Continuous insulin monitoring using an antibody-protecting zwitterionic microneedle patch

Continuous monitoring of protein and molecular biomarkers is essential for personalized disease tracking, but approaches for in vivo sensing are limited. Monitoring insulin, a peptide hormone, is an unmet need given the importance of this molecule in managing diabetes. Here we report a patch-based system with integrated electrochemical sensors that enables monitoring of insulin levels on an ongoing basis. We report a novel zwitterionic-based hydrogel microneedle patch with integrated molecular pendulum sensors that can measure insulin levels in the interstitial fluid of rats with type 1 diabetes. Our study demonstrates that the zwitterionic poly(carboxybetaine)-based microneedle patch stabilizes the antibody-based recognition elements, allowing them to withstand UV-induced crosslinking during patch fabrication and gamma-irradiation, often required for FDA-standard sterilization. We also investigate the impact of disrupted circadian rhythm on insulin levels, revealing circadian-dependent alterations in insulin absorption efficiency and distribution within the interstitial fluid and plasma. This platform not only enhances our understanding of in vivo insulin behaviour but also holds promise for personalized treatment strategies in diabetes management.