Magnetic hydrogels derived from polysaccharides with improved specific power absorption: potential devices for remotely triggered drug delivery

We report on novel ferrogels derived from polysaccharides (sodium alginate and chitosan) with embedded iron oxide nanoparticles synthesized in situ and their combination with thermally responsive poly (N-isopropylacrylamide) for externally-driven drug release using AC magnetic fields. Samples were characterized by Raman spectroscopy, transmission electron microscopy (TEM) and magnetic measurements. The obtained nanoparticles were found to be of ca. 10 nm average size, showing magnetic properties very close to those of the bulk material. The thermal response was measured by power absorption experiments, finding specific power absorption (SPA) values between 100-300 W/g, which was enough for attaining the lower critical solution temperature (LCST) of the polymeric matrix within few minutes. This fast response makes these materials good candidates for externally controlled drug release.