Green Synthesis of Fluorescent Biogenic Carbon Dots From <i>Cucumis maderaspatanus</i> for Bioimaging Applications

Carbon dots (CDs) are a novel class of carbon-based fluorescent nanomaterials with quasi-spherical particle sizes ranging from 1 to 10 nm. They possess distinctive features such as tunable photoluminescence, high water solubility, low toxicity, and excellent biocompatibility. These properties have driven their widespread exploration in biomedical applications, especially in drug delivery and disease diagnosis. Conventional physical and chemical synthesis methods often involve toxic reagents, longer reaction times, and higher energy requirements, raising environmental concerns. In this study, we report a green, microwave-assisted synthesis of CDs using Cucumis maderaspatanus (CM) leaves as a natural carbon source. This eco-friendly method offers advantages such as simplicity, reduced reaction time, and lower energy consumption. Characterization techniques including UV-visible spectroscopy, XRD, FTIR, SEM, HRTEM, DLS, and XPS were employed to confirm the structural integrity and optical properties of CM-derived CDs. CM-derived CDs exhibited excellent at neutralizing free radical and showed significant total antioxidant capacity. In vitro biocompatibility assessments further confirmed their safety for biological applications. Cellular uptake studies in oral cancer cells revealed effective internalization of the CDs, validating their potential as fluorescent probes for bioimaging. These findings highlight the promising role of CM-derived CDs in biomedical imaging and underscore the potential of green synthesis approaches for advanced nanomaterial development.