title: Enthalpy-Entropy Tuning in the Adsorption of Nucleobases at the Au(111) Surface.
abstract: The interaction of DNA molecules with hard substrates is of paramount importance both for the study of DNA itself and for the variety of possible technological applications. Interaction with inorganic surfaces strongly modifies the helical shape of DNA. Hence, an accurate understanding of DNA structure and function at interfaces is a fundamental question with enormous impact in science and society. This work sets the fundamentals for the simulation of entire DNA oligomers on gold surfaces in dry and wet conditions. Thanks to the new GolDNA-AMBER force field, which was derived from first principles and includes dispersion interactions and polarization effects, we simulated self-assembled guanine and adenine monolayers on Au(111) in vacuo and the adsorption of all nucleobases on the same substrate in aqueous conditions. The periodic monolayers obtained from classical simulations match very well those from first principle calculations and experiments, assessing the robustness of the force field and motivating the application to more complex systems for which quantum calculations are not affordable and experiments are elusive. The energetics of nucleobases on Au(111) in solution reveal fundamental physicochemical effects: we find that the adsorption paradigm shifts from purely enthalpic to dominantly entropic by changing the environment and aggregation phase.
authors.affiliation: Center S3, CNR Institute of Nanoscience , Via Campi 213/A, 41125 Modena, Italy.|Department of Physics, University of Modena and Reggio Emilia , 41125 Modena, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Rosa
authors.affiliation: Center S3, CNR Institute of Nanoscience , Via Campi 213/A, 41125 Modena, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Corni
authors.affiliation: Center S3, CNR Institute of Nanoscience , Via Campi 213/A, 41125 Modena, Italy.|Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Rosa
authors.initials: R
authors.lastname: Di Felice