Synthesis and Characterization of N‐Doped Carbon Quantum Dots and its Application for Efficient Delivery of Curcumin in Live Cell

To improve bioavailability, enhance the solubility and stability of the hydrophobic drug curcumin, nanoparticles such as carbon quantum dots (CQDs) are unique choices. In this study, we present a simple, cost-effective, and eco-friendly method for synthesizing nitrogen-doped carbon quantum dots (N-CQDs) and their application in the efficient delivery of hydrophobic drugs curcumin into live cancer cells. The N-CQDs produced in this study exhibit excellent water solubility, remarkable stability, and high biocompatibility. To synthesize the N-CQD, we use a carbon source found naturally (lemon juice) and for doping, we use N-rich doping agents such as ethylene diamine and urea by using eco-friendly chemical oxidation methods. The resulting N-CQDs, with particle sizes under 10 nm, exhibit a good quantum yield, reinforcing their utility for biomedical applications. N-CQDs and drug-loaded particles are evaluated using various techniques like UV-Vis, Fluorescence Spectroscopy, Dynamic Light Scattering (DLS), and Atomic Force Microscopy (AFM) as well. Additionally, we report a remarkable method to use N-CQDs as carriers for the anticancer drug curcumin, significantly enhancing the solubility in live cells. Our research also delved into the application of N-CQDs in in vivo bioimaging and drug release studies within live cancer cells, with a particular focus on their pH-dependence behavior.