Improvement on adsorption of amino-carboxy-functionalized graphene: A first-principles study

Different graphene surfaces have been proposed for modifying drug delivery of mesalazine as drug model. The adsorption of the drug on pristine graphene and functionalized graphene with amino group and amino-carboxyl groups were analyzed at the level of the functional density theory (DFT). Conclusive results were observed regarding the advantage of using the functionalized graphene surface with amino-carboxyl groups due to its greater stability in the adsorption energy compared to the lower energies obtained for pristine and amine functionalized graphene. The major changes in adsorption can be attributed to the changes in HOMO-LUMO orbitals of mesalazine specie at basic pH, and the decreased gap between valence-conduction bands on the bi-functionalized graphene DOS spectrum that facilitate the interactions between the drug and graphene surface.