed phases by means of a lipid fluorescent probe that is miscible in the fluid phase only. These studies provide valuable information on a wide variety of systems and problems. These include alkane chain order/disorder and other conformational transitions, cholesterol/lipid and drug membrane interactions and two-dimensional polymerization.
Analysis of the lipid components of the inner membrane of strains of the bacteria B. acidocaldarius, that exist in hot springs, shows that up to 70% of these are diacylglycerols with monoglucosyl polar head-groups and w-cyclohexyl alkyl chains. Comparative film studies of synthetic lipids having either phosphatidylcholine or monoglucosyl head-groups and either straight, methyl iso-branched or w-cyclohexyl chains, indicates that the monoglucosyl head-groups can provide a thermal stability up to about 70°C, whereas the phosphatidylcholine head-groups are unstable at temperatures in excess of 40°C. In addition the w-cyclohexyl alkyl chains create a highly condensed, but still liquid-crystalline-like state which provides low permeability and resists the effects of high acidity.
Recent studies have focused on the ability of molecules such as ethanol and procaine to penetrate biological membranes and the profound differences of one to the other as well as to their local anesthetic action. A totally different study looks at membrane formation on solids, edge effects and the wetting of edged solids.
Selected Recent Publications
Simulated 3-D miniscus created by the partial wetting of a thin edged plate. 