Université libre de Bruxelles (ULB), Engineering of Molecular Nanosystems, 50 Avenue F.D. Roosevelt, 1050 Bruxelles, Belgium.
Université libre de Bruxelles (ULB), Engineering of Molecular Nanosystems, 50 Avenue F.D. Roosevelt, 1050 Bruxelles, Belgium.
J Colloid Interface Sci. 2019 Dec 1;557:807-815. doi: 10.1016/j.jcis.2019.09.047. Epub 2019 Sep 14.
The functionalization of gold nanoparticles is commonly based on the use of thiol groups for the anchoring of organic ligands. To functionalize gold nanoparticles with mixed layers in defined proportions, different thiolated ligands are often used and assumed to graft equally on the surface. This assumption is however generally not verified and a quantitative investigation of the grafting density of mixed organic layers of thiolated ligands is therefore required.
Gold nanoparticles were exposed to solutions containing various proportions of two PEG ligands containing a thiol group at one extremity and a methoxy, carboxylate, or alkyne group at the other. A systematic study was performed on the resulting particles in order to quantify the composition of the PEG layer by quantitative H NMR spectroscopy.
Our results showed that the grafting of the PEG ligands with either a carboxylate or an alkyne group is strongly hindered in the presence of the methylated PEG ligands, despite the use of identical thiol anchoring groups. This is the first report on the quantification of mixed layers of PEGylated ligands on gold nanoparticles that demonstrates the severe limits of thiol chemistry for the functionalization of gold nanoparticles with mixed monolayers.
金纳米粒子的功能化通常基于使用巯基基团来锚定有机配体。为了以定义的比例用混合层功能化金纳米粒子，通常使用不同的巯基化配体，并假定它们在表面上均匀接枝。然而，这种假设通常未经证实，因此需要对混合有机层的接枝密度进行定量研究。
金纳米粒子暴露于含有两种聚乙二醇（PEG）配体的溶液中，这些配体在一端含有巯基，在另一端含有甲氧基、羧酸盐或炔基。对所得颗粒进行了系统研究，以便通过定量核磁共振光谱法定量确定 PEG 层的组成。
我们的结果表明，尽管使用了相同的巯基锚固基团，但在存在甲基化 PEG 配体的情况下，PEG 配体的羧酸盐或炔基接枝受到强烈阻碍。这是首次报道在金纳米粒子上定量混合层的 PEG 化配体，证明了硫醇化学在金纳米粒子的混合单层功能化方面的严重限制。
