Indian long pepper leaves-derived dual fluorescent carbon nano dots for environmental and health aspects

AbstractIn this article, we present the synthesis ofPiper longumleaves-derived ethanolic carbon dots (PLECDs) using the most simplistic environmentally friendly solvothermal carbonization method. The PLECDs fluoresced pink color with maximum emission at 670 nm at 397 nm excitation. Additionally, the dried PLECDs dissolved in water showed green fluorescence with higher emission at 452 nm at 370 nm excitation. The UV spectra showed peaks in the UV region (271.25 nm & 320.79 nm) and a noticeable tail in the visible region, signifying the efficient synthesis of nano-sized carbon particles and the Mie scattering effect. Various functional groups (-OH, -N-H, -C-H, -C = C, -C-N, and -C-O) were identified using Fourier-transform infrared spectroscopy (FTIR). Its nanocrystalline property was revealed by the sharp peaks in the X-ray diffraction (XRD). High-Resolution Transmission Electron Microscopy (HRTEM) photomicrograph displayed a roughly-spherical structure with a mean size of 2.835 nm. The Energy Dispersive X-ray (EDAX) spectra showed the presence of C, O, N, S, and P. The High-performance thin layer chromatography (HPTLC) fingerprint of PLECDs showed an altered pattern than its precursor (Piper longumleaves ethanolic extract or PLLEE). The PLECDs sensed Cu2+selectively with a limit of detection (LOD) of 0.11 µM. It showed excellent cytotoxicity towards MDA-MB-231 (human breast cancer), SiHa (human cervical carcinoma), and B16F10 (murine melanoma) cell lines with excellentin-vitrobioimaging outcomes. It also has free radical scavenging activity. The PLECDs also showed outstanding bacterial biocompatibility, pH-dependent fluorescence stability, photostability, physicochemical stability, and thermal stability.