2025 年 93 巻 10 号 p. 107001
We propose an impedimetric biosensor using the bipolar phenomenon with an open bipolar electrode (oBPE). The oBPE platform offers a structurally simple and highly flexible design. The unique electrochemical biosensor consists of a BPE, driving electrodes for detection, and an electrolytic cell as its components. We employed non-faradaic electrochemical impedance spectroscopy to detect biomolecular events occurring on the BPE surface. The biosensor showed a 45 % increase in impedance at 2 kHz after bovine serum albumin adsorption onto the BPE surface. Additionally, the significance of solution resistance, which was uniquely defined by the distance between driving electrodes and a BPE, was demonstrated through changes in impedance. We used the detection system as an immunosensor to detect the binding of C-reactive protein (CRP) to antibody-modified BPE, based on changes in impedance. The biosensor detected the binding of CRP to antibody without the need for redox-active reagents or complex signal amplification steps. The biosensor showed a linear response to the concentration of CRP in the range from 0.001 to 1 µg/mL, comparable to that of conventional three-electrode systems. These findings demonstrate the potential of non-faradaic impedimetric biosensors with an oBPE for sensitive detection of biomolecular events in biochemical analysis.
