Xu Linfeng, Lee Hun, Jetta Deekshitha, Oh Kwang W
SMALL (Sensors and MicroActuators Learning Laboratory), Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA.
Lab Chip. 2015 Oct 21;15(20):3962-79. doi: 10.1039/c5lc00716j. Epub 2015 Sep 2.
Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.
对于即时护理（POC）诊断的生物医学微流体系统而言，合适的流量控制泵送方法仍然是一个主要的技术障碍。一种真空驱动的无动力微泵送方法为应对这一挑战提供了一个有前景的解决方案。在这篇综述中，我们聚焦于基于聚二甲基硅氧烷（PDMS）的气体溶解性或渗透性的真空驱动无动力微流体技术；脱气后的PDMS因其高气体溶解性或气体可渗透特性能够在其内部恢复空气。由于其高气体渗透性，PDMS允许空气通过它进入真空。因此，有可能将空气存储或转移到可溶解气体或可渗透气体的PDMS中或通过其进行转移，以便将液体吸入嵌入式死端微流体通道。本文全面审视了PDMS的气体溶解性和渗透性的物理原理，系统综述了不同类型的真空驱动无动力微流体技术，给出了基于溶解性或渗透性的PDMS设备的设计指南以及现有应用情况。还将讨论利用PDMS气体溶解性或渗透性的微泵送技术的前沿主题和展望。我们强烈建议微流体和芯片实验室（LOC）领域利用真空能量来开发智能真空驱动微流体系统。
