POLYMERIZED PHOSPHOLIPID MEMBRANE MEDIATED SYNTHESIS OF METAL NANOPARTICLES

The synthesis of Au and Co/Co(OH)(2) nanoparticles has been accomplish ed with the use of polymerized vesicles composed of mixtures containin g 10% or 50% (w/w) of a palladium ion bound negatively charged phospho lipid, 10,12-diynoyl)-sn-glycero-3-phosphohydroxyethanol, and a zwitte rionic phospholipid ricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine. The divalent palladium ion bound to the negatively charged phospholip ids in the polymerized vesicle membrane initiated electroless metaliza tion of gold or cobalt on the vesicle surface leading to the formation of metallic nanoparticles. The particles have been characterized by t ransmission electron microscopy(TEM), high-resolution transmission ele ctron microscopy (HRTEM), and electron diffraction. Polymerized vesicl es containing catalytic sites only on the external membrane surface we re partially metalized with crystalline gold particles. By use of the internal volume of polymerized vesicles as the reaction vials, two typ es of unagglomerated nanoparticles (4-10 nm), Au and Co/Co(OH)(2), hav e been synthesized. HRTEM studies have demonstrated that particle nucl eation and-growth occurred within the vesicles and that particle growt h could be initiated by either single or multiple nucleation sites.