Abstract

Microfluidic Continuous-Flow Separation of Particles/Cells and Patterning of Particles with Dielectrophoresis

Charles Yang Chun, Associate Professor, Nanyang Technological University

Dielectrophoresis (DEP) is widely used in microfluidics for manipulation and separation of particle and cells. This talk will report our two recent developments by using DEP. First, I will introduce a complete polymer DEP device with sidewall conducting PDMS composite electrodes. This novel device can be used for dual functions (i) characterization of the DEP properties in terms of positive-DEP, native-DEP and cross-over frequencies for yeast cells and E. coli. in stagnant flow, and (ii) the continuous separation of yeast cells from similar-size 5 µm latex particles, E. coli from similar-size 2.9 µm latex particles and live yeast cells from dead yeast cells. Second, I will report a novel transmissive electronic-paper display (EPD) technology using the combined effect of dielectrophoresis and dipole attractive forces. Some of the salient features of our technique are increased switching response of the order of ~320 milliseconds, better contrast ratios (1:10), higher transmittance of >90% and improved resolution compared to the existing EPD technologies. The prototype developed currently is simple in structure, with a straightforward manufacturing protocol and can be assembled in several easy steps thus minimizing the manufacturing cost of the unit that is capable of displaying few letters. The display is also bistable i.e. it can hold the text indefinitely without the need of any electricity and hence be used in digital signage, electronic labels in retail shops, and electronic billboards.