Adsorption and Orientation of the Physiological Extracellular Peptide Glutathione Disulfide on Surface Functionalized Colloidal Alumina Particles

• Published in: Journal of the American Chemical Society Vol. 135; no. 16; pp. 6307 - 6316
• Main Authors: Meder, Fabian, Hintz, Henrik, Koehler, Yvonne, Schmidt, Maike M, Treccani, Laura, Dringen, Ralf, Rezwan, Kurosch
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.04.2013
• Subjects: Adsorption; Aluminum Oxide - chemistry; Amines - chemistry; Carboxylic Acids - chemistry; Colloids - chemistry; Disulfides - chemistry; Electrochemistry; Extracellular Space - chemistry; Glutathione Disulfide - chemistry; Hydrogen-Ion Concentration; Models, Chemical; Nanoparticles; Particle Size; Peptides - chemistry; Phosphates - chemistry; Surface Properties; Thermodynamics
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja401590c

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 (d 50 = 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.