Synthesis and Biological Toxicity Evaluation of Red Light-Emitting Carbon Quantum Dots

This study delineates the successful fabrication of red light-emitting carbon quantum dots (R-CQDs), approximately 3.5 nm in size, via hydrothermal methods. These carbon quantum dots (CQDs) display distinctive fluorescence properties, particularly a laser-dependency. The infrared and Raman spectra were subjected to a thorough investigation, revealing the presence of hydroxyl, amino, and carboxyl groups on the surface of the CQDs. Experimental findings indicate a significant correlation between the antibacterial effect of R-CQDs on E. coli and Yeast and their concentration. Subsequent research suggests that this antibacterial activity primarily stems from the CQDs’ disruption of cell membrane integrity, leading to the leakage of intracellular substances and consequently inhibiting the growth of these two microorganisms. The study also reveals that R-CQDs can trigger chromosomal aberrations in the root tip cells of broad beans and induce micronuclei formation. The frequency of micronuclei is directly proportional to the CQDs dosage, and an extended treatment duration results in an increased micronucleus rate. This suggests potential damage to the genetic material of broad beans by CQDs, which could adversely affect their growth and development. The study further identifies a significant impact of R-CQDs on the height of rice seedlings, causing a substantial reduction. Moreover, it was found that CQDs can infiltrate the rice body and instigate oxidative stress responses.