摘要

Nitrogen-doped carbon quantum dots (N-CQDs) were formed by one-step hydrothermal synthesis, using citric acid as carbon source and ethylene diamine as modifier in this study. The effects of N-CQDs on the growth of photosynthetic bacteria Rhodopseudomonas acidophila were investigated by analyzing the physiological indexes of photosynthetic pigment, protein and malondialdehyde. The results showed that N-CQDs inhibited the growth of R. acidophila and showed a concentration-effect relationship. Additionally, N-CQDs increased the content of carotenoid in R. acidophila while it decreased the content of bacteriochlorophyll. Furthermore, spectra analysis results showed that N-CQDs led to the leakage of intracellular sbustances such as photosynthetic pigment and protein. The strong light-induced electron transfer ability of N-CQDs resulted in excessive free radicals in the culture system of R. acidophila, which led to a series of lipid peroxidation reactions, which in turn led to the rupture of biofilms, material leakage and bacterial death. N-CQDs had a high toxicity on R. acidophila under light. The results of this study are valuable for understanding the phototoxicity and ecological effects of N-CQDs.