Minimally Invasive Power-Free Continuous Glucose Monitoring Sensor Using Full Color Tunable Photonic Gel of Poly(acrylamide-co-3-fluoro-4-acrylamidophenylboronic acid) Operating at Physiological pH

Real-time monitoring of blood glucose levels is critical for effective diabetes management. In this study, we demonstrate a minimally invasive power-free continuous glucose monitoring systems (CGMS) utilizing optical detection of glucose levels in interstitial fluid (ISF) which can provide intuitive perception of blood glucose level to patient. The system leverages structural color changes in an inverse opal photonic gel (IOPG) film to detect glucose levels with high sensitivity at physiological pH by incorporating 3-fluoro-4-acrylamido phenylboronic acid (3F4APBA) within the photonic gel. The glucose-responsive IOPG fabricated through opal-templated photopolymerization of 3F4APBA and acrylamide, exhibited reversible full color variations by glucose level changes from 0 to 300 mg/dL; a blue structural color at hypoglycemic glucose concentrations by Bragg diffraction, which reversibly changed to green color at normal glucose level, and further shifted to red under hyperglycemic condition. In a simulated CGM device, glucose solutions with varying concentrations were introduced through a porous microneedle array (PμNA) in a flow cell to emulate ISF extraction from human skin, and the 3F4APBA-containing IOPG was confirmed to be a promising CGMS for monitoring blood glucose and body fluids.