The efficient and precise extraction of target particles is a crucial prerequisite for achieving accurate detection and analysis in microfluidic cell analysis. In this study, a symmetrical contraction–expansion microchannel with sheath flow was designed, aiming to extract target larger particles from particles of different sizes within the channel. This paper conducted numerical simulations to investigate the three-dimensional migration mechanisms of particles and performed experimental studies to examine the separation performance of particles with different sizes under varying flow rate ratios and different numbers of contraction–expansion structures. The experimental results indicate that at moderate sample flow rates and higher flow rate ratios, microchannels with fewer contraction–expansion structures are likely to achieve better performance in extracting target particles compared to microchannels with a greater number of these structures. Our work advances the application of viscoelastic contraction–expansion microchannels in particle separation. This device is easy to set up in parallel and significantly enhances throughput, providing an accurate and efficient solution for future particle separation applications.

中文翻译：

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粘弹性收缩-膨胀微通道中目标颗粒的高效提取

目标颗粒的高效、精确提取是微流控细胞分析中实现准确检测和分析的关键前提。本研究设计了一种具有鞘流的对称收缩-膨胀微通道，旨在从通道内不同尺寸的颗粒中提取目标较大颗粒。本文通过数值模拟研究了颗粒的三维迁移机制，并通过实验研究了不同尺寸颗粒在不同流量比和不同数量的收缩-膨胀结构下的分离性能。实验结果表明，在中等样品流速和较高流速比下，与具有较多收缩-膨胀结构的微通道相比，具有较少收缩-膨胀结构的微通道可能在提取目标颗粒方面取得更好的性能。我们的工作推进了粘弹性收缩-膨胀微通道在颗粒分离中的应用。该设备易于并行设置，并显着提高吞吐量，为未来的颗粒分离应用提供准确、高效的解决方案。