Specific recognition of bovine serum albumin using superparamagnetic molecularly imprinted nanomaterials prepared by two-stage core-shell sol-gel polymerization

A novel type of uniform magnetic imprinted nanomaterial for the recognition of bovine serum albumin (BSA) was prepared by anchoring MIP shells on the surface of silica deposited Fe₃O₄ NPs via a surface imprinting process and two-stage core-shell sol-gel polymerization. The resulting magnetic nanomaterials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and a vibrating sample magnetometer (VSM). The measurements indicated that the as-synthesized nanospheres exhibited good dispersion, high crystallinity, and satisfactory superparamagnetic properties. Moreover, the obtained Fe₃O₄@BSA-MIPs had a high saturation magnetization (43.82 emu g^-1), which allowed them to be easily separated from solution by means of an external magnetic field. The thickness of the imprinted polymer layer was approximately 5 nm, which would be effective for the mass transport between the solution and the surface of Fe ₃O₄@BSA-MIPs. The kinetic adsorption experiment showed that the imprinted nanomaterials could reach equilibrium within 15 min and be well described by the second-order kinetics model, indicating chemical adsorption might be the rate-limiting step. Meanwhile, the imprinting factor and selectivity coefficient of the Fe₃O₄@BSA-MIPs were as high as 16.4 and 4.65, displaying excellent selectivity towards BSA. In addition, the resulting imprinted polymers were without obvious deterioration after ten adsorption-desorption cycles and different batches of which exhibited excellent reproducibility. Successful application in the selective separation and enrichment of BSA from a bovine blood sample and good recovery after a reasonably mild elution suggested that the Fe₃O₄@BSA-MIPs could specifically capture BSA from a real complex matrix and had potential value in practical applications.