Abstract:Novel hybrid magnetic hydrogels have demonstrated their influence in several areas, particularly in biomedical science where these innovative materials are showing interesting applications for controlled drug delivery. A hybrid hydrogel with CoFe 2 O 4 nanoparticles (NPs) as cross-linker agents of carboxymethylcellulose (CMC) polymer was obtained with the aim of testing it as a system for controlled drug release. The NPs were functionalized with (3-aminopropyl)-trimethoxysilane (APTMS) in order to introduce-NH 2 groups on the surface. Infrared spectroscopy, XPS and electrochemical analysis were performed to quantify the amino coating. The presence of magnetic nanoparticles makes the system suitable for an application with magnetic stimulus. Preliminary studies performed with alternating magnetic fields indicate a release of the drug-like molecules previously loaded in the matrix.

No abstract

Hybrid hydrogels of carboxymethylcellulose (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 and morphologically characterized and their viscoelastic properties and swelling degrees were analyzed. The hydrogels were tested as controlled drug delivery systems by applying one static and two different alternating magnetic fields. The application of the two alternating magnetic fields (AMF) to the hybrid hydrogels induced a higher release of methylene blue (MB), used as a model drug, than without the application of any magnetic field, especially at low frequency (4 Hz) and high magnetic intensity (0.5 T). In contrast, when the hybrid hydrogels were exposed to a static magnetic field (SMF) the release of MB was slowed down. Furthermore the two different amounts of magnetic nanoparticles induce different responses to the magnetic field. The greater number of nanoparticles in the CMC-NP-70 hydrogel leads to the formation of some NPs clusters limiting the drug release; conversely, the CMC-NP-50 hydrogel, containing a lower amount of nanoparticles, shows a higher release of MB vs. time. In conclusion, we were able to get a potential system for modulation of the drug delivery: the release behaviour of hybrid hydrogels can be modulated by applying alternating and static magnetic fields cyclically. A possible explanation for the release mechanism is about the structural modification of the polymeric chains that occurs when the hybrid hydrogels are exposed to the magnetic fields.* Corresponding author. M. Uva et al.117

No abstract