A novel microfluidic device with tapered sidewall electrodes for efficient ternary blood cells (WBCs, RBCs and PLTs) separation

Separation and counting of blood cells from whole blood is very significant in measurement and data extraction in health care diagnostics and monitoring health parameters. Many techniques are available for blood cell separation out of which dielectrophoresis (DEP) on lab on chip platform is an emerging technique due to its phenomenal advantages that the force in this technique acts directly on cells based on dielectric properties. In DEP more challenges lie in optimization of the electric field at lower operating voltages as higher voltages damage the biological cells via joule heating and the separation process cannot be accomplished. Due to this optimization of the electric field distribution in the microchannel of the cell separation device is very much important and can be achieved via numerical model or design optimization of electrodes shapes and material. In this work, a microfluidic cell separation device is optimized using the finite element method for the ternary separation of blood cells. The design is realized with two inlets, three outlets, and one main channel having tapered sidewall electrodes for cell separation purpose. Inlet velocities are optimized to achieve improved cell focusing before subjecting cells to separation effects by varying the velocity ratio of main inlet velocity to buffer inlet velocity. Results have shown successful separation of platelets, red blood cells, and white blood cells with 96.7%-100% yield and purity with velocity ratio from 1:4 to 1:5 at electrode excitation voltage of 1.5 V.