Electrochemical grafting is a suitable technology for fabricating electrode surfaces with new chemical functionalities whilst maintaining the bulk properties of the electrode, and electrochemical amine oxidation and diazonium salt reduction are two widely used techniques to achieve this end. Herein, we report the electrochemical reductive grafting of Azure A onto multiwalled carbon nanotube (MWCNT) electrodes for the efficient wiring of flavin adenine dinucleotide (FAD) dependent glucose dehydrogenase. The diazonium salt of Azure A is formed in situ and subsequently grafted onto the electrode surface through electrochemical reduction. The formal potential of the resultant Azure-A-modified electrode shifted to −0.05 V vs. Ag/AgCl upon radical coupling to the MWCNT electrode. Electron transfer from FAD buried in the protein shell to the electrode via Azure A was then observed in the presence of glucose in the buffer solution. This study focused on the important effect of CNT mass loading on Azure-A loading as well as bioelectrocatalytic activity and storage stability. The three-dimensional porous structure of the MWCNT electrode was determined to be favorable for the immobilization of flavin adenine dinucleotide dependent glucose dehydrogenase and efficient electron transfer via the Azure-A functionalities. The optimized 300 g CNT-loaded modified electrode on glassy carbon (3 mm diameter) retains its initial activity for 3 d and 25% of its initial activity after 10 d. Furthermore, we show that grafted Azure A is stably immobilized on the MWCNTs for 1 month; therefore, the limiting stability factor is enzyme leaching and/or deactivation.

电化学接枝是一种合适的技术，用于制造具有新化学功能的电极表面，同时保持电极的整体特性，电化学胺氧化和重氮盐还原是实现这一目标的两种广泛使用的技术。在此，我们报告了 Azure A 在多壁碳纳米管 (MWCNT) 电极上的电化学还原接枝，用于有效连接黄素腺嘌呤二核苷酸 (FAD) 依赖性葡萄糖脱氢酶。Azure A 的重氮盐原位形成然后通过电化学还原接枝到电极表面。在自由基耦合到 MWCNT 电极后，所得 Azure-A 修饰电极的形式电位相对于 Ag/AgCl 转变为 -0.05 V。然后在缓冲溶液中存在葡萄糖的情况下观察到电子从埋在蛋白质壳中的 FAD 经由 Azure A 转移到电极。本研究侧重于 CNT 质量负载对 Azure-A 负载以及生物电催化活性和储存稳定性的重要影响。MWCNT 电极的三维多孔结构被确定有利于黄素腺嘌呤二核苷酸依赖性葡萄糖脱氢酶的固定和通过 Azure-A 功能的有效电子转移。优化后的 300g 玻璃碳（直径 3 mm）上的载有 CNT 的修饰电极在 3 天内保持其初始活性，10 天后保持其初始活性的 25%。此外，我们表明嫁接的 Azure A 在 MWCNT 上稳定固定 1 个月；因此，限制稳定性因素是酶浸出和/或失活。