Ohara T J, Rajagopalan R, Heller A
Department of Chemical Engineering, University of Texas at Austin 78712-1062.
Anal Chem. 1993 Dec 1;65(23):3512-7. doi: 10.1021/ac00071a031.
Enzyme electrodes based on a redox hydrogel formed upon complexing water-soluble poly(1-vinylimidazole) (PVI) with [Os(bpy)2Cl]+ and cross-linked with water-soluble poly(ethylene glycol) diglycidyl ether (molecular weight 400, peg 400) are described. The properties of the electrodes depended on their polymers' osmium content, the extent of cross-linking, the pH, and the ionic strength in which they were used. The redox hydrogels' electron diffusion coefficients (De) increased with osmium content of their polymers. The De values were 1.5 x 10(-8), 1.3 x 10(-8), and 4.3 x 10(-9) cm2/s for PVI3-Os, PVI5-Os, and PVI10-Os, respectively, the subscripts indicating the number of monomer units per osmium redox center. De decreased with increasing ionic strength and increased upon protonation of the polymer. In glucose electrodes, made by incorporating into their films glucose oxidase (GOX) through covalent bonding in the cross-linking step, glucose was electrooxidized at > 150 mV (SCE). The characteristics of these electrodes depended on the GOX concentration, film thickness, O2 concentration, pH, NaCl concentration, and electrode potential. The steady-state glucose electrooxidation currents were independent of the polymers' osmium content in the studied (3-10 monomer units per osmium center) range. Electrodes containing 39% GOX reached steady-state glucose electrooxidation current densities of 400 microA/cm2 and, when made with thick gel films, were selective for glucose in the presence of physiological concentrations of ascorbate and acetaminophen.
本文描述了一种酶电极，它基于水溶性聚（1-乙烯基咪唑）（PVI）与[Os(bpy)₂Cl]⁺络合形成的氧化还原水凝胶，并用水溶性聚乙二醇二缩水甘油醚（分子量400，peg 400）交联而成。电极的性能取决于其聚合物的锇含量、交联程度、使用时的pH值和离子强度。氧化还原水凝胶的电子扩散系数（De）随聚合物的锇含量增加而增大。对于PVI₃-Os、PVI₅-Os和PVI₁₀-Os，De值分别为1.5×10⁻⁸、1.3×10⁻⁸和4.3×10⁻⁹ cm²/s，下标表示每个锇氧化还原中心的单体单元数。De随离子强度增加而减小，随聚合物质子化而增大。在通过交联步骤共价结合葡萄糖氧化酶（GOX）制成的葡萄糖电极中，葡萄糖在>150 mV（SCE）下被电氧化。这些电极的特性取决于GOX浓度、膜厚度、O₂浓度、pH值、NaCl浓度和电极电位。在所研究的（每个锇中心3 - 10个单体单元）范围内，稳态葡萄糖电氧化电流与聚合物的锇含量无关。含有39% GOX的电极达到了400 μA/cm²的稳态葡萄糖电氧化电流密度，并且当用厚凝胶膜制成时，在生理浓度的抗坏血酸和对乙酰氨基酚存在下对葡萄糖具有选择性。
