Silica nano-beads has a superparamagnetic Fe3O4 core and hydroxyl outer surface modified with SiO2. It features with -low non-specific adsorption by the optimized size of the microspheres, the thickness of SiO2 layer and -SiOH density. All these features lead to highly pure and effective isolation and purification of nucleic acids including DNA, RNA from E Coli, blood, cells and viruses.