開發金奈米粒子生物光學感測器進行農藥篩檢之分析研究

Gold nanoparticles-based optical biosensor for rapid screen analysis of pesticides

黃烱坤(Chiung-Kun Huang)

指導教授 ： 孫毓璋

國立清華大學/原子科學院/生醫工程與環境科學系/碩士(2010年)

摘要

自從二次世界大戰以後，農民為了要減少病蟲害及提高產量，即開始大量使用農藥。在種類繁多的農藥中，部分農藥具神經毒性之農藥，如有機磷劑與胺基甲酸鹽劑農藥，由於農藥被廣泛且大量的使用，因此，這些具危害性農藥的殘留問題長期以來也一直都是大眾普遍關心的議題。為滿足一般民眾對快速、簡單且便宜的農產品及飲用水中農殘留篩檢技術的需求，目前已有相當多的文獻針對此一議題出解決各式各樣的分析方法。然而，大部分被提出的篩檢方法往往因為所費昂貴、耗時且操作不易等問題，尚無法滿足現場試驗的需求。因此，研發出一套快速、便宜且操作簡易的現場農產品與飲用水農藥殘留篩檢方法，對分析化學家而言，至今仍是一極為重要的課題。

　　根據文獻報導可知，thiocholine會藉由金硫醇(gold-thio)鍵的形成，而改變金奈米粒子間的靜電作用力，使得金奈米粒子開始聚集，進而造成奈米粒子電漿共振吸收峰發生紅位移的現象；除此之外，thiocholine亦會藉由金-硫醇(gold-thio)鍵的形成，使得原修飾在金奈米粒子上的rhodamine B (RB)脫落，並放射出螢光訊號。根據上述金奈米粒子的特性，本研究中係利用acetylcholinesterase(AChE)水解酶水解acetylthiocholine(AtCH)的反應來產生thiocholine，並藉由thiocholine與單純金奈米粒子或修飾RB金奈米粒子間的作用，再搭配有機磷劑與胺基甲酸鹽劑農藥與AChE間的抑制作用，成功地發展出三套分別利用肉眼，UV/Vis分光光度計及螢光分析儀篩檢有機磷劑與胺基甲酸鹽劑農藥的分析方法。由實驗結果得知，本研究發展的方法確實可用來進行蔬菜及自來水中6種農藥最大容許殘留限制濃度的篩檢。

關鍵字

奈米金粒子 ； 乙醯膽酯酶 ； 有機磷劑農藥 ； 胺基甲酸鹽劑農藥

並列摘要

Since World War II, the use of pesticides has increased to not only reduce the agricultural labor but also increase productivity. However, the residual neurotoxic pesticides, such as organophosphorous or carbamate pesticides, in foods has become a major public health issue with a high degree of attention. Accordingly, the development and validation of a rapid, simple, and inexpensive method for screening analysis of the residual pesticides in foods has attracted wide attention. However, most of the currently reported screening methods are costly, time consuming, and inconvenient, especially for the in-situ test. Therefore, a rapid, in situ, inexpensive and simple method for screening the residual pesticides in foods and drinking water is still highly demanded.

Because the presence of thiocholine can cause the aggregation of gold nanoparticles (AuNPs) due to the electrostatic and gold-thiol interaction, which can result in a red-shift of the plasmon absorption. In addition to the aggregation of AuNPs, thiocholine can also cause the release of rhodamine B (RB) from the surface of AuNPs. To establish a series of AuNPs-based optical screening analytical methods, an enzymatic inhibition reaction coupling to the gold nanoparticles-based colorimetric and fluorometric detections were developed to determine several neurotoxic organophosphorous (OPPs) and carbamate pesticides.

To induce the aggregation of AuNPs and the release of RB from RB-AuNPs, in this study, thiocholine was formed based on the hydrolysis reaction of acetylthiocholine (AtCH) catalyzed by the enzyme, acetylcholinesterase (AChE). Meanwhile, because both OPPs and carbamate can inhibit the activity of AChE, the existence of pesticide residues described above was found can slow down and even prevent the aggregation of AuNPs. On the basis of this reaction mechanism, various analytical schemes were designed to detect OPPs and carbamate pesticides by the color change with naked eye (visual inspection), UV/Vis spectrophotometric measurement, or by the change in fluorescence intensity with fluorometric measurement. Based on the experimental results, our developed screening methods were found applicable to detect the maximum residual concentrations of six pesticides in tap water and vegetables.

並列關鍵字

Gold nanoparticles ； Acetylcholinesterase ； organophosphorous pesticides ； carbamate pesticides

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