A hemispherical microfluidic channel for the trapping and passive dissipation of microbubbles

Abstract

In this paper, we present that trapping and dissipating of bubbles in a microfluidic cell culture system can be simultaneously achieved by utilizing curved geometry principles. For this end, a simple and cost-effective method to fabricate a curved hemispherical microfluidic channel is presented. On the basis of an analytical model, the mechanism that the hemispherical well can trap various sizes of bubbles better than the cylindrical well is described, and we present a quantitative comparison of the trapping capabilities of the hemispherical versus conventional cylindrical wells through experiments. The surface tension is another important factor to trap bubbles, which was also verified through the analysis and experiments. In the hemispherical wells, the trapped bubbles were spontaneously dissipated under the flowing condition without using any active source, and we characterized the degassing process by measuring the area of bubbles occupied in the well over time. For an application to a biomedical system, a cell culture chamber was combined with the bubble trapping system, and the performance of the system was verified by culturing HeLa cells with the flowing bubbled culture media. Conclusively, the suggested method demonstrated excellent performance in trapping of microbubbles and dissipation without using any peripheral device, and will be broadly applied in biomedical microfluidic research.

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

“…148 Another effective geometrical approach involves the use of hemispherical channels and wells which can capture traveling bubbles in a highly gas permeable microchannel (e.g., Poly-dimethyl siloxane, PDMS, channels), such that the bubbles trapped spontaneously dissipate. 149 This approach is limited by the permeability of the gas in the channel material and is effective when the gas evolution rate is slow.…”

Dynamics of Blood Flow and Thrombus Formation in a Multi-Bypass Microfluidic Ladder Network

“…17,31,42,57,62 Microfluidic networks may have utility in extracorporeal devices to trap bubbles and emboli as well as measure levels of reagents and toxins. 25,26,29,36 However, the role of the microfluidic network geometry in the thrombogenicity of devices such as extracorporeal oxygenation machine (ECMO), left ventricular assist devices, and nanomembrane hemodialysis cassettes is not well defined. 6,8,67 An integrated approach of studying blood flow and thrombus formation within microfluidic networks in the presence of coagulation may be useful in understanding how the physical biology of a microfluidic device promotes thrombus formation, which may help in the development of safer therapeutic device designs.…”

A microfluidic bubble trap and oscillator

“…To avoid and minimize the unintended introduction of bubbles into microfluidic systems, a number of bubble trap concepts have been reported. They are based on membranes, 1-3 systems using vacuum, [4][5][6] specific channel geometries with or without hydrophobic coatings [7][8][9][10] or the use of ultrasound 11 or pressurized fluid. 12 All of these concepts either require advanced setups that are expensive or are complicated to fabricate, or only work with aqueous solutions.…”