Multi-wavelength emission nitrogen-doped carbon dots as fluorescent nanosensing platform for the detection of ascorbic acid and their application in bioimaging tracking

Vitamins are indispensable active components of the human body, and their abnormal levels are often closely related to various diseases. Therefore, searching for ultra-sensitive and accurate vitamin detection strategies is essential and significant for clinical examination and diagnosis. In this paper, multi-wavelength emission fluorescent nitrogen-doped carbon dots (N-doped CDs) were synthesized by a one-step solvothermal method using four-leaf green fluorescent extract, O-phenylenediamine, and beta-cyclodextrin as the raw materials, and N, Ndimethylformamide as the solvent. The CDs can achieve controllable fluorescence changes with multiwavelength emission at different excitation wavelengths and exhibit good photoluminescence optical properties. In addition, the fluorescence emission peak intensities of the N-doped CDs at 400, and 470 nm excitation wavelengths decreased with increased AA content. They showed good linearity in the 0.6-1.4, and 0.1-0.5 mu M ranges, with detection limit coefficients of 0.12, and 0.14 mu M, respectively. Moreover, due to their excellentphotostability and good biocompatibility, N-doped CDs have been successfully applied to the bioimaging and biosensing of exogenous AA in 4T1 cells, as well as in vivo imaging tracking of Kunming (KM) mice.