Ag and Ag─Au Introduced Silica-coated Magnetic Beads

We have developed novel metal-introduced and thiol-modified silica-coated magnetic beads (TM-bead) and report their optical property. A total of six different types of Ag or Ag with Au introduced TM-bead were prepared as follows: Ag was introduced onto TM-bead either by immobilizing pre-synthesized Ag nanoparticles (NPs) onto TM-bead (TM-bead@Ag NPs) or by growing Ag onto TM-bead (TM-bead@AgG). Subsequently, Au ions were introduced onto TM-bead@Ag NPs (TM-bead@Ag NPs@AuG) and TM-bead@AgG (TM-bead@AgG@AuG). Similarly, Au NPs were immobilized onto TM-bead@Ag NPs (TM-bead@Ag NPs&Au NPs) and TM-bead@AgG (TM-bead@AgG&Au NPs). The materials were analyzed by an UV–Vis spectroscopy, a scanning electron microscope and an energy-dispersive X-ray spectroscopy. Obtained under a unified frame, the results provide reliable and valid information against those types of metal based materials. The novel metal-immobilized magnetic beads can also function as plasmonic tunable magnetic beads in biological, material, and chemical applications.