Improved gel-protected bilayers

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