CuO Nanowire-Based Extended-Gate Field-Effect-Transistor (FET) for pH Sensing and Enzyme-Free/Receptor-Free Glucose Sensing Applications

In this work, multifunctional CuO nanowires (NWs) electrode-based extended-gate (EG) field-effect transistor (FET) has been explored for both pH and glucose sensing applications. The CuO nanowires (NWs) electrode-based EGFET gives good pH sensitivity (~48.34 mV/pH), high linearity (99.84%), good stability for pH level in between 2 and 12 for 12 hours with a drift rate of 2.5mV/h, and good reversibility in terms of low hysteresis loss of 2.5mV. The selectivity of this pH sensor towards hydrogen ion is significantly higher as compared to Na⁺, K⁺, Zn⁺⁺ and Mg⁺⁺ ions. In addition to the pH sensing, CuO NWs based electrode-based EGFET has also been explored for glucose-sensing for the first time without taking the help of neither any enzyme nor any organic receptor. The proposed glucose sensor gives a good sensitivity of 3.03 mV/mM with a high range of linearity (1mM-12mM), which covers up the glucose level of human blood ranging from 3.6 mM to 6.6 mM. This novel concept of CuO NWs based EG-FET glucose sensing is believed to be extended for sensing other saccharides such as fructose, sucrose, and mannose.