An integrated gas-liquid droplet microfluidic platform for digital sampling and detection of airborne targets
An integrated gas-liquid droplet microfluidic platform for digital sampling and detection of airborne targets
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DOI：
10.1016/j.snb.2018.03.057
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发表时间：
2018-08
期刊：
影响因子：
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通讯作者：
Pooyan Tirandazi;C. Hidrovo
中科院分区：
文献类型：
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作者：
Pooyan Tirandazi;C. Hidrovo
微流体液滴的使用在许多芯片实验室（Lab-on-a-Chip，简称LAB）应用中已经变得无处不在，从材料合成到新型生物化学传感。在本文中，我们介绍了一种新的液滴为基础的方法，采用气相生成液滴微反应器在微流控流聚焦格式。我们演示了随后的芯片上的过渡，收集和处理的液滴在一个多层PDMS结构内的二级液体载体。所提出的技术具有潜在的应用，在捕获和探测空气中的颗粒和气态蒸汽使用高表面体积皮升液滴。在这种方法中产生的离散的微流体气液界面极大地促进了气态目标分析物吸收和向上浓缩到液滴体积中。基于芯片的单元格式还允许将不同的微流体模块和分析技术集成到该平台中，用于液滴探测，提供高灵敏度的微流控检测系统。在这里，我们演示了样品分配的基本原理，通过捕获和检测在不同的气体浓度下，使用Nessler的反应液滴内的蒸发氨与气液液滴。这项工作的结果提供了一个简单而强大的定量方法，用于确定气态氨，可以进一步扩展到其他气相分析物在下一代的空气中的目标检测器，用于人体呼吸分析和环境监测。
The use of microfluidic droplets has become ubiquitous in many Lab-on-a-Chip (LOC) applications ranging from material synthesis to novel biochemical sensing. In this paper, we introduce a new droplet-based approach that incorporates a gas phase for generating liquid droplet microreactors in a microfluidic flow-focusing format. We demonstrate the subsequent on-chip transition, collection and handling of the droplets in a secondary liquid carrier inside a multilayer PDMS structure. The presented technique has potential applications in capturing and probing airborne particles and gaseous vapors using high surface-to-volume picoliter droplets. The discrete microfluidic gas-liquid interfaces created in this approach, greatly facilitate absorption and up-concentration of a gaseous target analyte into the droplet volume. The chip-based format of the units also allows for different microfluidic modules and analytical techniques to be integrated in this platform for droplet probing, providing highly-sensitive LOC detection systems. Here, we demonstrate the basic principles of sample partitioning with gas-liquid droplets by capturing and detection of vaporized ammonia at different gaseous concentrations using Nessler’s reaction inside the droplets. The results of this work provide a simple and robust quantification approach for determining gaseous ammonia which can be further expanded to other gas-phase analytes in next generation of airborne target detectors for human breath analysis and environmental monitoring.