探討參雜鈰或銪的碳酸鈣於聲動力療法上對於癌症治療之效果

Abstract

聲動力療法是以超音波為激發源來激發聲敏感藥物從而達到治療癌症的目的。當聲敏 感藥物於超音波作用之下，隨著聲波的震盪會發生超音波空化效應，於此同時往往伴隨著大 量的能量並以光的形式釋放，此放射現象稱為聲致發光(Sonoluminescence)，進而激發藥物 並產生自由基與活性氧族來毒殺癌細胞。相較於其他癌症治療方法，聲動力療法的副作用較 低、過程較不具侵入性且超音波的裝置簡單成本較低，除此之外，其也克服了光動力療法在 穿透深度上的限制。本研究將會使用具有脈衝性質的方波來激發材料。在材料方面，是以具 有好的生物相容性與低生物毒性之碳酸鈣為主體材料，並參雜具發光性質之稀土族元素:鈰 或銪，作為本研究欲激發的聲敏感藥物。期望此材料經超音波激發後得以產生自由基與活性 氧族來毒殺癌細胞達到治療癌症的效果。 利用含有硝酸鈰或硝酸銪的硝酸鈣溶液與含有 PVA 與 Tween 80 之碳酸鈉溶液合成製備 參雜鈰或銪碳酸鈣，PVA 與 Tween 80 的添加可使材料形成多孔狀來增加表面積並加快反應 速率。材料分析方面，利用 XRD 確認材料主要為碳酸鈣的球霰石相(Vaterite)，於 SEM 下 來看，參雜鈰的碳酸鈣顆粒大小約 2-4 μm，孔洞大小約 0.5-1 μm 左右;而參雜銪的碳酸鈣顆 粒大小約 3-5 μm，孔洞大小約 1 μm 左右。並以 EDX 確認材料參有鈰與銪，接著利用亞甲基 藍可降解的反應確認自由基的產生。 經 WST-1 及 LHD 測試，其結果符合 ISO10993 之規範，證明兩種材料皆具好的生物相容 性。在體外試驗結果中，兩種材料的聲動力療法組別相較於單照射超音波組別或純材料組別， 對癌細胞都有明顯的毒殺效果。在動物實驗方面，小鼠在實驗過程中皆具正常之動物行為， 從結果來看，每個組別的小鼠腫瘤皆呈現增大的趨勢，而兩種材料的聲動力療法組別增大的 趨勢較為緩慢，說明其具有抑制腫瘤增大的效果。

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.