肌红蛋白在Nafion/Fe_3O_4-CdTe/CdS量子点复合膜内的直接电化学及其应用于H_2O_2的生物传感

Direct Electrochemistry of Myoglobin on Nafion/Fe_3O_4-CdTe/CdS Composite Film and Its Application in Hydrogen Peroxide Biosensing

利用磁性纳米Fe3O4和CdTe/CdS量子点结合Nafion的良好成膜性,将肌红蛋白(Mb)固定在玻碳电极表面制备成Nafion/Fe3O4-CdTe/CdS-Mb/GCE修饰电极。在pH 7.0的0.1 mol/L磷酸盐缓冲溶液(PBS)中,固定在膜内的Mb表现出良好的直接电化学性质,在-0.351 V处有1对近乎可逆的氧化还原峰,为Mb中血红素辅基Fe(Ⅲ)/Fe(Ⅱ)电对的特征氧化还原峰,并显示了很好的稳定性。表明Nafion/Fe3O4-CdTe/CdS复合膜的微环境有利于Mb中Fe(Ⅲ)/Fe(Ⅱ)与电极之间的直接电子传递和Mb的固定。同时,探讨了该修饰电极表面固定的Mb对H2O2的催化还原,结果显示,该修饰电极可作为H2O2生物传感器,实现对H2O2的快速(响应时间小于5 s)、准确检测,灵敏度可达30.6 mA.L/mol,检出限(S/N=3)为0.89μmol/L。

A Nafion/Fe3O4-CdTe/CdS-myoglobin（Mb）modified glassy carbon electrode（GCE） was prepared by immobilizing Mb on the electrode surface using Fe3O4 nanoparticles and CdTe/CdS quantum dots combining the advantages of film formation ability of Nafion.Cyclic voltammetric data showed that the immobilized Mb exerted a good direct electrochemistric behavior and a good stability with a pair of well-defined and nearly reversible peaks at about-0.351 V in 0.1 mol/L pH 7.0 PBS corresponding to the characteristic peaks of the Mb heme Fe（Ⅲ）/Fe（Ⅱ） redox couples.The results indicated that the microenvironment of Nafion/Fe3O4-CdTe/CdS film could promote the direct electron transfer between Mb heme Fe（Ⅲ）/Fe（Ⅱ） and GCE and provide the matrix for the immobilization of Mb.The electrocatalytic ability of the immobilized Mb to the reduction of H2O2 was also investigated and the results suggested that the modified electrode could be used as a biosensor for the detection of hydrogen peroxide with high sensitivity（30.6 mA·L/mol）,low detection limit（0.89 μmol/L,S/N=3） and rapid response.