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.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

“…To a lesser extent, silver NPs are also used to evaluate glutathione in a biological medium with the same advantages as AuNPs described previously [ 85 , 86 ]. Other, more marginal examples of NPs developed specifically to quantify GSH or GSSG, such as NPs of alumina or zinc, can be found in the literature [ 87 , 88 ].…”

A Facile Route to Tailoring Peptide-Stabilized Gold Nanoparticles Using Glutathione as a Synthon

“…To improve their chemical versatility in aqueous environments, thiols with anionic or cationic hydrophilic groups such as 2-mercaptoethanesulfonate, (dimethylamino)ethanethiol hydrochloride, mercaptoundecanoic acid, or thiolated-poly(ethylene glycol) linkers have been employed [20,21]. Natural thiols such as cysteine (Cys) [12], reduced glutathione (GSH) [13,22,23,24,25,26] and synthetic Cys-peptide analogs have been used for stabilizing nanoparticles [3,25,27,28,29,30,31,32]. The structural and functional features of these peptide-capped AuNPs make them ideal for use as imaging agents [14,33], for integration into bioanalytical sensors [4,34], and as cellular mimics for delivery of chelating agents [13,15,24,35,36] or as cancer drugs [37,38].…”

Molecular level insight on the adsorption of carboxylic acids to oxide nanoparticles in aqueous solution by X-ray photoelectron spectroscopy

“…Aluminium oxide materials (Al x O y ) are of specific interest to this community and have been used extensively as substrates in model studies of biomolecule adsorption. 5,25,26 However, to further advance the design of tailored surfaces for bio-and nanomedical purposes requires a molecular level understanding of the interplay between the surface chemistry of colloidal NPs and the surface adsorption of biomolecules, 5 but is non-trivial to realize in practice. Often the analytical techniques employed to characterize these interfaces offer limited molecular scale detail (as we have already seen with the zeta-potential), or are sensitive to the adsorbate or the surface, and not both.…”