Preparation of porous magnetic silica microspheres and their application for genomic deoxyribonucleic acid extraction

Porous magnetic silica microspheres with high magnetization, uniform particle size distribution and large surface area were prepared by a polymer templated method. The microspheres were used as solid-phase adsorbents for extraction of genomic deoxyribonucleic acid (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 particles. Results show that recovery yields of DNA up to 80% can be obtained on solid-phase adsorbents with a capturing buffer composed of 20% polyethylene glycol (PEG) and 2 mol/L NaCl and elution time of 10 min. The magnetic microspheres and silica particles were applied for isolation of genomic DNA from Saccharomycescerevisiae after the cells were lysed and the genomic DNA fragments of about 5 kb were obtained with the A(260)/A(280) values in the range of 1.77 - 1.82. The magnetic microspheres are comparable with the silica particles in terms of yield and purity of DNA isolated.