Double-Layer Magnetic Nanoparticle-Embedded Silica Particles for Efficient Bio-Separation

Superparamagnetic Fe(3)O(4) nanoparticles (NPs) based nanomaterials have been exploited in various biotechnology fields including biomolecule separation. However, slow accumulation of Fe(3)O(4) NPs by magnets may limit broad applications of Fe(3)O(4) NP-based nanomaterials. In this study, we report fabrication of Fe(3)O(4) NPs double-layered silica nanoparticles (DL MNPs) with a silica core and highly packed Fe(3)O(4) NPs layers. The DL MNPs had a superparamagnetic property and efficient accumulation kinetics under an external magnetic field. Moreover, the magnetic field-exposed DL MNPs show quantitative accumulation, whereas Fe(3)O(4) NPs single-layered silica nanoparticles (SL MNPs) and silica-coated Fe(3)O(4) NPs produced a saturated plateau under full recovery of the NPs. DL MNPs are promising nanomaterials with great potential to separate and analyze biomolecules.