Efficient Extraction of White Blood Cells Using Modular Inertial Microfluidics

The existence of massive amounts of red blood cells (RBCs) and other blood cell components poses a challenge for the efficient extraction of white blood cells (WBCs) from blood. Herein, we proposed modular inertial microfluidics for efficient extraction of WBCs from lysed blood samples. The different WBC extraction needs could be met by flexibly combining the washing module and the concentration module in modular inertial microfluidics. First, the respective optimal flow rates for washing and concentration modules with different channel sizes were explored. Then, based on the modular combination of washing and concentration modules, three modes were proposed to meet the processing needs of large-volume sample, low volume expansion, and easy operation. The replacement efficiency and recovery rate of target particles in the three modes were all greater than 93%. Finally, efficient extraction of WBCs from lysed blood samples was tested. The combined use of Modes 1 and 2 achieved a replacement efficiency of 93.1% and a recovery rate of 93.6%, while the single use of Mode 3 achieved a replacement efficiency of 97.1% and a recovery rate of 95.9%. Compared with traditional centrifuges, our modular inertial microfluidics showed a better washing performance with reduced residual RBC fragments. More importantly, it provided an excellent free combination capability to meet different WBC extraction needs.