A general synthesis of metal (Mn, Fe, Co, Ni, Cu, Zn) oxide and silica nanoparticles based on a low temperature reduction/hydrolysis pathway

Abstract

A novel general synthesis of nanocrystalline manganese, cobalt, nickel, copper and zinc oxide as well as silica, in situ fluorescent dye-containing silica, and silica@iron oxide core–shell nanoparticles (NPs) is presented following a reduction-hydrolysis-precipitation pathway. As-synthesized manganese, copper and zinc oxide NPs were crystalline, cobalt and nickel oxide NPs were initially amorphous and required calcination. This general synthetic method was extended to larger silica NPs and silica NPs surface-modified with magnetic iron oxide NPs. All particles were characterized using powder X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction. The toxicity of the as-synthesized Mn₃O₄ NPs, which can easily be surface-modified with an aminosilane (hydrophilic) or oleic acid (hydrophobic), was assessed in vitro using three cell culture models.