Hydrophilic Co@Au yolk/shell nanospheres: synthesis, assembly, and application to gene delivery.

Co@Au yolk/shell nanospheres and linear assemblies of such are synthesized by controlled galvanic replacement reaction. The nanospheres are biocompatible, hydrophilic, and superparamagnetic, and gold nanocages can be prepared by etching. The potential applications of the nanospheres include use as nonviral gene transport vehicles, cellular optical imaging, and in vivo magnetic resonance imaging tracking during gene transfection.