Stable, Hydrophilic Nitrilotriacetic Acid-Capped Gold Monolayer Protected Clusters

A one step synthesis and functionalization of robust, hydrophilic monolayer protected clusters of gold (Au-MPCs) containing a nitrilotriacetic acid (NTA) is described. The 14 nm Au-MPCs were prepared by the attachment of two bifunctional thioalkylated-poly(ethylene glycol) ligands on the nanoparticles, one containing a nitrilotriacetic acid (NTA) terminal group, while the second hydroxyl (OH) terminated ligand was used as a co-stabilizer to promote the stability of the MPCs. The resulting PEGylated NTA functionalized Au MPCs, which are characterized by TEM, UV-vis and agarose gel electrophoresis are attractive probes for many target species e.g. hexahistidine-tagged proteins. Importantly, the NTA functionality on MPCs ligand shell can be varied.