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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster: Nanoparticles and Composite Materials
CPP 12.30: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
Gold nanoparticles decorated with oligo(ethylene glycol) thiols: surface charges, and interactions with proteins in solution — •Fajun Zhang1, Moritz Schollbach1, Felix Roosen-Runge1, Maximilian W. A. Skoda2, Robert M. J. Jacobs3, and Frank Schreiber1 — 1IAP, Universität Tübingen — 2STFC, ISIS, Rutherford Appleton Laboratory, UK — 3University of Oxford, UK
We have studied the stability of OEG SAM decorated gold nanoparticles (AuOEG) and their interactions with proteins in solutions using DLS and zeta-potential measurements. We show that AuOEG particles carry a low net negative charge and are stable under a wide range of experimental conditions [1]. When mixed with proteins, negatively charged proteins do not adsorb to the colloid surface. However, with positively charged protein (lysozyme), zeta-potential values increase with protein concentrations and lead to a charge inversion, indicating adsorption of lysozyme to the colloid surface. The colloidal solutions become unstable near zero charge. Washing protein-bound colloids by centrifugation can remove only part of the adsorbed lysozyme. The effective charge inversion and rather strongly bound lysozyme on the colloid surface suggest that in addition to the charges formed at the SAM-water interface, there are defects on the surface of the colloid, which are accessible to the proteins [2]. The results of this study of surface charge, and stability shed light on the interaction with proteins of SAM coated AuNPs and their applications. [1] F. Zhang, et al. J. Phys. Chem. A 2007, 111, 12229. J. Phys. Chem. C 2009, 113, 4839. [2] M. Schollbach, et al. 2012, Submitted