Polarization influences the evolution of nucleobase-graphene interactions

In recent years, graphene has attracted attention from researchers as an atomistically thin solid state material for the study on the self-assembly of nucleobases. Non-covalent interactions between nucleobases and graphene sheets play a fundamental role in understanding the self-assembly of nucleobases on the graphene sheet. A fundamental understanding of the effect of molecular polarizability on these non-covalent interactions between the nucleobases and the underlying graphene sheet is absent in the literature. In this paper, we present the results from polarizable molecular dynamics simulation studies to understand the effect of polarization on the strength of non-covalent interactions. To this end, we report the development of Drude parameters for describing the polarizable graphene sheet. The developed parameters were used to study the self-aggregation phenomenon of nucleobases on a graphene support. We observe a significant change in the interaction patterns upon the inclusion of polarization into the system, with polarizable simulations yielding results that closely resemble the experimental studies. Two of the key observations were the probability of the formation of stacks in guanine-rich systems, and the spontaneous formation of H-bonded structures over the graphene sheet, which allude to the importance of the DNA sequence and composition. Both these effects were not observed in the additive simulations. The present study sheds light on the effect of polarization on the adsorption of DNA nucleobases on a graphene sheet, but the methodology can be extended to include a variety of small molecules and complete DNA strands.