| Summary: | 碩士 === 國立臺灣大學 === 醫學工程學研究所 === 105 === Sonodynamic therapy is a potential modality for the cancer treatments, which uses ultrasound to excite the sonosensitizers to kill the cancer cells. The treated sonosensitizers will have ultrasound cavitation effects and cause to an amount of energy which will lead to the generation of light, and this emission is termed as sonoluminescence. It further induce free radicals and reactive oxygen species to kill the cancer cells. Comparing with the other treatments, SDT is less invasive, its apparatus is so simple that having less cost and it also lowers the side effects, moreover, it has better ability of penetration in our body than light as a result of being able to treat deeply located cancers. As for the used ultrasound, instead of the utilization of the continuous sine wave that are common in sonodynamic therapy, the square wave having pulsed property will be chosen in this research due to the better cavitation ability in pulsed ultrasound. About the sonosensitizers used in this research, we used calcium carbonate that has good biocompatibility and no bio-cytotoxicity as the host material, and doped with the rare-earth elements: cerium or europium which has remarkable luminescent properties. We hope that the prepared sonosensitizers will be successfully induced ROS and free radicals by ultrasound to kill the cancer cell as the excellent and developed alternative treatment of cancer.
Spherical porous cerium-doped or europium-doped calcium carbonate have been successfully synthesized by adding calcium nitrate including cerium nitrate or europium nitrate into sodium carbonate with PVA and Tween 80. The existence of PVA and Tween 80 will help materials be porous phase to enhance the rate of reaction. As for the analysis of materials, we used XRD to confirm the synthesized materials is mainly composed of the vaterite which is one of the phase of calcium carbonate. Under the SEM, the particle size of cerium-doped calcium carbonate is about 2-4 μm, and the size of the holes is about 0.5-1 μm; while the particle size of the europium-doped calcium carbonate is about 3-5 μm, and the size of hole is about 1 μm. After that, using the EDX to confirm that the materials are prospectively doped with cerium or europium. Finally, the generation of the free radicals was detected through the methylene blue test.
Through ISO10993 WST-1 and LDH test, both of materials are shown to be biocompatible. And the cancer cells killing in sonodynamic therapy group is significantly effective from the view of the result in in-vitro test. We also get the similar result in the in-vivo study, the tumor size in each group all enlarge in the end of the experiment, however, that of the sonodynamic therapy group get increasing slightly.
|
|---|
