Cholesteric Contact Lenses for Diabetics-Related Noninvasive Glucose Monitoring and Eye Healthcare

Blood sugar monitoring has crucial significance for diabetes mellitus diagnosis, and noninvasive continuous detection methods are the future development trend. Among various noninvasive detection methods, glucose detection in tears has the advantages of a high level of subject compliance, minimal pollution, and accuracy. However, sensors used for detecting glucose concentration in tears usually embed noble microelectrical components into contact lenses, making the process complicated and costly, and easily cause environmental pollution and resource wastage. Here, we propose a construction strategy for contact lenses based on the cellulose nanocrystal (CNC) cholesteric structure, preparing products that change color according to the concentration of glucose. In addition, the surface of the contact lenses can be loaded with drugs for adjuvant treatment of diabetic eye complications. Contact lenses offer advantages such as a fast response speed (<240 s), high sensitivity with distinct colors at specific glucose concentrations (green at 0 mM, yellow at 5 mM, and red at 10 mM), and a reversible response process. Furthermore, they exhibit good biocompatibility (90% cell viability by CCK-8 assay) and biodegradability (complete biodegradation in soil within 120 days). CNC cholesteric contact lenses realize noninvasive, wearable continuous glucose detection, providing a new strategy for health monitoring of diabetics.