Preparation of Porous Magnetic Silica Microspheres and Their Application in Genomic Deoxyribonucleic Acids Extraction

Porous magnetic silica microspheres with high magnetization, uniform particle-size distribution, and large surface area were prepared by a polymer-templating method. The microspheres were used as solid-phase adsorbents for the extraction of genomic deoxyribonucleic acids (DNA) from biological samples. Effects of experimental parameters including composition of capturing buffer and elution time on the yields of DNA isolated using the magnetic microspheres were examined and compared with those obtained with spherical and irregular silica. Results show that up to 80% recovery yields of DNA can be obtained on solid-phase adsorbents with a capturing buffer composed of 20% polyethylene glycol (PEG) and 2 M NaCl and an elution time of 10 min. After the cells were lysed, magnetic microspheres and silica particles were employed for the isolation of genomic DNA from Saccharomyces cerevisiae, and genomic DNA fragments of about 5 kb were obtained, with A260/A280values in the range of 1.77–1.82. Although silica particles are highly efficient adsorbents for extraction of genomic DNA, the incorporation of magnetic nanoparticles into the silica matrix offers distinct advantages in simplifying and expediating the sample preparation procedures involved in molecular biology and biomedical research.