Cell motion and recovery in a two-stream microfluidic device

The motion of cells in a two-stream microfluidic device designed to extract cryoprotective agents from cell suspensions was tested under a range of conditions. Jurkat cells (lymphoblasts) in a 10% dimethylsulfoxide solution were driven in parallel with phosphate-buffered saline solution wash streams through single rectangular channel sections and multiple sections in series. The influence of cell-stream flow rate and cell volume fraction (CVF) on cell viability and recovery were examined. The channel depth was 500 lm, and average cell stream velocity within the channels was varied from 3.6 to8.5 mm/s corresponding with cell stream Reynolds numbers of 2.6-6.0. Cell viability measured at device outlets was high for all cases examined indicating no significant cell damage within the device. Downstream of a single stage, cell recoveries measured 90-100% for average cell stream velocities ≥6 mm/s and for CVFs up to 20%. Cell recovery downstream of multistage devices also measured 90-100% after a critical device population time. This time was found to be five times the average cell residence time within the device. The measured recovery values were significantly larger than those typically obtained using conventional cell washing methods.