Electrosynthesis and characterization of biotin-functionalized poly(terthiophene) copolymers, and their response to avidin
作者:Fouzi Mouffouk、Stewart J. Brown、Anna M. Demetriou、Simon J. Higgins、Richard J. Nichols、R. M. Gamini RajapakseOn leave from Department o、Stuart Reeman
DOI:10.1039/b413974g
日期:——
Using a succinyl ester linker, a terthiophene bearing a pendant biotin hydrazide in the 3′ position (4-N′-[5-(4,6-dioxo-hexahydrothieno[3,4-c]pyrrol-3-yl)-pentanoyl]hydrazino}-4-oxo-butyric acid 2-[2,2′:5′,2″]terthiophen-3′-yl-ethyl ester, 4) has been prepared in three steps from 2-[2,2′:5′,2″]-terthiophen-3′-yl-ethanol, 2, via succinic acid mono-(2-[2,2′,5′,2″]-terthiophene-3′-yl-ethyl) ester, 3. Using the ‘oligomer as monomer’ approach, polyterthiophene (co)polymer films have been generated, on Pt, Au and ITO-coated glass working electrodes, by repetitive scan cyclic voltammetry of solutions of 2,2′:5′,2″-terthiophene, or either 3 or 4 along with 2,2′:5′,2″-terthiophene itself. These films have been characterized by cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and in situ reflectance FTIR spectroscopy. FTIR spectroscopy suggests that the 2,2′:5′,2″-terthiophene : 4 copolymer contains intact biotin moieties. The incubation of poly-2,2′:5′,2″-terthiophene and 2,2′:5′,2″-terthiophene : 4 copolymer with aqueous buffer solutions, followed by transfer back to CH3CN/0.1 M TEAT, results in only small changes in the film CV, whereas exposure of the biotin-functionalized 2,2′:5′,2″-terthiophene : 4 copolymer to avidin causes drastic changes to its CV and its EIS, consistent with the binding of avidin by biotin resulting in restricted ion transfer to and from the polymer. The minimum amount of avidin which causes a detectable change in the electrochemistry of a 0.03 cm2 2,2′:5′,2″-terthiophene : 4 copolymer-modified electrode is 5 × 10−14 moles. Exposure of the 2,2′:5′,2″-terthiophene : 4 copolymer to excess bovine serum albumin in buffer causes only the same small changes in its electrochemistry as exposure to buffer alone, ruling out nonspecific adsorption as a cause of the electrochemical changes on avidin exposure.
使用琥珀酰酯连接剂,在 3′位上带有生物素酰肼悬垂体的噻吩(4-N′-[5-(4,6-二氧代六氢噻吩并[3,4-c]吡咯-3-基)-戊酰基]酰肼}-4-氧代丁酸 2-[2,2′:4)由 2-[2,2′:5′,2″]-三噻吩-3′-基乙醇(2)通过琥珀酸单(2-[2,2′,5′,2″]-三噻吩-3′-基乙基)酯(3)分三步制备而成。通过对 2,2′:5′,2″-噻吩或 3 或 4 与 2,2′:5′,2″-噻吩本身的溶液进行重复扫描循环伏安法,利用 "低聚物为单体 "的方法,在涂有铂金、金和 ITO 的玻璃工作电极上生成了聚噻吩(共)聚合物薄膜。这些薄膜通过循环伏安法(CV)、电化学阻抗谱(EIS)和原位反射傅立叶变换红外光谱进行了表征。傅立叶变换红外光谱表明,2,2′:5′,2″-噻吩 : 4 共聚物含有完整的生物素分子。将聚-2,2′:5′,2″-噻吩和 2,2′:5′,2″-Terthiophene : 4 共聚物与缓冲水溶液孵育,然后转回到 CH3CN/0.而将生物素官能化的 2,2′:5′,2″-噻吩:4 共聚物暴露于阿维丁后,其 CV 和 EIS 会发生急剧变化。在 0.03 cm2 的 2,2′:5′,2″-噻吩:4 共聚物改性电极上引起可检测到的电化学变化的最小阿维丁量为 5 × 10-14 摩尔。将 2,2′:5′,2″-四联噻吩:4 共聚物暴露于缓冲液中过量的牛血清白蛋白,其电化学变化与单独暴露于缓冲液中的变化相同微小,排除了非特异性吸附导致阿维丁暴露时电化学变化的原因。