The efficiency enhancement of magnetically heating and controlling drug release using orthogonally synchronous bi-directional AC magnetic field
| Autor: | Shih-Wei Chen, 陳世偉 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 The self-heating property of magnetic nanoparticles (MNPs) under single magnetic field has been a promising candidate for tumor therapy due to its non-invasive and targetable property. Recent studies showed that the heating ability of MNPs under single field was significantly influenced by particle size, size distribution and magnetic anisotropy. MNPs were prepared under these optimal parameters to maximize heating ability. However, the present challenge lies in the fact that the heating ability of MNPs was inevitably attenuated by the immobilization and aggregation of MNPs in tumor cells. To improve the problem, we proposed a new orthogonally synchronous bi-directional AC magnetic field (OSB field). The concept of the system was derived from the application of MNPs to the high density storage device. The numerical and experimental investigations showed that the poor heating ability of aggregated MNPs with superparamagnetic property under single field was significantly enhanced by applying OSB field. The large MNPs in size used could generate strong heating ability and reduce the influence of biocompatible surfactant under OSB field. We found that the enhanced effect on the heating ability of ferromagnetic MNPs was not limited even though applying lower strength than the coercivity. Moreover, applying OSB field could significantly weaken the influence of size distribution to only 1/10 of that under single field. We also proved that poor heating ability of CoFe2O4 MNPs under single field were not suitable as thermal seeds due to its high magnetic anisotropy. However, such the magnetic material could generate heat 11 times more than that under single field. Finally, we firstly used OSB field to magnetically control the phenolic acid release from Fe3O4@chitosan nano-carriers. The results showed that applying OSB field promoted the release of model drug from nano-carriers and the rate of drug release was about 3 times quicker than that under single field without increasing field strength. In addition to Fe3O4, CoFe2O4 MNPs were also suitable as nano-carriers for drug-release. This major was attributed to the outstanding heating abilities of both MNPs under the OSB field. From the results, the advantage of applying OSB field lies in the fact that a variety of MNPs can be served as strong thermal seeds even though these nanoparticles are prepared by simple and low-cost procedures and present a broad size distribution and magnetic anisotropy. Therefore, we expect that OSB field is a promising tool for tumor therapy. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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