Wireless Light-Gated Photoelectrochemical Microneedle Wearables for Zero-Bias Longitudinal Monitoring in Interstitial Fluid
Continuous metabolic monitoring in interstitial fluid remains difficult. Here, authors develop a wireless light-gated microneedle wearable that performs zero-bias photoelectrochemical sensing and tracks uric acid dynamic
Wearable chemical sensors hold significant promise for continuous health monitoring, yet long-term measurements within subcutaneous interstitial fluid face substantial technical barriers. Power consumption, electrochemical interference, and signal drift during extended wear periods have historically limited the utility of such devices in metabolic research contexts. This study addresses these challenges by introducing a novel light-gated photoelectrochemical microneedle wearable designed for zero-bias chemical monitoring.
The device architecture integrates a swelling-tolerant conductive hydrogel microneedle array with a plasmon-enhanced photoelectrode and a miniaturized module capable of light excitation, current recording, and Bluetooth transmission. Visible light drives oxygen-mediated redox chemistry without the need for an applied electrical bias. This design specifically reduces interfering electrochemical reactions and minimizes power demand during operation.
Using uric acid as a representative analyte, the wearable provides wireless readout under hydration and mechanical deformation conditions. In vivo validation was performed in male rats and mice to track uric acid dynamics across various disease models. The device successfully monitored parameters associated with chronic kidney disease, diabetic hyperuricemia, and bacterial treatment responses.
Results demonstrated that trends measured by the wearable correlated with blood measurements, confirming its utility for longitudinal monitoring of interstitial-fluid chemistry. This light-gated microneedle architecture offers a modular route for future research applications in metabolic studies. The findings suggest potential for non-invasive chemical sensing without requiring external power sources or applied bias voltages.
This work provides a technical framework for wearable sensors that operate under physiological conditions without compromising signal integrity. However, the study was conducted in animal models and does not establish clinical utility for human subjects. Researchers should note that further validation is required before translation to human metabolic research applications.