Fabrication of Transparent Microneedle Patch for Minimally Invasive Glucose Monitoring Optical Biosensor

Diabetes is a growing global health concern that requires continuous glucose monitoring. Conventional methods involve painful blood sampling, which is particularly challenging for young and elderly patients. Microneedle (MN) emerges as minimally invasive devices that enable blood glucose monitoring without pain. However, most reported MN sensors rely on amperometric methods, which reduce biocompatibility due to mediator release and toxicity. To address this, acetic acid and chitosan MN (A.C. MN) were fabricated using biocompatible chitosan and glycerin for mechanical strength. Glucose oxidase (GOx) is incorporated as a probe, enabling glucose detection without additional immobilization. The A.C. MN array (15 × 15, 700 μm length) absorbs ≈5 μL of interstitial fluid in agarose skin models and nude mice. An optical biosensor integrated with a Bluetooth module captures GOx‐mediated colorimetric responses and transmits real‐time glucose data. Luminosity values increase linearly with glucose concentration, achieving a detection limit of 23.9 mg dL−1. Specificity tests confirm selective glucose detection in interstitial fluid. In vivo evaluation using diabetic and normal mice demonstrates distinct glucose responses, validating device functionality. This minimally invasive A.C. MN biosensor eliminates enzyme immobilization steps, enhances patient comfort, and provides portable real‐time monitoring, making it a promising platform for glucose management.