Characteristics of the Multifunctional Biosensors for the Measurements of Bioactive Substances in the Living Body

本课题旨在研制一种能够检测影响大脑神经元活动的内源性物质的生物传感器。为此，对以下传感器的特性进行了研究；(1)用于分离和分析生物活性物质的微透析传感器；(2)用于葡萄糖氧化酶固定的葡萄糖检测的酶生物传感器；(3)用于免疫吸附测定的石英晶体微天平传感器。研究了微透析生物传感器在大鼠内侧前额叶皮层和脾脏的去甲肾上腺素释放。微透析传感器系统对去甲肾上腺素的检出限为500 fg/40 μ l，信噪比为3:1。一系列药理学和生理学实验表明，透析液中恢复的去甲肾上腺素主要来源于神经末梢。将葡萄糖氧化酶固定在铂电极上以获得稳定的活性。研究了该传感器在0.1 ~ 10.0 mm葡萄糖浓度范围内的响应特性和稳定性。在5 mm以内，传感器稳态响应与葡萄糖浓度成正比，传感器响应的线性相关斜率与溶解氧浓度成反比。二茂铁甲醛作为电子介质，克服了溶解氧浓度降低对传感器响应的影响。石英晶体微平衡传感器采用由at切割石英压电晶体、振荡器和频率计数器组成的压电晶体生物传感器系统检测人免疫球蛋白G （IgG）。将抗人IgG用酪胺和戊二醛固定在金电极表面。抗-IgG与IgG亲和反应引起的共振频移与IgG浓度在10mug/ml-50mug/ml范围内相关。晶体传感器对牛血清白蛋白无反应。少

The purpose of this research project was to accomplish the biosensors which can detect the endogenous substances influencing neuronal activity in the brain. For this purpose, the characteristics of the following sensors were studied ; (1) microdialysis sensor for separation and analysis of bioactive substances, (2) enzyme biosensor for detection of glucose immobilized with glucose oxidase and (3) a quartz crystal microbalance sensor for immunosorbent assay.1. Microdialysis biosensorNoradrenaline release in the medial prefrontal cortex and spleen of rats was studied. The detection limit of the microdialysis sensor system for noradrenaline was 500 fg/40 mul at a 3 : 1 signal to noise ratio. A series of experiments using pharmacological and physiological manipulations indicated that the noradrenaline recovered in the dialysate was mainly derived from nerve terminals.2. Enzyme biosensorGlucose oxidase was immobilized onto platinum electrode to attain stabilized activity. The concentration … More response characteristics and the stability of the sensor were studied for glucose concentrations of 0.1-10.0mM.Steady state response of the sensor was proportional to the glucose concentration up to 5 mM.The slope of the linear correlation of sensor response was inversely proportional to the dissolved oxygen concentration. The decrease in sensor response caused by the reduction of dissolved oxygen concentration was overcome by using ferrocene carboxialdehyde as an electron mediator.3. Quartz crystal microbalance sensorDetermination of human immunoglobulin G (IgG) was performed by using a piezoelectric crystal biosensor system, which was consist of an AT-cut quarts piezoelectriccrystal, oscillator and frequency counter. Anti-human IgG was immobilized onto the surface of the gold electrode with tyramine and glutaraldehyde. The resonant frequency shift resulting from the affinity reaction of anti-IgG and IgG correlated with a concentration of IgG in the range of 10mug/ml-50mug/ml. The crystal sensor showed no response to bovine serum albumin. Less