近20年来,基于半导体离子敏场效应晶体管(ISFET)的生化传感器研究越来越引起人们的关注,目前利用ISFET能够实现对p H、金属离子、血糖、基因和蛋白质等的检测。为了使检测结果准确,在检测过程中需要参比电极保持试液电势稳定。综述了ISFET和传统参比电极的工作原理,分析了参比电极对ISFET检测系统的必要性和传统参比电极的可靠性。介绍了多种易于在芯片上集成的微型化参比电极和参比电极系统并探讨了他们的特点。对ISFET电路模型进行了分析并提出了一种基于微流控技术的金属参比电极系统,结合仿真结果认为微流型金属参比电极系统的尺寸可以控制在毫米量级,具有良好的应用前景。
Over the past two decades, there has been growing interest in the development of bio- sensors based on the concept of the semiconductor ion-sensitive field-effect transistor (ISFET) , which can detect the pH, metal ions, blood glucose, DNA and protein and so on. To achieve accurate detection results, a reference electrode (RE) is required to maintain a stable potential of analytes. Working principles of the ISFET and conventional RE are summarized. The necessity of the RE to ISFET-based detection system and the reliability of the conventional RE are analyzed. A variety of the miniaturized easy-on-chip RE and its system are introduced and their characteristics are discussed. With analysis of ISFET circuit model, a microfluidics-based metal RE system is proposed and miniaturization of the system to millimeter-dimensions is shown viable by simulation, which may open the possibility for its on- chip integration and real-world application.