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勾易行, 孙国伟, 孙润泽, 李子瑞. 压力驱动双膜离子浓差极化系统中带电粒子分离与富集数值模拟研究[J]. 力学学报.
引用本文: 勾易行, 孙国伟, 孙润泽, 李子瑞. 压力驱动双膜离子浓差极化系统中带电粒子分离与富集数值模拟研究[J]. 力学学报.
Numerical simulation of charged particle separation and enrichment in a pressure driven dual-membrane ion concentration polarization system[J]. Chinese Journal of Theoretical and Applied Mechanics.
Citation: Numerical simulation of charged particle separation and enrichment in a pressure driven dual-membrane ion concentration polarization system[J]. Chinese Journal of Theoretical and Applied Mechanics.

压力驱动双膜离子浓差极化系统中带电粒子分离与富集数值模拟研究

Numerical simulation of charged particle separation and enrichment in a pressure driven dual-membrane ion concentration polarization system

  • 摘要: 微纳流体器件中的离子浓差极化现象可以高效富集低浓度粒子,但多种粒子的富集与分离仍然存在分离效果差的问题。在本文中,我们提出了一种基于离子浓差极化现象的粒子分离与富集系统,该系统通过设置两个离子交换膜构建两个微纳界面调控带电粒子所受的电场环境,依据不同淌度粒子所受电场力和流体曳力的竞争机制使得DNA和BSA在不同膜前富集,进而实现二者的区位分离。数值模拟分析了外部压力和不同离子交换膜跨膜电压的影响,其中,入口压力控制通道内的流体流速以影响粒子所受的流体曳力,跨膜电压调节影响流场内由于离子浓差极化形成的电场以影响粒子所受的电场力。数值模拟分析表明双膜系统的分离机制为不同耗尽区产生的高电场对两种粒子施加的电场力与其本身所受的流体曳力的竞争作用,即在第一个膜前BSA所受的电场力小于流体曳力,而DNA的受力则相反。同时,本文揭示了离子浓差极化形成下带电粒子在压力驱动双膜系统的富集机制。结果表明,当Vcm1=5VT,Vcm2=10VT,P0=400Pa时,DNA和BSA可实现高效的区位分离且二者的富集倍数可分别达到1.2×105和6×104,这将为多带电粒子的同时富集并分离及多级离子浓差极化级联系统设计提供新的思路和理论指导。

     

    Abstract: Ion concentration polarization phenomenon in micro-nano fluidic devices can efficiently enrich low-concentration particles, yet there remains an issue with the separation and enrichment of multiple particles with poor separation efficiency. In this paper, we propose a particle separation and enrichment system based on the ion concentration polarization phenomenon. This system constructs two micro-nano interfaces by employing two ion exchange membranes to regulate the electric field environment experienced by charged particles. This mechanism enables the differential enrichment of DNA and BSA in front of different membranes, thus achieving their positional separation. Numerical simulations analyze the effects of external pressure and different transmembrane voltages of the ion exchange membranes. Specifically, inlet pressure controls the fluid velocity within the channel, affecting the fluid drag force experienced by particles. The transmembrane voltage regulates the electric field formed due to ion concentration polarization within the flow field, affecting the electric field force experienced by particles. The numerical simulation analysis demonstrates that the separation mechanism of the dual-membrane system involves the competition between the high electric field generated in different depletion zones and the fluid drag force applied to the particles. This competition scenario indicates that in front of the first membrane, the electric field force on BSA is smaller than the fluid drag force, while the opposite is observed for DNA. Simultaneously, this paper reveals the mechanism of charged particle enrichment in a pressure-driven dual-membrane system formed under ion concentration polarization. The results indicate that when Vcm1=5VT, Vcm2=10VT, and P0=400Pa, efficient positional separation of DNA and BSA is achievable. The enrichment multiples for DNA and BSA respectively reach 1.2×105 and 6×104. This offers a new perspective and theoretical guidance for simultaneously enriching and separating multiple charged particles and the design of multistage ion concentration polarization cascade system.

     

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