Effect of Serpentine Microchannel Geometry on the Focusing an‎d Separation of Charged Particles

2/2/2027 12:00:00 AM

Precise, sheathless manipulation of blood microscale components remains a central challenge in microfluidics, particularly for Lab on a Disc (LOD) platforms where inertial, rotational, an‎d electrokinetic effects coexist. This study proposes a two phase particle han‎dling strategy that integrates rotation assisted inertial focusing with high frequency dielectrophoretic (DEP) sorting inside serpentine microchannels. In Phase I, three channel geometries an asymmetric sinusoidal, symmetric sinusoidal, an‎d rectangular layout were systematically eva‎luated to determine their ability to confine 3 µm particles using inertial lift, Dean vortices, an‎d rotation induced centrifugal an‎d Coriolis forces. The asymmetric sinusoidal design produced the strongest hydrodynamic ordering, achieving focusing efficiencies above 96%, especially when combined with higher inlet velocity, narrow channel width, an‎d increased serpentine turns. Rotational actuation further enhanced focusing, with the combined centrifugal Coriolis contribution improving performance from ~34% (no rotation) to ~64% at 800 rad/s. In Phase II, rotation was removed an‎d the pre focused stream was directed into a DEP electrode array for label free separation of red blood cells (RBCs) an‎d platelets (PLTs). Here, the rectangular geometry despite being the weakest inertial focuser outperformed the sinusoidal channels by stabilizing particle trajectories before entering regions of steep ∇|E|². Under |20| V an‎d 10 GHz actuation, the device achieved ~95% platelet isolation with concurrent ~25% RBC diversion, while higher inlet velocities reduced separation due to shorter DEP residence times. The combined findings establish a unified inertial DEP mechanism for high precision, pump free blood component han‎dling on LOD systems an‎d provide design rules for next generation point of care hematology platforms.

ميكروكانال‌هاي مارپيچ , ريزسيالش , جداسازي سلولي , نيروي دي‌الكتروفورز

Serpentine Microchannel , Flow Focusing , Cell Separation , Dielectrophoresis Force

Marziye Razmjoo

Dr. Ashrafizade