Precise Size-Based Cell Separation via the Coupling of Inertial Microfluidics and Deterministic Lateral Displacement.

We report here a novel two-stage i-DLD sorter through coupling inertial microfluidics with deterministic lateral displacement (DLD), allowing for precise, continuous, and size-based cell separation. The first stage spiral inertial microfluidic sorter is responsible for removing the overwhelming majority of background blood cells at a high-throughput manner. The precise and flow-rate insensitive DLD sorter with triangular posts serves as the second stage sorter which further removes the residual blood cells for obtaining high-purity tumor cells. After demonstrating the conceptual design, we characterize the performances of our two-stage i-DLD sorter for the separation of differently sized particles and cells. The characterization results show that a 100% complete separation of 15 and 7 μm particles was achieved, whereas a separation efficiency of over 99.9% and a target sample purity of 93.59% was realized for the separation of differently sized cells. Finally, we successfully apply our sorter for the separation of rare tumor cells from the diluted whole blood or WBCs at good performances. Our two-stage i-DLD sorter offers numerous advantages of label- and external field-free operation, high-efficiency and high-reliability separation, and high-throughput processing without clogging, and is promising as a potential tool for precise cell separation in low-resource settings.