Effect of taste substances on electric characteristics of a lipid cast membrane with a single pore

The effect of taste substances was investigated for a lipid membrane constructed by casting complexes of synthetic lipid (double-chain ammonium salt) and sodium polystyrenesulfonate on a silicon wafer with a single minute pore. Reproducibility of the electric properties was improved remarkably by the use of the present construction method for the lipid membrane. It was found that this membrane showed a sensitive response to negatively-charged chemicals having strong bitterness such as picric acid because the lipids are positively charged. A membrane with non-equimolar lipid-polymer complexes showed a phase separation between two phases composed of liquid-crystal lipid multi-bilayers and crystal lipid-polymers within a limited temperature range. This membrane in the phase-separation state generated a self-sustained electric oscillation, whose mechanism was explained with the aid of a non-equilibrium theory. The waveform of the oscillation changed by using picric acid on the membrane. This bio-mimetic membrane has the possibility of acting as a biological chemoreceptor.