FORMATION OF TETHERED SUPPORTED BILAYERS VIA MEMBRANE-INSERTING REACTIVE LIPIDS

Fluid phospholipid bilayers partially bound to a supporting polymer cu shion (tethered supported membranes) have been widely discussed as mod el systems for studying biomembrane structure and function. Sire have synthesized a new isothiocyanstte-functionalized lipid from dimyristoy lphosphatidylethanolamine, which closely resembles naturally occurring membrane lipids. Monolayers containing the reactive Lipid at the air- water interface covalently bind to the amino functionalities of branch ed polyethylenimine (PEI) added to the water subphase which could be s hown by infrared spectroscopy. At neutral pH, PEI is cationically char ged which guarantees the transfer of a polymer-supported lipid monolay er onto a mica substrate during Langmuir-Blodgett deposition. A second layer of pure dimyristoylphosphatidylcholine can be deposited by vesi cle adsorption. This system should allow the application of techniques such as the surface forces apparatus (SFA) technique to investigate i nterbilayer forces, membrane-polymer interactions, and other dynamic m embrane properties under near in-vivo conditions. (C) 1998 Elsevier Sc ience S.A. All rights reserved.