Green Synthesis of Carbon Dots and Evaluation of Its Pharmacological Activities

Abstract

In this study, an eco-friendly, cost-effective and fast microwave method of preparation of carbon dots was employed. The antimicrobial and cytotoxic activities of metal-based nanoparticles are well known, but the effects of carbon dot nanoparticles (C-dot NPs) are less explored. Stable C-dot NPs were prepared from organic waste of pomegranate and watermelon peels and characterized by UV-visible spectrophotometer, fluorescent spectroscopy, Fourier transform infrared (FTIR) spectra, high-resolution transmission electron microscopy (HRTEM) and Raman’s spectroscopic techniques. The different biological applications of C-dots such as anti-microbial activity against Fusarium oxysporum, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli and the cytotoxic activity against MCF-7 and HepG2 cell lines were evaluated. The study revealed that the C-dots synthesized from pomegranate peel (P-C dots) have larger effect than those synthesized from the watermelon peel (W-C dots) on therapeutic properties. C-dots synthesized by pomegranate peel extract and watermelon peel extract have shown the anti-bacterial activity at the concentration of 80 μL (19.67 ± 0.37) on bacterial strains versus ciprofloxacin at 10 μg/mL (19.67 ± 0.40) which was used as control. P-C dots (61.00 ± 1.90) have shown significant antifungal activity when compared with the fluconazole (85 ± 0.90) and the W-C dots did not show any activity. Further, P-C dots and W-C dots were evaluated for cytotoxic activity. Both P-C dots and W-C dots have shown strong anti-cancer effects for cell lines; for MCF-7, P-C dots have shown significant effect when compared with W-C dots, whereas for HepG2 cell lines, both the C-dots are showing almost equal range of effects. This study reveals that the C-dots synthesized from organic wastes can be used as a therapeutic agent to treat human microbial infections.