Fernández Ana C Rossi, Castellani Norberto J
IFISUR, Universidad Nacional del Sur, CONICET, Departamento de Física, Av. L. N. Alem 1253, B8000CPB, Bahía Blanca, Argentina.
Chemphyschem. 2017 Aug 5;18(15):2065-2080. doi: 10.1002/cphc.201700252. Epub 2017 Jun 8.
The role of noncovalent interactions in the adsorption of biological molecules on graphene is a subject of fundamental interest regarding the use of graphene as a material for sensing and drug delivery. The adsorption of dopamine on regular graphene and graphene with monovacancies (GV) is theoretically studied within the framework of density functional theory. Several adsorption modes are considered, and notably those in which the dopamine molecule is oriented parallel or quasi-parallel to the surface are the more stable. The adsorption of dopamine on graphene implies an attractive interaction of a dispersive nature that competes with Pauli repulsion between the occupied π orbitals of the dopamine ring and the π orbitals of graphene. If dopamine adsorbs at the monovacancy in the A-B stacking mode, a hydrogen bond is produced between one of the dopamine hydroxy groups and one carbon atom around the vacancy. The electronic charge redistribution due to adsorption is consistent with an electronic drift from the graphene or GV surface to the dopamine molecule.
非共价相互作用在生物分子吸附于石墨烯上的过程中所起的作用，是关乎将石墨烯用作传感和药物递送材料的一个具有根本重要性的课题。在密度泛函理论框架内，从理论上研究了多巴胺在常规石墨烯以及具有单空位（GV）的石墨烯上的吸附情况。考虑了几种吸附模式，特别值得注意的是，那些多巴胺分子与表面平行或准平行排列的模式更为稳定。多巴胺在石墨烯上的吸附意味着一种具有色散性质的吸引相互作用，这种相互作用与多巴胺环的占据π轨道和石墨烯的π轨道之间的泡利排斥相互竞争。如果多巴胺以A - B堆叠模式吸附在单空位处，多巴胺的一个羟基与空位周围的一个碳原子之间会形成氢键。由于吸附导致的电荷重新分布与电子从石墨烯或GV表面向多巴胺分子的漂移相一致。
