Abstract
Particle/cell washing is an essential technique in biological and clinical manipulations. Herein, we propose a novel circular contraction–expansion array (CCEA) microdevice. It can be directly connected to a needle tip without connection tubes. Its small size and centrosymmetric structure are beneficial to low sample consumption, high connection stability, and a wide application range. Computational fluid dynamics (CFD) simulation results show that the CCEA structure can produce a stronger Dean flow and lead to faster particle/cell focusing than the circle structure and CEA structure with the same length. Experimentally, an optimal flow rate ratio of 1:3 and an optimal total flow rate of 120 μL/min were found to ensure a stable fluid distribution. Under these conditions, rapid focusing of 10–20 μm particles with high efficiencies was achieved. Compared with a normal CEA device using tubes, the particle loss rate could be reduced from 64 to 7% when washing 500 μL of a rare sample. Cell suspensions with concentrations from 3 × 105/mL to 1 × 103/mL were tested. The high cell collection efficiency (>85% for three cell lines) and stable waste removal efficiency (>80%) reflected the universality of the CCEA microfluidic device. After the washing, the cell activities of H1299 cells and MCF-7 cells were calculated to be 93.8 and 97.5%, respectively. This needle-tip CCEA microfluidic device showed potential in basic medical research and clinical diagnosis.
Highlights
Cell washing is a basic biotreatment technology and is widely used in cell identification, culture, and analysis[1,2,3]
We propose a circular contraction–expansion array (CCEA) microfluidic device to achieve cell washing on a needle tip
It was obvious that the CCEA structure can produce a much stronger Dean flow
Summary
Cell washing is a basic biotreatment technology and is widely used in cell identification, culture, and analysis[1,2,3]. It transfers cells from an original fluid to a new fluid, removing metabolic waste, cell debris, or other unwanted solutes. The most common method for cell washing is centrifugation. The reliability and efficiency of centrifugation are high, evidence shows that high shear rates and centrifugal forces can potentially result in cell damage[7,8]. Some shear-sensitive microalgae can be damaged by residence in the pellet and the g-force applied[9].
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