類澱粉纖維複合材料之應用:製備具有催化活性之以金奈米粒子修飾的類澱粉纖維材料

Applications of Amyloid Fibril-Based Composite Materials: Preparation of Gold Nanoparticle-Decorated Amyloid Fibrils with Catalytic Activity

蕭翔銘(Hsiang-Ming Hsiao)

指導教授 ： 王勝仕

國立臺灣大學/工學院/化學工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201900857

摘要

奈米金小尺寸、具有高表面能的特性使其常被作為一氧化碳過濾、工業廢水中對硝基苯酚（4-nitrophenol）過濾等生活中重要的觸媒，然而奈米金的高表面能也為其帶來容易聚集的現象，造成比表面積高的優勢降低，進而劣化催化效能，因此，藉由將奈米金接載在穩定的支撐性基材上，可使奈米金粒子較均勻的分佈而減少聚集現象，進而增加可用比表面積進而提高催化效能，亦可利用基材的特性使用不同方法將觸媒回收再利用。類澱粉纖維（amyloid fibril）在研究上雖被認為是導致阿茲海默病（Alzheimer’s disease）、帕金森氏症（Parkinson's disease）疾病的原因，然而類澱粉纖維高機械強度、穩定性的結構與高生物相容性使其成為在組織工程、藥物輸送、生物感測器方面混合材料良好的選擇。本研究以母雞蛋白溶菌酶（hen egg white lysozyme）培養的類澱粉纖維作為生物基材，使四氯酸金與類澱粉纖維因靜電作用力結合，並以氧化還原法將類澱粉纖維上的四氯金酸還原成奈米金，透過穿透式電子顯微鏡（Transmission electron microscope）瞭解類澱粉纖維上奈米金粒子分布的形態、利用能量色散X射線光譜儀(Energy Dispersive X-ray Spectrometer, EDX)確定混合材料中含有金元素，最後使用可見光/紫外光光譜儀(UV/VIS Spectophotometer)由對硝基苯酚還原成4-氨基苯酚（4-aminophenol）的實驗評估不同條件奈米金/類澱粉纖維混合材料催化效能。
研究結果顯示，類澱粉纖維可使奈米金更均勻的分布以減少奈米金的聚集，且含有類澱粉纖維作為基材的奈米金在將對硝基苯酚還原所需的時間較僅含有奈米金的溶液所需時間要少，此外，隨著奈米金與類澱粉纖維復合溶液中奈米金濃度的增加，還原對硝基苯酚的時間也隨之減少，利用一級反應數據擬合所得的反應速率常數也隨之增加，故母雞蛋白溶菌酶的加入可使奈米金相較於原本有更好的催化效能。

關鍵字

母雞蛋白溶菌? ； 類澱粉纖維 ； 奈米金 ； 對硝基苯酚 ； 生物分子材料

並列摘要

Gold nanoparticles have been widely used as the catalysts in industry as a result of their high surface energy and nice catalytic efficiency. Gold nanoparticle can act as important catalysts for the filtration of p-nitrophenol (4-nitrophenol) in industrial wastewater and have been used as carbon monoxide filters. However, the high surface energy of gold nanoparticles also leads to aggregation, resulting in a decrease in catalytic activity. Hence, by immobilizing gold nanoparticles on to a supporting carrier, they can uniformly be arranged. Moreover, these catalysts could also be reused through different recycled methods.
Amyloid fibrils are widely known to be the major cause for a range of degenerative diseases including Alzheimer's disease and Parkinson's disease. Yet, the stable structure of amyloid fibrils and their high biocompatibility make them good choices to serve as templates in the fields of tissue engineering, drug delivery, and biosensors. Therefore, using hen lysozyme as a model protein, this study was aimed at synthesizing amyloid-like fibrils decorated with gold nanoparticles through the redox reaction from chloroauric acid. Transmission electron microscopic analysis has been performed to understand the morphology of gold nanoparticle-decorated amyloid fibrils and energy dispersive X-ray analysis has been conducted to confirm the gold content in the said composite materials. In addition, UV/Vis spectrophotometer has been used to investigate the catalytic efficiency of the synthesized gold nanoparticle-decorated amyloid fibrils via the reduction of p-nitrophenol.
Our results showed that the aggregation propensity of gold nanoparticles was reduced upon incorporation of amyloid fibrils as the supporting matrix due to the dispersion of gold nanoparticles. In addition, the reduction of p-nitrophenol under the conditions examined was determined to follow the pseudo-first order kinetics. Moreover, we found that a rise in the concentration of gold nanoparticles present in the solution containing amyloid fibrils was found to bring about a decrease in the time needed for 4-nitrophenol reduction, thereby an increase in the rate constant of the associated pseudo-first order reaction. Our study presents a nice example of implementing amyloid fibrils in the material-based applications.

並列關鍵字

hen egg white lysozyme ； amyloid fibrils ； gold nanoparticles ； 4-nitrophenol ； biomaterials

參考文獻

[1] Lewandowski, J. R., van der Wel, P. C. A., Rigney, M., Grigorieff, N., and Griffin, R. G. (2011) Structural Complexity of a Composite Amyloid Fibril, Journal of the American Chemical Society 133, 14686-14698.

[2] Shi, W., and Chance, M. R. (2007) 3.25 - Structural Genomics, In Comprehensive Medicinal Chemistry II (Taylor, J. B., and Triggle, D. J., Eds.), pp 551-560, Elsevier, Oxford.

[3] Gurry, T., and Stultz, C. M. (2014) Mechanism of Amyloid-β Fibril Elongation, Biochemistry 53, 6981-6991.

[4] Zhang, S., Iwata, K., Lachenmann, M. J., Peng, J. W., Li, S., Stimson, E. R., Lu, Y. a., Felix, A. M., Maggio, J. E., and Lee, J. P. (2000) The Alzheimer's Peptide Aβ Adopts a Collapsed Coil Structure in Water, Journal of Structural Biology 130, 130-141.

[5] Bhasikuttan, A. C., and Mohanty, J. (2017) Detection, inhibition and disintegration of amyloid fibrils: the role of optical probes and macrocyclic receptors, Chemical Communications 53, 2789-2809.