A Computational Study on Lomustine Adsorption on the Surface of Graphene Quantum Dots

In this study, lomustine interaction with graphene quantum dots was evaluated by infrared (IR), natural bond orbital (NBO) and frontier molecular orbital (FMO) computations. The negative values of adsorption energy, enthalpy changes, Gibbs free energy variations showed lomustine adsorption on the surface of graphene quantum dots is exothermic, spontaneous and experimentally feasible. Structural parameters including the energy of HOMO and LUMO orbitals, bandgap, electrophilicity, chemical potential, chemical hardness, density and zero-point energy were also calculated and discussed. The remarkable decrease in bandgap after the lomustine adsorption on the surface of graphene quantum dots demonstrated that the electrochemical conductivity and electrocatalytic properties increased after adsorbate interaction with the adsorbent and graphene quantum dots can be used for construction of new electrochemical sensor in order to lomustine detection and quantitation. In addition, this phenomenon showed lomustine complexes with graphene quantum dots have better reactivity and bioavailability than the pure drug molecule without nanostructure.