Assembly of Plasmonic and Magnetic Nanoparticles with Fluorescent Silica Shell Layer for Tri-functional SERS-Magnetic-Fluorescence Probes and Its Bioapplications

In this study, we report on the fabrication of multilayered tri-functional magnetic-SERS-fluorescence nanoprobes (MF-SERS particles) containing clustered superparamagnetic Fe3O4 nanoparticles (NPs), silver NPs, and a fluorescent silica layer. The MF-SERS particles exhibited strong SERS signals from the silver NPs as well as both superparamagnetism and fluorescence. MF-SERS particles were uptaken by cells, allowing successful separation using an external magnetic field. SERS and fluorescence signals could be detected from the NP-containing cells, and CD44 antibody-conjugated MF-SERS particles selectively targeted MDA-MB-231 cells. Based on these properties, MF-SERS particles proved to be a useful nanoprobe for multiplex detection and separation of cancer cells.