title: Single Molecule Investigation of Glycine-Chlorite Interaction by Cross-Correlated Scanning Probe Microscopy and Quantum Mechanics Simulations.
abstract: In this work, we studied the interaction of glycine with the (001) surface of chlorite mineral at a single molecule level by cross-correlating scanning probe microscopy (SPM) and ab initio quantum mechanics (QM) investigations. Chlorite mineral is particularly interesting and peculiar for the interaction with organic molecules because it presents an alternated stacking of brucite-like (hydrophobic) and talc-like (hydrophilic) layers of different polarities. Brucite-like is positive, whereas talc-like is negative. The experimental atomic force microscopy (AFM) observations show that glycine is stably and selectively adsorbed on the brucite-like layer, organized in monolayers with different patterns. The sizes of single molecules of glycine measured by AFM are in agreement with those calculated by QM. Glycine molecules were found to align both at the edges and on the terraces of the brucitic surface. QM simulations confirmed the AFM observations that glycine molecule is adsorbed with high adsorption energy preferentially with its plane parallel to the (001) brucite-like surface. QM also provided the geometry conformation of the molecule and the bonding scheme between glycine and brucite surface. This kind of data can be very helpful both to biotechnological applications of this substrate and to depict some important processes that might have been occurred in prebiotic environments.
authors.affiliation: Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna "Alma Mater Studiorum", Piazza di Porta San Donato 1, 40126 Bologna, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Moro
authors.affiliation: Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna "Alma Mater Studiorum", Piazza di Porta San Donato 1, 40126 Bologna, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Ulian
authors.affiliation: Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna "Alma Mater Studiorum", Piazza di Porta San Donato 1, 40126 Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Valdrè
mesh_terms: D002712:Chlorides / Q000737:chemistry*; D005998:Glycine / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D064347:Microscopy, Electrochemical, Scanning; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D002712:Chlorides; D005998:Glycine; C001599:chlorite