用於提升光熱治療效果之奈米金液滴與相關技術

Enhanced Photothermal Therapy Using Gold Nanodroplets

劉恕維(Shu-Wei Liu)

指導教授 ： 李百祺

國立臺灣大學/電機資訊學院/生醫電子與資訊學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.00759

摘要

光熱治療是一種將電磁波轉換成熱能的癌症治療方式，研究人員以帶有腫瘤標靶的奈米金粒子當作媒介，待奈米金粒子結合到腫瘤組織後，再利用近紅外光照射使組織溫度上升，進一步造成腫瘤細胞壞死。與其他治療方式相比，光熱治療有高效率及低副作用的特性，然而奈米金粒子在腫瘤組織的濃度會嚴重影響治療效率，因此如何增加奈米金粒子的釋放效率是重要的研究課題。過去有人利用微氣泡當作載體進行運輸，然而微氣泡的穩定性不足，因此本研究以液滴取代氣泡，我們假設若能增強載體的穩定度，就有機會提升釋放效率。除此之外，本研究也利用雷射與超音波共同作用載體，希望藉著此方式增強穴蝕效應強度，並提升釋放效率。本研究利用實驗室自製的載體進行實驗，首先進行奈米金液滴的性質評估，了解其在超音波、雷射及雷射輔助超音波下的特性；接著，利用穴蝕效應劑量評估不同狀況下，奈米金液滴的穴蝕效應強度差異；接續是比較奈米金氣泡與奈米金液滴，在雷射輔助超音波作用下奈米金粒子的釋放效率差異；最後進行細胞及小動物實驗，藉由體外及體內實驗評估此方法在光熱治療上的效果。結果顯示雷射輔助超音波技術可以產生更強的穴蝕效應並有相輔相成的現象，奈米金液滴在雷射輔助超音波下破裂比例約45%、吸光值約0.027均高於奈米金氣泡的結果。除此之外，細胞在雷射輔助超音波作用奈米金液滴下的存活率剩下42%，也是全部實驗條件中最低的結果。總而言之，用雷射及超音波同時作用奈米金液滴的確有增強光熱治療的潛力。

關鍵字

光熱治療 ； 奈米金液滴 ； 雷射輔助超音波

並列摘要

Photothermal therapy refers to the use of heating from electromagnetic radiation to treat various medical conditions, including cancer. For example, researchers have been using targeting gold nanoparticles to specific tumor sites as a therapeutic agent with the application of near infrared laser irradiation to induce heating and concomitant tumor cell necrosis. Comparing to other technologies, photothermal therapy can be highly effective with low side effects. It becomes clear that the quantity of gold nanoparticles that can be delivered and accumulated in the tumor is a key factor determining the therapeutic efficacy as well as an important research subject. One of the common approaches to enhancing delivery of the therapeutic agent is to employ micro bubbles as a carrier. Nonetheless, these microbubbles are generally not stable. Therefore, the hypothesis of this study is that by using nanodroplets as the carrier, the stability can be improved and thus the delivery can be enhanced. Moreover, we further hypothesize that by combining laser and ultrasound, liquid-to-gas phase change can be effectively induced and the subsequent bubble destruction can improve the cavitational effects and thus the delivery of therapeutic agent. To test these hypotheses, in vitro and in vivo experiments were conducted in this study. First, the in house therapeutic agents were characterized. Second, the inertial cavitation does was measured under various conditions to quantitatively represent the amount of the cavitational effects. Third, the delivery efficiency of gold nanoparticles between microbubbles and nanodroplets was compared. Finally, cell toxicity tests and animal experiments were conducted to evaluate photothermal therapeutic effects. Results show that the combination of laser with ultrasound provides stronger cavitational effects and synergistic treatment efficacy. Specifically, the destruction ratio of gold nanodroplets using both laser and ultrasound is approximately 45% and the optical density value representing the amount of gold delivered into the cells is 0.027, both are higher than those from gold microbubbles. Furthermore, the cell viability under both laser and ultrasound is 42%, which is also the lowest among all the treatment strategies that were included in this study. It is concluded that the use of gold nanodroplets and the combination of laser and ultrasound does have the potential to be an effective technology for plasmonic phothermal therapy.

並列關鍵字

photothermal therapy ； gold nanodroplet ； laser and ultrasound

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