Optical fiber integrated photoelectrochemical sensing patch: towards non-invasive blood glucose detection

In recent years, non-invasive blood glucose detection has received increasing attention. Among them, sweat glucose detection is expected to become an alternative to blood glucose detection due to advantages such as its samples easily to obtain. This study was proposed and preliminarily verified a prototype of photoelectrochemical sensing patch based on an optical fiber modified by ITO/ZnO/polydopamine/glucose oxidase and printed electrode, enabling close contact with human skin. In this innovative design, the optical fiber to serve both as a light transmission medium and a working electrode, while the printed electrode functions as the counter electrode and reference electrode. The electrode materials were characterized by SEM, EDS, XRD and XPS, and the reaction kinetics of the optical fiber electrode studied through SWV, EIS, and Mott-Schottky analysis. A linear relationship was established between the photocurrent and the logarithm of glucose concentration in the concentration range from 10 μM to 1 mM, with a detection limit of 3.5 μM, and a response time of less than 1 s. In addition, the specificity and stability of the sensing patch were evaluated, and an attempt was made to detect real sweat glucose in situ. This work presents a novel prototype for the development of wearable sensors, with promising applications in biochemical analysis and health monitoring.