Hydroxylated Dendrimer-Stabilized Gold and Silver Nanoparticles: Spontaneous Formation, Characterization, and Surface Properties

We present a general route to the facile and spontaneous synthesis of gold (Au) and silver (Ag) nanoparticles (NPs) through the use of hydroxylated poly(amidoamine) (PAMAM) dendrimers as both stabilizers and reducing agents. The formation of Au NPs can be achieved by simply mixing the generation 4 (G4) and 5 (G5) glycidol-modified PAMAM dendrimers with HAuCl4 in either methanol or water at room temperature. The size of the formed Au NPs can be varied through the change of dendrimer generations and reaction solvents. We also show that 1,2-epoxyhexane-modified G4 PAMAM dendrimers can be used as both stabilizers and reducing agents to form Au NPs, providing a useful approach to tuning the surface hydrophilicity of Au NPs. Furthermore, using the same strategy of spontaneous formation of Au NPs, Ag NPs can be readily formed through the use of glycidol hydroxyl-terminated G5 PAMAM dendrimers as both stabilizers and reducing agents. The facile synthesis of Au and Ag NPs using hydroxylated PAMAM dendrimers may offer many opportunities for their uses in a variety of applications.