Photosynthetic–bacteria–derived red emissive carbon dots with low toxicity for lysosomal imaging

Abstract A novel red emissive carbon dots (CDs) derived from photosynthetic bacteria are synthesized successfully via a simple microwave–assisted hydrothermal process. The CDs exhibit good water solubility, biocompatibility, and red photoluminescence emission with an absolute quantum yield of 15.17% in water. More importantly, 5 mg/ml CDs present low toxicity after co–cultured with human umbilical vein endothelial cells (HUVECs) and HeLa cells. Furthermore, the red emissive CDs can clearly image the HUVECs and HeLa cells within 10 min and maintain stable emission for 1 h. It is also proved that the organelle of CD imaging is mainly lysosome. This work provides a new method to prepare long–wavelength fluorescence–emission CDs and explores a new material with potential applications in the biomedical field.