Hydrothermal Synthesis of Clove Bud-Derived Multifunctional Carbon Dots Passivated with PVP- Antioxidant, Catalysis, and Cellular Imaging Applications

The present study reports a one-step clean synthesis of carbon dots (CDs) using clove buds and polyvinylpyrrolidone (PVP) as the starting precursor via hydrothermal routes. The adopted technique is facile, reproducible, and cost-effective for the production of externally passivated carbon dots owing to an environmentally friendly process utilizing natural precursors. The study evidenced the synergetic effect of passivation on light absorption and fluorescence properties in comparison to non-passivated carbon dots (CCDs). The structural and morphological study revealed that the PVP-passivated clove-derived carbon dots (PPCCDs) were spherical with an average diameter of ~ 2 nm and crystalline with an interlayer spacing of 0.33 nm. The PPCCDs showed excellent antioxidant activity against DPPH free radicals and also showed good catalytic activity for the degradation of Rhodamine-B (Rh-B) dye under studied conditions. Synthesized PPCCDs showed dose-dependent toxicity in L929 (mouse fibroblast) cell lines, while the appropriate concentration used in biological studies was found to be biocompatible as evidenced by MTT assays and also revealed in bioimaging potential. To conclude, synthesised PPCCDs is an economically potent candidate with multifunctional aspects, which can serve as an excellent antioxidant, catalyst, and efficient multicolor bioimaging tool.