CQDs exert antibacterial effects primarily by generating reactive oxygen species (ROS), which damage cell walls and disrupt biofilms. Crucially, CQDs derived from natural sources like chitosan or probiotic bacteria can inherit beneficial traits, such as the presence of quaternary ammonium groups, making them as effective as antibiotics in rodent models but with a lower risk of inducing bacterial resistance.
The research demonstrates that using specific precursors, such as modified chitosan or protein-rich bacteria, results in CQDs with enhanced ROS generation. This is linked to the formation of specific nitrogen types, like pyrrolic nitrogen, during synthesis. Furthermore, the thesis establishes a robust framework for evaluating antibacterial activity, recommending that viability assessments combine assays measuring reproductive capability and metabolic activity.
In conclusion, this work provides detailed guidelines for selecting carbon sources to design CQDs with targeted antimicrobial and antibiofilm properties for clinical and industrial use.
