Browsing by Author "Tsai, Chia-Hui"

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Controlled Rupture of Magnetic Polyelectrolyte Microcapsules for Drug Delivery
(2008-10-21)
Hu, Shang-Hsiu
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Tsai, Chia-Hui
;
Liao, Chen-Fu
;
Liu, Dean-Mo
;
Chen, San-Yuan
In this study, a magnetic-sensitive microcapsule was prepared using Fe3O4/poly(allylamine) (Fe3O4/PAH) polyelectrolyte to construct the shell. Structural integrity, microstructural evolution, and corresponding release behaviors of fluorescence dyes and doxorubicin were systematically investigated. Experimental observations showed that the presence of the magnetic nanoparticles in the shell structure allowed the shell structure to evolve from nanocavity development to final rupture of the shell under a given magnetic stimulus of different time durations. Such a microstructural evolution of the magnetic sensitive shell structure explained a corresponding variation of the drug release profile, from relatively slow release to burst-like behavior at different stages of stimulus. It has proposed that the presence of magnetic nanoparticles produced heat, due to magnetic energy dissipation (as Brown and Neel relaxations), and mechanical vibration and motion that induced stress development in the thin shell. Both mechanisms significantly accelerated the relaxation of the shell structure, causing such a microstructural evolution. With such a controllable microstructural evolution of the magnetic-sensitive shell structure, active substances can be well-regulated in a manageable manner with a designable profile according to the time duration under magnetic field. A cell culture study also indicated that the magnetic-sensitive microcapsules allowed a rapid uptake by the A549 cell line, a cancerous cell line, suggesting that the magnetic-sensitive microcapsule with controllable rupturing behavior of the shell offers a potential and effective drug carrier for anticancer applications.
Preparation and characterization of magnetic ferroscaffolds for tissue engineering
(2007-03-01)
Hu, Shang-Hsiu
;
Liu, Ting-Yu
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Tsai, Chia-Hui
;
Chen, San-Yuan
;
材料科學與工程學系
Magnetic-based scaffolds (ferroscaffolds) were fabricated using an in-situ synthesis of iron oxide nanoparticles in the presence of various concentration of biodegradable gelatin. The resulting ferroscaffolds show an interconnected pore structure with pore sizes ranging from 50 to 200 mm depending on gelatin concentrations. However, the yield of the iron oxide nanoparticles decreases with the increase of gelatin contents, which is due to the presence of polymeric chains that hindered the growth of iron oxide upon coprecipitation. The content of deposited magnetic nanoparticles could reach up to 9.41% and its saturation magnetization (Ms) was 23.5 emu/g. In addition, while applying a magnetic field (MF), the magnetic interparticles forces immediately formed to reduce the drug release rates in the ferroscaffolds. The ferroscaffolds which possess an excellently magnetic-sensitive behaviors can be potentially used as stimuli-responsive drug carriers and scaffolding materials for tissue engineering. (C) 2006 Elsevier B.V. All rights reserved.