| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 101 === A method was proposed for selective isolation and separation of particles/cells of similar sizes based on their different Clausius-Mossotti factors using dielectrophoresis and microfluidics in the literature. The associated device is a straight micro channel (glass for the bottom wall and PDMS for the rest walls) with four grooves on its ceiling for capturing particles, and two electrodes on both sides of the groove region for generating electric field. A particle may be carried downstream by the imposed fluid stream or pushed into the groove, depending on the local force balance between dielectrophoretic force, fluid drag, gravity and buoyancy. The present study aims to clarify the capturing efficiency of various particles/cells under different geometric designs and operating conditions, and hope to develop a microfluidic chip capable of separating different cells of similar size efficiently. In order to simplify the problem, a single groove design is employed in the present experiment. Capture rates for polystyrene particles, two lung cancer cells, CL1-0 and CL1-5 (more invasive), and one colorectal cancer cells, Colo205, were measured for different channel heights, groove widths, applied electric frequencies, and background volume flow rates. The device was also demonstrated of capturing CL1-0 cells from a mixture of CL1-0 and blood cells. A modified design of the device was also proposed and tested. The groove and the electrodes are orientated obliquely to the background flow in the modified design (but are perpendicular in the original design), such that the captured particles/cells in the groove can be guided smoothly and effectively to designed destination downstream.
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