Preparation of highly fluorescent sulfur doped graphene quantum dots for live cell imaging

Herein, we reported a facile one-step hydrothermal strategy to synthesize stable, strong blue fluorescence and water-soluble sulfur doped graphene quantum dots (S-GQDs) with the citric acid (CA) and powdered sulfur (S) as the precursors. The results indicated that S atoms were successfully introduced into the structure of graphene, and sulfur doping indeed improved the intensity of blue emission of GQDs. The as-prepared S-GQDs, as the effective cell-imaging material, would easily penetrated into the cell membranes of Hela cell and exhibited relatively low cytotoxicity. When treated with the typical bacteria medium (Staphylococcus aureus LZ-01 and Escherichia coli DH5α), it also did not show the conspicuous antiseptic qualities. Therefore, the S-GQDs would have potential applications in the bio-imaging.