Chitosan-coated magnetic nanoparticles; exploring their potentialities for DNA and Cu(II) recovery

Chitosan-coated magnetic nanoparticles were prepared using four different methodologies and their potentialities for DNA and Cu(II) recovery were studied. The first synthesis was done using a one-step approach, while the second one was a one-step method with pH compensation. The third methodology was done by coating the previously obtained uncoated magnetic nanoparticles and the last one was performed using glutaraldehyde as crosslinker agent after a one-step synthesis. X-Ray diffraction analysis demonstrated the crystallinity of the nanoparticles and a crystallite size between 14 and 16 nm was determined. Particle sizes between 13 and 16 nm were measured using scanning electron microscopy. The vibrational bands observed in the infrared spectrum confirmed the formation of a chitosan layer on the magnetic nanoparticles surface.The thermograms proved that the nanoparticles obtained with the first and the third methodologies resulted in particles with greater chitosan content. The highest copper adsorption capacity (22 mg/g) was obtained with the nanoparticles produced using glutaraldehyde as a crosslinker agent. The chitosan-coated nanoparticles present higher DNA adsorption capacity than the uncoated nanoparticles and the third methodology adsorbed the highest amount of DNA (27 μg).