Carbon Dots as Fluorescent/Colorimetric Probes for Real-Time Detection of Hypochlorite and Ascorbic Acid in Cells and Body Fluid.

Hypochlorite (ClO-) and ascorbic acid (AA) are reported to have a high correlation with oxidative stress and related diseases, so it is necessary and critical to develop sensitive and fast response sensors to investigate the dynamical variation of these redox substances, especially those sensors which can detect ClO- and AA in real time in two manners. However, it is still an unmet challenge for now. Herein, novel carbon dots (RD-CDs) which can respond to ClO- and AA rapidly, reversibly, and dynamically by fluorescence and colorimetry were synthesized. In the fluorescence manner, the constructed nanosensor possessed high selectivity toward ClO- in the range of 0.1-100 μM with a detection limit of 83 nM, and can be selectively recovered by AA. It endows this sensor with good capacity as a fluorescent probe for dynamic detection of ClO- and AA in living cells, which can be monitored by a fluorescence microscope. In the colorimetric manner, ClO- and AA can be detected by UV-vis in the range of 5-200 μM and 1-30 μM, respectively. The concentrations of ClO- and AA in humor can be measured by RD-CDs in both fluorescence and colorimetric mode. The results above-mentioned demonstrate its great potential in biosensing.