Influence of Alternating and Static Magnetic Fields on Drug Release from Hybrid Hydrogels Containing Magnetic Nanoparticles

Abstract

Hybrid hydrogels of\rcarboxymethylcellulose (CMC), containing two different amounts of CoFe2O4 magnetic nanoparticles (50% and 70% in relation to the quantity of the polymer) as crosslinkers, were prepared. The hybrid hydrogels were chemically\rand morphologically characterized and their viscoelastic properties and swelling\rdegrees were analyzed. The hydrogels were tested as controlled drug delivery\rsystems by applying one static and two different alternating magnetic fields.\rThe application of the two alternating magnetic fields (AMF) to the hybrid\rhydrogels induced a higher release of methylene blue (MB), used as a model\rdrug, than without the application of any magnetic field, especially at low frequency (4 Hz) and high magnetic intensity (0.5\rT). In contrast, when the hybrid hydrogels were exposed to a static magnetic field\r(SMF) the release of MB was slowed down. Furthermore the two different amounts of magnetic nanoparticles\rinduce different responses to the magnetic field. The greater number of\rnanoparticles in the CMC-NP-70 hydrogel leads to the formation of some NPs\rclusters limiting the drug release; conversely, the CMC-NP-50 hydrogel,\rcontaining a lower amount of nanoparticles, shows a higher release of MB vs.\rtime. In conclusion, we were\rable to get a potential system for modulation of the drug delivery: the release\rbehaviour of hybrid hydrogels can be modulated by applying alternating and\rstatic magnetic fields cyclically. A possible explanation for the release\rmechanism is about the structural\rmodification of the polymeric chains that occurs when the hybrid hydrogels are\rexposed to the magnetic fields.