Bajgiran Khashayar R, Cordova Alejandro S, Elkhanoufi Riad, Dorman James A, Melvin Adam T
Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
Micromachines (Basel). 2021 Oct 4;12(10):1211. doi: 10.3390/mi12101211.
Droplet microfluidics offers a wide range of applications, including high-throughput drug screening and single-cell DNA amplification. However, these platforms are often limited to single-input conditions that prevent them from analyzing multiple input parameters (e.g., combined cellular treatments) in a single experiment. Droplet multiplexing will result in higher overall throughput, lowering cost of fabrication, and cutting down the hands-on time in number of applications such as single-cell analysis. Additionally, while lab-on-a-chip fabrication costs have decreased in recent years, the syringe pumps required for generating droplets of uniform shape and size remain cost-prohibitive for researchers interested in utilizing droplet microfluidics. This work investigates the potential of simultaneously generating droplets from a series of three in-line T-junctions utilizing gravity-driven flow to produce consistent, well-defined droplets. Implementing reservoirs with equal heights produced inconsistent flow rates that increased as a function of the distance between the aqueous inlets and the oil inlet. Optimizing the three reservoir heights identified that taller reservoirs were needed for aqueous inlets closer to the oil inlet. Studying the relationship between the ratio of oil-to-water flow rates (Φ) found that increasing Φ resulted in smaller droplets and an enhanced droplet generation rate. An ANOVA was performed on droplet diameter to confirm no significant difference in droplet size from the three different aqueous inlets. The work described here offers an alternative approach to multiplexed droplet microfluidic devices allowing for the high-throughput interrogation of three sample conditions in a single device. It also has provided an alternative method to induce droplet formation that does not require multiple syringe pumps.
微滴微流控技术有广泛的应用，包括高通量药物筛选和单细胞DNA扩增。然而，这些平台通常限于单输入条件，这使得它们无法在单个实验中分析多个输入参数（例如联合细胞处理）。微滴复用将带来更高的整体通量，降低制造成本，并减少诸如单细胞分析等多种应用中的实际操作时间。此外，虽然近年来芯片实验室的制造成本有所下降，但对于有兴趣利用微滴微流控技术的研究人员来说，生成形状和大小均匀的微滴所需的注射泵成本仍然过高。这项工作研究了利用重力驱动流从一系列三个串联的T型接头同时生成微滴的潜力，以产生一致、明确的微滴。采用等高的储液器会产生不一致的流速，该流速随着水入口和油入口之间距离的增加而增加。优化三个储液器的高度发现，对于更靠近油入口的水入口，需要更高的储液器。研究油水流速比（Φ）之间的关系发现，增加Φ会导致更小的微滴和更高的微滴生成速率。对微滴直径进行了方差分析，以确认来自三个不同水入口的微滴大小没有显著差异。这里描述的工作为复用微滴微流控设备提供了一种替代方法，允许在单个设备中对三种样品条件进行高通量检测。它还提供了一种无需多个注射泵即可诱导微滴形成的替代方法。
