Competitive Adsorption of Thiolated Polyethylene Glycol and Mercaptoproprionic acid on Gold Nanoparticles Measured by Physical Characterization Methods

Published

May 24, 2010

Author(s)

De-Hao D. Tsai, Frank W. DelRio, Robert I. MacCuspie, Tae Joon Cho, Michael R. Zachariah, Vincent A. Hackley

Abstract

Adsorption kinetics between thiolated polyethylene glycol (SH-PEG) and mercaptoproprionic acid (MPA) on gold nanoparticles (Au-NP) were studied using dynamic light scattering (DLS) and electrospray differential mobility analysis (ES-DMA). Through a cumulant analysis, the changes in hydrodynamic z-average particle size due to the formation of SH-PEG coatings on Au-NPs were measured by DLS in both two component (Au-NP + MPA or SH-PEG) and three component (Au-NP +MPA + SH-PEG) systems. ES-DMA was employed to quantify the surface coverage of SH-PEG and establish a correlation function between surface coverage and the change in particle size measured by DLS. A change in equilibrium binding constant for SH-PEG on Au-NPs at various concentrations of SH-PEG and MPA showed that the presence of MPA reduced the binding affinity of SH-PEG to the Au-NP surface. Kinetic studies showed SH-PEG was desorbed from the Au-NP surface following a second-order desorption model after subsequently introducing MPA. The desorption rate constant of SH-PEG from the Au-NP surface by MPA displacement was strongly affected by the concentration of MPA and the excess SH-PEG in solution.

Citation

Langmuir

Pub Type

Journals

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Keywords

dynamic light scattering (DLS), electrospray, differential mobility analysis (DMA), gold, nanoparticle, polyethylene glycol (PEG), Mercaptoproprionic acid (MPA), binding constant, adsorption, desorption

Citation

Tsai, D. , DelRio, F. , MacCuspie, R. , Cho, T. , Zachariah, M. and Hackley, V. (2010), Competitive Adsorption of Thiolated Polyethylene Glycol and Mercaptoproprionic acid on Gold Nanoparticles Measured by Physical Characterization Methods, Langmuir, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904724 (Accessed December 2, 2024)