Mask-Free Laser-Defined Nonenzymatic Glucose Biosensors for High-Sensitivity and Durable Monitoring

Reliable and noninvasive monitoring of glucose remains a critical challenge for wearable healthcare devices. Conventional enzymatic sensors, while selective, suffer from limited stability and short operational lifetimes, highlighting the need for robust nonenzymatic alternatives. Here, we report a nonenzymatic, noninvasive glucose biosensor fabricated through the combination of laser irradiation (LI) and electroless plating (ELP). LI of a SnO₂/polyurethane acrylate (PUA) composite selectively exposed catalytic sites, enabling uniform Cu/Ni/Au metallization via ELP. The resulting electrodes were well-formed, exhibiting low resistivity (21.94 ± 1.09 mΩ·cm) and strong mechanical stability, maintaining conductivity even after 100,000 folding cycles at a bending radius of 5 mm. Functionalization with catalytic Pt/C endowed the electrodes with high catalytic activity, yielding reliable cyclic voltammetry (CV) responses and superior glucose detection capability. Compared with a commercial electrode, the LI-ELP biosensor achieved nearly 18-fold higher sensitivity (16.3 ± 1.40 vs 0.92 ± 0.10 mA mM^-1 cm^-2) and improved linearity (0.96 vs 0.94) over the 0-0.5 mM glucose range. The superior performance is attributed to the enlarged active surface area, optimized electrode structure, and efficient catalyst utilization, which collectively reduced overpotentials and enhanced charge-transfer efficiency. Overall, these findings establish LI-ELP as an effective and scalable strategy for fabricating durable, conductive, and efficient electrodes, highlighting its strong potential for next-generation wearable biosensors and broader nonenzymatic electrochemical sensing applications.