On August21, 2024, the research team led by Dr. Sheng Yan from the Advanced Institute of Shenzhen University published a paper titled " Deciphering theEvolution ofInertial Migration inSerpentine Channels" in Analytical Chemistry. The master's student Liu YongfromShenzhen University, is the first author of the paper. Dr.Sheng Yan from the Advanced Institute of Shenzhen University and Dr.Xiaobo Peng fromtheCollege ofMechatronics and Control Engineeringof Shenzhen University are the corresponding authors. This work also received support from Dr. Jun Zhang at Griffith University, Australia.

Figure 1.This report was selected as the journal cover of Analytical Chemistry.

Serpentine channels coupling inertial andsecondary flows enable the effective particle focusing and separation, showing the great potentials in clinical diagnostics and drug screening. However, the non-steady secondary flows in the serpentine channel turn the evolution of inertial migration unclear, hindering the developmentandapplication of serpentine channel.Herein, to refineinertial migrationmechanism, we established a model with varying curvature ratios to study the effect of secondary flow on particle migrationin the serpentine channel.This method useddirect numerical simulationto calculate inertial lift, mapped the inertial lift to cross-sections of the serpentine channel,anddeciphered the inertial migration usingthe Lagrangian particle tracking method.Theinertial migration of microparticles isexperimentallyinvestigated to validate theestablished numerical model.The resultsindicatethat particle migration in serpentine channels follows a two-stage migration.An increase in secondary flow accelerates the second stage of the migration process while slowing down the first stageprocess.Subsequently,we investigated the effects of different parameters, including Reynolds number, aspect ratio, and blockage ratio, on the equilibrium positions of particles, providing guidelines forhigh-resolutionseparation of particles. Taking flow resistance into account, the dimensionless study makes the separation of arbitrary-sized particles possible.Thisworkreveals the migration mechanism in serpentine channels, paving the way for the inertial separation of particles.

Figure2.Two-stage migration of particles in a serpentine channel.

The link to the original paper:https://pubs.acs.org/doi/10.1021/acs.analchem.4c03474