Density functional calculations on the adsorption of Ampyra drug on graphene nanosheet

In this study, the interaction between graphene nanosheet (GNS) and Ampyra drug is investigated using density functional computations to exploit graphene potential application as a drug delivery system. All calculations on the GNS and different configurations are performed using density functional theory at M06-2X [1,2] functional along with the 6–31G(d,p) basis set in the gas phase as well as the water solution.DFT calculations give valuable information on the structural properties, orientation, adsorption energy and charge transfer between Ampyra molecule and graphene nanosheet in the equilibrium GNS-Ampyra complexes in the gas phase and water solution.The optimization of different GNS-Ampyra geometries shows that drug molecule tends to adsorb via its six-membered aromatic ring to the hexagonal ring of Graphene nanosheet by π–π stacking interaction at the most stable physisorption (Fig. 1).Incorporation of aqueous medium imparts significant impact on the solvation energy and dipole moments of the GNS-Ampyra systems which indicate GNS applicability as a drug carrier in the living system