基于PCB的微流控芯片的制备及其在液滴操控中的应用

发布时间：2018-08-14 16:07

【摘要】：微流控芯片作为生物化学的分析平台,近年来在细胞分析、DNA分析、药物研究等众多领域获得了极为广泛的应用,微流控芯片的制备是微流控芯片系统中一个非常重要的研究内容。传统的微流控芯片的制备一般是基于光刻方法进行的,对加工设备的要求很高,价格昂贵,并且芯片制备周期较长,其他的微流控芯片制备方法如激光刻蚀法、热压法等也存在工艺复杂、成本较高的问题,为了降低芯片的加工难度,一些研究者基于印刷电路板(Printed circuit board, PCB)来制备微流控芯片,不过依然存在键合成本较高、键合强度不牢的问题。对此,本课题成功摸索出了一套廉价、快速、便捷的聚二甲基硅氧烷(Polydimethylsiloxane, PDMS)微流控芯片的加工工艺,与光刻法相比,芯片制备成本降到了原来的1/10,芯片制备周期缩短为了4天。进一步地,基于采用PCB方法制备得到的PDMS微流控芯片,我们成功实现了对液滴的有效操控,这对于液滴微流控具有重要的意义。主要的研究内容和成果如下：1、基于使用PCB作为模具制备PDMS微流控芯片的可行性,我们用Protel设计了微流控芯片的结构,然后将PCB文件交给厂家制备得到PCB。以PCB作为阳模,采用模塑法将PCB表面凸起的铜箔的形状转印到PDMS上,采用热压法将表面有微流道结构的PDMS与一片平整的PDMS键合,实现PDMS微流控芯片的制备。通过对芯片的显微结构的分析,我们发现制备得到的芯片的流道的深度为70um,流道宽度的最小尺寸可以达到150um；从芯片的微流体实验的结果来看,芯片没有发生阻塞和漏液现象,证明了芯片的强度可以耐受流体的压力。2、基于PCB的方法,我们制备了具有T型结构和流动聚焦结构的PDMS微流控芯片。然后,我们分别在两个芯片上进行了油相速度为50ul/h、80ul/h、100ul/h,水相速度分别从10ul/h到50ul/h下的液滴产生实验。我们统计了油相速度为50ul/h、水相速度为10ul/h下,两种结构生成液滴的大小和频率,发现两种结构生成的液滴大小是比较均一的、生成液滴的频率也是比较稳定的。进一步地,我们统计了不同油相速度和水相速度下,两种结构生成液滴的大小,发现生成液滴的大小与油相速度成反比,与水相速度成正比。3、基于PCB的方法,我们制备了不同结构的PDMS微流控芯片,实现了对液滴的基本操控。具体包括：(1)、在微流道中分别引入了对称T型和不对称T型结构,实现了液滴的等分分裂和不等分分裂；(2)、在微流道中引入一个腔体实现了液滴的融合,并通过一个Y型结构改变了融合后液滴的表面活性剂的浓度,增加了融合后的液滴的表面张力和稳定性；(3)、在微流道中引入了一个蛇形弯曲结构来拉伸折叠液滴,从而实现了液滴内组分的有效混合；(4)、在微流道中引入了一个T型结构,在一个已有液滴中引入了新的组分,从而实现了液滴加样的功能；(5)、在微流道中引入了两个不同宽度的流道,制备了一个具有两个深度的PDMS微流控芯片,基于大小液滴的流阻的不同,实现了大小液滴的有效分选。
[Abstract]:Microfluidic chips have been widely used in many fields, such as cell analysis, DNA analysis and drug research. The preparation of microfluidic chips is a very important research content in microfluidic chips. In order to reduce the difficulty of chip fabrication, some researchers fabricate microfluidics based on printed circuit board (PCB) in order to reduce the difficulty of chip fabrication. However, there are still some problems such as the high cost of bonding synthesis and the weak bonding strength. In this paper, a cheap, fast and convenient processing technology of polydimethylsiloxane (PDMS) microfluidic chip has been successfully explored. Compared with photolithography, the cost of chip preparation has been reduced to 1/10 of the original, and the cycle of chip preparation has been reduced. Further, based on the PDMS microfluidic chip fabricated by PCB method, we have successfully realized the effective control of droplets, which is of great significance for droplet microfluidic control. The main research contents and achievements are as follows: 1. Based on the feasibility of using PCB as a mold to fabricate PDMS microfluidic chip, we use Protel to set it up. The structure of the microfluidic chip is considered, and then the PCB file is handed over to the manufacturer to prepare the PCB. The shape of the copper foil on the surface of the PCB is transferred to the PDMS by molding method. The PDMS with the microfluidic structure on the surface is bonded with a flat PDMS by hot pressing method to realize the preparation of the PDMS microfluidic chip. Microstructure analysis showed that the depth of the channel was 70 um and the minimum width of the channel was 150 um. According to the results of microfluidic experiment, there was no blockage and leakage, which proved that the strength of the chip could withstand the pressure of the fluid. 2. Based on the PCB method, we fabricated the chip. PDMS microfluidic chips with T-type structure and flow focusing structure were used. Then, the droplet generation experiments were carried out on the two chips with oil phase velocity of 50 ul/h, 80 ul/h and 100 ul/h, and water phase velocity of 10 ul/h to 50 ul/h, respectively. Furthermore, we calculated the droplet size of the two structures under different oil phase velocities and water phase velocities. It was found that the droplet size was inversely proportional to the oil phase velocity and was proportional to the water phase velocity. Methods: PDMS microfluidic chips with different structures were fabricated to realize the basic manipulation of droplets, including: (1) symmetrical T-type and asymmetrical T-type structures were introduced into the microfluidic channel to realize the equal and unequal splitting of droplets; (2) a cavity was introduced into the microfluidic channel to realize the fusion of droplets. The Y-shaped structure changed the concentration of surfactant and increased the surface tension and stability of the fused droplets; (3) a snake-shaped bending structure was introduced to stretch the folded droplets in the micro-channel, thus achieving effective mixing of the components in the droplets; (4) a T-shaped structure was introduced in the micro-channel and a T-shaped structure was introduced in the micro-channel. New components were introduced into the existing droplets to realize the function of droplet sampling. (5) Two different width channels were introduced into the micro-channel, and a PDMS microfluidic chip with two depths was fabricated.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN492

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