One-pot facile synthesis of PEGylated Au nanoparticles in an aqueous media

We describe a facile protocol for the synthesis of PEGylated Au nanoparticles by simply mixing aqueous solutions of HAuCl4 and oligo(ethylene glycol) ethyl ether methacrylate. This method was applied to generate uniform multiply-twinned Au nanostructures of ∼21 nm in diameter with high yields. Our proposed mechanism indicates that the generation of primary alcohol intermediates from the nucleophilic addition reaction of water (nucleophile) with AuIII–vinyl complex is responsible for the reduction of gold ions. This protocol was also used to synthesize Ag nanoparticles and small aggregates of Pd nanoparticles. Due to the exclusion of sophisticated synthesis of PEG containing stabilizers, additional surfactants, or reducing agents, this approach provides a remarkably simple, versatile, and environmentally benign protocol to prepare PEGylated noble-metal nanocrystals. A comparative BSA adsorption study proved the lack of non-specific binding, a common obstacle in designing biocompatible nanoparticles. A facile, one-pot, and green protocol was applied to synthesize monodisperse PEGylated gold nanoparticles (PEG-AuNPs) with an average diameter of 21 nm using an inexpensive and commercially available PEG oligomer, oligo(ethylene glycol) ethyl ether methacrylate (PEGEEM), as both the reductant and stabilizer in an aqueous media. Excluding extra reducing agents or multi-step synthesis of PEG containing stabilizers make our approach an attractive alternative to prepare PEG-AuNPs. Besides AuNPs, we generated Pd and Ag nanoparticles using the same method. The mechanistic study of AuNPs generation is also proposed. Furthermore, PEG-AuNPs showed an excellent blockage of the BSA adsorption when compared to citrate-coated AuNPs. [Display omitted] ► Facile, one-pot, aqueous synthesis of monodisperse PEGylated gold nanoparticles. ► Oligo(ethylene glycol)ethylethermethacrylate(PEGEEM) as reductant and stabilizer. ► Exclusion of extra reducing agents or multi-step synthesis of PEG stabilizers. ► Fabrication of Pd and Ag nanoparticles using PEGEEM in aqueous media. ► An excellent blockage of the BSA adsorption by PEGylated gold nanoparticles.