title: Adsorption and orientation of the physiological extracellular peptide glutathione disulfide on surface functionalized colloidal alumina particles.
abstract: Understanding the interrelation between surface chemistry of colloidal particles and surface adsorption of biomolecules is a crucial prerequisite for the design of materials for biotechnological and nanomedical applications. Here, we elucidate how tailoring the surface chemistry of colloidal alumina particles (d50 = 180 nm) with amino (-NH2), carboxylate (-COOH), phosphate (-PO3H2) or sulfonate (-SO3H) groups affects adsorption and orientation of the model peptide glutathione disulfide (GSSG). GSSG adsorbed on native, -NH2-functionalized, and -SO3H-functionalized alumina but not on -COOH- and -PO3H2-functionalized particles. When adsorption occurred, the process was rapid (≤5 min), reversible by application of salts, and followed a Langmuir adsorption isotherm dependent on the particle surface functionalization and ζ potential. The orientation of particle bound GSSG was assessed by the release of glutathione after reducing the GSSG disulfide bond and by ζ potential measurements. GSSG is likely to bind via the carboxylate groups of one of its two glutathionyl (GS) moieties onto native and -NH2-modified alumina, whereas GSSG is suggested to bind to -SO3H-modified alumina via the primary amino groups of both GS moieties. Thus, GSSG adsorption and orientation can be tailored by varying the molecular composition of the particle surface, demonstrating a step toward guiding interactions of biomolecules with colloidal particles.
authors.affiliation: Faculty of Production Engineering, Advanced Ceramics, University of Bremen, Bremen, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Meder
authors.forename: Henrik
authors.initials: H
authors.lastname: Hintz
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Koehler
authors.forename: Maike M
authors.initials: MM
authors.lastname: Schmidt
authors.forename: Laura
authors.initials: L
authors.lastname: Treccani
authors.forename: Ralf
authors.initials: R
authors.lastname: Dringen
authors.forename: Kurosch
authors.initials: K
authors.lastname: Rezwan
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D003102:Colloids / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry; D004563:Electrochemistry; D005110:Extracellular Space / Q000737:chemistry*; D019803:Glutathione Disulfide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D053758:Nanoparticles; D010316:Particle Size; D010455:Peptides / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D000588:Amines; D002264:Carboxylic Acids; D003102:Colloids; D004220:Disulfides; D010455:Peptides; D010710:Phosphates; D000537:Aluminum Oxide; D019803:Glutathione Disulfide