An air-stable biomimetic Langmuir-Blodgett bilayer

The long-chain amphiphiles in biomembranes have their hydrophilic headgroup s oriented outwards towards the aqueous environment, and their long aliphat ic chains innermost. In Langmuir-Blodgett (LB) films the hydrophobic chains are normally outermost. LB films of long-chain derivatives can be prepared under water with the headgroups outermost and are stable while kept there, but the act of removing them from the aqueous environment removes the top monolayer. We demonstrate an adaptation of the LB technique which is approp riate for the preparation of biocompatible surfaces. It produces essentiall y bilayer films of long-chain derivatives on standard substrates with a hyd rophilic outer surface. The films are stable in air. The films show large c ontact angle hysteresis with water, but the receding angle is in most cases less than 10 degrees. The films can be immersed and withdrawn from water m any times before wettability or average thickness change significantly. Com pared to previously reported air-stable surfaces with a structure mimicking biological membranes, the substrate for the present surface is experimenta lly more convenient. (C) 2000 Elsevier Science S.A. All rights reserved.