基于激光散射效应的微流控芯片寄生虫免标记实时检测方法研究

Parasites in drinking water,such as cryptosporidium parvum and giardia lambia, can cause many kinds of intestinal illnesses,such as diarrhea and vomiting,and even fatal deaths. Currently, the standard method for detection of cryptosporidium parvum and giardia lambia is USEPA 1623 method. This method consists of many boring procedures, and requires fluorescent labeling. The limitations of this method also include the high cost and time consuming. This project proposes an optofluidic detection system, which integrates microfluidics and laser scattering technology. The system could identify the two parasites by analyzing the laser scattering patterns from the parasites flowing in the microfluidic channel, and it can overcome the shortages of current method, and realizes a real-time monitoring of parasites in drinking water without labeling..In the project, a physical model of the laser scattered by parasites is built firstly, and the laser scattering patterns are simulated by using FDTD method. The influence of crucial parameters of the detection system and physical parameters of the parasites on the scattering patterns are analyzed and studied. Followingly, a microfluidic chip and a laser scattering module for collection of laser scattering pattern of a single particle are designed, and a laser scattering microfluidic detection system with high accuracy and S/N ratio is built, and a principal component analysis(PCA) algorithm is developed to recognize the patterns. Finally, the experimental studies on the performance of the detection system is carried out. This project aims to solve the problems of establishment of laser scattering physical model,design of microfluidic laser scattering system, and extraction and recognition of scattering patterns. The project can lay a solid theoretical and technological foundation for the application of this technology into the detection of microorganisms in drinking water.

饮用水中隐孢子虫和贾第鞭毛虫会引起呕吐和腹泻等疾病，严重时可致死亡。目前，国际上两虫标准检测方法为美国EPA 1623方法，该方法步骤繁琐，需要荧光标记，成本高，检测时间长。本项目提出了一种集成微流控芯片技术和激光散射方法的微流光学检测系统，通过分析微流通道内流动寄生虫特异性的激光散射图案进行两虫识别，可克服当前检测方法不足，实现两虫免荧光标记实时检测。 .本项目首先建立寄生虫等微生物的激光散射物理模型，利用FDTD方法模拟散射图案，并仿真分析光学系统主要参数和微生物的特征物理参数对于散射图案的影响；其次，设计微流芯片及激光散射图案采集系统，建立高精度和高信噪比的激光散射微流控动态检测系统，开发主成份分析算法对散射图案进行识别；最后开展检测系统特性的实验研究。本项目旨在解决微流光学检测系统的设计、激光散射图案的获取和识别等问题，为该方法用于饮用水中微生物检测奠定理论和技术基础。

饮用水中隐孢子虫和贾第鞭毛虫会引起呕吐和腹泻等疾病，危害人民群众的身体健康和生命安全。目前，国际上两虫标准检测方法为美国EPA 1623方法，该方法需要荧光标记，步骤繁琐，成本高，检测时间长。本项目提出了一种集成微流控芯片技术和激光散射方法的微流光学检测方法，通过分析寄生虫特异性的激光散射图案进行两虫识别，可克服当前检测方法不足，实现两虫免荧光标记快速检测。.项目建立了寄生虫卵激光散射物理模型，模拟了单个隐孢子虫和贾第鞭毛虫的激光散射图案；分析设计了微流控浓缩芯片和微流控检测芯片，利用光刻和深硅刻蚀工艺制造了高回收率微流控浓缩芯片和高信噪比微流控检测芯片；开发了用于激光散射图案的主成分分析识别算法。建立了一套激光微流控水源性寄生虫快速检测系统，获取了单个寄生虫卵的激光散射图案。开展了检测系统检测特性的研究，对于寄生虫浓度在0～600 个/10L 范围内的10L 饮用水进行了测试，平均检测精度优于72%，检测时间小于1小时。该方法解决了微流控芯片快速浓缩和单个微粒微弱激光散射信号获取等问题，为液态生物医疗样品中微生物的无标记快速检测奠定了理论和技术基础。