A non-enzymatic microneedle electrochemical biosensor based on Pt@PDA-MWCNTs modified electrode for in vivo and in situ glucose detection

Real-time glucose monitoring is essential for diabetes care, but existing non-enzymatic electrochemical biosensors have great challenges, including poor selectivity, insufficient stability and bad long-term reliability. In this work, a non-enzymatic electrochemical biosensor integrated with a porous microneedle array and a Pt@PDA-MWCNTs electrode was developed for continuous in vivo and in situ glucose monitoring. The microneedle component had a built-in reservoir and iontophoresis system. The developed biosensor exhibited a sensitive glucose response within the linear range of 0.1–30 mM, with a sensitivity of 3.91 μA·mM −1 ·cm −2 , a detection limit of 0.14 mM, and favorable selectivity against common interferents, including ascorbic acid, dopamine, uric acid, chloride ions, and bovine serum albumin (BSA). In addition, the sensor enables stable long‑term operation, resists biofouling, and retains its performance even in complex biological matrices. In diabetes rat models, the biosensor showed high consistency with commercial glucometers over short-term (4.5-h) and long-term (12-h) monitoring, with Mean Absolute Relative Difference (MARD) values below 5% and all data points in zone A of the Clarke error grid analysis (CEGA). Histological examination, cytotoxicity and hemolysis tests showed no obvious inflammation, apoptosis or tissue damage, proving good biocompatibility and rapid skin recovery after insertion. This strategy provides a feasible approach for the non-enzymatic continuous glucose monitoring, and holds promising potential for long-term diabetes management.