Optimizing electrochemical-impedance-spectroscopy-based immunoassays on zinc-oxide-nanowire paper-based electrodes

Infectious diseases cause tremendous morbidity/mortality and economic burdens to developing countries. Accurate, affordable and rapid diagnostic tools play a significant role in mitigating the public health challenges. Among a variety of point-of-care diagnostic tools, microfluidic paper-based analytical devices (µPADs) stand out as a particularly promising technology [1]. We have developed a µPAD integrating zinc oxide nanowires (ZnO NWs), and applied it to enzymatic glucose sensing [2] and electrochemical impedance spectrometry (EIS)-based immunoassays [3]. The EIS-based immunoassay is label-free, rapid (25 min), and highly sensitive. Here, we report the experimental optimization of design parameters of the ZnO-NW µPAD for EIS-based immunoassay.