A Highly Efficient DLD Microfluidic Chip With Two-Stage Inclined Elliptical Pillars for Particle Separation and Purification.

Deterministic lateral displacement (DLD), a hydrodynamic particle manipulation technology, has been extensively studied for the development of fast and efficient microfluidic chips for particle manipulation and detection. However, particles are prone to clogging in DLD chips with closely spaced pillars, which can reduce sorting efficiency. Previous studies have shown that elliptical pillars provide better separation performance than equilateral triangular pillars. In elliptical-pillar DLD, a negative angle of inclination (Aoi) reduces the particle period and facilitates efficient isolation of large particles, whereas a positive Aoi decreases the critical diameter, thereby improving the sorting of smaller particles. On the basis of these findings, we designed a two-stage DLD microfluidic chip with inclined elliptical-pillar arrays, using an Aoi of -45° in the first stage and 45° in the second stage. The combination of negative and positive Aoi values enhanced the isolation of large particles, improved the purification of medium- and small-sized particles, and reduced the risk of clogging. This design provides a practical approach for improving the separation and purification performance of DLD devices and offers potential for efficient multi-size particle separation.