中文摘要：

以FeCl3作为铁源,乙二醇作为溶剂,采用溶剂热法合成单分散Fe3O4微球。通过调节铁源的浓度,改变Fe3O4的粒径（250～1 000 nm）以及磁特性（Ms：51.0～83.1 emu/g;Hc：82.2～165.6 Oe）。并采用改进的Stber法在Fe3O4微球表面包覆不同厚度的SiO2（35～150 nm）,以进行其表面的修饰。,对Fe3O4@nSiO2@mSiO2微球的表面进行聚乙烯亚胺修饰以改善其亲水性和表面偶联性。寻找合适于生物细胞载体的磁珠的制备工艺。

英文摘要：

By selecting FeC13 as an iron source, ethylene glycol as a solvent, the monodispersed Fe304 micro- spheres were synthesized by solvothermal method. By changing the concentration of the iron source, the Fe3 04 micro- spheres with different particle size （250 -1 000 nm） and magnetic properties （Ms：51.0 -83.1 emu/g, Hc：82.2 - 165.60e） were achieved. Then the particles were covered with a silica coating to form Fe304@ SiO2 core- shell structures by using the improved conventional Stober polyconde＇nsation method. And the thicknesses of the SiO2 layer were changed from 35nm to 150nm to find preparation techniques of optimum for DNA cell carrier. In order to im- prove the hydrophilicity and surface coupling of the composite microspheres, the surface of microspheres with PEI were modified.