基于诱导电荷电渗聚集与介电泳偏移的颗粒分离研究
发布时间：2018-08-16 17:37
【摘要】：连续性介电泳颗粒分离是微流控系统中对微纳米样品进行精确操控的核心手段,因为它在癌症的早期诊断,水质的污染分析等方面都有重要的应用。通常情况下,连续性介电泳颗粒分离的过程需要将样本聚集为宽度很小的粒子流以保证颗粒沿着相同轨迹运动并从相同的位置进入介电泳力作用范围。然而,目前实现样本颗粒聚集的方法只有流体挤压效应,并且这种效应需要冗余的外接设备,价格昂贵的微泵,复杂的多相流体操控。这使得微流芯片的高度集成化成了一个重大的挑战。诱导电荷电渗聚集是发生在物体表面的一种电化学效应,已经被证明是一种有效的颗粒聚集方法。因此,本文基于诱导电荷电渗流体聚集和介电泳偏移提出了一种新的颗粒分离方法。首先,分析了颗粒分离方法中的物理机理:基于对导体表面在交流电场中双电层的形成机理的分析,推导了复振幅形式的诱导电荷电渗滑移速度公式;基于介电颗粒在非均匀电场中的偏极化效应,推导了颗粒在交流电场中受到介电泳力的形式;考虑电场,流场,重力场等因素的影响,分析了介电颗粒的受力情况并推导了颗粒在微流控芯片中的速度方程和轨迹方程。其次,对微流控芯片的关键位置进行初步设计并确定了合适的工作参数:根据设计要求,对聚集区域,过渡区域,分离区域进行了初步设计;通过数值仿真研究确定了聚集区域的通道高度和工作参数;基于拉格朗日颗粒轨迹追踪的方法研究了过渡区域的结构对粒子流状态的影响规律;耦合电场,流场,重力场,通过数值仿真确定了适合颗粒分离的通道尺寸,分析了粒子流入口位置对颗粒分离效果的影响。再次,完成了微流控芯片的整体结构设计与加工及实验平台的搭建:从改善整体性能和加工的角度出发,进行了微流控芯片的整体结构设计;运用标准软光刻等技术完成了微流控芯片的加工;连接实验器材,完成了实验平台的搭建。最后,在微流控芯片中进行了系统实验:进行了颗粒诱导电荷电渗聚集特性和介电泳偏移特性研究;通过综合实验研究了入口流速对颗粒分离效果的影响,并对最佳状态下颗粒分离效率进行了评估。
[Abstract]:Continuous meso-electrophoresis particle separation is the core method for accurate manipulation of microfluidic system, because it has important applications in the early diagnosis of cancer and the analysis of water pollution. In general, the process of separation of continuous meso-electrophoretic particles requires that the samples be clustered into a very small particle flow in order to ensure that the particles move along the same trajectory and move from the same position to the range of action of the medium electrophoretic force. However, the only way to achieve particle aggregation is the squeeze effect, which requires redundant external devices, expensive micropumps, and complex multiphase fluid manipulation. This makes the high degree of integration of microfluidic chips into a major challenge. Electroosmotic aggregation induced by charge is an electrochemical effect on the surface of an object, which has been proved to be an effective method for particle aggregation. Therefore, a new particle separation method is proposed based on the induced charge electroosmotic fluid aggregation and dielectric migration. Firstly, the physical mechanism of the particle separation method is analyzed. Based on the analysis of the formation mechanism of the double layer on the conductor surface in the alternating current field, the formula of the induced charge electroosmotic slip velocity in the form of complex amplitude is derived. Based on the polarization effect of dielectric particles in non-uniform electric field, the form of dielectric electrophoretic force in alternating current field is deduced, and the influence of electric field, flow field, gravity field and other factors are considered. The stress of dielectric particles is analyzed and the velocity equation and trajectory equation of particles in microfluidic chip are derived. Secondly, the key position of the microfluidic chip is preliminarily designed and the appropriate working parameters are determined: according to the design requirements, the initial design of the aggregation region, the transition region and the separation region is carried out; The channel height and working parameters of the agglomeration region are determined by numerical simulation. The influence of the structure of the transition region on the particle flow state is studied based on the Lagrangian particle trajectory tracing method; the coupling electric field, the flow field, the gravity field, the coupled electric field, the flow field, the gravity field, The size of the channel suitable for particle separation was determined by numerical simulation, and the influence of the inlet position of particle flow on the particle separation effect was analyzed. Thirdly, the whole structure design and machining of microfluidic chip and the construction of experimental platform are completed. From the point of view of improving the overall performance and machining, the whole structure design of microfluidic chip is carried out. The fabrication of microfluidic chip is accomplished by using standard soft lithography technology, and the experimental platform is built by connecting the experimental equipment. Finally, systematic experiments were carried out in microfluidic chip. The characteristics of particle induced charge electroosmotic aggregation and dielectric electrophoresis migration were studied, and the effect of inlet velocity on particle separation was studied. The particle separation efficiency was evaluated at the best condition.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O658.9
