Cen Lian, Neoh K G, Kang E T
Department of Chemical and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
Biosens Bioelectron. 2003 Apr;18(4):363-74. doi: 10.1016/s0956-5663(02)00149-5.
A surface modification technique was developed for the functionalization of polypyrrole (PPY) film with glucose oxidase (GOD) and viologen moieties. The PPY film was first graft copolymerized with acrylic acid (AAc) and GOD was then covalently immobilized through the amide linkage formation between the amino groups of the GOD and the carboxyl groups of the grafted AAc polymer chains in the presence of a water-soluble carbodiimide. Viologen moieties could also be attached to the PPY film via graft-copolymerization of vinyl benzyl chloride with the PPY film surface followed by reaction with 4,4'-bipyridine and alpha,alpha'-dichloro-p-xylene. X-ray photoelectron spectroscopy (XPS) was used to characterize the PPY films after each surface modification step. Increasing the AAc graft concentration would allow a greater amount of GOD to be immobilized but this would decrease the electrical conductivity of the PPY film. The activity of the immobilized GOD was compared with that of free GOD and the kinetic effects were also studied. The immobilized GOD was found to be less sensitive to temperature deactivation as compared to the free GOD. The results showed that the covalent immobilization technique offers advantages over the technique involving the entrapment of GOD in PPY films during electropolymerization. The presence of viologen in the vicinity of the immobilized GOD also enabled the GOD-catalyzed oxidation of glucose to proceed under UV irradiation in the absence of O(2).
开发了一种表面改性技术，用于用葡萄糖氧化酶（GOD）和紫精部分对聚吡咯（PPY）薄膜进行功能化。首先使PPY薄膜与丙烯酸（AAc）接枝共聚，然后在水溶性碳二亚胺存在下，通过GOD的氨基与接枝的AAc聚合物链的羧基之间形成酰胺键，将GOD共价固定。紫精部分也可以通过苄基氯乙烯与PPY薄膜表面的接枝共聚，然后与4,4'-联吡啶和α,α'-二氯对二甲苯反应，连接到PPY薄膜上。在每个表面改性步骤之后，使用X射线光电子能谱（XPS）对PPY薄膜进行表征。增加AAc接枝浓度会使更多的GOD被固定，但这会降低PPY薄膜的电导率。将固定化GOD的活性与游离GOD的活性进行比较，并研究了动力学效应。发现固定化GOD与游离GOD相比，对温度失活不太敏感。结果表明，与在电聚合过程中将GOD包埋在PPY薄膜中的技术相比，共价固定技术具有优势。固定化GOD附近存在紫精，也使得在没有O(2)的情况下，GOD催化的葡萄糖氧化在紫外线照射下能够进行。
