Formation of water-soluble iron oxide nanoparticles derived from iron storage protein.

This paper reports novel findings of an investigation of the formation of water-soluble iron oxide nanoparticles from iron-storage protein ferritin. The strategy couples thermal removal of the protein shell on a planar substrate and subsequent sonication in aqueous solution under controlled temperature. Advantages of using ferritin as a precursor include well-defined core size, core composition, water-solubility and processibility. The formation of the nanoparticles was characterized using TEM, UV-Vis and FTIR techniques. Iron oxide nanoparticles in the size range of 5-20 nm diameters were produced. In addition to thermal treatment conditions, the sonication temperature of the nanoparticles in water was found to play an important role in determining the resulting particle size. This simple and effective route has important implications to the design of composite nanoparticles for potential magnetic, catalytic, biomedical sensing and other nanotechnological applications.