Understanding loading, diffusion and releasing of Doxorubicin and Paclitaxel dual delivery in graphene and graphene oxide carriers as highly efficient drug delivery systems

Abstract

The adsorption mechanism of Doxorubicin (DOX) and Paclitaxel (PTX) mixture (1:1) on graphene (GRA) and graphene oxide (GOX) is determined using the molecular dynamics (MD) simulation and free energy calculation. The results indicate that the drug molecules spontaneously move toward the carriers. In the GRA system, the drug molecules form strong π-π interactions with the graphene surface, while the formation of intermolecular hydrogen bonds between the drug molecules and carrier expects in the GOX system due to different surface chemistry. The range of the drug-carrier intermolecular distances is around 2.5–4 A°. It is found that the binding energy of PTX (−487.67 Kj/mol) with the graphene is higher than DOX (−373.53 Kj/mol). In the GOX system, the oxygen-containing functional groups lead to a decrease in the binding of PTX (−414.79 Kj/mol) and DOX (−121.12 Kj/mol) to the carrier. Moreover, the study of drug release in acidic pH shows that some drug molecules can be desorbed from the carrier due to strong electrostatic repulsion. Finally, the interaction of the drug delivery systems (DDSs) and membrane cell is investigated. It is found that the graphene-based DDS cannot spontaneously diffuse into the membrane cell, while the GOX-based DDS easily penetrate in the membrane cell.