Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Colloidal and Nanoparticles
CPP 13.7: Vortrag
Dienstag, 26. Februar 2008, 16:30–16:45, C 264
Depletion-Driven Aggregation Kinetics and Protein Resistance of Surface Decorated Au Nanoparticles — •Fajun Zhang1, Donald G. Dressen1,2, Maximilian W. A. Skoda1,3, Robert M. J. Jacobs3, Stefan Zorn1, Richard A. Martin4, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany — 2Department of Physics and Astronomy, University of Denver, USA — 3CRL, University of Oxford, UK — 4Department of Physics, University of Bath, UK
Self-assembled monolayers with oligo(ethylene glycol) (OEG) termination are of great importance in biomedical applications due to their protein resistance. We have successfully prepared OEG-thiol decorated gold colloids and studied various interactions, stability and aggregation kinetics of colloid in the mixture of protein and colloid by SAXS and UV-vis spectroscopy [1]. Results proved the protein resistance of the OEG SAM at curved interfaces. Above a critical protein concentration, c*, the colloids lose their stability and form aggregates due to the depletion-attraction [1]. Depletion-driven aggregation kinetics was studied under various protein concentrations and ionic strength. A kinetic crossover from RLCA to DLCA is observed at low salt addition, which is caused by the effective repulsive interaction barrier between colloids within the oscillatory depletion potential. Above 0.5 M NaCl, the surface charge of proteins is screened significantly, and the energy barrier disappeares, thus the growth kinetics becomes DLCA only [1]. [1] F. Zhang, et al., J. Phys. Chem. B. 2007, 111, 251. J. Phys. Chem. A. 2007, DOI: 10.1021/jp074293v. Euro. Biophys. J. Submitted.