▎ 摘　　要

The adsorption of Ampyra drug on the graphene nanosheet (GNS) and functionalized graphene nanosheets (f-GNSs) with an epoxide, hydroxyl, carboxyl, and carbonyl group was investigated using DFT computations in the gas phase and aqueous solution. The optimization of different structures for GNS-Ampyra indicated that the drug molecule was attracted by its hexagonal aromatic ring, to the six-membered ring of GNS by pi-pi stacking interaction. By functionalization of GNS with a carboxyl group, the maximum adsorption energy obtained. By adsorption of Ampyra on functionalized nanosheets, the energy gap and global hardness decreased which indicated an increase in the reactivity of considered complexes. In addition, Ampyra adsorption increased the polarity, which revealed that the dispersion and solubility of intended complexes increased after adsorption. The values of solvation energy showed a noticeable increase in the stability of f-GNSs after adsorption of Ampyra in the presence of water solvent. The physical nature of the Ampyra adsorption represented an advantage of easy desorption of the drug molecule without any electronic or structural variation. These results confirmed that the chemical modification of GNS using the mentioned functional groups was an effective method for the delivery of Ampyra drug in the living systems.