銅為基底之奈米粒子性質及於光熱治療之應用

Characterization of Copper-Based Nanoparticles and the Application to Photothermal Therapy

戴淯瑋(Yu-Wei Tai)

指導教授 ： 游佳欣

共同指導教授 ： 黃志嘉(Chih-Chia Huang)

國立臺灣大學/工學院/化學工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701346

摘要

光熱治療是在癌症治療中一種結合奈米科技以及生醫工程的新技術。銅奈米粒子與其他金屬奈米粒子相同具有獨特的光學性質，在其吸收光譜中可以觀察到一個吸收峰值，顯示了其局部表面電漿共振(LSPR)的作用，代表了波長590奈米的光子能量可以轉移至奈米粒子上的自由電子，造成電場的震盪，而共振的能量隨後轉換成熱能，造成溫度的上升。此一現象可以透過標靶以及光激發的局部加熱效應用於殺死癌細胞。然而，由於銅奈米粒子的不穩定性，其並沒有作為光熱治療藥劑而廣泛使用，因為其會誘使的活性氧物質(ROS)會造成細胞毒性。若要將銅奈米粒子作為生醫方面的應用，此一缺陷是必須要被控制的。
在此一研究中，我們透過一步驟的水熱反應製造包有高分子殼層的銅奈米粒子(Cu@polymer NPs)，而此奈米粒子的構成對反應中所存在的鹵素離子敏感。接著，我們發展出一個溫和的銅離子氧化程序，用以生成一個具有高分子表面包覆，具有金屬銅中心及氧化亞銅外殼的奈米複合物(Cu@Cu2O@polymer NPs)。透過紫外光─可見光光譜可以確定所製成的Cu@Cu2O@polymer NPs具有從紅光到近紅外光波長的吸收帶，表示其在具有較高組織穿透性、較適合於光誘導治療的近紅外光的激發下可以產生LSPR作用，而此奈米粒子在水溶液環境中展現了光學及物理的穩定性。此外，當細胞在有Cu@Cu2O@polymer NPs的環境中培養時，其促使的ROS生成及細胞毒性情況與Cu@polymer NPs相比較為減少，而此一因奈米粒子與細胞的相互作用導致的細胞死亡路徑也有在此實驗中研究。
最後，透過光的激發我們測試了奈米粒子的光熱效應，在紅光的照射下，我們可以由20至50 ppm的Cu@Cu2O@polymer NPs 及300至650 mW/cm2的雷射功率得到顯著的光子─熱量轉換，相較之下，純Cu@polymer NPs在紅光照射下得到較不顯著的光熱效應。在體外光熱治療實驗也顯示了與Cu@Cu2O@polymer NPs共同培養的細胞在經過紅光照射後活性顯著地降低，此一結果顯示了Cu@Cu2O@polymer NPs較Cu@polymer NPs.更為適合應用在光熱治療上。

關鍵字

銅奈米粒子 ； 核─殼層結構 ； 活性氧物質 ； 近紅外光 ； 光熱治療

並列摘要

Photothermal therapy (PTT) is a new technique combining nanotechnology and biomedical engineering for cancer treatment. As other metallic nanoparticles (NPs), copper nanoparticles (CuNPs) have unique optical characteristics. An adsorption peak of CuNPs was observed in adsorption spectra, indicating that CuNPs will exhibit localized surface plasmon resonance (LSPR) effect, which means energy of photon at a wavelength of 590 nm can be transferred to the free electron on NPs, leading the oscillation of electronic field. The energy of the resonance subsequently transfer to heat and cause a temperature elevation. This phenomenon can be used as a way to kill cancer cells by targeting and partial heating in tumor tissue with light stimulation. However, due to the instability, CuNPs were not widely used as a PTT agent because they may induce reactive oxygen species (ROS) generation and cause cytotoxicity. This drawback is needed to be controlled if we want to introduce CuNPs.to biomedical application.
In the work, we synthesized CuNPs with polymer shell via one-step hydrothermal reduction reaction. The formation of Cu@polymer NPs is sensitive to the presence of halide ions in the reaction. Next, we developed a smooth oxidation process of Cu@polymer NPs to fabricate polymer surface coating-Cu2O shell-Cu core nanocomposite. UV-visible spectra determined the as-prepared Cu@Cu2O@polymer NPs with absorption band covered from red to near infrared (NIR) wavelengths. It indicates that the LSPR effect of Cu@Cu2O@polymer NPs can be stimulated by NIR light, which has higher penetration to tissue and is more appropriate for light-induced therapy. Also, these nanoparticles exhibited optical and physical stability in the aqueous solution. Moreover, compared with Cu@polymer NPs, less ROS generation and cytotoxicity were induced while cells were incubated with Cu@Cu2O@polymer NPs. The cell death pathway attributed to NP-cell interaction was also studied.
Finally, the photothermal effect was examined by light stimulation. As exposure to red light, an obvious photon-to-thermal conversion was obtained for 20-50 ppm of Cu@Cu2O@polymer NPs and 300-650 mW/cm2 of laser power. In contrast, pure Cu@polymer NPs plus red light received less significant PTT effect. In vitro PTT studies also showed that viability of cells incubated with Cu@Cu2O@polymer NPs was significantly decreased after light exposure. The results indicated that Cu@Cu2O@polymer NPs are more appropriate to be applied in PTT therapy than Cu@polymer NPs.

並列關鍵字

copper-based nanoparticles ； core-shell structure ； reactive oxygen species ； near infrared ； photothermal therapy

參考文獻

1. Liu, X., et al., Enhanced retention and cellular uptake of nanoparticles in tumors by controlling their aggregation behavior. ACS Nano, 2013. 7(7): p. 6244-57.

2. Duan, X. and Y. Li, Physicochemical characteristics of nanoparticles affect circulation, biodistribution, cellular internalization, and trafficking. Small, 2013. 9(9-10): p. 1521-32.

3. Albanese, A., P.S. Tang, and W.C. Chan, The effect of nanoparticle size, shape, and surface chemistry on biological systems. Annu Rev Biomed Eng, 2012. 14: p. 1-16.

4. Dinarvand, R., et al., Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents. Int J Nanomedicine, 2011. 6: p. 877-95.

5. Zhang, S., et al., Size-dependent endocytosis of nanoparticles. Adv Mater, 2009. 21: p. 419-424.