High-precision particle sorting chip with double-layer helical structure coupled constriction-expansion channels

Abstract As microfluidic lab-on-a-chip technology advances, microfluidic microarrays, particularly those designed for cell sorting, have become increasingly vital in biomedical research. In inertial microfluidics, the use of a single helical channel has been a prevalent approach. However, this method often exhibits suboptimal separation efficiency, frequently falling below the 90% threshold. In this research, we introduce an innovative approach by integrating a conventional helical channel with a constriction-expansion channel design, creating a dual-layer helical structure. Furthermore, we introduced triangular micropillars into the microfluidic array, which successfully prevented the backflow of particles separated into the second layer from returning to the first layer, thereby further enhancing the stability and efficiency of the separation. The combination of this triangular micropillar configuration with the implementation of the double-layer helical structure significantly enhances the precision and purity of particle separation. Experimental results demonstrate exceptionally high separation efficiency. At a speed of 200 µl/min, the separation efficiency of the chip for particles is up to 99.1%, and the separation purity is up to 98.3%. This study presents a novel spiral channel design that facilitates microfluidic particle sorting. Leveraging the combined benefits of triangular micropillars and a dual-layer helical structure to achieve unprecedented performance in particle separation.