Hoshi T, Anzai J, Osa T
Pharmaceutical Institute, Tohoku University, Sendai, Japan.
Anal Chem. 1995 Feb 15;67(4):770-4. doi: 10.1021/ac00100a013.
A facile method for the regulation of enzyme loading on an electrode surface has been studied using avidin and biotinylated glucose oxidase (GOx). It was demonstrated that an alternate and repeated deposition of avidin and biotinylated GOx gives a protein thin film probably composed of avidin monolayers and biotinylated GOx monolayers which are connected with each other through strong affinity between avidin and biotin moieties of the enzyme (binding constant, 10(15) M-1). Amperometric response of the glucose sensors constructed by this method was controlled stepwise and rather precisely by regulating the number of GOx layers deposited (or the loading of GOx). For example, the output current of the sensors to 1 mM glucose was enhanced to ca. 1300 and 2800 nA after deposition of 10 and 20 layers of GOx, respectively, as compared with 110 nA for the monolayer GOx sensor. The enhanced response contributed to the extension of the dynamic range of the sensors, especially at a lower glucose concentration. The response time of the sensors was satisfactorily fast (ca. 20 s), irrespective of the number of GOx layers.
利用抗生物素蛋白和生物素化葡萄糖氧化酶（GOx）研究了一种在电极表面调节酶负载量的简便方法。结果表明，抗生物素蛋白和生物素化GOx交替重复沉积可形成一种蛋白质薄膜，该薄膜可能由抗生物素蛋白单层和生物素化GOx单层组成，它们通过酶的抗生物素蛋白和生物素部分之间的强亲和力相互连接（结合常数为10¹⁵ M⁻¹）。通过这种方法构建的葡萄糖传感器的安培响应可通过调节沉积的GOx层数（或GOx负载量）逐步且相当精确地控制。例如，与单层GOx传感器的110 nA相比，在沉积10层和20层GOx后，传感器对1 mM葡萄糖的输出电流分别提高到约1300和2800 nA。增强的响应有助于扩展传感器的动态范围，尤其是在较低葡萄糖浓度下。传感器的响应时间令人满意地快（约20 s），与GOx层数无关。
