Adsorption of bovine serum albumin on superparamagnetic composite microspheres with a Fe3O4/SiO2 core and mesoporous SiO2 shell

Abstract

Magnetic sandwich structured mesoporous silica microspheres containing a silica-coated Fe₃O₄ core and a layered mesoporous silica shell have been successfully synthesized by multi-step reactions. The as-prepared Fe₃O₄/SiO₂/mesoporous SiO₂ (Fe₃O₄/SiO₂/mSiO₂) microspheres were characterized via X-ray diffractometry (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption and vibrating sample magnetometry (VSM). The results indicate that these materials possess superior porosity with high surface areas and large pore volumes, while still maintaining the microspheres morphologies, which is beneficial for enrichment and purification applications. The microspheres were applied as adsorbents for bovine serum albumin (BSA). The adsorption equilibrium was well explained in the entire experimental region by the Langmuir isotherm model and the maximum adsorption amounts of BSA were calculated as high as 289 mg g⁻¹. This work provides a promising approach for the design and synthesis of multifunctional microspheres, which can be used for potential applications in a variety of biomedical fields including drug delivery and biosensors.