A novel pungency biosensor prepared with fixing taste-bud tissue of rats

A novel taste biosensor based on ligand-receptor interaction was developed through fixing taste-bud tissues of SD rats to a glassy carbon electrode. Using the sodium alginate-starch gel as a fixing agent, taste-bud tissues of SD rats were fixed between two nuclear microporous membranes to make a sandwich-type sensing membrane. With the taste biosensor, the response current induced by capsaicin and gingerol stimulating the corresponding receptors was measured. The results showed that the lowest limit of detection of this biosensor to capsaicin was 1×10−13 mol/L and the change rate of response current was the highest at the concentration of 9×10−13 mol/L, indicating that the capsaicin receptor was saturated at this point. The lowest limit of detection of this biosensor to gingerol was 1×10−12 mol/L, and the gingerol receptor was saturated when the concentration of gingerol was 3×10−11 mol/L. It was demonstrated that the interaction curves of capsaicin and gingerol with their respective receptors exhibited high correlation (R2: 0.9841 and 0.9904). The binding constant and dissociation constant of gingerol with its receptor were 1.564×10−11 and 1.815×10−11 respectively, which were all higher than those of capsaicin with its receptor (1.249×10−12 and 2.078×10−12). This study, for the first time, made it possible to quantitatively determine the interaction of the taste receptor and pungent substances with a new biosensor, thus providing a simple approach for monitoring pungent substances and investigating the mechanism of ligand-receptor interaction.