An electrochemical microfluidic paper-based glucose sensor integrating zinc oxide nanowires

This paper reports, for the first time, an electrochemical microfluidic paper-based analytical device (EμPAD), featuring a highly-sensitive working electrode (WE) decorated with zinc oxide nanowires (ZnO NWs), for glucose detection in human serum. Besides common features of μPADs such as low cost, high portability/disposability, and ease of operation, the reported EμPAD has three additional advantages. (i) It provides higher sensitivity and lower limit of detection (LOD) than previously reported μPADs, owing to the high electron-transfer efficiency and high surface-to-volume ratio of the ZnO NWs. (ii) It does not need light-sensitive electron mediator (usually required in enzymatic glucose sensing), leading to enhanced biosensing stability. (iii) The ZnO NWs are directly synthesized on the paper substrate via low-temperature hydrothermal growth, representing a simple, low-cost, highly-consistent, and mass-producible process.