Core-shell of FePt@SiO(2)-Au magnetic nanoparticles for rapid SERS detection

In this study, multifunctional hybrid nanoparticles composed of iron platinum (FePt), silica (SiO(2)), and gold nanoparticles (AuNPs) had been developed for surface-enhanced Raman scattering (SERS) application. Core-shell structure of SiO(2) and FePt nanoparticles (FePt@SiO(2)) was fabricated through sol-gel process and then immobilized gold nanoparticles onto the surface of FePt@SiO(2), which displays huge Raman enhancement effect and magnetic separation capability. The resulting core-shell nanoparticles were subject to evaluation by transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), zeta potential measurement, and X-ray photoelectron spectroscopy (XPS). TEM observation revealed that the particle size of resultant nanoparticles displayed spherical structure with the size ~30 nm and further proved the successful immobilization of Au onto the surface of FePt@SiO(2). Zeta potential measurement exhibited the successful reaction between FePt@SiO(2) and AuNPs. The rapid SERS detection and identification of small biomolecules (adenine) and microorganisms (gram-positive bacteria, Staphylococcus aureus) was conducted through Raman spectroscopy. In summary, the novel core-shell magnetic nanoparticles could be anticipated to apply in the rapid magnetic separation under the external magnetic field due to the core of the FePt superparamagnetic nanoparticles and label-free SERS bio-sensing of biomolecules and bacteria. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s11671-015-1111-0) contains supplementary material, which is available to authorized users.