本文编号：2186698
[Abstract]:Continuous meso-electrophoresis particle separation is the core method for accurate manipulation of microfluidic system, because it has important applications in the early diagnosis of cancer and the analysis of water pollution. In general, the process of separation of continuous meso-electrophoretic particles requires that the samples be clustered into a very small particle flow in order to ensure that the particles move along the same trajectory and move from the same position to the range of action of the medium electrophoretic force. However, the only way to achieve particle aggregation is the squeeze effect, which requires redundant external devices, expensive micropumps, and complex multiphase fluid manipulation. This makes the high degree of integration of microfluidic chips into a major challenge. Electroosmotic aggregation induced by charge is an electrochemical effect on the surface of an object, which has been proved to be an effective method for particle aggregation. Therefore, a new particle separation method is proposed based on the induced charge electroosmotic fluid aggregation and dielectric migration. Firstly, the physical mechanism of the particle separation method is analyzed. Based on the analysis of the formation mechanism of the double layer on the conductor surface in the alternating current field, the formula of the induced charge electroosmotic slip velocity in the form of complex amplitude is derived. Based on the polarization effect of dielectric particles in non-uniform electric field, the form of dielectric electrophoretic force in alternating current field is deduced, and the influence of electric field, flow field, gravity field and other factors are considered. The stress of dielectric particles is analyzed and the velocity equation and trajectory equation of particles in microfluidic chip are derived. Secondly, the key position of the microfluidic chip is preliminarily designed and the appropriate working parameters are determined: according to the design requirements, the initial design of the aggregation region, the transition region and the separation region is carried out; The channel height and working parameters of the agglomeration region are determined by numerical simulation. The influence of the structure of the transition region on the particle flow state is studied based on the Lagrangian particle trajectory tracing method; the coupling electric field, the flow field, the gravity field, the coupled electric field, the flow field, the gravity field, The size of the channel suitable for particle separation was determined by numerical simulation, and the influence of the inlet position of particle flow on the particle separation effect was analyzed. Thirdly, the whole structure design and machining of microfluidic chip and the construction of experimental platform are completed. From the point of view of improving the overall performance and machining, the whole structure design of microfluidic chip is carried out. The fabrication of microfluidic chip is accomplished by using standard soft lithography technology, and the experimental platform is built by connecting the experimental equipment. Finally, systematic experiments were carried out in microfluidic chip. The characteristics of particle induced charge electroosmotic aggregation and dielectric electrophoresis migration were studied, and the effect of inlet velocity on particle separation was studied. The particle separation efficiency was evaluated at the best condition.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O658.9
【参考文献】
相关期刊论文 前2条
1 TAO Ye;REN Yukun;YAN Hui;JIANG Hongyuan;;Continuous Separation of Multiple Size Microparticles using Alternating Current Dielectrophoresis in Microfluidic Device with Acupuncture Needle Electrodes[J];Chinese Journal of Mechanical Engineering;2016年02期
2 ;DC dielectrophoresis separation of marine algae and particles in a microfluidic chip[J];Science China(Chemistry);2012年04期
相关博士学位论文 前2条
1 陶冶;基于液滴微流控的病毒颗粒检测与分选关键技术研究[D];哈尔滨工业大学;2016年
2 任玉坤;微粒与微流体交流电动操控机理及实验研究[D];哈尔滨工业大学;2011年
相关硕士学位论文 前2条
1 贾延凯;基于新型3D电极的介电泳微粒分离微流控芯片研究[D];哈尔滨工业大学;2014年
2 任玉坤;基于介电泳力的微粒子收集机理分析与实验研究[D];哈尔滨工业大学;2008年
，本文编号：2186698
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2186698.html
教材专著
