Fabrication of ferrogels using different magnetic nanoparticles and their performance on protein adsorption

Magnetic biomaterials were prepared using magnetite and chitosan-coated magnetite nanoparticles (CSNPs) dispersed in poly(vinyl alcohol) gels. Two different methods were developed to obtain ferrogels: in situ co-precipitation of magnetite (Ferro-IS) and by adding previously synthesized CSNPs to the neat matrix (Ferro-CSNPs). In both cases, the crosslinking was carried out by freezing-thawing (F-T). The as-prepared materials as well as precursor CSNPs were characterized by Fourier transform infrared spectroscopy, electronic microscopy (scanning and transmission), X-ray diffraction, potential, dynamic light scattering, thermogravimetric analysis, differential scanning calorimetry and magnetic properties. The performance of these gels as protein adsorbents was evaluated. Batch adsorption experiments were carried out using bovine serum albumin (BSA) as a model. Substantially different adsorption behaviour was found using Ferro-IS and Ferro-CSNPs. This was assigned to dissimilar bonding mechanisms of BSA to the ferrogel matrix. Hence, biomaterials potentially useful in drug delivery as well as in protein purification fields may be prepared by a relatively simple, non-toxic and low cost method. (c) 2013 Society of Chemical Industry