Carbon quantum dots for efficient delivery of curcumin in live cell

Carbon quantum dots (CQD) are a novel class of nanomaterials that has significant importance for applications in bioimaging, drug loading and delivery. Their easy preparation, tunable optoelectronic property, low toxicity, excellent biocompatibility, superior photostability, and exceptional water solubility contribute to their tremendous potentials for various applications. In this study, we synthesized carbon quantum dots using a greener and cost-efficient top-down reflux methods, and characterized the CQDs by various spectroscopy techniques. Furthermore, we investigated the potential application of CQDs as carrier of antitumor drug curcumin (Cur) in vitro by investigating the drug loading and release mechanism of the CQDs. Solubility of hydrophobic drug curcumin is increased when it forms complex with CQD, and hence increases the potential for its application. Moreover, the pH responsive drug release mechanism of the curcumin loaded CQDs is found to follow anomalous diffusion as per Korsmeyer-Peppas model. Additionally, we explored the in vivo bioimaging application of the CQDs, and used fluorescence resonance energy transfer (FRET) technique using CQDs (as donor) and curcumin (as acceptor) to understand the heterogeneity of drug loading in live Escherichia coli (E. coli) cells. Our findings provide a detailed insight into the application of CQDs as probes in bioimaging and FRET, and as well as their potential for targeted curcumin delivery in live cells.