Synthesis of Composite Particles with Fe3O4core and Ag Shell for the Development of Fingerprints

The Fe3O4 -core and Ag- shell (Fe3O4@Ag nanoeggs) were prepared through the encapsulation of 3aminopropyltriethoxysilane-coated magnetite nanoparticle in nano-Ag shell by a simple chemically controlled procedure. The Fe3O4@Ag nanoeggs were characterized by scanning electron microscopy, transmission electron microscopy, UV-vis spectrum and superconducting quantum interference device magnetometer, respectively. A detailed analysis is provided of how the hydrolysis and condensation of 3-aminopropyltriethoxysilane and the pH value are vital in fabricating the Fe3O4@Ag nanoeggs. The prepared Fe3O4@Ag nanoeggs possessed uniform size, improved monodispersity, stability against aggregation and high magnetization, which were utilized for the detection of latent fingerprints deposited onto different surfaces. The experimental results showed that the latent fingerprints developed with the Fe3O4@Ag nanoeggs powders exhibited excellent ridge details with minimal background staining.