Droplet microfluidics systems hold great promise in their ability to conduct high-throughput assays for a broad range of life science applications. Despite their promise in the field and capability to conduct complex liquid handling steps, currently, most droplet microfluidic systems used for real assays utilize only a few droplet manipulation steps connected in series, and are often not integrated together on a single chip or platform. This is due to the fact that linking multiple sequential droplet functions within a single chip to operate at high efficiency over long periods of time remains technically challenging. Considering sequential manipulation is often required to conduct high-throughput screening assays on large cellular and molecular libraries, advancements in sequential operation and integration are required to advance the field. This current limitation greatly reduces the type of assays that can be realized in a high-throughput droplet format and becomes more prevalent in large library screening applications. Here we present an integrated multi-layer droplet microfluidic platform that can handle large numbers of droplets with high efficiency and minimum error. The platform combines two-photon photolithography-fabricated curved microstructures that allow high-efficiency (99.9%) re-flow of droplets and a unique droplet cleaving that automatically synchronizes paired droplets enabling high-efficiency (99.9%) downstream merging. We demonstrate that this method is applicable to a broad range of droplet sizes, including relatively large droplet sizes (hundreds of micrometers in diameter) that are typically more difficult to manipulate with high efficiency, yet are required in many cell assay applications requiring large organisms or multiple incubation steps. The utility of this highly efficient integrated droplet microfluidic platform was demonstrated by conducting a mock antibiotic screening assay against a bacterial pathogen. The approach and system presented here provides new avenues for the realization of ultra-high-efficiency multi-step droplet microfluidic systems with minimal error.

中文翻译：

---

超高效液滴微流控平台，使用自动同步的液滴配对和合并。

液滴微流体系统在进行广泛的生命科学应用中进行高通量分析的能力方面具有广阔的前景。尽管它们在该领域中具有前景并能够执行复杂的液体处理步骤，但是，目前，大多数用于实际测定的液滴微流体系统仅利用了串联连接的几个液滴处理步骤，并且通常没有集成在一起在单个芯片或平台上。这是由于以下事实：在单个芯片中链接多个顺序的小滴功能以长时间高效地运行仍然在技术上具有挑战性。考虑到在大型细胞和分子文库上进行高通量筛选测定通常需要顺序操作，因此需要顺序操作和整合方面的进展来推动该领域的发展。当前的局限性极大地减少了可以以高通量液滴形式实现的化验类型，并且在大型文库筛选应用中变得更加普遍。在这里，我们提出了一个集成的多层液滴微流控平台，该平台可以高效且最小的误差处理大量的液滴。该平台结合了双光子光刻制造的弯曲微结构，可实现液滴的高效（99.9％）回流，并具有独特的液滴切割功能，该功能可自动同步配对的液滴，从而实现高效（99.9％）的下游合并。我们证明了该方法适用于各种液滴尺寸，包括相对较大的液滴尺寸（直径数百微米），通常难以高效地对其进行操纵，但是在许多需要大型生物体或多个孵育步骤的细胞分析应用中仍然需要。通过对细菌病原体进行模拟抗生素筛选试验，证明了这种高效的集成液滴微流控平台的实用性。此处介绍的方法和系统为实现具有最小误差的超高效多步液滴微流控系统提供了新途径。