Optimizing the design of a serpentine microchannel based on particles focusing and separation: A numerical study with experimental validation

Abstract

Cell-based diagnosis and the introduction of personalized drugs are key factors, motivating researchers to discover an efficacious tool for effective cell isolation. Optimal systems were presented through the finite element method by adjusting the arrangement of hydrodynamic forces within a serpentine micro-channel, which managed to separate different cell lines in addition to their focusing. Considering the parameters of flow, particle, and geometry, two optimal serpentine systems (fixed and variable slope) were presented and the accuracy of the simulation results was verified by their comparison with the experimental findings of the optimized microchannel. The results indicated that the channel heights of ~1800μm and ~2200μm are the most suitable choices for particle separation in the range of ~7μm to ~18μm (blood cells) for fixed-slope and the last cycle of the variable-slope microchannel, respectively. Both fixed-slope and variable-slope geometries with the vertical channel width of ~400μm offered a high separation efficiency (about ~60μm) with a difference of less than ~3% in separating red blood cells (RBCs) from circulating tumor cells (CTCs). In addition to separation, the particle focusing efficiency of the microchannels was approximately ~98% for low diameter particles (7-21μm) and ~95% and ~93% for ~24μm and ~27μm diameter particles, respectively. Through experimental validation, this study presented a reliable optimized structure to improve our ability to separate white blood cells (WBCs) (18μm >diameter>12μm) and CTCs (27μm>diameter>21μm) from RBCs, opening new horizons to eliminate at least one of the limitations of the field of diagnosis.