Superparamagnetic core–shell structured microspheres carrying carboxyl groups as adsorbents for purification of genomic DNA

Magnetic composite microspheres present a promising candidate for applications in bioseparation, drug delivery, and biocatalysis. We report here the synthesis of carboxyl-functionalized and core–shell structured Fe3O4/PS-PAA microspheres via a dispersion interfacial polymerization method, using styrene (St) and acrylic acid (AA) as monomers. The magnetic composite microspheres exhibit good dispersity, superparamagnetism, and high saturation magnetization. The samples were characterized with XRD, XPS, FTIR, FESEM, TEM, and VSM techniques, and further tested as adsorbents for purification of genomic DNA from Aspergillus niger NA1003 cells. Complexation mechanism of DNA with the adsorbent is discussed. The magnetic separation yields high-quality genomic DNA and satisfying productivity comparable to those isolated by the conventional phenol–chloroform extraction.