Synthesis and characterization of Au-core Ag-shell nanoparticles from unmodified apoferritin

Abstract

Narrow-size distributed, water-soluble Au-core Ag-shell nanoparticles with a size range from 1 to 5 nm are synthesized using unmodified apoferritin as a template. Fast protein liquid chromatography reveals that the nanoparticles are formed inside the apoferritin cavity and are stable in aqueous solution. Electron microscopy shows that the particles are uniform in size and composed of both Au and Ag. In addition, extended X-ray absorption fine structure confirms that the particles have a core–shell structure with a Au core covered with a Ag shell. By varying the loading amounts of the silver precursor, the Ag shell thickness is controlled from one layer to several layers.