Facile green synthesis of hyaluronic acid-functionalized graphene quantum dots from Lepidium sativum for in vitro breast cancer cell imaging and cytotoxicity evaluation

Green-synthesized graphene quantum dots (LS-GQDs) have emerged as highly promising nanomaterials in the biomedical domain due to their strong fluorescence, high stability, and excellent biocompatibility. In particular, the surface modification of these quantum dots with targeting agents such as hyaluronic acid (HA) further enhances their specificity and biomedical utility. This study investigates the cytotoxicity and bioimaging capabilities of HA-modified LS-GQDs synthesized via a green, microwave-assisted method using Lepidium sativum seed extract, with a focus on their application in breast cancer cell imaging. The synthesized HA-LS-GQDs were thoroughly characterized using UV-Vis, Raman, FTIR, XRD, fluorescence spectroscopy, TEM, and FESEM and confirm the particle size of HA-LS-GQD 4.05 nm. The synthesized HA-LS-GQDs exhibited a visible-range fluorescence quantum yield of 14.78% under 490 nm excitation. The structural and optical characterizations revealed bright fluorescence and stable morphology. Cytotoxicity assays demonstrated that the HA-LS-GQDs possess low toxicity against breast cancer cells, indicating favorable biocompatibility. Additionally, the HA-functionalized LS-GQDs exhibited efficient cellular uptake and bright fluorescence, highlighting their strong potential for cellular imaging applications. The study confirms that HA-modified LS-GQDs synthesized via a green route offer excellent optical properties, high biocompatibility, and negligible cytotoxicity. These features make them ideal candidates for future biomedical applications, particularly in targeted drug delivery and fluorescence-based imaging of cancer cells.