Ligand Adsorption and Exchange on Pegylated Gold Nanoparticles
详细信息 查看全文
- 作者：Kumudu Siriwardana ; Manuel Gadogbe ; Siyam M. Ansar ; Erick S. Vasquez ; Willard E. Collier ; Shengli Zou ; Keisha B. Walters ; Dongmao Zhang
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：May 22, 2014
- 年：2014
- 卷：118
- 期：20
- 页码：11111-11119
- 全文大小：400K
- 年卷期：v.118,no.20(May 22, 2014)
- ISSN：1932-7455
文摘
Previous researchers proposed that thiolated poly(ethylene glycol) (PEG-SH) adopts a 鈥渕ushroom-like鈥?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 25%, 20%, and 9% for PEG-SHs with molecular weights of 2000, 5000, and 30鈥?00 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.