Direct numerical simulations of the motion of an elastic plate in a deterministic lateral-displacement device

Deterministic lateral displacement (DLD) is a powerful microfluidic technique for the separation of microscale and nanoscale particles. In this paper, an efficient three-dimensional direct numerical simulation method (i.e., a fictitious domain method) is used to study the motion and deformation of an elastic plate within the DLD device. The effects of plate rigidity, array depth, initial configuration, and active deformation on the behavior of the plate are systematically investigated. Our results indicate that there exists a critical rigidity, below which the zigzag period of the plate motion (i.e., lateral displacement) increases with increasing rigidity, and above which, the zigzag period decreases with increasing rigidity. The lateral displacement of the plate increases as the depth of the DLD device (i.e., post-length) increases. In addition, active deformation of the plate can either enhance or reduce the lateral displacement of the elastic plate, depending on its rigidity. The insights gained in this study provide new insights into the physics of deformable matter transport in structured microfluidic environments, offering potential for rapid and label-free detection of parasitic infections in clinical and field settings.