Improved gel-protected bilayers

We report improved techniques for the fabrication of biomimetic membranes p rotectively sandwiched between two slabs of agarose gel and the evaluation of their characteristics relevant for use in a biosensor based on gated cha nnel proteins. The gel protects the membrane from mechanical contact, from low-energy solvents and from drying out. The new methods allow the preparat ion in high yield of sensor cells with a front gel thickness less than 100 mu m. During fabrication, gel-protected membranes of DOPC (dioleoyl phospha tidylcholine) readily incorporate valinomycin in functional form. DOPC memb ranes respond as expected and within a few minutes to aqueous solutions of gramicidin applied to the front gel layer. In long-term studies of protecte d membranes of the synthetic lipid PSPC, no failures were observed over run s of up to 3 weeks and the membrane leakage decreased, reaching within 7 da ys values comparable to those reported for unsupported bilayer lipid membra nes. Initial attempts to incorporate functional nicotinic acetylcholine rec eptors have shown promise. (C) 1999 Elsevier Science S.A. All rights reserv ed.