Wafer-scale nanowell array patterning based electrochemical impedimetric immunosensor

•An impedimetric sensor based on nanowell array electrode is described to detect STIP-1, a biomarker of ovarian cancer.•Wafer scale fabrication method by using KrF stepper has high-throughput for the fabrication of nanowell array electrode.•In NWA electrode, STIP-1 at the level of 10pg/mL could be detected and their signal to noise ratio is high. We have reported that nanowell array (NWA) can enhance electrochemical detection of molecular binding events by controlling the binding sites of the captured molecules. Using NWA biosensor based amperometric analysis, we have detected biological macromolecules such as DNA, protein or aptamers at low concentrations. In this research, we developed an impedimetric immunosensor based on wafer-scale NWA for electrochemical detection of stress-induced-phosphoprotein-1 (STIP-1). In order to develop NWA sensor through the cost-effective combination of high-throughput nanopattern, the NWA electrode was fabricated on Si wafer by krypton-fluoride (KrF) stepper semiconductor process. Finally, 12,500,000ea nanowell with a 500nm diameter was fabricated on 4mm×2mm substrate. Next, by using these electrodes, we measured impedance to quantify antigen binding to the immunoaffinity layer. The limit of detection (LOD) of the NWA was improved about 100-fold compared to milli-sized electrodes (4mm×2mm) without an NWA. These results suggest that wafer-scale NWA immunosensor will be useful for biosensing applications because their interface response is appropriate for detecting molecular binding events.