title: Probing Silica-Biomolecule Interactions by Solid-State NMR and Molecular Dynamics Simulations.
abstract: Understanding the molecular interactions between inorganic phases such as silica and organic material is fundamental for chromatographic applications, for tailoring silica-enzyme interactions, and for elucidating the mechanisms of biomineralization. The formation, structure, and properties of the organic/inorganic interface is crucial in this context. Here, we investigate the interaction of selectively13C-labeled choline with29Si-labeled monosilicic acid/silica at the molecular level. Silica/choline nanocomposites were analyzed by solid-state NMR spectroscopy in combination with extended molecular dynamics (MD) simulations to understand the silica/organic interface. Cross-polarization magic angle spinning (CP MAS)-based NMR experiments like1H-13C CP-REDOR (rotational-echo double resonance),1H-13C HETCOR (heteronuclear correlation), and1H-29Si-1H double CP are employed to determine spatial parameters. The measurement of29Si-13C internuclear distances for selectively13C-labeled choline provides an experimental parameter that allows the direct verification of MD simulations. Atomistic modeling using classical MD methodologies is performed using the INTERFACE force field. The modeling results are in excellent agreement with the experimental data and reveal the relevant molecular conformations as well as the nature and interplay of the interactions between the choline cation and the silica surface. Electrostatic interactions and hydrogen bonding are both important and depend strongly on the hydration level as well as the charge state of the silica surface.
authors.affiliation: Chair for Bioanalytical Chemistry, Department of Chemistry and Food Chemistry, TU Dresden , 01062 Dresden, Germany.
authors.forename: Stephan Ingmar
authors.initials: SI
authors.lastname: Brückner
authors.affiliation: Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden , 01062 Dresden, Germany.
authors.forename: Sergii
authors.initials: S
authors.lastname: Donets
authors.affiliation: Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden , 01062 Dresden, Germany.
authors.forename: Arezoo
authors.initials: A
authors.lastname: Dianat
authors.affiliation: Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden , 01062 Dresden, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Bobeth
authors.affiliation: Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden , 01062 Dresden, Germany.
authors.forename: Rafael
authors.initials: R
authors.lastname: Gutiérrez
authors.affiliation: Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden , 01062 Dresden, Germany.|Dresden Center for Computational Materials Science (DCMS), TU Dresden , 01062 Dresden, Germany.|Center for Advancing Electronics Dresden, TU Dresden , 01062 Dresden, Germany.
authors.forename: Gianaurelio
authors.initials: G
authors.lastname: Cuniberti
authors.affiliation: Chair for Bioanalytical Chemistry, Department of Chemistry and Food Chemistry, TU Dresden , 01062 Dresden, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Brunner