Biogenic Synthesis of Blue Luminescent Carbon Quantum Dots From Gymnema sylvestre for Anticancer Studies

ABSTRACT In this study, we report the sustainable synthesis of blue luminescent carbon quantum dots (CQDs) derived from Gymnema sylvestre (GS) using a one‐step microwave‐assisted hydrothermal method. The GS–CQDs exhibit significant blue fluorescence, characterized by UV–visible and fluorescence spectroscopy. The optical properties reveal absorption peaks at 267 and 314 nm and fluorescence emission at 415 nm when excited at 320 nm. Structural analysis through x‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy confirms the amorphous nature of the CQDs and the presence of functional groups essential for fluorescence and stability. High‐resolution transmission electron microscopy (HR‐TEM) shows that the GS–CQDs are spherical, monodispersed, and have an average particle size of 8 ± 2.6 nm. The zeta potential measurement indicates a negative surface charge of −12.2 ± 5.61 mV, attributed to hydroxyl, carbonyl, and carboxyl groups. Notably, the GS–CQDs demonstrate promising anticancer activity against breast cancer cells (MDA‐MB‐231), suggesting their potential as effective therapeutic agents. This sustainable approach not only provides a cost‐effective method for CQD production but also highlights the potential of plant‐derived quantum dots in biomedical applications.