本文選題：慣性聚焦　切入點：介電電泳　出處：《中北大學(xué)》2017年碩士論文

【摘要】：隨著微制造技術(shù)的發(fā)展,應(yīng)用于生物學(xué)的集成流體、電場以及光學(xué)元件的芯片發(fā)展迅速。這些芯片充分利用不同的技術(shù)進行樣品的制備以及分析。在樣品制備方面,一種重要的技術(shù)就是粒子分離,其中介電電泳是一種不需要對粒子進行標(biāo)記,對細(xì)胞無損傷,可同時對多細(xì)胞進行操作,而且還可以與其他技術(shù)相結(jié)合進而提高分離效率的方法。傳統(tǒng)的介電泳分離方法多采用斷續(xù)分離的方法,根據(jù)粒子的正負(fù)介電泳不同將一種粒子吸附在電極表面,通過流體的流動將未吸附的粒子沖走從而實現(xiàn)兩種粒子的分離,該種方法所需時間長,需等粒子吸附完全之后才可以進行。其次,為提高分離的效率,避免目標(biāo)粒子被沖走,需設(shè)置較高的電場,引起電熱流的產(chǎn)生,影響分離效果。因此,本文設(shè)計了一種集成慣性聚焦結(jié)構(gòu)的粒子連續(xù)分離介電泳微流控芯片,將慣性聚焦技術(shù)與介電泳分離技術(shù)相結(jié)合,實現(xiàn)粒子快速、高通量的連續(xù)分離。本文首先對慣性聚焦原理和介電泳粒子分離原理進行研究。由粒子在通道中的受力情況分析粒子聚焦的影響因素和粒子所受介電泳大小的影響因素。對聚苯乙烯小球、酵母菌細(xì)胞和NB4細(xì)胞的頻率響應(yīng)特性進行分析,確定不同粒子在芯片中的受力情況,分析其運動趨勢。其次,根據(jù)粒子聚焦原理和分離原理設(shè)計芯片的結(jié)構(gòu)。在通道入口側(cè)壁設(shè)置梯形結(jié)構(gòu)使經(jīng)過的粒子受慣性升力的作用產(chǎn)生聚焦;通道底部光刻一組傾斜叉指電極產(chǎn)生非均勻電場,利用介電泳力和流體曳力的合力使不同的粒子發(fā)生角度不同的偏轉(zhuǎn)進入不同通道,從而實現(xiàn)分離。利用Comsol Multiphysis軟件對芯片內(nèi)部電場進行仿真模擬,優(yōu)化并確定芯片微通道的高度和叉指電極的寬度與間距。再次,加工制作了微流控芯片:根據(jù)芯片功能選取合適的材料,采用光刻工藝在ITO玻璃表面加工微電極,采用PDMS加工帶有聚焦結(jié)構(gòu)的微通道,并對芯片進行氧等離子鍵合,制成實驗所需要的芯片。最后,搭建了實驗平臺,進行了粒子連續(xù)分離實驗:首先,采用微尖電極分別測試聚苯乙烯小球、酵母菌細(xì)胞的臨界頻率,確定二者的分離頻率,并對其進行斷續(xù)分離;其次,采用設(shè)計的電極對聚苯乙烯小球和酵母菌細(xì)胞進行連續(xù)分離,分析流速、電壓對二者分離的影響并且優(yōu)化分離條件,實現(xiàn)二者的連續(xù)分離;最后,對酵母菌細(xì)胞、NB4細(xì)胞和聚苯乙烯小球、NB4細(xì)胞進行連續(xù)分離,并對實驗的分離效率和分離純度進行統(tǒng)計分析。
[Abstract]:With the development of microfabrication technology, microchips used in biology integrated fluid, electric field and optical components are developing rapidly.These chips make full use of different techniques for sample preparation and analysis.In sample preparation, one of the most important techniques is particle separation, in which dielectric electrophoresis is one that does not need to label particles, does not damage cells, and can operate on multiple cells at the same time.Moreover, it can be combined with other techniques to improve the separation efficiency.The traditional separation methods of dielectric electrophoresis usually adopt the method of intermittent separation. According to the positive and negative dielectric electrophoresis of particles, one particle is adsorbed on the electrode surface, and the unadsorbed particles are washed away by the flow of fluid to realize the separation of the two kinds of particles.This method takes a long time and can not be carried out until the particle adsorption is complete.Secondly, in order to improve the separation efficiency and avoid the target particles being washed away, it is necessary to set a higher electric field to cause the electrothermal current and affect the separation effect.Therefore, a microfluidic chip integrated with inertial focusing structure for continuous separation and dielectric electrophoresis of particles is designed, which combines the inertial focusing technology with the dielectric electrophoresis separation technology to realize the rapid and high-throughput continuous separation of particles.In this paper, the inertial focusing principle and the separation principle of dielectric electrophoresis particles are studied.The influence factors of particle focusing and the size of dielectric electrophoresis were analyzed according to the stress of particles in the channel.The frequency response characteristics of polystyrene pellets, yeast cells and NB4 cells were analyzed.Secondly, the structure of the chip is designed according to the principle of particle focusing and separation.The trapezoidal structure on the side wall of the entrance of the channel causes the particles passing through to be focused by inertial lift, and a set of tilted cross finger electrodes at the bottom of the channel generate a non-uniform electric field.By using the combination of electrophoretic force and fluid drag force, different particles are deflected into different channels at different angles, and the separation is realized.The internal electric field of the chip is simulated by Comsol Multiphysis software, and the height of the microchannel and the width and spacing of the interDigital electrode are optimized and determined.Thirdly, the microfluidic chip is fabricated. According to the function of the chip, the appropriate materials are selected, the microelectrode is fabricated on the surface of ITO glass by photolithography, the microchannel with focusing structure is fabricated by PDMS, and the chip is bonded by oxygen plasma.Make the chips needed for the experiment.Finally, the experiment platform was set up and the particle separation experiments were carried out. Firstly, the critical frequency of polystyrene pellets and yeast cells was measured by microtip electrode, and the separation frequency was determined and separated intermittently.Continuous separation of polystyrene pellets and yeast cells was carried out by using the designed electrode. The effects of flow rate and voltage on the separation were analyzed and the separation conditions were optimized to realize the continuous separation of polystyrene pellets and yeast cells.The separation efficiency and purity of yeast cell line Nb4 and polystyrene pellet Nb4 cells were analyzed statistically.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN492

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本文編號：1701403