Ligand Adsorption and Exchange on Pegylated Gold Nanoparticles

    Authors

    K. Siriwardana; M. Gadogbe; S. M. Ansar; E. S. Vasquez; W. E. Collier; S. L. Zou; K. B. Walters;D. M. Zhang

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. C

    Keywords

    THIOLATED POLY(ETHYLENE GLYCOL); ENHANCED RAMAN-SPECTROSCOPY; SURFACE-PLASMON RESONANCE; PROTEIN ADSORPTION; SILVER NANOPARTICLES; SINGLE GOLD; QUANTIFICATION; ORGANOTHIOLS; STABILITY; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, ; Multidisciplinary

    Abstract

    Previous researchers proposed that thiolated poly(ethylene glycol) (PEG-SH) adopts a "mushroom-like" conformation on gold nanoparticles (AuNPs) in water. However, information regarding the size and permeability of the PEG-SH mushroom caps and surface area passivated by the PEG-SH mushroom stems are unavailable. Reported herein is our finding that AuNPs that are covered by saturation packed PEG-SHs all have large fractions of AuNP surface area available for ligand adsorption and exchange. The model ligands adenine and 2-mercaptobenzimidazole (2-MBI) can rapidly penetrate the PEG-SH overlayer and adsorb onto the AuNP surface. Most of the ligand adsorption and exchange occurs within the first minutes of the ligand addition. The fraction of AuNP surface area passivated by saturation packed model PEG-SHs are similar to 25%, similar to 20%, and similar to 9% for PEG-SHs with molecular weights of 2000, 5000, and 30 000 g/mol, respectively. Localized surface plasmonic resonance and dynamic light scattering show that the PEG-SH overlayer is drastically more loosely packed than the protein bovine serum albumin on AuNPs. Studies investigating the effect of aging the AuNP/PEG-SH mixtures on subsequent adenine adsorption onto the pegylated AuNPs revealed that PEG-SHs reach approximately a steady-state binding on AuNPs within 3 h of sample incubation. This work sheds new insights into the kinetics, structures, and conformations of PEG-SHs on AuNPs and demonstrates that pegylated AuNPs can be used as an important platform for studying ligand interaction with AuNPs. In addition, it also opens a new avenue for fabrication of multicomponent functionalized nanoparticles.

    Journal Title

    Journal of Physical Chemistry C

    Volume

    118

    Issue/Number

    20

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    11111

    Last Page

    11119

    WOS Identifier

    WOS:000336509400066

    ISSN

    1932-7447

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