Bio-affinity Chemical Sensors for in Vivo Monitoring of Bio-active Substances

本课题的研究目的是实现能够检测影响大脑神经元活动的内源性化学物质的生物传感系统。为此，对以下传感器的特性进行了研究；(1)酶微透析生物传感器和(2)用于免疫吸附测定的石英晶体微平衡生物传感器。酶微透析生物传感器由尖端有半透膜的玻璃体、工作电极和用于酶溶液灌注的进出口毛细管组成。将工作电极和进口毛细管插入半透中空纤维（od =220 μm）中。该生物传感器的优点是通过灌注酶溶液可以很容易地改变工作电极周围的微环境。本研究使用葡萄糖氧化酶，传感器的稳态响应与葡萄糖浓度成正比，最高可达5mM。葡萄糖浓度的检出限为0.01 mm，二茂铁羧醛作为电子介质克服了溶解氧浓度降低引起的灵敏度下降。石英晶体微平衡生物传感器研究了压电晶体在各种操作条件下的作用，并将其应用于人体IgG浓度的测定。用酪胺和戊二醛将山羊抗人IgG固定在晶体电极表面，修饰at切割晶体，其基本共振频率为9 MHz。固定化技术提高了生物传感器的长期稳定性，材料在电极表面吸附引起的频率变化为1 Hz/ng。人抗人IgG与山羊抗人IgG反应引起的频率移位与10μg/ml ~ 50 μg/ml的浓度范围相关。该技术在神经生理学研究中的适用性被证实用于体内化学波动的研究。少

The purpose of this research project was to accomplish the biosensing system which can detect the endogenous chemical substances influencing neuronal activities in the brain. For this purpose, the characteristics of the following sensors were studied ; (1) enzyme microdialysis biosensor and (2) a quarts crystal microbalance biosensor for immunosorbent assay.1. Enzyme microdialysis biosensorThe concentric biosensor was consisted of glass body with a semi-permeable membrane at the tip, working electrode and an inlet and outlet capillary for the perfusion of enzyme solution. The working electrode and the inlet capillary were inserted into a semi-permeable hollow fiber (o.d.=220 μm). The advantage of the biosensor was that the micro-environment around the working electrode could be easily changed by perfusing the enzyme solution. Glucose oxidase was used in this study and steady state response of the sensor was proportional to the glucose concentration up to 5mM.The detection limit of the … More glucose concentration was 0.01 mM.The decrease in the sensitivity caused by the reduction of dissolved oxygen concentration was overcome by using ferrocene carboxyaldehyde as an electron mediator.2. Quarts crystal microbalance biosensorThe piezoelectric crystals were studied under various operational conditions and were also applied to the determination of human IgG concentration. AT-cut crystals, with a basic resonant frequency of 9 MHz, were modified by immobilizing goat anti-human IgG onto the surface of crystal electrode with tyramine and glutaraldehyde. The immobilization technique improved the long term stability of the biosensor, and the change in frequency caused by the adsorption of material onto the surface of electrode was confirmed to be 1 Hz/ng. The shift in frequency resulting from the reaction of human IgG and goat anti-human IgG correlated with a concentration range of 10μg/ml-50 μg/ml. The suitability of this technique for neurophysiological studies was confirmed for investigation of the chemical fluctuations in vivo. Less