Tuning the Localized Microenvironment near a Continuous Glucose Meter to Ensure Monitoring Accuracy and Longevity by Plasma-Induced Grafting Zwitterionic Brushes

Abstract

Diabetes mellitus is a metabolic disorder that affects millions of individuals worldwide. Continuous glucose monitoring (CGM) offers a prevalent method for continuously monitoring interstitial glucose levels instead of traditional self-monitoring of blood glucose (BG), eliminating the need for finger pricking and providing only discrete data. However, challenges in accuracy persist in CGM, including substantial noise interference and tissue fluid erosion, as well as the pH fluctuations in the localized ISF microenvironment during acute inflammation periods. Herein, we reported a facile atmospheric plasma-induced grafting technique to surface functionalize a zwitterionic brush coating on the sensor, with the aim to adjust the sensor's microenvironmental chemistry. The zwitterionic brush-coated CGM (Z-coated CGM) could regulate pH values with a good glucose response in the pH range from 6.2 to 7.6 and a prolonged sensor life over the uncoated sensor. We evaluated the rat practice that the Z-coated CGM consistently outperformed the uncoated in tracking BG fluctuations, with higher correlation coefficients and significant noise reduction for both non-recalibration and recalibration. This technology holds substantial implications for subcutaneous embedded glucose monitors and facilitates CGMs in achieving independence from routine BG fingerstick calibrations.