Ga2O3 nanorods synthesized by hydrothermal method for dual-functional sensing of pH value and glucose

In this work, hydrothermal (HT)-synthesized gallium oxide (Ga2O3) nanorods were applied on indium tin oxide (ITO) glass substrates to create a dual-functional pH-glucose sensing device. Extended-gate field-effect transistors (EGFETs) were designed for pH and glucose sensing, and the response to pH levels ranging from 1 to 11 was tested using both chemical bath deposition (CBD) and high-pressure hydrothermal methods. Two sensor configurations, Ga2O3(CBD)/ITO/glass and Ga2O3(HT)/ITO/glass, were immersed in solution pH1 to 11 and cultured medium for hydrogen ion and glucose sensing. The results demonstrated that, for pH sensing in different samples, both IDS-VDS analysis and IDS-VGS analysis showed superior linearity and sensitivity with the HT method. For glucose detection, the HT method was selected for further experiments due to its maintained concentration-dependent relationship and selectivity towards various common sugars. When using culture medium DMEM as the sample (4.5 mg/ml glucose concentration), the accuracy of glucose estimation reached 99%. Stability and biocompatibility tests were also conducted, and the results indicated consistent performance. In summary, the HT-synthesized Ga2O3 nanorods exhibited high sensitivity, selectivity, and stability without affecting cell growth. Therefore, they hold great potential for applications not only in general blood glucose sensing but also in studying cell microenvironment metabolism.