Hybrid Bilayer Membrane Research Articles

Supported phospholipid/alkanethiol biomimetic membranes: insulating properties

A novel model lipid bilayer membrane is prepared by the addition of phospholipid vesicles to alkanethiol monolayers on gold. This supported hybrid bilayer membrane is rugged, easily and reproducibly prepared in the absence of organic solvent, and is stable for very long periods of time. We have characterized the insulating characteristics of this membrane by examining the rate of electron transfer and by impedance spectroscopy. Supported hybrid bilayers formed from phospholipids and alkanethiols are pinhole-free and demonstrate measured values of conductivity and resistivity which are within an order of magnitude of that reported for black lipid membranes. Capacitance values suggest a dielectric constant of 2.7 for phospholipid membranes in the absence of organic solvent. The protein toxin, melittin, destroys the insulating capability of the phospholipid layer without significantly altering the bilayer structure. This model membrane will allow the assessment of the effect of lipid membrane perturbants on the insulating properties of natural lipid membranes.

Enantioselective β-Replacement Reaction Mediated by an Artificial Enzyme Composed of a Hydrophobia Vitamin B6, Chiral Bilayer-forming Lipids, and Copper(II) Ions

Abstract A hybrid bilayer membrane, composed of a synthetic lipid having an (S)-alanine residue, one having (S)-binaphthol and (S)-alanine moieties, a hydrophobic pyndoxal derivative, and copper(II) ions, exhibited a tryptophan synthase-like reactivity that affords tryptophan from serine and indole in an enantiomeric excess of the (S)-isomer.