中国生物工程杂志

This study employed surface amino-modified magnetic nanosphere prepared by our research group. First prepared Staphylococcal protein A (SPA) immobilized magnetic nanosphere carrier (SPA-MP) by covalent coupling method, and discussed the optimization condition for carrier preparation. Then according to the specific affinity between biological molecules, application feasibility of the SPA-MP carrier for antibody purification field was investigated through the oriented controlling of additional magnetic field, affinity adsorption, washing and elution operations. The optimization experiments appeared that we can prepare SPA-MP carriers with different surface density by changing the protein concentration, cross-linker concentration and activation time of cross-linker. Under the conditions of 300 μg SPA,2.5% (V/V) glutaraldehyde concentration and 3h activation time, the SPA-MP carrier with surface density as high as 35 mg SPA per gram magnetic nanosphere can be prepared. In addition, application results indicated that 1g SPA-MP carrier can bind CD25 monoclonal antibody up to 14 mg, and is effective for IgG antibody purification from human antiserum samples.