本實驗開發一種新穎的電化學生物感測元件，用於檢測有機磷農藥甲基巴拉松(methyl parathion)以及馬拉松(malathion) ，其所製備的感測元件以生物酶乙醯膽鹼酯酶(AChE)的生化感測器為主軸，並且利用PAMAM可以被質子化的特性，將PAMAM當作反應產物CH3COOH的接收器，利用其接收H+離子產生的電流進行檢測。而在穩定度方面，則以AChE 、胺化樹枝狀聚合物(PAMAM)和3-巰基丙酸(MPA)與醯胺偶合試劑(EDC/NHS)反應而產生層接式共價性醯胺鍵結，使AChE能牢固共價於金電極上，大幅度增強了感測器的穩定性。本實驗結合AChE與PAMAM的特質，並搭配層接式胜肽共價鍵結，研發檢測有機磷農藥之新型電流式生化感測元件。且利用SEM以及EIS探討AChE/G5-NH2/MPA/Au感測薄膜的結構與特性。對於檢測甲基巴拉松與馬拉松而言，AChE/G5/MPA/Au 生物感測元件擁有極佳的靈敏度以及極低的偵測極限(~10-14M)，除此之外，其感測元件也同時具有線性範圍廣泛以及穩定性良好的感測特性。
A novel electrochemical biosensor for detecting methyl parathion and malathion was fabricated by covalently binding acetylcholinesterase (AChE), generation 5 amine-terminated PAMAM dendrimer (G5-NH2) and 3-mercaptopropionic acid (MPA) layer-by-layer on a gold electrode using N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) (EDC/NHS) as the peptide coupling reagent. The key step in the operation of this biosensor was the AChE-acetylcholine enzymatic reaction, which changes the local pH in the vicinity of the surface of an electrode. The modification of the gold electrode with PAMAM improved both the analytical and operational characteristics of cholinesterase sensors. The AChE-G5-NH2-MPA/Au electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Factors that influenced the detection processes were optimized. The electrochemical biosensor that was based on the AChE-G5-NH2-MPA/Au electrode for the determination of methyl parathion and malathion exhibited a strong response, satisfactory linearity, a low detection limit and favorable long-term stability.
