中文摘要：

在利用自主研发的专利技术制备球形磁性硅胶微球的基础上，对磁性硅胶微球进行表面改性，使其表面分别键合硅羟基、环氧基、邻二醇基和羧基等官能团，并对表面官能团进行了定量研究。以小牛胸腺基因组脱氧核糖核酸（DNA）为模型化合物，研究了核酸在不同表面官能团的磁性硅胶上的吸附和脱附行为，发现表面具有硅醇基的磁球对DNA的回收率最高。将改性后磁性微球应用于玉米DNA的提取，得到了平均长度大于8kb的高纯度基因组DNA。与传统的有机溶剂抽提法相比，基于磁性微球的核酸固相萃取法具有快速简便、省时省力、易于自动化的特点，适合于大规模植物基因组DNA的样品制备。

英文摘要：

Solid phase extraction of nucleic acids using magnetic particles has found widespread applications in biotechnology and biomedical research. On the basis of successful preparation of magnetic silica microspheres by a proprietary process, we performed a further study on the surface modification of the magnetic silica microspheres and their applications in isolation of plant genomic nucleic acids. The surfaces of the magnetic silica microspheres were chemically bonded with silanol, epoxide, diol and carboxyl groups respectively, followed by quantitative research of the functional groups on the surface. The adsorption and elution behaviors of nucleic acids on surfaced modified magnetic silica microspheres were evaluated using calf thymus deoxyribonucleic acid （DNA） as model compound. It was found that the magnetic silica microspheres which were surfacemodified by silanol groups got the highest DNA recovery yields. The surface modified magnetic silica microspheres were applied to extraction of genomic DNA from corn flour with high purity DNA of fragment lengths 〉 8 kb obtained. In comparison with traditional methods using liquid-liquid extraction, the solid-phase process developed in this work is characterized by convenience, speed, time-saving, and being amenable to automation. The method can be adapted for large-scale preparation of plant genomic DNAs.