Blue light activated nitrogen doped poly floral carbon quantum dots: multifunctional agent for anti-microbial and...

Carbon Quantum Dots (CQDs) represent a versatile class of biocompatible nanomaterials for photodynamic therapy (PDT). In present study, nitrogen-doped carbon quantum dots derived from the polyfloral resources of R. indica and H. rosa-sinensis (N-PFCQDs) were prepared and chemically characterized via different spectroscopic techiniques. N-PFCQDs were studied for their photodynamic antimicrobial and anticancer effects upon blue light exposure for different time intervals. Agar well diffusion assay demonstrated a light and time-dependent increase in their antimicrobial potential against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Aspergillus niger with a zone of inhibition (mm) ranging from 14.8 ± 0.46 at 0 min to 29.8 ± 0.44 at 90 min of exposure time for bacterial strains and for fungal strains ranging from 13.8 ± 0.16 at 0 min to 23.1 ± 0.21. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analysis identified their potential for high levels of bactericidal action for Staphylococcus aureus (MIC: 15.2 to 7.3 mg/L and MBC: 30.3 to 18.2 mg/L) and Escherichia coli (MIC: 16.2 to 8.1 mg/L and MBC: 29.8 to 19.3 mg/L) upon exposure to blue light from 0 to 90 min time interval. The combined treatment of conventional antibiotics with blue-light-activated N-PFCQDs revealed the enhancement of bacterial susceptibility. Under PDT, N-PFCQDs effectively inhibited Staphylococcus aureus and Pseudomonas aeruginosa biofilm formation, achieving up to 96.33 ± 1.20% and 98.67 ± 0.88% respectively. In addition, the concentration and time-dependent cytotoxicity effect was observed by utilizing the PDT approach with ROS generation on HepG2 cancer cells. Over all, these results demonstrate the effectiveness of N-PFCQDs as photosensitizing agents for therapeutic potential.