Circular-channel particle focuser utilizing viscoelastic focusing
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The miniaturization of flow focuser is a challenge in developing microflow cytometers. Most previously reported microfluidic cell focusers require complex structures or external force fields to achieve the 3D cell focusing. Herein, we propose a novel circular-channel particle focuser utilizing viscoelastic focusing. The circular-channel particle focuser is fabricated using a simple and low-cost microwire molding technique. Whole PDMS channels with perfect circular cross-sections can be fabricated using this protocol. We then characterize the particle focusing performances in our circular-channel particle focuser and discuss the effects of particle size, operating flow rate, cross-sectional dimension and fluid rheological property on particle focusing. The experimental results show that a perfect single-line focusing can be achieved exactly at the channel centerline. Finally, our circular-channel particle focuser is employed for the focusing of blood cells. As it offers special advantages of simple structure, easy fabrication, and sheathless operation, our circular-channel particle focuser may serve as a potential flow focuser for microflow cytometers.
KeywordsViscoelastic focusing Circular channel Single-line focusing Microflow cytometer
This research work is supported by the National Natural Science Foundation of China (81727801, 51875103, 51505082, and 51775111), the Natural Science Foundation of Jiangsu Province (BK20150606), the Fundamental Research Funds for the Central Universities (2242017K41031), the Six Talent Peaks Project of Jiangsu Province (SWYY-005) and the ZhiShan Young Scholar Fellowship.