磁性纳米微粒的制备方法及其在放射免疫分析中的初步应用

采用化学共沉淀法合成水溶性正癸酸包覆的Fe3O4磁性纳米微粒，并以此为核心物理吸附羊抗兔IgG制备磁性纳米第二抗体，作为磁性分离载体用于放射免疫分析中。用光子相关光谱仪与透射电镜测定了磁性纳米微粒的粒径大小、粒径分布和多分散度等。研究了羊抗兔IgG包被磁性纳米微粒的包被介质的pH、羊抗兔IgG用量和包被时间等制备条件对磁性纳米微粒二抗免疫反应结合能力和非特异结合的影响。结果表明：化学共沉淀法制得的Fe3O4平均粒径约为10-20nm，吸附羊抗兔IgG后其平均粒径为1000nm左右，并可用于放射免疫分析中。提示羊抗兔IgG可通过物理吸附的方法固定在磁性纳米微粒上，其优点是制备方法简便、省时和成本低，在放射免疫分析中具有磁性分离的方便性，具有较大的医学应用价值。

Preparation of magnetic nanoparticles and its application in radioimmunoassay

To prepare magnetic nanoparticles and to explore its application in radioimmunoassay (RIA) , aqueous decanoic acid-coated Fe3O4 magnetic nanoparticles were synthesized by chemical coprecipitation with Fe2+ and Fe3+ ions included in microemulsions with ammonia water. The sheep anti-rabbit IgG was immobilized into the magnetic nanoparticles by physical adsorption. The complex of the magnetic nanoparticles and the sheep anti-rabbit IgG (magnetic nanoparticle second antibody) was then used as magnetic separation carrier for RIA. The magnetic nanoparticle size, size distributions, polydispersity etc were determined by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM). Some influence factors such as of buffer pH used for immobilizing sheep anti-rabbit IgG, amount of sheep anti-rabbit IgG, time of immobilizing sheep anti-rabbit IgG on specific and nonspecific binding of magnetic nanoparticle second antibody in RIA were studied. The results indicated that the average diameter of the decanioc acid-coated Fe3O4 nanoparticle and magnetic nanoparticle second antibody is 10-20 run and around 1000 nm, respectively. The second antibody labeled magnetic nanoparticle can be used in RIA. In conclusion the magnetic nanoparticle second antibody is characterized by the simplicity, time-saving in preparation, low cost and the conveniences of magnetic separation. So it has practical value in medical application.