Metal coordination assisted thermo-sensitive magnetic imprinted microspheres for selective adsorption and efficient elution of proteins

Abstract Protein recognition and separation with high efficiency, low cost and facile construction has been hampered by the deficient development of fabrication methods. Toward this issue, we proposed a functionally integrated strategy by combining metal coordination, thermo-sensitive building blocks and hollow Fe3O4@mSiO2 microspheres (mSiO2 referred as mesoporous silica) with molecularly imprinted polymers (MIPs), to realize selective adsorption and effective desorption of the targeted protein bovine serum albumin (BSA). Herein, a series of metal ions (Mn2+, Fe3+, Ni2+, Cu2+, Zn2+) were selected to chelate onto the surface of amino groups modified substrates to investigate the metal coordination effect, wherein Ni2+ exhibited the optimal BSA immobilization ability. Beneficial from the sufficient templates coordinated by Ni2+, our MSS@Ni2+-MIPs (represented Ni2+-involved imprinted microspheres) with well-designed composite structure showed the best rebinding performance (Q = 182.18 mg/g, IF = 4.78) and rapid adsorption equilibrium kinetics (30 min) at 32 °C. Although template proteins were seized by the strong metal coordination, we obtained the satisfactory elution efficiency (61.97 %) at 20 °C assisted with the swollen thermo-sensitive components. Based on this facile, smart and versatile imprinting approach, the well-defined materials would hold great promising in bio-applications.