Synthesis of intrinsic dual-emission type N,S-doped carbon dots for ratiometric fluorescence detection of Cr (VI) and application in cellular imaging

In this paper, intrinsic dual-emission fluorescent carbon dots (CDs) doped with N and S atoms have been firstly fabricated. The characterization results show that CDs are successfully synthesized with two separate fluorescence emissions at 468 nm and 628 nm, respectively. The strong and selective interaction of Cr (VI) ions with CDs lead to obvious fluorescence decrease of CDs at 468 nm, which is caused by a mixed quenching mechanism. At the same time, the fluorescence at 628 nm increase. Interestingly, the CDs solution show obvious color change under the daylight and UV light, so visualization detection of Cr (VI) can be realized in water samples. Based on the data of the emission intensity ratios of F-468/F-628, Cr (VI) can be detected from 3.8 to 38.9 mu M combined with the linear correlation coefficient of 0.998, and the lowest detection concentration is 47.2 nM. The platform is satisfactorily applied to the detection of Cr (VI) ions in water samples. In addition, the CDs could be applied as fluorescent probes for cell imaging with dual fluorescent emission.

Automated summary

In this study, fluorescent carbon dots (CDs) doped with N and S atoms were successfully synthesized, exhibiting dual emission fluorescence at two separate wavelengths. The interaction between Cr (VI) ions and CDs led to a decrease in fluorescence at one wavelength and an increase at the other. This property allowed for the visualization detection of Cr (VI) in water samples. Additionally, the CDs were applied as fluorescent probes for cell imaging with dual emission fluorescence.