Nitrogen-doped carbon dots with high selectivity for hydrosulfide sensing and their living cells imaging

Hydrosulfuric acid is an aqueous solution of hydrogen sulfide (H₂S). At physiological pH, approximately 80% of the total amount of H₂S exists in the form of monoanionic HS^-. Because HS^- is both widely distributed and highly toxic to humans, it is necessary to design an efficient method to detect HS^- with high sensitivity and selectivity. So, the nitrogen-doped carbon dots (NCDs) with green fluorescence are synthesized using a one-step hydrothermal method. The as-prepared NCDs show it can be effectively used as an indicator for monitoring HS^-. And the NCD fluorescence intensity exhibits a linear relationship with HS^- concentration. In addition, NCDs as a probe can be applied for fluorescence imaging in living cells to detect the presence of trace exogenous HS^-.