title: Study on controlled drug permeation of magnetic-sensitive ferrogels: effect of Fe3O4 and PVA.
abstract: A PVA-based magnetic-sensitive hydrogel (ferrogel) was fabricated by physical cross-linking through a freezing-thawing method. The influence of the constituting components, i.e., Fe3O4 and PVA, on the magnetic-sensitive behavior of the ferrogels was systematically investigated in terms of permeability coefficient (P), partition coefficient (H), space restriction and magnetization. The results show that, the P value in these ferrogels decreases and displays a magnetic sensitivity when it is subjected to magnetic field (MF), which is correlated with the change of H value. In addition, it was found that although the factor of space restriction or magnetization exerts opposite effect on resulting magnetic-sensitive behavior, the superior magnetic-sensitive behavior was observed for the ferrogels with an optimal composition of 17-34% Fe3O4 and 10-12.5% PVA, and can be well correlated with theoretical calculation from the critical parameters of available free volume per nanoparticle (V(free)) and magnetization. A map of magnetic-sensitive behavior was constructed, where a region with relatively stable and highly stimuli-responsive behavior in terms of the concentration of Fe3O4 was observed, however, below or above the "saturation" region (17-34% Fe3O4), a reduction in the magnetic-sensitive behavior was detected. The resulting ferrogels can be engineered with a precise control of the opening and closure of pore configuration, which allows a burst release or no-release action of therapeutically active agent to be controlled externally and magnetically. This suggests that this type of ferrogel can be considered as a class of novel magnetically-tunable drug delivery system.
authors.affiliation: Department of Materials Sciences and Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC.
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Liu
authors.forename: Shang-Hsiu
authors.initials: SH
authors.lastname: Hu
authors.forename: Kun-Ho
authors.initials: KH
authors.lastname: Liu
authors.forename: Dean-Mo
authors.initials: DM
authors.lastname: Liu
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Chen
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D008280:Magnetics; D008954:Models, Biological; D053758:Nanoparticles; D010316:Particle Size; D010539:Permeability; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D016062:Porosity
chemical_list: D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D020100:Hydrogels; D011142:Polyvinyl Alcohol; D052203:Ferrosoferric Oxide