微纳粒子介电泳与流体对流传质过程的耦合机理研究

Efficient enrichment and rapid detection of immunoglobulins(IgG) in blood or urine is the basis of early diagnosis. It shows that the target IgG can be well concentrated and manipulated to get a higher overall or local concentration in the microchannel. Thus the rapid diagnosis is improved due to the dielectrophoresis as well as the fluid convection and mass transfer within the channel. However, the flow convection and mass transfer were not in consideration in the current dielectrophoresis theory system. And the effects of particle enrichment on electric field, flow field contribution and temperature gradient were also ignored. So the mechanism of dielectrophoretic effects coupled with flow convection and mass transfer is not clear yet. We aim to study the particle motion behaviors under the intervention of fluid flow, and the effects of particle motions on the flow field herein. Then the model of dielectrophoresis coupled with flow field is setup to reveal the logic implications between the particle dielctrophoresis and flow convection and mass transfer. As a result, the theoretical foundations of microparticle enrichment, sensing and control are solved based on the synergistic effects of multi-physics. Finally, microfluidic chips are to be developed and integrated with smartphone for low concentration IgG enrichment and rapid biosensing in blood or urine. This research has important theoretical and practical significance for the disease diagnosis, especially for the early warning and prevention of large scale infectious diseases.

对血液、尿液中低浓度免疫球蛋白的高效富集和快速检测是疾病早期诊断的重要依据。研究表明，利用介电泳效应和流场的对流传质过程对免疫球蛋白进行富集和操控，可显著提高其在微通道内的整体或局部浓度，实现快速诊断。但目前的介电泳理论未考虑流场的干预，流场理论也未涉及粒子的富集对电场、流场、温度梯度等物理过程的影响，微纳粒子介电泳和流体对流传质过程的耦合机制尚不明确。本项目拟借助仿真和实验手段，研究流场干预下粒子的运动，以及粒子的运动对流场所产生的影响，进而揭示微纳粒子介电泳和流体对流传质过程的内在联系，建立“介电泳-流场”耦合模型，从多种物理效应协同的角度解决微纳粒子高效富集、传感和控制的基础问题。最后，拟开发微流控芯片，并与智能手机集成，实现对血液、尿液中低浓度免疫球蛋白的高效富集和快速检测。研究成果对疾病的早期诊断尤其是大规模传染病的预警和防控具有重要的理论和现实意义。

对血液、尿液中低浓度免疫球蛋白的高效富集和快速检测是疾病早期诊断的重要依据。研究表明，电极边缘附近的介电泳效应最强，微通道内流体的ACET流动可将通道内远离电极附近的微纳粒子通过对流产生的漩涡输送到电极附近，进而使其受到较强的介电泳力产生快速富集。本课题的主要研究内容和重要成果有：（1）利用介电泳效应和流场的对流传质过程对免疫球蛋白进行富集和操控，可显著提高其在微通道内的整体或局部浓度，从而实现对目标检测物的快速甄别和检测。（2）通过研究流场的对流与传质过程干预下微纳粒子的运动行为，解决了基于交流电热和介电泳效应对微通道内微纳介电粒子(如抗体)进行快速富集和检测的基本科学问题，并进行了相关的基础实验研究，为低浓度抗体的快速富集和检测提供依据。（3）开发了便携式显微成像系统，与微流控芯片、智能手机集成，通过自主开发的智能终端APP，可以实现对微米尺度细胞的成像和自动识别。特别地，开发了基于智能终端的牛奶体细胞计数系统，用于奶牛隐形乳房炎的初步诊断。（4）利用微纳粒子介电泳效应与流体对流传质的耦合效应，可以实现对血清中目标蛋白的高效富集和快速检测。特别地，本课题开发了低成本快速免疫检测微流控芯片，在实现了一分钟内的快速免疫检测，判断血清中是否含有阳性D-dimer血栓因子。该研究成果对疾病的早期诊断尤其是基于芯片实验室的大规模传染病的预警和防控具有重要的理论和现实意义。