Formation and stabilization in water of metal nanoparticles by a hyperbranched polymer chemically analogous to PAMAM dendrimers

A synthesized hyperbranched polymer, which is chemically analogous to PAMAM dendrimers, was used to prepare water soluble gold nanoparticles. The open structure of the hyperbranched polymer compared to the dendrimer architecture facilitates the interactions of metal ions (e.g., AuCl4(-)) with the internal chemical functions, increasing therefore the maximum load of ions per polymer. Nevertheless, it maintained control on the gold nanoparticles formed after reduction by sodium borohydride. Quite monodisperse nanoparticles of ca 4 nm were indeed obtained and stabilized in solution by the hyperbranched polymer. Such a cheap and easy to obtain polymer may presumably be used as a substitute for expensive PAMAM dendrimers in a large variety of experiments.