Aggregatable thiol-functionalized carbon dots-based fluorescence strategy for highly sensitive detection of glucose based on target-initiated catalytic oxidation

Carbon dots (CDs) have been widely applied in analysis of glucose due to their advantages of ultra-small size and good biocompatibility, but tedious steps and few functional groups associated with current CDs-based biosensors hamper their practical application. Herein, we report the thiol-functionalized CDs (S-CDs) for developing a sensitive and selective glucose biosensor. S-CDs were prepared by a simple hydrothermal carbonization and additional surface modification method, and emitted bright yellow-green light with exceptional pH/salt stability. After exposure to H2O2, S-CDs were transformed into nonluminous S-CDs assembly based on target-initiated catalyzed oxidation of -SH into -S-S-. Given the fact that glucose can be catalyzed decomposition into H2O2 by glucose oxidase, S-CDs were further employed to detect glucose with a low limit of detection (0.03 mu M) and high selectivity for discriminating glucose against other saccharine. Finally, S-CDs were applied for glucose sensing in human serum with satisfactory result. This is the first documented example of S-CDs for glucose sensing. We expected this work will open new avenues for developing high-performance fluorescence biosensors based on CDs.