Abstract Droplet microfluidic systems are becoming routine in advanced biochemical studies such as single cell gene expression, immuno profiling, precise nucleic acid quantification (dPCR) and particle synthesis. For all these applications, ensuring droplet monodispersity is critical to minimize the uncertainty due to droplet volume variation. Despite the wide usage of droplet-based microfluidic systems, the limit of monodispersity for droplet generation systems is still unknown. Here, we present an analytical approach that takes into account all the system dynamics and internal/external factors that disturb monodispersity. Interestingly, we are able to model the dynamics of a segmented two-phase flow system using a single-phase flow analogy, electron flow, in electrical circuits. We offer a unique solution and design guidelines to ensure ultra-monodisperse droplet generation. Our analytical conclusions are experimentally verified using a T-junction droplet generator. Equally importantly, we show the limiting experimental factors for reaching the theoretical maximum of monodispersity.

中文翻译：

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单分散液滴生成的理论和实验限制

摘要 液滴微流体系统正在成为高级生化研究的常规，例如单细胞基因表达、免疫分析、精确核酸定量 (dPCR) 和粒子合成。对于所有这些应用，确保液滴的单分散性对于将液滴体积变化引起的不确定性降至最低至关重要。尽管基于液滴的微流体系统被广泛使用，但液滴生成系统的单分散性限制仍然未知。在这里，我们提出了一种分析方法，该方法考虑了干扰单分散性的所有系统动力学和内部/外部因素。有趣的是，我们能够使用电路中的单相流类比电子流来模拟分段两相流系统的动力学。我们提供独特的解决方案和设计指南，以确保产生超单分散液滴。我们的分析结论使用 T 型接头液滴发生器进行了实验验证。同样重要的是，我们展示了达到单分散性理论最大值的限制实验因素。