Using liquid slugs as microreactors and microvessels enable precise control over the conditions of their contents on short-time scales for a wide variety of applications. Particularly for screening applications, there is a need for control of slug parameters such as size and composition. We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of different compositions. The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes. The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

中文翻译：

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微流体装置，用于稳定生成具有单独控制成分的双组分空气中液体段塞。


使用液塞作为微反应器和微容器可以在短时间内精确控制其内容物的条件，适用于各种应用。特别是对于筛选应用，需要控制段塞参数，例如尺寸和成分。我们描述了一种在空气中创建段塞的新微流体方法，每个段塞都包含可以为每个段塞单独选择的尺寸和成分。双组分段塞的形成方法如下：首先计量所需体积的每种试剂，将两个体积合并成端到端的段塞，然后推动段塞以引起混合。体积控制是通过一种新颖的机制实现的：芯片上的两个封闭室最初充满空气，每个室中的阀门短暂打开以进入其中一种试剂。每种试剂的压力可以单独选择，并确定空气压缩量，从而确定进入每个室的液体量。我们描述了工作原理，描述了段塞生成芯片的特征，并演示了不同成分段塞的创建。在这种方法中使用微型阀可以对不同的液体进行稳定的操作，并且还可以处理极小的样品，甚至小到几个段塞体积。后者对于涉及珍贵试剂的应用非常重要，例如优化放射性标记生物分子作为正电子发射断层扫描示踪剂的反应条件。电子补充材料：本文的在线版本 (doi:10.1007/s10404-010-0617-0) 包含补充材料，可供授权用户使用。