title: Adsorption and reduction of glutathione disulfide on α-Al2O3 nanoparticles: experiments and modeling.
abstract: Glutathione disulfide (GSSG; γ-GluCysGly disulfide) was used as a physiologically relevant model molecule to investigate the fundamental adsorption mechanisms of polypeptides onto α-alumina nanoparticles. Its adsorption/desorption behavior was studied by enzymatic quantification of the bound GSSG combined with zeta potential measurements of the particles. The adsorption of GSSG to alumina nanoparticles was rapid, was prevented by alkaline pH, was reversed by increasing ionic strength, and followed a nearly ideal Langmuir isotherm with a standard Gibbs adsorption energy of -34.7 kJ/mol. Molecular dynamics simulations suggest that only one of the two glutathionyl moieties contained in GSSG binds stably to the nanoparticle surface. This was confirmed experimentally by the release of GSH from the bound GSSG upon reducing its disulfide bond with dithiothreitol. Our data indicate that electrostatic interactions via the carboxylate groups of one of the two glutathionyl moieties of GSSG are predominantly responsible for the binding of GSSG to the alumina surface. The results and conclusions presented here can provide a base for further experimental and modeling studies on the interactions of biomolecules with ceramic materials.
authors.affiliation: Center for Biomolecular Interactions Bremen, University of Bremen, Germany. ralf.dringen@uni-bremen.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Dringen
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Koehler
authors.forename: Ludmilla
authors.initials: L
authors.lastname: Derr
authors.forename: Giulia
authors.initials: G
authors.lastname: Tomba
authors.forename: Maike M
authors.initials: MM
authors.lastname: Schmidt
authors.forename: Laura
authors.initials: L
authors.lastname: Treccani
authors.forename: Lucio
authors.initials: L
authors.lastname: Colombi Ciacchi
authors.forename: Kurosch
authors.initials: K
authors.lastname: Rezwan
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D019803:Glutathione Disulfide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000537:Aluminum Oxide; D019803:Glutathione Disulfide