Karube I, Yokoyama K, Tamiya E
Research Center for Advanced Science and Technology, University of Tokyo, Japan.
Biosens Bioelectron. 1993;8(3-4):219-28. doi: 10.1016/0956-5663(93)85037-o.
Microbiosensors based on carbon and and platinum fibers are described. Carbon fibers were used to construct microelectrodes of 7 microm diameter. Electrochemical operations for pre-electrolysis and measuring were examined for the highly sensitive determination of hydrogen peroxide. A triangular potential (-2 to +2V vs Ag/AgCl) was applied before measuring each pair of double pulses (first pulse: 750 mV; second pulse: 1100 mV). The determination limit was 0.1 microM of hydrogen peroxide. The reproducible determination of hydrogen peroxide is possible even in samples containing albumin protein. The separation of hydrogen peroxide from ascorbic acid is also possible because the oxidation potential of ascorbic acid is different from that of hydrogen peroxide. An acetylcholine microsensor was fabricated by immobilizing acetylcholine esterase and choline oxidase on the carbon fiber by entrapment with poly(vinyl alcohol)-quarternized stilbazole (PVA-SbQ). This sensor gave a linear calibration plot for the range 0.1-1.0 mM with a linear correlation coefficient of 0.9842. Glucose oxidase (GOD) and glucose dehydrogenase (GDH) immobilized cylindrical platinum microelectrodes were fabricated, and their characteristics were evaluated, respectively, by using 1,4-benzoquinone (BQ) and ferricyanide as electron mediators. Each enzyme was immobilized by using PVA-SbQ on a cylindrical microelectrode of 2 microm diameter. A linear range in the calibration curve of the GOD-based glucose microsensor was observed to be wider than that obtained using a disk electrode of 1 mm diameter. The mediated response of the 2 microm glucose sensor was compared with the response resulting from hydrogen peroxide detection. This result showed that a higher response and a wider linear range were observed with highly concentrated mediator. A much higher response of the GDH immobilized 2 microm microelectrode was obtained when not only ferricyanide but also diaphorase was employed to reoxidize the NADH produced by the enzyme reaction of GDH. The GHD-based glucose microsensor was found to be unaffected by the concentration of dissolved oxygen.
描述了基于碳纤维和铂纤维的微生物传感器。碳纤维用于构建直径为7微米的微电极。研究了用于预电解和测量的电化学操作，以实现对过氧化氢的高灵敏度测定。在测量每对双脉冲之前（第一个脉冲：750 mV；第二个脉冲：1100 mV）施加三角电位（相对于Ag/AgCl为-2至+2V）。过氧化氢的测定限为0.1微摩尔。即使在含有白蛋白的样品中，也能够对过氧化氢进行可重复测定。由于抗坏血酸的氧化电位与过氧化氢不同，因此也能够将过氧化氢与抗坏血酸分离。通过用聚（乙烯醇）-季铵化 stilbazole（PVA-SbQ）包埋将乙酰胆碱酯酶和胆碱氧化酶固定在碳纤维上，制备了乙酰胆碱微传感器。该传感器在0.1-1.0 mM范围内给出线性校准曲线，线性相关系数为0.9842。制备了固定有葡萄糖氧化酶（GOD）和葡萄糖脱氢酶（GDH）的圆柱形铂微电极，并分别使用1,4-苯醌（BQ）和铁氰化物作为电子媒介体对其特性进行了评估。每种酶都通过PVA-SbQ固定在直径为2微米的圆柱形微电极上。观察到基于GOD的葡萄糖微传感器校准曲线的线性范围比使用直径为1毫米的圆盘电极获得的线性范围更宽。将2微米葡萄糖传感器的介导响应与过氧化氢检测产生的响应进行了比较。结果表明，使用高浓度媒介体时观察到更高的响应和更宽的线性范围。当不仅使用铁氰化物而且使用黄递酶来重新氧化GDH酶反应产生的NADH时，固定有GDH的2微米微电极获得了更高的响应。发现基于GHD的葡萄糖微传感器不受溶解氧浓度的影响。
