發(fā)布時間：2018-05-22 08:42

  本文選題：誘導電荷電滲 + 液滴調(diào)控��； 參考：《哈爾濱工業(yè)大學》2017年碩士論文

【摘要】：基于微流控技術(shù)的生化反應(yīng)或藥物診斷過程中,使細菌或生物細胞等微小顆�？焖俑患�,并將樣本體積縮減到微流控器件能夠操控的有效范圍是分析過程的最基本環(huán)節(jié)。常規(guī)的顆粒收集方法如介電泳、交流電滲、誘導電荷電滲等大多存在諸如收集效率低等問題,因此,本文提出了一種基于液滴調(diào)控的誘導電荷電滲顆粒高效濃縮及定向收集方法,利用液滴在直通道中構(gòu)建可以靈活調(diào)控的收縮區(qū),并通過收縮區(qū)形成的特殊尾流模式提高顆粒的收集效率,最后通過液滴的調(diào)控實現(xiàn)粒子束的定向收集。首先,分析了誘導電荷電滲顆粒聚集的機理:基于經(jīng)典的RC電路理論推導了正弦穩(wěn)態(tài)信號下懸浮電極表面的電滲滑移流速;通過對微通道內(nèi)流場的數(shù)值求解得到了空間流場的分布特性,闡明了懸浮電極上方反向漩渦形成的流動停滯線與顆粒聚集現(xiàn)象的關(guān)系并研究了誘導電荷電滲的電控特性。其次,揭示了收縮區(qū)影響顆粒收集現(xiàn)象的機理:提出了空間中顆粒運動軌跡的物理描述,分析了顆粒在收縮區(qū)上游的流動誘導電荷電滲聚焦過程;闡明了對稱液滴構(gòu)成的收縮區(qū)尾部特殊的發(fā)散-匯聚模式的機理,解釋了上游泄漏到通道兩側(cè)的顆粒被重新收集的原因;分析了非對稱液滴對流場的影響,歸納了液滴調(diào)控粒子束定向收集的規(guī)律。再次,設(shè)計制作了微芯片并分析了實驗參數(shù)的影響:根據(jù)誘導電滲流的幾何特性,基于實驗器件的關(guān)鍵尺寸設(shè)計了液滴調(diào)控的顆粒高效濃縮芯片和集成芯片;研究了電導率、入口流速和液滴曲率半徑等關(guān)鍵實驗參數(shù)對顆粒收集的影響,優(yōu)選了實驗參數(shù)取值;確定了芯片的加工工藝并進行了實驗準備和實驗平臺的搭建。最后,進行了顆粒高效濃縮實驗和粒子束定向收集實驗:顆粒高效濃縮實驗確認了收縮區(qū)結(jié)構(gòu)的實時可調(diào)控性和用于提高顆粒收集效率的可行性,實驗效果與理論模型相符;粒子束定向收集實驗體現(xiàn)了集成芯片對顆粒的多種操控模式,證明了非對稱液滴對粒子束的定向收集具有準確有效的調(diào)控作用,實驗結(jié)果驗證了本文所提方案在實現(xiàn)顆粒高效濃縮和定向收集方面的有效性。
[Abstract]:In the process of biochemical reaction or drug diagnosis based on microfluidic technology the microparticles such as bacteria or biological cells are rapidly enriched and the sample volume is reduced to the effective range that the microfluidic device can control. Conventional particle collection methods, such as dielectric electrophoresis, alternating current electroosmosis, induced charge electroosmosis, and so on, have problems such as low collection efficiency. In this paper, a method of high efficiency concentration and directional collection of induced charge electroosmotic particles based on droplet control is proposed. The particle collection efficiency is improved by the special wake mode formed in the constriction region, and the directional collection of the particle beam is realized through the droplet regulation. Firstly, the mechanism of induced charge electroosmotic particle aggregation is analyzed. Based on the classical RC circuit theory, the electroosmotic slip velocity on the surface of the suspended electrode is derived under the sinusoidal steady state signal. Through the numerical solution of the flow field in the microchannel, the distribution characteristics of the spatial flow field are obtained, the relationship between the flow stagnation line formed by the reverse vortex over the suspension electrode and the phenomenon of particle aggregation is clarified, and the electrically controlled characteristics of the induced charge electroosmosis are studied. Secondly, the mechanism of particle collection in shrinkage region is revealed. The physical description of particle trajectory in space is presented, and the flow induced charge electroosmotic focusing process of particles upstream in the shrinkage region is analyzed. The mechanism of the special divergence-convergence model in the tail of the contraction region of symmetrical droplets is explained, the reason for the recollection of particles from upstream to both sides of the channel is explained, and the effect of asymmetric droplets on the flow field is analyzed. The rule of directional collection of droplet controlled particle beam is summarized. Thirdly, the microchip is designed and fabricated and the influence of experimental parameters is analyzed. According to the geometric characteristics of induced electroosmotic flow, the droplet controlled particle high efficiency concentration chip and integrated chip are designed based on the key dimensions of the experimental device, and the conductivity of the chip is studied. The influence of the key experimental parameters such as inlet velocity and the radius of curvature of the droplet on the particle collection is optimized. The processing technology of the chip is determined and the experimental preparation and experimental platform are built. Finally, the experiments of particle high efficiency concentration and particle beam directional collection were carried out. The experiment confirmed the real time controllability of the constriction region structure and the feasibility of using it to improve the particle collection efficiency. The experimental results were consistent with the theoretical model. The experiments of particle beam directional collection show that the integrated chip controls the particles in a variety of modes, which proves that the directional collection of asymmetric droplets to particle beams has an accurate and effective control effect. The experimental results verify the effectiveness of the proposed scheme in achieving high efficiency particle concentration and directional collection.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O652.9
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本文編號：1921382