Magnetic Fe70Co30 nanoparticles with a cubic shape and a mean size of 15±1.5nm were fabricated using a magnetron-sputtering-based gas phase condensation deposition method. The particles had a high saturation magnetization of 220emu/g, which is much higher than that of commercially available iron oxide nanoparticles. The FeCo nanoparticles were modified by 3-aminopropyltriethoxy silane and subsequently activated by glutaraldehyde, leading to successful attachment of aldehyde groups onto nanoparticle surfaces. Three proteins, namely streptavidin, PAPP-A antibody and Nectin-4 antibody, were immobilized on glutaraldehyde activated FeCo nanoparticles, and their loading levels were quantitatively evaluated. Our results show that loading capabilities are 95μg of streptavidin, 128μg of PAPP-A, and 125μg of Nectin-4 antibody per milligram of FeCo nanoparticles, and that the three immobilized proteins retain their binding bioactivity. The protein-FeCo conjugates may find valuable applications involving magnetic separation and purification of proteins and cells, and the magnetic detection of biomolecules.
- FeCo magnetic nanoparticles
- Surface modification