Oligosaccharide-modified dendrimers for templating gold nanoparticles: Tailoring the particle size as a function of dendrimer generation and -molecular structure

Dendrimer-stabilized nanoparticles are promising candidates for the application of functional nanoparticles in bio- and physiological environments. Herein, a new class of glycodendrimers, 2nd-5th generation poly(propyleneimine) (PPI) dendrimers with dense maltose shell, is used to guide the formation of colloidal gold nanoparticles ill aqueous solution at room temperature. The nanoparticles are synthesized by complexing metal ions to the maltose-modified PPI dendrimers followed by chemical reduction or by auto-reduction in the presence of glycodendrimers. In the auto-reduction process. the dendrimer simultaneously serves as effective reducing- and stabilizing agent. The particle size and -size distribution call be controlled directly as a function of dendrimer's generation with formation of smaller particles at higher dendrimer generations. The results also suggest that different mechanisms (interfacial uptake and dendritic box) are responsible for the stabilization of the nanoparticles in the presence of the glycodendrimers. (C) 2009 Elsevier B.V. All rights reserved.