One-pot preparation of nitrogen-doped carbon dots for sensitive and selective detection of Ag plus and glutathione

Herein, a novel nitrogen-doped carbon dots (N-CDs) nanosensor for detecting Ag+ and glutathione (GSH) has been designed. Interestingly, Ag+ could significantly improve the fluorescence (FL) intensity of the N-CDs we prepared, which is different from most other metal ions with FL quenching effects on N-CDs. The sensing mechanism can be attributed to the oxidation characteristics of Ag+ and the formation of silver nanoparticles (AgNPs). In the reaction, the N-CDs acted as the reducing agent and stabilizer. Under the optimal conditions, the N-CDs could detect Ag+ with a nice linear relationship of R2 = 0.992 and the limit of detection was 0.091 ?M. Furthermore, the FL of N-CDs solutions could return to nearly original intensity after introducing glutathione (GSH), which allowed the N-CDs to be applied for GSH detection sensitively and selectively. In addition, the NCDs were also successfully applied to cellular multicolor imaging of Hela cells. The results reported here pave the way for N-CDs-based fluorescent ?off-on-off? sensor in environment, bioassay and bioimaging.

Automated summary

A novel nitrogen-doped carbon dots nanosensor for detecting Ag+ and GSH has been designed, with Ag+ significantly enhancing the fluorescence intensity of the N-CDs while GSH can restore it. This sensor not only detects Ag+ but also can be applied for cellular imaging.