Stability of an Agar-Supported Bilayer Lipid Membrane and Its Application to a Chemical Sensor

Abstract

Lipid membranes made of lecithin and cholesterol were formed by self-assembly in a small aperture on an agar support. The membranes exhibited an average electric resistance of 135 Gfl and a capacitance of 0.43 µF/cm2. Gramicidin, known to form a channel in uni-lamellar lipid bilayers, reduced the electric resistance to a Mf level, thus showing the membranes to be of a uni-lamellar bilayer type. The membrane stability was investigated against perturbation with electric potentials and against mechanical agitation in the contacted aqueous solution. About 80% of the membrane preparations remained intact after applying electric potentials of between +1500 mV and -1500 mV. A similar percentage of the membranes stayed intact under 100 rpm magnet stirring in a 30 ml vessel. Membranes containing valinomycin responded to K+ ions with changes in both the membrane conductance and the membrane potential.

Polysaccharide-Supported Planar Bilayer Lipid Model Membranes

“…BLM-like membranes were formed either on top of an agarose cushion exposed to electrolyte [24][25][26][27][28][29] or sandwiched between two agarose sheets. 20,30,31 Additionally, monolayer lipid membranes were transferred to agarose films by means of LangmuirBlodgett transfer.…”

Supported Bilayer Lipid Membranes as Ion and Molecular Probes

“…6 The procedure for forming a planar BLM on agar or agarose gel has been published. 9,10 Briefly, a small diameter (~0.5 mm) Teflon tubing is filled with a hot hydrogel solution (e.g., 0.3 g agar in 15 ml of 3 M KCl). For electrical connection as well as serving as a reference electrode, an Ag/AgCl wire is inserted at one end.…”

“…The results obtained with these s-BLMs compare favorably with conventional BLMs containing related compounds such as valinomycin. 5,10 Umezawa and his colleagues, for example, earlier reported in an elegant comparative study on the potentiometric responses between a valinomycin-based BLM and a solvent polymeric membrane. Minami et al 10 found that the detection limit, dynamic range and optimum valinomycin concentration for the K + ion-induced Nernstian slope for the BLM were comparable to those of the polymeric membranes.…”

“…5,10 Umezawa and his colleagues, for example, earlier reported in an elegant comparative study on the potentiometric responses between a valinomycin-based BLM and a solvent polymeric membrane. Minami et al 10 found that the detection limit, dynamic range and optimum valinomycin concentration for the K + ion-induced Nernstian slope for the BLM were comparable to those of the polymeric membranes. On the basis of their findings, Umezawa and co-workers concluded that they have made the first successful planar lipid bilayers using totally synthetic lipids.…”

“…On the basis of their findings, Umezawa and co-workers concluded that they have made the first successful planar lipid bilayers using totally synthetic lipids. 10 In this connection, Kunitake and colleagues reported the use of calixarenes, which are one of the most sophisticated synthetic host (receptor) molecules as selective transporters in BLM. 34 Kimizuka et al concluded that calix [4]arene displayed a mediated transport of alkali metal ions selectively across BLMs formed from double-chained amphiphiles with cationic, anionic and non-ionic polar groups.…”