细胞色素c在纳米氧化铝模板修饰电极上的直接电化学

细胞色素c(Cytochrome c,Cyt c)是生物体中最常见的氧化一还原蛋白质,研究其在电极上的直接电化学,对于理解和认识生命体内的电子转移机制具有重要意义。Cytc与裸固体电极表面的直接接触通常会使其失去生物活性,因此,Cytc的电化学研究常借助于媒介体以实现其与电极之间的电子转移。纳米金属氧化物模板的表面积大且化学和光化学性质稳定,被广泛应用于太阳能电池和金属沉积等领域,本文研究氧化铝(AAO)模板对4,4’-二硫二吡啶存在下Cytc直接电化学促进作用。     

细胞色素c在无机复合纳米材料修饰电极上的直接电化学研究

采用超声辅助湿法合成的方法制备了羟基磷灰石与碳纳米管(HAp/MWNT)无机复合纳米材料,并将其修饰到玻碳电极表面上。研究了细胞色素c(Cyt c)在该复合纳米材料修饰电极表面上的电化学行为。实验结果表明,复合修饰材料对细胞色素c有很好的催化作用,其氧化还原峰峰差(ΔEp)为78 mV,式电位为15mV。在6.0×10-7-5.0×10-5mol/L浓度范围内,Cyt c的峰电流与其浓度呈良好的线性关系,其检测下限为3.0×10-7mol/L。关键词:细胞色素c;羟基磷灰石;碳纳米管;HAp/MWNT复合材料     

细胞色素c在纳米杂化膜修饰玻碳电极上的直接电化学

以多壁碳纳米管(MWNTs)修饰玻碳(GC)电极为基底,自组装金纳米粒子(AuNPs)及L-半胱氨酸(L-Cys)研制杂化膜修饰电极(L-Cys/AuNPs/MWNTs/GC).实验表明,该膜修饰电极在pH=7.0的KH2PO4-K2HPO4缓冲溶液中对细胞色素c(Cyt c)的直接电子转移反应具有良好的电催化作用,C...     

纳米ZnO修饰电极的制备及其对血红蛋白, 细胞色素c的直接电化学研究

A novel electrochemical method as a sensitive and convenient technique for the determination of heme proteins based on their interaction with ZnO nanorods was developed. A ZnO nanorod modified glassy carbon electrode (ZnO/GCE) was prepared and the electrochemical behaviors of heme proteins, such as hemoglobin (HB) and cytochrome c (Cyt-c), on this modified electrode have been studied. The results showed that both HB and Cyt-c could be oxidized on the modified electrode and the oxidation currents were linear to the concentrations of the analytes in aqueous solutions. In addition, the results of flow injection analysis (FIA) further suggested the high stability and reproducibility of the ZnO nanorod modified electrode. So this method can be applied to the determination of HB and Cyt-c in biological systems.     

细胞色素c在Fe_2O_3修饰电极上的直接电化学和电催化特性

采用全氟磺酸树脂Nafion将金属氧化物Fe2O3颗粒细胞色素c(Cyt c)固定玻碳电极(GCE)表面,制备了Nafion-Cyt c-Fe2O3修饰的玻碳电极,构建了基于直接电子传递的过氧化氢生物传感器。在0.10mol/L pH7.0的磷酸盐缓冲溶液中,修饰电极的循环伏安曲线上显示出一对准可逆的氧化还原峰,式量电位为22mV。Cyt c在修饰电极表面的异相电子转移速率常数为1.21s-1。修饰后的电极对过氧化氢有良好响应,响应时间小于10s,电极的安培响应与过氧化氢浓度在2.0×10-6～3.0×10-3mol/L范围内成线性关系,检出限为1.0×10-6mol/L,米氏常数为1.35mmol/L,显示出较好的亲和力。     

细胞色素c在2-巯基嘧啶衍生物修饰金电极上的直接电化学

用循环伏安法研究了2-巯基嘧啶(MP)、4-氨基-2-巯基嘧啶(AMP)及4,6-二氨基-2-巯基嘧啶(DAMP)自组装修饰金电极的制备及其对细胞色素c直接电子传递的促进作用。用扫描电子显微镜(SEM)表征了2-巯基嘧啶衍生物修饰金电极的表面形貌。细胞色素c在MP、AMP修饰金电极上能进行准可逆的电化学反应,氧化还原峰电位差(ΔEp)分别为61 mV和86 mV,氧化与还原峰电流比ipa/ipc接近1,峰电流与电位扫描速率平方根(v1/2)呈正比,是扩散控制的准可逆过程,异相电子迁移速率常数(Ks)分别为1.4×10-3cm·s-1和5.1×10-5cm·s-1。金电极在2.0 mmol·L-1MP、AMP溶液中分别浸泡3 h和9 h,促进效果较好。随2-巯基嘧啶环上取代氨基数的增加,对细胞色素c电化学反应的促进作用及电极的稳定性逐渐减弱,即MP>AMP,而DAMP基本无促进作用。     

