Ishida Kazuya, Orihara Kouhei, Muguruma Hitoshi, Iwasa Hisanori, Hiratsuka Atsunori, Tsuji Katsumi, Kishimoto Takahide
Graduate School of Engineering and Science, Shibaura Institute of Technology.
Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).
Anal Sci. 2018;34(7):783-787. doi: 10.2116/analsci.17P613.
Direct and mediated electron transfer (DET and MET) in enzyme electrodes with a novel flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) from fungi are compared for the first time. DET is achieved by placing a single-walled carbon nanotube (CNT) between GDH and a flat gold electrode where the CNT is close to FAD within the distance for DET. MET is induced by using a free electron transfer mediator, potassium hexacyanoferrate, and shuttles electrons from FAD to the gold electrode. Cyclic voltammetry shows that the onset potential for glucose response current in DET is smaller than in MET, and that the distinct redox current peak pairs in MET are observed whereas no peaks are found in DET. The chronoamperometry with respect to a glucose biosensor shows that (i) the response in DET is more rapid than in MET; (ii) the current at more than +0.45V in DET is larger than the current at the current-peak potential in MET; (iii) a DET electrode covers the glucose concentration range for clinical requirements and is not susceptible to interfering agents at +0.45 V; and (iv) a DET electrode with the novel fungal FAD-GDH does not affect sensing accuracy in the presence of up to 5 mM xylose, while it often shows a similar response level to glucose with other conventionally used fungus-derived FAD-GDHs. It is concluded that our DET system overcomes the disadvantage of MET.
首次比较了采用一种来自真菌的新型黄素腺嘌呤二核苷酸依赖性葡萄糖脱氢酶（FAD-GDH）的酶电极中的直接电子转移和介导电子转移（DET和MET）。通过在GDH和平坦金电极之间放置单壁碳纳米管（CNT）实现DET，其中CNT在DET的距离范围内靠近FAD。通过使用自由电子转移介质六氰合铁酸钾诱导MET，其将电子从FAD穿梭至金电极。循环伏安法表明，DET中葡萄糖响应电流的起始电位低于MET，并且在MET中观察到明显的氧化还原电流峰对，而在DET中未发现峰。关于葡萄糖生物传感器的计时电流法表明：（i）DET中的响应比MET更快；（ii）DET中高于+0.45V时的电流大于MET中电流峰电位处的电流；（iii）DET电极覆盖临床要求的葡萄糖浓度范围，并且在+0.45V时不易受干扰剂影响；（iv）带有新型真菌FAD-GDH的DET电极在存在高达5 mM木糖的情况下不影响传感准确性，而它与其他常规使用的真菌来源的FAD-GDHs通常对葡萄糖表现出相似的响应水平。得出的结论是，我们的DET系统克服了MET的缺点。
