光纤倏逝波生物传感器系统研究

【作者】 李维；

【导师】 许雪梅；

【作者基本信息】 中南大学 ， 物理电子学， 2008， 硕士

【摘要】 光纤倏逝波生物传感器作为生物传感器的一个重要分支,有着30多年的发展历史。由于其具有独特的优势在水质监测、食品卫生检测、生物战剂检测等方面有着巨大的应用潜力。本文在研究了光纤倏逝波生物传感器工作原理和基本结构的基础上,构建了光纤倏逝波生物传感器系统。由于探针产生的荧光信号属于微弱信号,并且伴随则强激光信号和系统噪声,因此怎样从强噪声中提取出微弱的荧光信号是整个系统的关键。针对这个问题,本文从两个方面着手解决:一方面通过结合倏逝波理论和模式匹配理论,采用几何光学的方法对组合型探针结构进行了设计,提高了探针的效率。另一方面由于传统光纤倏逝波生物传感器检测平台分立元件多,系统噪声大的缺点,构建了FPGA+LabVIEW系统平台。通过在FPFA上构造片上子系统,采用NiosⅡ软核处理器作为控制器,实现了对A/D采样、DDS信号产生、UART通讯口的控制。该系统集数据采集、数据传输、调制信号产生于一体,极大的减少了系统分立元件的个数,提高了系统集成度和信噪比。上位机则使用LabVIEW软件,实现了锁相检测、上位机与FPGA的串口数据通讯,界面显示等功能。最后对所构建的光纤倏逝波生物传感器系统进行了实验研究,实验结果表明,系统对Cy5溶液的浓度检测可达0.1umol/L,能满足实际生物物质检测中较高精度的应用要求。系统具有稳定性好、体积小和结构简单的特点,适合现场检测的系统结构要求。更多还原

【Abstract】 Evanescent wave-based optical fiber biosensors is an important branch of biosensor, it has 30 years of development history. Because of its unique advantages, it has great potential for application in terms of water quality monitoring, food hygiene inspection, detection of biological warfare agents. In this paper detection and processing systems is build, based on the study of the principle and the basic structure of the Evanescent wave-based optical fiber biosensor.Because of the weak fluorescence signal from probe which accompanying with the strong laser signal and system noise, so how to extract a weak fluorescent signal from the strong noise is critical to the whole system. In order to solve the problem, we work in two aspects. In on hand, the probe structure is design by using geometrical optics method, through a combination of Evanescent wave theory and pattern matching theory. It can improve the efficiency of the probe. On the other hand, because of the more discrete components and high system noise in traditional evanescent wave-based optical fiber biosensors, we build a platform based on FPGA+LabVIEW. An on-chip system is build, the A/D sampling, signal generator DDS and UART interface are control by Nios II soft-core microprocessor.The system that including data acquisition, data transmission, modulation signal integrated, greatly reduced the number of discrete components system, improve the system integration and SNR. An application softwave providing signal detection by digital lock-in amplifier, data communication with FPGA and Interface display is builded by using LabVIEW.Finally, the experiment is carried on after building the Evanescent wave-based optical fiber biosensors. The experimental results show that the system sensitivity reach to 1nmol/L when detect the Cy5 solution. This biosensors can use in the actual detection of biological material in high precision application requirements. This system has long-term stability, small volume and simple structure which make it suitable for filedwork.更多还原