Lateral Degassing Method for Disposable Film-Chip Microfluidic Devices.

Suhee Park,Junhyeong Kim,Hyungseok Cho,Ki-Ho Han

doi:10.3390/membranes11050316

Abstract

It is critical to develop a fast and simple method to remove air bubbles inside microchannels for automated, reliable, and reproducible microfluidic devices. As an active degassing method, this study introduces a lateral degassing method that can be easily implemented in disposable film-chip microfluidic devices. This method uses a disposable film-chip microchannel superstrate and a reusable substrate, which can be assembled and disassembled simply by vacuum pressure. The disposable microchannel superstrate is readily fabricated by bonding a microstructured polydimethylsiloxane replica and a silicone-coated release polymeric thin film. The reusable substrate can be a plate that has no function or is equipped with the ability to actively manipulate and sense substances in the microchannel by an elaborately patterned energy field. The degassing rate of the lateral degassing method and the maximum available pressure in the microchannel equipped with lateral degassing were evaluated. The usefulness of this method was demonstrated using complex structured microfluidic devices, such as a meandering microchannel, a microvortex, a gradient micromixer, and a herringbone micromixer, which often suffer from bubble formation. In conclusion, as an easy-to-implement and easy-to-use technique, the lateral degassing method will be a key technique to address the bubble formation problem of microfluidic devices.

Highlights

The gas permeability of PDMS is related to the porosity of PDMS [44], which is determined by the curing temperature [45]
This study introduced the lateral degassing method which is compatible with the This study introduced the lateral degassing method which is compatible with the film-chip technique for using it in disposable microfluidic devices
The derate increased as the thickness of the degassing wall decreased and the vacuum pressure gassing rate increased as the thickness of the degassing wall decreased and the vacuum increased

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Bubbles are often introduced during a microfluidic setup [2] or induced by microscopic air pockets [3] and dissolved gases [4] in microchannels Once formed, they usually become attached to complex microstructures and microgrooves with a high surface-to-volume ratio [5] and are very difficult to remove. Most PDMS-based active degassing methods use vacuum microchambers for bubble extraction [34,35], which is usually implemented in a multi-layered structure, making device fabrication difficult and impractical. In-plane degassing methods has been developed for PDMS-based microfluidic devices [36,37,38,39] In this case, it is necessary to place degassing lines near the microchannels where air bubbles form frequently.

Design and Working

Fabrication Process

Degassing Test

Bonding Stability

Applications of Microfluidic Devices with Complex Structures

Conclusions