基于金纳米棒/多壁碳纳米管-壳聚糖复合膜电极的肌红蛋白直接电化学和电催化研究

采用金纳米棒(AuNRs)/多壁碳纳米管-壳聚糖(MWCNTs-Chit)复合膜促进肌红蛋白在电极上的直接电子转移,并用于构建H2O2生物传感器.首先将金纳米棒固定到玻碳电极表面,然后把MWCNTs-Chit分散溶液和肌红蛋白(Mb)固载到玻碳电极上,得到MWCNTs-Chit/Mb/AuNRs复合膜电极.通过循环伏安法对膜电极进行表征,在pH=7.0磷酸缓冲溶液中,Mb表现出一对峰形良好且可逆的氧化还原峰,其中氧化峰和还原峰电位分别为-0.291 V、-0.235 V,式电位(Eθ’)为-0.263 V.与此同时还探讨了修饰电极的电催化活性,结果表明其对H2O2具有良好的电催化还原作用,可作为检测H2O2的生物传感器.传感器对H2O2的米氏常数为0.0494 mM,线性范围为5.0×10-5～5.0×10-3M(R=0.986 7,n=10),检测限为3.2×10-6M(信噪比为3).

Direct Electrochemistry and Electrocatalysis of Myoglobin Based on AuNRs/ MWCNTs-Chit Composite Membrane Electrode

A new H2O2 biosensor was fabricated based on the immobilization of myoglobin(Mb),gold nanorods(AuNRs),and multiwalled carbon nanotubes(MWCNTs)–chitosan(Chit) dispersed solution on glassy carbon electrode(GCE).The direct electron transfer of Mb on the MWCNTs-Chit/Mb/AuNRs modified glassy carbon electrode(GCE) was investigated.The immobilized Mb displayed a pair of well-defined and reversible redox peaks with the formal potential(Eθ’) of-0.263V in 0.1M pH 7.0 PBS.The electrode reactions showed a surface-controlled process with a single proton transfer at the scan rate range from 10 to 500mV/s.Meanwhile,the reduction to H2O2 of biosensor was discussed.Its apparent Michaelis–Menten constant(KappM) for H2O2 was 0.049 4 mM,showing a good affinity.The experiment results showed that the linear range for H2O2 was from 5.0×10-5 to 5.0×10-3M,with a correlation coefficient of 0.986 7,and the detection limit of the sensor was 3.2×10-6M(S/N=3).Moreover,the biosensor showed a rapid response to H2O2,with a good stability and reproducibility.