Tunable Photoluminescence of Carbon Dots used for Homogeneous Glucose Sensing Assay

Abstract

Carbon dots (CDs) with tunable photoluminescence in a large range (80 nm) are produced by a microwave-assisted polyol method. The emission of CDs in aqueous can be adjusted by simply changing the precursors’ concentrations. The CDs with tunable photoluminescence have been further functionalized to develop a homogeneous glucose biosensor by incorporating with enzyme-conjugated graphene oxide. The fluorescence of CDs can be quenched through covalently interacting with the graphene oxide. The restored fluorescence is observed in the presence of glucose. The performance of the homogeneous sensing system has been evaluated by testing glucose levels in a range from 0.2 mM to 10 mM. Two linear relationships of the restored fluorescence intensity as a function of the concentration of glucose are obtained, i.e. 2 mM to 10 mM, and 0.2 mM to 1 mM, respectively. In addition, streptozotocin-induced diabetic rats are utilized to evaluate the performance of the designed sensor for testing diabetic rat’s plasma glucose. The results demonstrate that the homogeneous carbon-based biosensor can measure glucose in the blood and in other conditions.