细胞色素c在植物凝胶-离子液体复合膜修饰电极上的直接电化学

用植物凝胶（GG）和亲水性离子液体（ILs）氯化1-庚基-3-甲基咪唑（[HMIM]Cl）制得一种有效的复合膜（GG-ILs）.将细胞色素c（Cyt c）包埋在该复合膜中并修饰于玻碳电极（GCE）表面,构置了细胞色素c修饰玻碳电极（GG-Cyt c-ILs/GCE）.紫外-可见光谱表明,复合膜内的Cyt c仍保持其原始...     

羟基磷灰石修饰碳纳米电极制备及其对抗坏血酸的测定

通过恒电位沉积法,将纳米羟基磷灰石（HAP）成功修饰到碳纳米电极（CNE）上,制备出一种能快速检测抗坏血酸（AA）的修饰电极（HAP-CNE）。采用循环伏安法（CV）和计时安培法（CA）研究了HAP-CNE电极对AA的检测,考察了多巴胺（DA）和模拟体液pH对电极检测AA的影响。扫描电镜（SEM）结果表明,HAP已经成功修饰于CNE尖端与外壁上。电化学实验表明,与CNE相比,HAP-CNE电极信噪比显著提高,同时AA在HAP-CNE上能发生氧化还原反应,电荷转移速率提高。AA浓度在1×10-5～2×10-3 mol/L范围内与响应电流呈近似线性关系,检出限为1.3×10-7 mol/L。利用HAP-CNE检测AA具有广泛的pH适应性且对DA的抗干扰能力强。该电极是一种潜在原位探针,有望为生物医学研究提供新的检测方法,并成为一种能应用于活体实时检测生物小分子代谢过程的新型传感器。     

电化学活化玻碳电极上葡萄糖氧化酶的吸附与直接电化学

利用循环伏安法和SNIFTIRS法研究了葡萄糖氧化酶(GOD)在经电化学活化的玻碳(GC)电极上的吸附与直接电化学行为。GC电极经活化后对GOD的吸附大为增强。吸附速度与吸附量同GC电极活化时高电位氧化时间、GOD浓度、溶液pH值及通氮搅拌有关。SNIFTIRS实验表明,GOD可能主要吸附于活化新生石墨结构晶棱或晶面上。表面微晶石墨结构可能为吸附GOD同GC电报的直接电子传递场所。     

磷灰石通道离子替换对细胞色素C直接电化学的影响

采用沉淀法合成了以OH^-、F^-、Cl^-为通道离子的磷灰石纳米晶体。利用其独特的多位点吸附特性,研究了磷灰石不同通道离子替换对细胞色素c直接电化学的影响。在pH7．0的磷酸盐缓冲溶液中,细胞色素C在磷灰石修饰玻碳电极表面于0．074V(us．Ag／AgCl)附近有一对准可逆的氧化还原峰,为细胞色素C血红素辅基Fe(Ⅲ）／Fe(Ⅱ)电对的特征峰。细胞色素C与磷灰石之间的静电作用使深藏在细胞色素C内部的电活性中心靠近电极表面,加速了细胞色素C在玻碳电极表面扩散控制的准可逆单电子转移过程。其中氟磷灰石对细胞色素C直接电化学的促进作用最显著,羟基磷灰石次之,氯磷灰石最弱。     

Direct Electrochemistry of Cytochrome c on EDTA-ZrO_2 Organic-inorganic Hybrid Film Modified Electrodes

Introduction Cytochrome c (cyt c) is probably the most thor-oughly studied redox protein. It contains one Fe(III) redox center located in a haem unit which is approxi-mately spherical shape with 3.4 nm diameter and 12384 Dalton molecular weight. On metal electrode surfaces it usually shows a short lived, transient response. Many factors can impede direct electron transfer between electrodes and cyt. c, including adsorption onto elec-trode surfaces of macromolecular species (impurities) or de…     

聚乙烯醇微透镜阵列的制备及其固载细胞色素c的直接电化学

利用自组装法以聚苯乙烯有序多孔膜为膜板制备聚乙烯醇微透镜阵列膜.在pH6.89的磷酸盐(PBS)缓冲溶液中,固载在聚乙烯醇微透镜阵列膜修饰的玻碳电极上的细胞色素c于0.072V(vs·Ag/AgCl)处显示一对准可逆的氧化还原峰,是细胞色素c血红素辅基Fe(Ⅲ)/Fe(Ⅱ)电对的特征峰.考察了扫速、溶液pH及支持电解质浓度等因素对细胞色素c电子传递的影响,体系的表观异相电子传递速率常数k0为2.98×10-6cm·s-1.     

