肌红蛋白在碳纳米管修饰电极上的直接电化学和电催化性能

将肌红蛋白(Mb)通过吸附的方法固定在碳纳米管(CNT)表面, 用AFM、XPS、UV-Vis和FTIR对其进行了表征, 研究了CNT对Mb直接电子转移反应的促进作用. 循环伏安结果表明, Mb在CNT表面能进行有效和稳定的直接电子转移反应, 其循环伏安曲线上表现出一对良好的、几乎对称的氧化还原峰; 在20−160 mV•s−1的扫速范围内, 式量电位E0′几乎不随扫速而变化, 其平均值为(−0.343±0.001) V (vs SCE, pH 7.0); Mb在CNT表面直接电子转移的表观速率常数为(3.11±0.98) s−1; 式量电位E0′与溶液pH的关系表明, Mb的直接电化学过程是一个有H+参与的电极过程. 进一步的实验结果显示, 固定在CNT表面的Mb能保持其对H2O2和O2还原的生物电催化活性.

Direct Electrochemistry and Bioelectrocatalysis of Myoglobin at a Carbon Nanotube-Modified Electrode

Myoglobin (Mb) was immobilized onto the surface of carbon nanotube (CNT) and was characterized by AFM, XPS, UV-Vis, and FTIR spectroscopy. The promotion effect of CNT on direct electron transfer (DET) reaction of Mb was studied. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to DET of Mb, with the formal potential (E0') of (-0.343±0.001) V (vs SCE) in the phosphate buffer solution (PBS, pH 7.0).The electrochemical parameters, such as apparent heterogeneous electron transfer rate constant (ks) and E0', were determined. The dependence of E0' on solution pH indicated that DET reaction of Mb was coupled with proton transfer. The experimental results also demonstrated that the immobilized Mb retained its bioelectrocatalytic activity toward the reduction of H2O2 and O2.