Green synthesis of nitrogen-doped carbon dots from ginkgo fruits and the application in cell imaging

In the report, microwave-assisted and hydrothermal methods were adopted respectively to produce nitrogen doped carbon dots (N-CDs) using ginkgo fruits as the sole carbon source without additional surface passivation agents. The differences between these two N-CDs were compared in luminescence properties, particle sizes and morphologies. The TEM images showed that both microwave-assisted N-CDs (M-N-CDs) and hydrothermal N-CDs (H-N-CDs) were well dispersed, and the morphology of H-N-CDs was more uniform. The fluorescence results indicated the H-N-CDs possessed better fluorescence emission characteristic. Thus, the H-N-CDs with better luminescence properties were characterized by FT-IR, XPS, fluorescence and UV–Vis spectroscopy. Also, the stability and cytotoxicity of H-N-CDs synthesized by ginkgo fruits as the fluorescent probes were studied. Eventually, the H-N-CDs were applied in cell imaging using HeLa cells and KYSE410 cells as the cell models.