An Energy Autonomous Microneedle Array-Based Sensing System for Continuous Biomarker Monitoring

Wearable bioelectronics are revolutionizing personalized healthcare by enabling continuous monitoring of physiochemical indicators. Despite significant advancements, challenges remain in creating platforms that can accurately detect multiple biomarkers while being energy autonomous. This study introduces a wearable, minimally invasive microneedle array platform for real-time monitoring of clinically relevant biomarkers during exercise. The device features stainless-steel microneedles (SS-MNs) with ion-selective membranes and a glucose-sensing layer, allowing simultaneous detection of sodium (Na⁺), potassium (K⁺), calcium (Ca^{2 +}), pH levels, and glucose in interstitial fluid (ISF). A triboelectric nanogenerator (TENG) paired with an electromagnetic generator (EMG) harnesses energy from mechanical movements to power the data transmission system, eliminating the need for external power sources. Material characterization confirmed the composition and structure of the ion-selective membranes, while in vitro electrochemical tests showed excellent sensitivity and selectivity across physiologically relevant concentration ranges. The hybrid power generation system (HPGS), combined with the microneedle array-based biosensing system (MABS), offers a modern solution for wearable electronics. Additionally, on-body trials confirmed the platform's ability to continuously track biomarker levels during daily activities. This innovative, minimally invasive system marks a significant advancement in wearable biosensing technology, with potential uses in personalized medicine, chronic disease management, and telemedicine.