合成 MOF525/PEDOT 複合物作為多巴胺感測之微電極

Abstract

本研究的目的是利用有機金屬框架(MOF525)作為主要材料，輔以導電高分子(PEDOT)改善其導電性，合成出一複合材料並修飾在Pt/Ir 微電極上。先藉由電化學氧化聚合法於微電極上直接聚合導電高分子PEDOT，並分別調控高分子氫鍵數量、電聚合時的溫度、電解質濃度及官能基的種類來最佳化，找出具有效能最好的微結構，然後再將PEDOT修飾過的微電極簡單的浸入MOF525溶液，讓MOF525自行吸附到PEDOT上，最後成為修飾在微電極上的PEDOT/MOF525複合材料。我們藉由氮氣等溫吸脫附曲線、X-射線繞射分析、場發射式掃瞄電子顯微鏡及能量色散X-射線光譜等結果證實我們成功製備出PEDOT/MOF525並修飾在微電極上，具有極高的比表面積及良好的導電性，而位於MOF525結構中心的配體具有很好的電催化特性，因此PEODT/MOF525可以作為一種有效的電催化材料。在生物感測上，我們利用循環伏安法及微分脈衝伏安法偵測多巴胺濃度，發現使用poly(EDOT-ph-COOH)(PEpM)作為高分子修飾電極時有最高達11 nA/μM的靈敏度及4~100 μM線性範圍。同時亦表現出在干擾物AA及UA下對多巴胺有良好的選擇性。

We synthesize a composite material consisting of metal-organic frameworks (i.e. MOF525) and conducting polymer (i.e. PEDOT) on microelectrodes for efficient detection of dopamine. First, we successfully synthesized the PEDOT on the microelectrode directly by electrochemical oxidation polymerization with the optimization of several synthetic conditions such as different amount of hydrogen bonds, temperature of electro-polymerization, concentration of supporting electrolyte, and the type of functional group. Then, MOF525 was attached on the PEODT-modified microelectrode by a simple immersed method. The synthesized MOF525/PEDOT composite-modified microelectrodes exhibit good conductivity and high specific surface area, confirmed by nitrogen adsorption-desorption isotherm, X-ray diffraction (XRD), field-emission scanning electron microscope (FT-SEM), and energy dispersive X-ray spectroscopy (EDX). For bio-sensing application, we proceed cyclic voltammetry and differential pulse voltammetry to measure the concentration of dopamine by using the synthesized MOF525/PEDOT modified microelectrodes. It was found that the MOF525/PEDOT modified microelectrodes with poly(EDOT-ph-COOH) exhibit the highest sensitivity of 11 nA/μM with linear range of 4 to 100 μM. The composite microelectrode also exhibited excellent selectivity for dopamine against common interference ascorbic acid (AA) and uric acid (DA).