Hydrothermal synthesis of PVP-passivated clove bud-derived carbon dots for antioxidant, catalysis, and cellular imaging applications

Abstract

In recent times, carbon dots (CDs) are emerging for numerous interdisciplinary applications by modulating their inherent chemical functionality during or post-synthesis modification. The current study reports the hydrothermal synthesis of polyvinylpyrrolidone K-30 (PVP) passivated clove bud-derived carbon dots (PPCCDs) for multifaceted applications. The adopted technique is facile and environmentally friendly for the production of CDs with in situ PVP passivation. Physicochemical characterization of CDs is performed using various spectroscopic and microscopic techniques. The study reveals the formation of nitrogen-doped spherical PPCCDs with an average hydrodynamic size of ∼ 4.9 nm. It is also evident that there is modulation in optical properties and quantum efficiency as a result of PVP passivation. The study further demonstrates their suitability in biological environments as observed by pH stability, photostability, and cytocompatibility results. PPCCDs have shown significant antioxidant activity against DPPH (EC50: 57 µg/mL), suppression of superoxide anion radical (EC50: 53 µg/mL), and an efficient catalytic activity towards degradation of Rhodamine-B (Rh-B) dye. UV-Visible spectroscopy unveil the reaction mechanism during antioxidant and catalytic activities of CDs that are validated by Electron paramagnetic resonance (EPR) spectroscopy with an indication of effective electron or proton donating abilities. Its bioimaging potential is evidenced through cellular fluorescence imaging with 3T3 and L929 cell lines.