Microfluidic Sample Preparation Device for Environmental DNA Separation and Washing **********

环境DNA(EDNA)是生物体以极低浓度排泄到环境中的DNA，已成为识别水生系统中危险或濒危物种的一种有效方法。精密生物监测(PBI)为现场检测稀有EDNA提供了一项突破性的技术。它包括一个用于过滤淡水样品的样品制备单元和一个用于检测EDNA的检测单元。该公司的问题与复杂的淡水性质有关，使样品过滤变得复杂，而样品中的悬浮物充当抑制剂，对系统的检测下限和灵敏度产生负面影响。针对上述问题，必须研究一种适用于多种水样、可与公司平台集成、便携、电池供电、低成本的微流控样品制备方案。多半径连续弯曲微通道将被用来利用弹性和惯性力从样品中顺序地提取抑制颗粒，这些力可以根据颗粒的大小施加到感兴趣的颗粒上。两名研究助理(RA)和一名博士生将进行两个阶段的研究。在第一阶段，我们将表征水样的颗粒和生物含量。在第二阶段，我们将利用第一阶段中的信息和我们对流体-颗粒流动的知识来开发和测试微流控设备。从大到小的颗粒将被顺序地从样品中分离出来，在微珠上捕获的DNA含量将从其他分子含量中分离出来，并被洗入干净的缓冲液中，用于PBI系统的检测。我们建议的设备是创新的，因为它将能够提纯已经以非常低的浓度分散在抑制颗粒中的DNA分子，同时能够处理具有非牛顿性质的复杂流体，而不是通常使用的水基溶液。**

Detection of environmental DNA (eDNA), excreted from organisms into the environment at very low concentrations, has emerged as a powerful method for identification of dangerous or at-risk species in aquatic systems. Precision Biomonitoring (PBI) offers a ground-breaking technology for detection of rare eDNA on-field. It includes a sample preparation unit for filtration of freshwater samples and a detection unit for sensing eDNA. Company's problem is associated with the complex freshwater properties making sample filtration complicated, while the suspended matter in the samples act as inhibitors negatively affecting the detection limit and sensitivity of the system. The above problem is significant for which a sample preparation solution must be researched that is 1) effective on a broad range of water samples, 2) integrate-able with company's platform, 3) portable and battery-operated, and 4) low cost.**We propose developing a microfluidic particle separation, DNA isolation and DNA washing device to meet the attributes of environmental sample preparation. Multi-radius serial curved microchannels will be used to sequentially extract inhibitory particles from the sample using elastic and inertial forces that can be applied to particles of interest based on their sizes. Two Research Assistants (RAs) and one PhD student will conduct a two-phase research. In Phase 1, we will characterize the particle and biological content of water samples. In Phase 2, we will use the information in Phase 1 and our knowledge of fluid-particle flow to develop and test the microfluidic device. Particles from large to small will be sequentially separated from the sample and the DNA content, captured on microbeads, will be separated from the other molecular content and washed into clean buffers for detection with the PBI system. Our proposed device is innovative because it will be capable of purifying DNA molecules that are already dispersed at very low concentrations among the inhibitory particles, while being able to process complex fluids with non-Newtonian properties instead of the commonly-used water-based solutions. **