Electrochemical/Piezoelectric dual-response biosensor for heme ligands.

A heme peptide-modified quartz crystal oscillator is fabricated as a dual-response biosensor, giving electrochemical and piezoelectric responses simultaneously. Binding of a ligand to heme peptide causes inhibition of its catalytic activity, which is observed as the electrochemical response, and a mass increase is monitored as the piezoelectric response. The dual-response sensor can give two independent pieces of information at the same time. That is, qualitative (identification of the species) and quantitative (determination of its concentration) analyses can be made simultaneously. Simultaneous quantitative analysis for two components is also possible. These two modes are theoretically explained and then experimentally demonstrated employing imidazole and histidine as interferants.