Microscopic droplets or slugs of mixed reagents provide a convenient platform for performing large numbers of isolated biochemical or chemical reactions for many screening and optimization applications. Myriad microfluidic approaches have emerged for creating droplets or slugs with controllable size and composition, generally using an immiscible carrier fluid to assist with the formation or merging processes. We report a novel device for generation of liquid slugs in air when the use of a carrier liquid is not compatible with the application. The slug generator contains two adjacent chambers, each of which has a volume that can be digitally adjusted by closing selected microvalves. Reagents are filled into the two chambers, merged together into a contiguous liquid slug, ejected at the desired time from the device using gas pressure, and mixed by flowing in a downstream channel. Programmable size and composition of slugs is achieved by dynamically adjusting the volume of each chamber prior to filling. Slug formation in this fashion is independent of fluid properties and can easily be scaled to mix larger numbers of reagents. This device has already been used to screen monomer ratios in supramolecular nanoparticle assembly and radiolabeling conditions of engineered antibodies, and here we provide a detailed description of the underlying device.

中文翻译：

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按需生成和混合具有数字可编程成分和尺寸的液包气段塞


混合试剂的微观液滴或团块提供了一个方便的平台，可以为许多筛选和优化应用进行大量分离的生化或化学反应。已经出现了多种微流体方法来产生具有可控尺寸和成分的液滴或段塞，通常使用不混溶的载体流体来协助形成或合并过程。我们报告了一种当载液的使用与应用不兼容时在空气中产生液塞的新型装置。段塞发生器包含两个相邻的室，每个室的容积都可以通过关闭选定的微型阀进行数字调节。试剂被填充到两个室中，合并在一起形成连续的液塞，在所需的时间使用气压从设备中喷射出来，并通过在下游通道中流动而混合。通过在填充之前动态调整每个室的体积，可以实现可编程的尺寸和成分。这种方式的段塞形成与流体特性无关，并且可以轻松扩展以混合更多数量的试剂。该设备已用于筛选超分子纳米颗粒组装中的单体比例和工程抗体的放射性标记条件，在这里我们提供了基础设备的详细描述。