EGFET-Based Noninvasive Glucose Sensor Integrated with Enzyme-Mimicking Bi₂O₃ Microrods Derived from Bi-BTC Tested in Artificial Sweat

For diabetic patients, effective glucose monitoring is critical, which makes the development of inexpensive, enzyme-free, and nonintrusive glucose sensors necessary. Conventional techniques have not been consistent, necessitating intricate instrumentation and protocols that drive up prices, impede downsizing, and take too long. The presented research attempts to develop a stable Bi 2 O 3 (bismuth oxide)-sensing electrode derived from Bi-BTC [bismuth (Bi)─1,3,5-benzenetricarboxylic acid (BTC)]. This electrode operates through an extended gate field-effect transistor configuration and is designed to facilitate noninvasive glucose monitoring. This electrode exhibits a high sensitivity of 351.68 μA mM –1 cm –2, a limit of detection of 3.7 μM, and a quick response time of less than 5 s in 1× phosphate-buffered saline, effectively covering a linear range from 20 to 1300 μM. The Bi-BTC-derived Bi 2 O 3 -sensing electrode follows Michaelis–Menten kinetics in response to glucose, with a K m value of 0.86 mM, which is lower than the K m value of 0.89 mM for glucose oxidase, implying that Bi 2 O 3 has strong affinity toward glucose. Most remarkably, we used measurements with a scanning Kelvin probe to show a relationship between the glucose response and the electrode’s work function. Additional research using standard artificial sweat has demonstrated the excellent recovery of the Bi-BTC-derived Bi 2 O 3 -sensing electrode. Overall, our findings have shown how well the prepared electrode can quickly detect sweat glucose levels, providing encouraging opportunities for the noninvasive diagnosis of diabetes mellitus.