Synthesis, antibacterial activity, and cytotoxicity of newly synthesized carbon dots derived from dibasic carboxylic acids via conventional microwave-assisted method

Abstract

A simple, rapid, single-step microwave-assisted method was developed to prepare CQDs with narrow size distribution using dibasic carboxylic acids as a carbon source. The synthesized CQDs were well characterized using spectroscopic techniques such as P-XRD, FT-IR, high-resolution transmission electron microscopy (HR-TEM), UV-Vis absorption, and photoluminescence spectroscopy. The synthesized CQDs demonstrated excellent photostability, with particle size in the 1.5-6 nm range. The fluorescence quantum yield was found to be 28 percent, 7 percent, 13 percent, 38 percent, and 31 percent for CQD-AO, CQD-AT, CQD-AA, CQD-AS, and CQD-AM, respectively. Cytotoxicity tests and cellular uptake experiments of the CQDs further showed their viability in biomedical applications. All five synthesized CQDs showed effective antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This work is pivotal in advancing antibacterial nanomaterials, offering a promising alternative to conventional antibacterial agents.