Topology optimization based deterministic lateral displacement array design for cell separation.

Circulating tumor cell (CTC) can be used to guide cancer theranostics. How to isolate efficiently CTCs from blood owns great clinical requirement. Deterministic lateral displacement (DLD) is a pillar-array-based effective passive microfluidic method to separate cells based on their sizes. DLD is a potential CTC isolation tool. Pillar shape is one of the key priorities in DLD array design. Altered zigzag mode is a normally undesired phenomenon that leads zigzag particles away from flow direction. This work makes use of the altered zigzag mode to manipulate zigzag particles for the first time, and developed a novel DLD chip with topology optimized pillar shape and a wide DLD channel. The novel designing method based on topology optimization (TO) greatly increases lateral displacement of different sized cells, meanwhile demonstrates its universality and expansibility. The proposed structure has the ability to shorten the device and to manipulate cells flexibly. Bead experiment has been applied to determine the critical diameter of the DLD array. Numerical, bead and cell experiment have been carried out to verify the separation efficiency of the structure. The TO-based wide DLD channel promotes the separation efficiency.