Antibacterial Potential of Carbon Quantum Dots against Escherichia coli Bacteria Strains

Carbon quantum dots (CQDs) with exciting optical properties, low toxicity, and high biocompatibility which are suitable for research in biomedical applications. In this work, the CQDs were prepared through microplasma treatment of orange juice as a carbon source, employing atmospheric pressure and low temperatures. The resulting CQDs exhibited a narrow size distribution, with an average diameter of approximately 4.5 nm. These CQDs displayed strong blue emission characteristics. We evaluated the antibacterial properties of these CQDs against Escherichia coli ( E. coli ) bacteria strains, using minimum inhibitory concentration assays. Our findings revealed that the minimum inhibitory concentration required for effective inhibition of E. coli was 0.1 ppm, while the minimum bactericidal concentration for this kind of bacteria was 1 ppm with an average antibacterial efficacy of 57%. The antibacterial processes of CQDs could occur without additional light or oxidant.