Graphene quantum dots based magnetic nanoparticles as a promising delivery system for controlled doxorubicin release

Abstract

In this study, a nanocarrier was prepared for targeted delivery of doxorubicin (DOX), as a drug model, to cancer cells. To this end, nontoxic Fe3O4 nanoparticles (NPs) were first synthesized by the co-precipitation method. The NPs then underwent surface functionalization by hydrophilic and biocompatible polyethylene glycol (PEG) to improve their stability. The Fe3O4@PEG was eventually decorated by graphene quantum dots (GQDs) for imparting specific optical properties and increase its drug loading capacity. The obtained nanocarriers (Fe3O4@PEG@GQD) exhibited low toxicity, hydrodynamic diameter of 129 nm, and a drug loading content of 27%, along with superior superparamagnetic properties. Also, the morphology of nanocarrier was surveyed by transmission electron microscopy (TEM). The drug release studies indicated a pH-dependent profile where higher release rates were observed at acidic pH (5.0) as compared with the physiological pH (7.4). The anticancer activity of Fe3O4@PEG@GQD-DOX was comparable to free drugs in the case of human breast cancer cells. The introduced nano-drug delivery system can be considered as a promising candidate for the controlled release of DOX. Finally, quantum mechanical computations were employed in a better understanding of drug release mechanism. The results showed a decline in the adsorption energy of the drug on GQDs from −107.1 kJ mol−1 at pH 7 to −66.2 kJ mol−1 at pH 5. Moreover, the HOMO-LUMO calculation and the electrostatic surface potential method were applied to further explore the drug-GQDs interactions.