Investigation of the electrode reaction of cytochrome c through mixed self-assembled monolayers of alkanethiols on gold(111) surfaces
Investigation of the electrode reaction of cytochrome c through mixed self-assembled monolayers of alkanethiols on gold(111) surfaces
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DOI：
10.1016/s0022-0728(96)05065-6
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发表时间：
1997-11-25
影响因子：
4.5
通讯作者：
Niki, K
中科院分区：
文献类型：
--
作者：
Arnold, S;Feng, ZQ;Niki, K
将马心细胞色素c固定在Au（111）电极上的羧基和甲基硫醇酯（HOOC（CH 2）（10）S + CH 3（CH 2）（9）S）混合自组装膜上。用交流阻抗法测定了细胞色素C混合SAM金电极体系的电子转移表观标准速率常数k（obs）。阻抗和交流调制紫外-可见电反射技术。一个强烈的依赖性K（obs）上的组合物的混合的烷基乙醇的解决方案，从该单分子膜已组装，观察。对于由含有摩尔分数χ接近0.8的羧基封端的烷硫醇的溶液形成的自组装膜，发现k（obs）的最大值接近200 s（-1）。该速率常数比具有HOOC（CH 2）（10）S（chi = 1）的单组分单层的系统快约6倍。还原脱附表明，两种硫醇烷酯在单分子膜中均匀混合，在Au（111）电极上没有相当大的相分离。双层电容测量确定了混合自组装膜在pH 6-9范围内的质子化程度。电子转移速率的提高归因于蛋白质结合位点在混合单分子膜中的有利分布。(C)1997年Elsevier Science S.A.
Horse heart cytochrome c was immobilized on mixed self-assembled monolayers (SAMs) of carboxyl-and methyl-terminated alkanethiolates (HOOC(CH2)(10)S + CH3(CH2)(9)S) on Au(111) electrodes. The apparent standard rate constant k(obs) of electron transfer for the electrode system of cytochrome c\mixed SAM \gold electrode was measured by a.c. impedance and a.c. modulated UV-visible electroreflectance techniques. A strong dependence of k(obs) on the composition of the mixed alkanethiol solution, from which the monolayers had been assembled, was observed. A maximum of k(obs) approximate to 200 s(-1) was found for SAMs formed from solutions containing a mole fraction chi approximate to 0.8 of carboxyl-terminated alkanethiols. This rate constant is about six times faster than that of a system with a single-component monolayer of HOOC(CH2)(10)S (chi = 1). Reductive desorption suggested that the two alkane thiolates mix homogeneously in the monolayer and there is no sizable phase separation on the Au(111) electrode. Double-layer capacitance measurements determined the degree of protonation of the mixed SAMs in the pH range 6-9. The enhancement of electron-transfer rate is attributed to a favorable distribution of protein binding sites in the mixed monolayers. (C) 1997 Elsevier Science S.A.