Synthesis and Characterization of Functionalized Superparamagnetic Nanoparticles for Isolation of Dna

Iron oxide nanoparticles were synthesized and coated with silica by conventional coprecipitation method. Silica coated iron oxide nanoparticles were surface functionalized with chitosan. Silica coating and chitosan functionalization were confirmed by FTIR and TG-DTA analysis. XRD pattern revealed that the pure phase of Fe3O4 was retained even after coating. Particles of average size 12 nm were obtained as revealed in TEM images. The chitosan functionalized Fe3O4@Silica superparamagnetic nanoparticles show a saturation magnetization as high as 56emu/g and enriched rapidly under external magnetic field. The results point out the prospective of these nanoparticles to be used as adsorbent and desorbent of negatively charged DNA. The nanoparticles were successfully exploited for purification of DNA from Escherichia coli bacterial culture. The A260/A280 value of eluted DNA was close to 1.8, indicating that the isolated DNA is relatively pure and without RNA and protein contamination. The whole process relied on an instrument free “green chemistry” approach and eliminates the need of toxic chemicals.