Presentation on theme: "Chien-Yu ChenMSCL1 LATERAL CELL SEPARATION IN MICROFLUIDIC CHANNEL BY 3D ELECTRODE DIELECTROPHORESIS Teacher : Cheng-Hsien Liu Student : Chien-Yu Chen."— Presentation transcript:
Chien-Yu ChenMSCL1 LATERAL CELL SEPARATION IN MICROFLUIDIC CHANNEL BY 3D ELECTRODE DIELECTROPHORESIS Teacher : Cheng-Hsien Liu Student : Chien-Yu Chen ( 陳鍵瑜 ) Date : 06/20/2007 Reference : μTAS2006, p
Chien-Yu ChenMSCL3 Introduction Most of current DEP electrodes utilize planar electrodes on the surface of the substrate to generate DEP force. The electric field decays exponentially with the height of the channel for the planar electrode configuration Dielectrophoresis (DEP) : determined by frequency Positive DEPNegative DEP
Chien-Yu ChenMSCL4 Design concept 3-D vertical electrode The force balance plot of the cells in the separation zone. Inlet Outlet
Chien-Yu ChenMSCL5 (a) Planar electrodes at bottom of channel. (b) Trapezoidal channel from silicon wet etching. (c) Electrodes embedded in the vertical side wall of the channel. Electrodes at the side walls produce uniform field in the channel. Simulation ： side-wall vertical electrodes
Chien-Yu ChenMSCL6 Simulation ： electrical field gradient The center of the channel ： minimum electrical field. Close to the electrodes ： maximum electrical field.
Chien-Yu ChenMSCL7 Fabrication The flexible PDMS sheet can conformably seal the channels. The curvature of the channel top surface from the previous lithography step makes it difficult for the rigid glass cover slip to seal the channel.
Chien-Yu ChenMSCL8 DEP forces The equilibrium points (zero DEP forces) of two objects with different polarization factors can be tuned to away from the center as shown by the dashed line m
Chien-Yu ChenMSCL9 Experiment result : fabrication SEM of vertical electrode before channel layer is constructed. The final channel with electrodes embedded in the sidewall.
Chien-Yu ChenMSCL10 Experiment result : separation method1: both electrodes are turned on Cells (white circles) are sorted to top channel outlet and beads (black circles) are sorted to bottom outlet. Left : free flow without DEP forces. Right : with DEP separation.
Chien-Yu ChenMSCL11 Experiment result : separation method2: only top electrode are turned on N115 cells repelled from the top electrodes and flow into the bottom channel. HEK293 cells are released from the top electrodes and flow into the top channel.
Chien-Yu ChenMSCL12 Conclusion Advantage: Vertical electrodes in the side wall of the micro-channels to generate electric field. The electrical field can extend to the entire channel space to avoid any dead electrical field region. Continuous flow through separation system enables high throughput microfluidic sorting. Disadvantage: Need to find the frequencies to fit the two kinds of cells/beads simultaneously. Only two kinds of cells/beads can be separated in the meantime. Only a small amount of cells/beads can be separated.
Chien-Yu ChenMSCL13 Thank you !
Chien-Yu ChenMSCL14 Side-Wall Vertical Electrodes for Lateral Field Microfluidic Applications, Lisen Wang, Lisa Flanagan, and Abraham P. Lee, 2007 IEEE. Other references :