官能化3, 4-乙烯二氧基噻吩聚合物塗層與快速掃描循環伏安法在多巴胺偵測之應用

Abstract

神經科學家會使用微電極植入動物的大腦來記錄不同活動下所產生的電訊號，然而，我們希望能同時去捕捉一些重要神經傳導物質的訊號。我們選擇的是多巴胺(Dopamine, DA)，這種物質在人體中參與了非常多種反應，包括但不限於運動、學習、成癮等。根據研究，羧酸官能化的3, 4-乙烯二氧基噻吩(3,4-ethylenedioxythiophene, EDOT)聚合後會形成poly(EDOT-COOH)，因為擁有帶負電的官能基，能夠吸引帶正電的DA，增加對低濃度的偵測效果，再加上poly(EDOT-COOH)受生物體內其他蛋白質或離子的干擾不大，對於在生物體內偵測相當有優勢。除此之外，快速掃描循環伏安法(Fast-scan cyclic voltammetry, FSCV)因為掃描速率遠高於傳統電化學偵測技術，像是循環伏安法(Cyclic voltammetry, CV)或微分脈衝伏安法分析(Differential pulse voltammetry, DPV)，所以FSCV可以提供即時的偵測結果，增加了時間上的解析度與動態變化的探索。將導電高分子聚合在微電極表面後，利用FSCV的技術偵測DA訊號，發現即使是在小鼠大腦切片的活組織中，依然能夠偵測的到0.5 μM的DA訊號，而一般小鼠大腦釋放的DA濃度約為1、2 μM，這代表我們的做法的確可以在生物體的複雜環境下偵測DA訊號。

Neuroscientists employ microelectrodes implanted into the brains of animals to record electrical signals generated during various activities. However, we aim to simultaneously capture signals of certain important neurotransmitters. Our choice is dopamine (DA), which participates in numerous bodily responses, including but not limited to movement, learning, and addiction. Research suggests that carboxylic acid-functionalized 3,4-ethylenedioxythiophene (EDOT) polymerizes to form poly(EDOT-COOH), which, owing to its negatively charged functional groups, can attract positively charged DA, enhancing detection at low concentrations. Moreover, poly(EDOT-COOH) exhibits excellent antifouling properties, advantageous for detection within biological systems. Furthermore, fast-scan cyclic voltammetry (FSCV), with scan rates much higher than traditional electrochemical detection techniques like cyclic voltammetry (CV) or differential pulse voltammetry (DPV), can provide real-time detection results, increasing temporal resolution and dynamic exploration. By polymerizing conductive polymers on the surface of microelectrodes and utilizing FSCV, we discovered that even in live tissue slices of mice brains, DA signals as low as 0.5 μM could be detected. Typically, the concentration of DA released in mice brains is around 1-2 μM, indicating the efficacy of our approach in detecting DA signals within the complex environment of a living organism.