A High-Throughput Microfluidic Cell Sorter Using a Three-Dimensional Coupled Hydrodynamic-Dielectrophoretic Pre-Focusing Module

Dielectrophoresis (DEP) is a powerful tool for label-free sorting of cells, even those with subtle differences in morphological and dielectric properties. Nevertheless, a major limitation is that most existing DEP techniques can efficiently sort cells only at low throughputs (<1 mL h(-1)). Here, we demonstrate that the integration of a three-dimensional (3D) coupled hydrodynamic-DEP cell pre-focusing module upstream of the main DEP sorting region enables cell sorting with a 10-fold increase in throughput compared to conventional DEP approaches. To better understand the key principles and requirements for high-throughput cell separation, we present a comprehensive theoretical model to study the scaling of hydrodynamic and electrostatic forces on cells at high flow rate regimes. Based on the model, we show that the critical cell-to-electrode distance needs to be <= 10 m for efficient cell sorting in our proposed microfluidic platform, especially at flow rates >= 1 mL h(-1). Based on those findings, a computational fluid dynamics model and particle tracking analysis were developed to find optimum operation parameters (e.g., flow rate ratios and electric fields) of the coupled hydrodynamic-DEP 3D focusing module. Using these optimum parameters, we experimentally demonstrate live/dead K562 cell sorting at rates as high as 10 mL h(-1) (>150,000 cells min(-1)) with 90% separation purity, 85% cell recovery, and no negative impact on cell viability.

Automated summary

This study demonstrates a significant improvement in cell sorting throughput by integrating a three-dimensional coupled hydrodynamic-DEP cell pre-focusing module prior to the main DEP sorting region. Theoretical models were developed to understand the key principles and requirements for high-throughput cell separation, leading to the determination of optimum operation parameters. Experimental results show that using the optimum parameters, cell sorting at high flow rates can achieve high separation purity and cell recovery.