PEC-DFM Hybrid-Sensor Based on Nanoparticle-Resolved Estimation for Sensitive and Reversible Glucose Monitoring

The accurate detection of glucose in wound exudate is critically important for monitoring chronic wound healing. While photoelectrochemical (PEC) sensors are widely used, they often suffer from material degradation caused by redox reactions during operation. Herein, we introduce a dark-field microscopy (DFM) setup integrated with a PEC system, creating a PEC-DFM hybrid-sensing platform. This system allows for conjoint measurement of photocurrent and monitoring of nanoparticle behavior via scattering spectroscopy. We further introduce Ag NP@Au NCs nanocomposites to drastically improve sensor performance, achieving a 193-fold increase in signal-to-noise ratio. The PEC-DFM hybrid-sensing system guides the optimization of the nanocomposite's structure, enabling exclusion of damaged nanoparticles during measurement. Moreover, through continuous, long-term (up to 1800 s) observation of scattering spectrum parameters, we decipher the photocurrent generation mechanism, confirming electron transfer from Au NCs to Ag NP inside single Ag NP@Au NCs nanocomposite. Finally, a non-invasive sensing mechanism based on molecular-level competition for glucose is developed, enabling reversible (20 rounds) and ultrasensitive detection of glucose with a detection limit of 0.49 pM. This work not only provides a powerful tool for wound management but also offers profound insights into the design of advanced hybrid sensing systems.