Preparation of lysosomal targeted fluorescent carbon dots and its applications in multi-color cell imaging and information encryption

Abstract

In this study, carbon dots (CDs) were obtained by secondary hydrothermal method using ammonium citrate and folic acid as precursors. It had stable properties, small particle size and good water solubility, and its absolute quantum yield was up to 19.48%. Moreover, the emission centers of CDs shifted from green to yellow under different excitation and were successfully used for multi-color cell imaging and targeting of lysosomes. The CDs also showed different color in 254 nm and 365 nm UV light, which could be used to a fluorescent ink for information encryption. In addition, the fluorescence of CDs was quenched at pH 6–8 and showed a good linear relationship with a linear correlation coefficient of 0.9989, which had been implemented for the measurement of pH in tap water.