Protein A磁性纳米颗粒载体的制备及应用

本研究采用本课题组合成的表面氨基化磁性纳米微球，首先通过化学共价交联制备了葡萄球菌Protein A磁性纳米微球载体（SPA-MP），并探讨了载体制备的优化条件。然后根据生物分子特异性亲合作用原理，在外加磁场的定向控制下，通过亲和吸附、清洗和解吸附等操作，探讨了SPA-MP载体在抗体分离纯化领域的应用可行性。载体制备优化实验结果显示，通过改变蛋白质浓度、交联剂浓度和交联剂活化时间可以制备不同表面密度的SPA-MP载体。300 μg SPA,2.5% (V/V)戊二醛浓度和3小时的活化时间可以获取表面密度高达35 mg SPA/g磁性纳米微球的载体。此外，应用结果显示每克SPA-MP磁性微球载体可以结合高达14 mg 的CD25抗体，同时可有效地分离纯化人抗血清样品中的IgG抗体。

Study on preparation of protein A magnetic nanosphere carrier and its application feasibility

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.