Institute of Applied Mechanics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan, ROC.
Lab Chip. 2019 Aug 20;19(17):2834-2843. doi: 10.1039/c8lc01286e.
In this paper, a new type of lab-on-a-chip system, called vacuum pouch microfluidic (VPM) system, is reported. The core of this technology is a thin-film vacuum pouch that provides negative pumping pressure once it is activated. It is a degassed plastic bag that encloses a microfluidic chip. To demonstrate its performance, a passive thin-film micromixer is developed to integrate with the vacuum pouch. Since both the vacuum pouch and the thin-film micromixer are made of plastic film, they can be laminated together to construct a multi-layered microfluidic system. Excluding the storage reservoir, the overall thickness is 0.4 mm and the total weight is 0.3 g. This system provides a simple and straightforward strategy to construct a standalone, portable, flexible and low cost microfluidic system. The thin-film micromixer uses a serpentine channel to perform the mixing process, and it is found to have distinct mixing mechanisms under different Reynolds (Re) numbers, where lateral diffusion dominates for Re < 1 and chaotic mixing starts to contribute for Re > 10. Integrating this thin-film micromixer with the vacuum pouch, it is demonstrated that the negative pumping pressure can be adjusted by different storage reservoirs being placed at the channel exit. Reynolds numbers ranging from 0.0064 to 45.2 can be achieved. It also is verified that the VPM micromixer can be stored for 4 weeks to provide a sufficient flow rate for mixing applications. Finally, to demonstrate the feasibility of applying this VPM-based thin-film micromixer for on-site detection, this system is integrated with the colorimetric method. It is verified that a 10 μl ferrous ion solution and a 10 μl potassium ferricyanide solution can be mixed in 12 seconds, and concentrations of 10 ppm to 1000 ppm can be quantified by analyzing the colorimetric signal in hue values.
本文报道了一种新型的微流控芯片系统，称为真空袋微流控（VPM）系统。该技术的核心是一种薄膜真空袋，一旦激活，它就会提供负压。它是一种抽气的塑料袋，其中封装了一个微流控芯片。为了展示其性能，开发了一种被动式薄膜微混合器与真空袋集成。由于真空袋和薄膜微混合器均由塑料薄膜制成，因此可以将它们层压在一起以构建多层微流控系统。不包括储液器，总厚度为 0.4 毫米，总重量为 0.3 克。该系统提供了一种简单直接的策略来构建独立、便携、灵活且低成本的微流控系统。薄膜微混合器使用蛇形通道进行混合过程，并且发现其在不同雷诺数（Re）下具有不同的混合机制，其中横向扩散在 Re < 1 时占主导地位，而混沌混合开始在 Re > 10 时起作用。将这种薄膜微混合器与真空袋集成在一起，证明可以通过在通道出口处放置不同的储液器来调整负压。可以实现从 0.0064 到 45.2 的雷诺数。还验证了 VPM 微混合器可以存储 4 周，以提供足够的流速进行混合应用。最后，为了证明将这种基于 VPM 的薄膜微混合器用于现场检测的可行性，将该系统与比色法集成在一起。验证了可以在 12 秒内混合 10μl 的亚铁离子溶液和 10μl 的铁氰化钾溶液，并且可以通过分析色调值中的比色信号来定量测量 10ppm 至 1000ppm 的浓度。
