A Sensitive Potentiometric Biosensor Using MBs-AO/GO/ZnO Membranes-Based Arrayed Screen-Printed Electrodes for AA Detection and Remote Monitoring

In this paper, we used sputtering and screen-printing technology to develop a sensitive potentiometric ascorbic acid (AA) biosensor with the magnetic beads-ascorbate oxidase/graphene oxide/zinc oxide (MBs-AO/GO/ZnO) membrane-based arrayed screen-printed electrodes (SPEs). The morphology of membranes was characterized by using a scanning probe microscope (SPM) and a field-emission scanning electron microscope (FE-SEM). The sensing characteristics were analyzed via the voltage-time (V-T) measurement system. The potentiometric arrayed AA biosensor showed the exceptional average sensitivity of 70.68 mV/decade over a wide linear range of AA concentration ( $7.8125~\mu \text{M}$ -2 mM), the short response time of 25 s, the lower limit of detection (LOD) of $0.04~\mu \text{M}$ , and the excellent selectivity. Furthermore, we investigated other analytical parameters of the potentiometric arrayed AA biosensor, such as the temperature effects, the lifetime, and the average sensitivity under microfluidic flow. The optimal average sensitivity of the biosensor integrated with the microfluidic framework was 72.21 mV/decade under microfluidic flow. Finally, the biosensor was applied to the remote AA detection by using the wireless sensing system. The results indicated that the average sensitivity of the potentiometric arrayed AA biosensor based on MBs-AO/GO/ZnO was 77.38 mV/decade during the monitoring in a long distance.