介孔碳修饰玻碳电极上葡萄糖氧化酶的直接电化学

使用简单的方法将葡萄糖氧化酶(GOD)固定在介孔碳(Mesoporous Carbon)修饰的玻碳电极(GCE)表面.循环伏安测试表明:修饰电极上的GOD在0.1mol/L磷酸缓冲溶液(PBS)(pH=7.1)中发生了准可逆的氧化还原反应,其克式量电位为-0.4294 V,并且该电化学反应包含有两电子两质子的传递.在氮气饱和的情况下,以羧基二茂铁作为电子传递中介体,GOD能将葡萄糖彻底催化氧化,可见介孔碳修饰电极上的GOD保持了其生物学活性.     

The NADH Electrochemical Detection Performed at Carbon Nanofibers Modified Glassy Carbon Electrode

In this work, the capability of carbon nanofibers to be used for the design of catalytic electrochemical biosensors is demonstrated. The direct electrochemistry of NADH was studied at a glassy carbon electrode modified using carbon nanofibers. A decrease of the oxidation potential of NADH by more than 300 mV is observed in the case of the assembled carbon nanofiber‐glassy carbon electrode comparing with a bare glassy carbon electrode. The carbon nanofiber‐modified electrode exhibited a wide linear response range of 3×10^?5 to 2.1×10^?3 mol L^?1 with a correlation coefficient of 0.997 for the detection of NADH, a high specific sensitivity of 3637.65 (μA/M cm²), a low detection of limit (LOD=3σ) of 11 μM, and a fast response time (3 s). These results have confirmed the fact that the carbon nanofibers represent a promising material to assemble electrochemical sensors and biosensors.     

Direct Electrochemistry of Cytochrome c on a Silica Sol‐Gel Film Modified Electrode

Dilute silica sol‐gel was simply dropped on the surface of a basal plane graphite electrode (BPGE) to form a silica sol‐gel film modified electrode. Direct electrochemical response of cytochrome c (Cyt c) on the modified electrode was observed by cyclic voltammetry (CV). The results suggested that Cyt c could be tightly adsorbed on the surface of the silica sol‐gel film modified electrode. A couple of well‐defined and nearly reversible redox peaks can be observed in a phosphate buffer solution (pH 7.0), which anodic and cathodic peak potentials were at ?0.243 and ?0.306 V (vs. Ag/AgCl), respectively. Cyt c adsorbed on the surface of silica sol‐gel film shows a remarkable electrocatalytic activity for the reduction of oxygen. Based on these, a third‐generation biosensor could be constructed to detect the concentration of oxygen in aqueous solution.     

Direct Electrochemistry of Cytochrome c at Gold Electrode Modified with Fumed Silica

Direct electrochemistry of horse heart cytochrome c (cytc) has been obtained at a gold electrode constructed by self‐assembling fumed silica particles (FSPs) onto a silane monolayer. A pair of well‐defined and nearly symmetrical redox peaks of cytc is obtained at the FSPs film modified gold electrode. Cyclic voltammetry (CV) and tapping‐mode atomic force microscopy (AFM) are used to characterize the FSPs film modified electrode, showing that the FSPs can provide a favorable microenvironment for cytc and facilitate the direct electron transfer between the cytc and the gold electrode, which may propose an approach to realize the direct electrochemistry of other proteins.     

Reversible Electrochemistry of Cytochrome c on Recompressed,Binderless Exfoliated Graphite Electrodes

The direct electrochemistry of cytochrome c (cyt‐c) has been investigated on exfoliated graphite (EG) electrodes. The as‐polished and roughened (using SiC emery sheet) EG surfaces are inactive for the direct electron transfer. However, when the EG electrode was sonicated before the experiment, a pair of redox waves were obtained for freely diffusing cyt‐c in the solution phase. The formal potential was found to be 0.01 V (vs. SCE) in 0.1 M phosphate buffer at a pH of 7.1. The electrochemical response for the adsorbed cyt‐c on sonicated EG electrodes, which is shown to have carbonyl functional groups on its surface, shows nearly reversible voltammograms in the same electrolyte. However, the formal potential in the adsorbed state is more negative than that observed for the solution phase cyt‐c. A structure based on an open heme conformation proposed by Hildebrandt and Stockburger is probably present on the EG surface. It is suggested that the electrochemistry at the EG electrode is essentially governed by favourable electrostatic interactions.