Adsorption of bovine serum albumin on functionalized silica-coated magnetic MnFe2O4 nanoparticles

Two kinds of pH-dependent magnetic nanoadsorbent based on silica-coated MnFe2O4 nanoparticles (SMNPs) and amino-modified silica-coated MnFe2O4 nanoparticles (AS-MNPs) have been synthesized using sol–gel method. X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy have been employed to characterize the structure and morphology of the nanoadsorbents. The magnetic properties and zeta potential were also investigated. These nanoadsorbents were used to adsorb bovine serum albumin (BSA). The adsorption capacity of BSA largely depended on the pH and ionic strength of solution. In the best result, BSA was adsorbed on AS-MNPs at a high value of 164 mg g−1, which is much higher than that of SMNPs (100 mg g−1). This may due to the increased surface amino that can be conjugated to BSA by a chemical bond and the electrostatic attraction between BSA and magnetic nanoparticles.