Preparation and evaluation of FeO-core@Ag-shell nanoeggs for the development of fingerprints.

The surface of individual, relatively dispersed FeO nanospheres is coated with a thiol-terminated silane, then the thiol on the FeO particles' surfaces treats with nano-Ag colloidal solution to form Ag-modified FeO nanoparticles. Eventually, a solid shell of Ag is capped onto the Ag-modified FeO nanoparticles by reducing aliquots of AgNO solution using NaBH as a reducing agent. The as-prepared FeO-core@Ag-shell nanoeggs, which are uniform in size, highly monodisperse, stable against aggregation and have high magnetization, were depended on thin shell of the attached nano-Ag, the size of FeO nanoparticles, the volume of thiol-terminated silane as well as the ultrasonication. The FeO-core@Ag-shell nanoeggs are proposed to detect fingermarks on different surface, with which the fingermarks can be viewed directly, due to the clear ridge detail. [ABSTRACT FROM AUTHOR]