Wearable fluorescent contact lenses for monitoring glucose via a smartphone

Real-time, continuous and non-invasive glucose monitoring is essential for the health of diabetic. In this work, we developed soft and transparent smart contact lenses which could detect glucose in tear with high sensitivity. The smart contact lenses were prepared by immobilizing a sensitive glucose fluorescent probe and another reference fluorescent dye into the hydrogel network of the contact lenses. With the increase of glucose concentration, the fluorescent color of the smart contact lenses changed from pink to blue. The fluorescent images could be collected by a smartphone and transformed into RGB signals to quantify the glucose levels. These smart contact lenses could successfully monitor glucose level of 23 μM–1.0 mM in tears by a smart phone. The animal experiments further demonstrate the biosafety of smart contact lenses and the potential application of glucose monitoring. The fluorescence sensor platform is expected to be a new method for painless glucose monitoring.