pH sensitive loading and release of doxorubicin by chitosan-graphene quantum dots hybridized material.

The effective delivery of doxorubicin (DOX) to tumor tissues remains a significant challenge in cancer therapy. In this study, molecular dynamics (MD) simulations were employed to investigate the loading and release mechanisms of DOX in chitosan-graphene quantum dots (GQDs) complexes under varying pH levels and DOX concentrations. The results show that chitosan aggregates at basic pH, thereby enhancing DOX encapsulation via hydrogen bonding. Meanwhile, GQDs exhibit higher DOX capture efficiency at acidic pH via π-π stacking interactions. At higher DOX concentrations, self-aggregation of DOX molecules reduces their availability for interaction with chitosan and GQDs, leading to decreased encapsulation efficiency. Furthermore, our simulations mimicking the pH transition from a neutral to an acidic tumor-like environment show that chitosan disperses in solution, leading to the sensitive release of DOX. These findings demonstrate that the controllable loading and release of DOX by chitosan-GQDs hybridized material can be achieved by adjusting the solution pH (the protonation state of chitosan) and the concentration of DOX.