Effects of Film Morphology and Surface Chemistry on the Direct Electrochemistry of Cytochrome c at Boron-Doped Diamond Electrodes.
Effects of Film Morphology and Surface Chemistry on the Direct Electrochemistry of Cytochrome c at Boron-Doped Diamond Electrodes.
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DOI：
10.1016/j.electacta.2016.02.032
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发表时间：
2016-04-10
影响因子：
6.6
通讯作者：
Swain GM
中科院分区：
文献类型：
--
作者：
Dai Y;Proshlyakov DA;Swain GM
研究了掺硼超纳米晶（B-UNCD）和微晶（B-MCD）金刚石薄膜电极表面形貌和表面终止对马心细胞色素c直接电子转移的影响。准可逆的，扩散控制的循环伏安响应上观察到的氧终止（原子O/C ~0.015），但不是氢终止（原子O/C ~0.02）的金刚石薄膜。对于在晶界中具有sp2键合碳原子的纳米结构B-UNCD膜和具有微米尺寸颗粒且基本上不含sp2碳的良好刻面B-MCD膜来说，表面终止的效果是相同的。记录了两种氧封端膜的稳定循环伏安i-E曲线，表明不存在蛋白质变性和电极结垢。峰电流随扫描速率和蛋白质浓度的平方根线性增加;两者均指示受蛋白质的半无限线性扩散限制的反应速率。在氧封端的B-UNCD（3.48（± 1.25）× 10−3 cm/s）和B-MCD薄膜（2.38（± 0.72）× 10−3 cm/s）中观察到类似的异质电子转移速率常数。结果清楚地表明，氧封端的表面是更积极的电子转移与这种可溶性氧化还原蛋白比氢封端的表面。膜形态不影响氧化还原蛋白的扩散控制响应。
The effects of film morphology and surface termination on the direct electron transfer of horse heart cytochrome c on boron-doped ultrananocrystalline (B-UNCD) and microcrystalline (B-MCD) diamond thin-film electrodes were investigated. Quasi-reversible, diffusion-controlled cyclic voltammetric responses were observed on oxygen-terminated (atomic O/C ~0.015), but not hydrogen-terminated (atomic O/C ~0.02) diamond thin films. The effect of the surface termination was the same for both the nanostructured B-UNCD film with sp2-bonded carbon atoms in the grain boundaries and the well faceted B-MCD film with micron-sized grains and largely devoid of sp2 carbon. Stable cyclic voltammetric i-E curves were recorded with cycling for both oxygen-terminated films indicating the absence of protein denaturation and electrode fouling. The peak currents increased linearly with the square root of the scan rate and the protein concentration; both indicative of a reaction rate limited by semi-infinite linear diffusion of the protein. Similar heterogeneous electron-transfer rate constants were observed for oxygen-terminated B-UNCD (3.48 (± 1.25) × 10−3 cm/s) and B-MCD films (2.38 (± 0.72) × 10−3 cm/s). The results clearly reveal that the oxygen-terminated surface is more active for electron-transfer with this soluble redox protein than is the hydrogen-terminated surface. The film morphology does not influence the diffusion-controlled response of the redox protein.