Simulation Study Of Erythrocyte Deformation Separation In A Deterministic Lateral Displacement Device

Cell deformation and isolation are essential for a wide range of clinical applications and analytical procedures,Cells such as platelets,red blood cells,and white blood cells(such as neutrophils,lymphocytes,monocytes),basophils,and eosinophils can undergo different morphological changes according to physiological conditions or conditions.Cell biophysics changes in the biomechanical pillars can occur through a large number of biological,chemical and physical stimuli.It is known that changes in the deformability of cells can be used to determine the pathology of many diseases.Among them,red blood cells are an essential part of biological blood,and research on their deformation and separation has become an essential diagnostic method in medicine.Many scholars use the theoretical,simulation,and experimental perspectives to compare the deformation and separation of red blood cells.In recent years,the mechanism of the deformation and separation method of the deterministic lateral displacement device has gradually been clarified,and has potential application prospects in many fields,especially in the application of deformation and separation of red blood cells.The deterministic lateral displacement device is a micro-column array in the flow channel,which can sort cells or other micro particles with high resolution.In 2004,a simple and effective microfluidic device based on the size of separated particles was first proposed by Huang et al.,Which is the deterministic lateral displacement device(DLD).Studies have confirmed that this device has been widely used to process particles based on intrinsic properties rather than(bio)chemical pretreatment or separation of external fields.The basic idea of sorting is the interaction between flowing particles and micro-pillar array,resulting in irreversible trajectories and cross-streamline motion.Therefore,the deterministic lateral displacement device can collect different particles or cells separated by designing different device outlets.Through the deterministic lateral displacement device,it can be scaled according to needs,which meets the use conditions under various research conditions.In this paper,through theoretical model analysis and COMSOL simulation,the relationship between the velocity change of fluid working fluid and the micro-pillar array in the device is obtained.Focus on the comparison of the arrangement,shape of the micro-pillars in the micro-pillar array,the aspect ratio of the triangular micro-pillars,the inclination angle,the staggering height,and the design angle of the triangular micro-pillars.According to the comprehensive comparison of simulation results,it is considered that the height-diameter ratio is h / d= 3 ? 4,the inclination angle is ?= 45 °,and the fluid working fluid can thoroughly and uniformly flow.Based on this simulation,a deterministic lateral displacement device of the triangular micro-pillar array is selected for subsequent follow-up numerical simulation.Rigid red blood cells were used to analyze the movement of red blood cells,and the trajectory of the red blood cells,the surface stress and the speed of the red blood cell movement were observed.It is found that the deformation of rigid red blood cells is almost negligible.At the same time,the corresponding movement pattern is obtained according to the arrangement pattern of red blood cells in the micro-column array.,Rigid red blood cells with high row displacement(??> 1.5 ?m)enter "displacement mode".The triangular micro-pillar arrays show the high speed and uniform surface stress in the simulation of deformation and separation of rigid red blood cells,which also indicates the distinct potential advantages of triangular micro-pillar arrays.In order to explore the difference between the deformed morphology of soft red blood cells in smooth round tubes and micro-pillar arrays,the effects of the diameter of red blood cells,the Young's modulus of the red blood cell membrane,the initial velocity and density of the fluid working medium on the deformation of red blood cells,and The existence of the triangular micro-pillar array increases the possibility of collision of soft red blood cells with the micro-pillar array,and the deformed shape of red blood cells is also affected.This paper systematically analyzes the deformation and separation of red blood cells by deterministic lateral displacement devices through theoretical analysis and numerical simulation.The existing experimental research on the deformation of red blood cells by adding micro-pillar arrays is not complete.I hope that the simulation research in this paper can be used in the future about the experimental study and provides corresponding research ideas and references.