Combining Inertial Microfluidics with Cross-Flow Filtration for High-Fold and High-Throughput Passive Volume Reduction

We reporte a three-stage spiral channel device for achieving high-fold and high-throughput passive volume reduction through coupling inertial microfluidics with cross-flow filtration. To understand the device physics and optimize the structure, the effects of critical channel design on particle dynamics and volume reduction performance were explored. Then the principle of volume reduction was used for concentrating cells from large-volume fluids, and the concentration performance of differently sized particles/cells in the determined device was quantitatively characterized over wide flow rates. The results indicated that our device could achieve high-efficiency cell concentration at a high throughput of over 4 mL/min. Finally, we successfully applied our device for the enrichment of rare tumor cells after being separated from the blood or peritoneal fluid and the extremely high fold concentration of white blood cells from the large-volume fluid. Using a serial concentration, an ultrahigh concentration fold of approximately 1100 could be achieved. Our device offers numerous advantages, such as high-processing throughput, high concentration fold, simple channel design, and low-cost fabrication. Thus, it holds the potential to be used as a sample concentration tool for disposable use in low-resource settings.