There is provided a method of preparing nanoparticles and novel nanoparticles. The nanoparticle preparation comprises the generation of a mixture comprising a plurality of metal-containing compounds and a copolymer of a polyethylene glycol and an amine-containing polyamino acid such as polylysine where a metal core and polymer shell nanoparticle is formed. The novel nanoparticles have a metallic core and a graft copolymer shell of polyethylene glycol and an amine-containing polyamino acid where the shell least partially surrounds the metallic core and is non-ionically bound to the metallic core via metal-amine bonds.
