Self-assembled films of dimyristoylphosphatidylcholine

Self-assembled films of dimyristoylphosphatidylcholine (DMPC) have been gen erated at the air/water interface and examined to identify structural chara cteristics. Powdered lipid, small unilamellar vesicles and multilamellar ve sicles have been used as precursors to form interfacial films. Lipids were transported to the air/water interface either from the subphase dispersion or via a bridge from a remote reservoir. The isolation of the self-assemble d film from the source of lipid molecules in the latter method has enabled studies of compressional behaviour and neutron reflectivity to be carried o ut directly at the interface, and for films to be deposited for atomic forc e microscopy. It was found that the structure of a DMPC self-assembled film was highly dependent on the lipid form from which the film was derived and also on the conditions of spreading. Self-assembled films derived from pow der and multilamellar liposomes had bilayer structures associated with them . In contrast, the films formed from unilamellar vesicles behaved as isolat ed monolayers. The structure of the film formed by self-assembly from the p owder form of the lipid was related to the surface pressure to which the fi lm had been allowed to spread before transfer from the reservoir was interr upted. (C) 1999 Elsevier Science B.V. All rights reserved.