Improvement of Electrochemical Conditions for Detecting Redox Reaction of K₃[Fe(CN)₆] toward the Application in Norovirus Aptasensor

Electrochemical biosensors have attracted significant attention as a novel tool for the sensitive detection of pathogens and contaminants, with the potential capability of rapid, on-site diagnosis. In this study, we intended to improve the sensitivity of electrochemical biosensor using Fe(CN)63−/4− as redox marker, toward its application to norovirus aptasensors. Although many researchers have developed electrochemical aptasensors for various analytes using redox markers, the reported electrochemical conditions under which an aptasensor was examined varied across multiple studies. Here, we performed square-wave voltammetry (SWV) for electrodes modified with aptamer specific to murine norovirus and compared the reduction peak currents of Fe(CN)63− under various conditions. Effects of working electrode materials and NaCl and [Ru(NH3)6]Cl3 concentration in the electrolyte were examined. Among conditions we tested, the best sensitivity was obtained using a screen-printed gold electrode in an electrolyte containing 1 M NaCl with 4 mM K3[Fe(CN)6], in which the concentration of murine norovirus showed linearity with SWV peak current. This study provided useful information on the electrochemical measurement conditions regarding the development of electrochemical aptasensors.