Influence of alkyl chain length of lipid in caffeine detection using taste sensor with lipid/polymer membranes

The taste sensor was widely used in distinguishing various taste substances. However, the taste sensor has poorer sensitivity to uncharged molecules such as caffeine, a bitter substance, than to charged taste substances. In the present study, we discussed the sensitivity of caffeine detection using a taste sensor with lipid/polymer membranes that were formed with different length of methyl group of lipid, namely, tetra-n-ctylammonium bromide (R8), tetrakis-(decyl)-ammonium bromide (R10), tetradodecylammonium bromide (TDAB; R12), and tetrahexadecylammonium bromide (R16). As a result, we observed that the electric responses of the lipid membranes to caffeine were associated with the length of alkyl chain of a lipid and an optimum concentration of the lipids in membranes was also observed to enhance the sensitivity of caffeine with taste sensor.