Modeling and ab initio study of the adsorption of histidine on a graphene sheet

SINDY JULIETH RODRÍGUEZ SOTELO; LEONARDO MAKINISTIAN; EDUARDO ALBANESI

La Plata

Workshop; VI Workshop on Novel Methods for Electronics Structure Calculations; 2015

The graphene is a bidimensional crystal with unique physical and chemical properties: high carriers mobility, flexible, transparent, foldable, atomic thickness, among others. These properties make it promising for biomedical, bioelectronics and biosensor applications. With respect to other materials used for the construction of biosensors, graphene has great advantages; it is a sensitive, selective, biocompatible and flexible (and also it is an intrinsically low-noise material). In this work we present the results of modeling from first principles the adsorption of histidine on graphene sheet. The calculations were implemented in the context of the density functional theory DFT within a pseudopotentials approach. The study was carried out for two systems: the histidine molecule with carboxyl -COOH and amino groups -NH2 and the imidazole ring alone (i.e., the histidine without its carboxyl and amino groups), with the aim to evaluate the relevance of including the carboxyl and amino groups of amino acid in the adsorption process onto the graphene sheet. We report the total energy vs. final mean distance of the molecule, adsorption distances, adsorption energies, electronic properties of each system, densities of states before and after the adsorption, equilibrium geometries and charge transfer from graphene to the histidine molecule. Furthermore, we discuss some results to implement three approaches for exchange-correlation approximation, local LDA, generalized gradient GGA-PBE and one including van der Waals forces DFT-D2. This work would contribute to the evaluation of graphene as a sensor for biomolecules, providing initials tools for functionalization and characterization of new devices. Finally, we also comment some ongoing preliminary calculations of electronic transport in the system under a bias voltage.