Nitrogen-Doped and Surface Functionalized CDs: Fluorescent Probe for Cellular Imaging and Environmental Sensing of ClO.

A novel nitrogen doped and surface functionalized fluorescent CDs (T1) was synthesized by one-step and green hydrothermal method, which exhibits a satisfactory fluorescence quantum yield and a series of admirable features such as good aqueous solubility, narrow particle size distribution, resistance to photobleaching as well as excitation-dependent behavior. Benefitting from above merits, T1 can be employed to serve as an outstanding sensing platform for sensitive and accurate detection of ClO- by remarkable fluorescence "on-off" process with rapid and anti-interference. More notably, the good biocompatibility and photostability can ensure enormous bioimaging potential and successful application of T1 in monitoring of exogenous ClO- in MG-63 cells. Meanwhile, T1 can also be regarded as a filter paper sensor providing a convenient and efficient analyzing technology for monitoring of free residual chlorine in practical environmental samples. All these results demonstrate that there exists promising possibility for practical applications of T1 in bioimaging systems and environmental monitoring.