The method of separating plasmid DNA by using the silica-magnetite nano-composite

The present invention provides a method of separating plasmid DNA by using the silica-magnetite nano-composite. The method includes the following steps: (1) utilizing the method of chemical precipitation to prepare the superparamagnetic iron oxide nano-particles by using the Fe+2/Fe+3 salts and ammonium hydroxide at the nitrogen gas condition; (2) the silica-magnetite nano-composite vector prepared by that the aforementioned magnetic iron oxide nanoparticles are coated with silica by proceeding the acid hydrolysis of tetraethoxysilane (TEOS); (3) contacting the plasmid DNA-containing sample with the vectors and then absorbing to the vector at the high salt condition; (4) recoverying the plasmid DNA by deabsorption. In a practical example, it just spends 8 minutes to complete the plasmid purification and recovery which starts with preparing the bacterial lysate. Comparing with the other methods or the methods based on the commercial silicas, the method of separating plasmid DNA by using the silica-magnetite na