Preparation Of Magnetic Monodisperse Microspheres For Plasmid DNA Purification

In this article, magnetic polymer microspheres with polyglycidyl methacrylate (PGMA) cross-linked by divinylbenzene (DVB) are fabricated by dispersion polymerization and penetration-deposition method. The morphology, size and magnetic characteristics of the microspheres were extensively characterized. The M-PGMA microspheres were nonporous, of smooth surface and superparamagnetic with a saturation magnetization of 16.48 emu/g.Recycled use of the latter material for plasmid purification exhibited stability of the M-PGMA, The chemical stability was also confirmed by examining its plasmid adsorption after incubation in various solutions such as 0.1 mol/L NaOH for 24 h. The adsorption capacity of plasmid DNA reached 90.35μg/mg dry resin when pH is 6.5 and salt concentration is 0.5mol/L and the elution yield 97.2% when pH 9 and salt concentration 1.25 mol/L. The magnetic beads are effective at binding DNA from a crude cell lysate. The plasmid is isolated from 1.5ml cell culture, following alkaline lysis yielding 19.4μg and 24.8μg(with ribonuclease A). The results presented in this article show that M-PGMA beads are suitable for isolation and purification plasmid DNA.In order to gain smaller particles,magnetic nanoparticles are prepared by soap-free emulsion polymerization and swelling-deswelling method, with a diameter range of 200-600nm and saturation magnetization of 10.99 emu/g.