Surface modification of magnetic silica microspheres and its application to the isolation of plant genomic nucleic acids

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 surface-modified 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.