An intact-chemoreceptor-based biosensor based on the gustatory organ, the maxillary palp of Periplaneta americana, is reported, in which the maxillary palp serves as not only the molecular recognition elements but also the biological transducers. The binding events between ligand and chemoreceptor induce action potentials (APs) whose frequency correlates directly to the concentration of stimulants. The APs were recorded with a three-electrode system and collected by sound card method developed by our group. This is the first time that the biosensor is reported to yield quantitative linear dose-response data over the concentration range from 5 * 10~(-5) to 5 * 10~(-2) mol/L. The new biosensor possesses some advantages over the biosensor based on isolated receptor: shorter response time (<1 s), higher degrees of sensitivity (detect-limitation below 10~(-6) mol/L), broader dynamic response range (over four orders of magnitude) and more preferable reproducibility.

Key words: BIOSENSORS, VITAMINC