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Characterization of Protein Adsorption onto FePt Nanoparticles using Dual-focus Fluorescence Correlation Spectroscopy

Maffre, P.; Amin, F.; Parak, W. J.; Nienhaus, K.; Nienhaus, G. U.

Using dual-focus fluorescence correlation spectroscopy, we have analyzed the adsorption of three human blood serum proteins, namely serum albumin, apolipoprotein A-I and apolipoprotein E4, onto polymer-coated, fluorescently labeled FePt nanoparticles (~12 nm diameter) carrying negatively charged carboxyl groups on their surface. For all three proteins, a step-wise increase in hydrodynamic radius with protein concentration was observed, strongly suggesting the formation of protein monolayers that enclose the nanoparticles. Consistent with this interpretation, the absolute increase in hydrodynamic radius can be correlated with the molecular shapes of the proteins known from X-ray crystallography and solution experiments, indicating that the proteins bind on the nanoparticles in specific orientations. The equilibrium dissociation coefficients, measuring the affinity of the proteins to the nanoparticles, were observed to differ by almost four orders of magnitude. These variations can be understood in terms of the electrostatic properties of the proteins. From structure-based calculations of the surface potentials, positively charged pat ... mehr

Zugehörige Institution(en) am KIT Institut für Angewandte Physik (APH)
Publikationstyp Zeitschriftenaufsatz
Jahr 2011
Sprache Englisch
Identifikator ISSN: 2190-4286
KITopen ID: 1000027139
Erschienen in Beilstein Journal of Nanotechnology
Band 2
Seiten 374 - 383
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