论文部分内容阅读
Ac electric field effect on micro fluid or charged particles through microelectrode,may produce a variety of electrical characteristics [1,2].Including electrophoresis(EP),dielectrohoresis(DEP),and AC electrothermal flow(ACEF)etc.Electrokinetics has been one of the most powerful approaches for microfluidic manipulation [3].Predecessors controlled micro-and nano-scale biological targets with electric mainly focuses on low conductivity solutions(<0.01 S/m).However,most of the physiological fluids(blood,white blood cells,urine,etc.)have high conductivities(~1 S/m),and due to the required in numerous diagnostic applications of cell operation based on a microfluidic device,there is a strong interest to manipulate biotargets in conductive biological fluids.Hybrid electrokinetic microfluidic technology [4],which combined varieties of electric technologies,can carry out cell sorting and enrichment in physiological media of high conductivity directly.This abstract reports an electrokinetic manipulation to separate polystyrene(PS)microspheres in high-conductivity media.A PDMS/glass microfluidic chip with a Ti– Au–Ti sandwich electrode and a 3-parallel-electrode configuration was fabricated [3,4] for the different size of PS microspheres separation.With optimized AC voltage and frequency,we demonstrated that 25 μm microspheres can be isolated from 5 μm or/and 10 μm microspheres and concentrated onto the inner electrode in dozen sec.The results show that,when the applied voltage was 14 Vpp at 100 KHz,the separation efficiency of 10 μm and 25 μm polystyrene microspheres was the best.Similarly,with a voltage of 10 Vpp at 2 MHz,the separation efficiency of 5 μm and 25 μm polystyrene microspheres could achieve the highest.Meanwhile,to separate 5 μm、10 μm and 25 μm polystyrene microspheres,the application of the voltage of 11 V at 1 MHz was suitable and the separation was quickly and efficiently.The separation efficiency can reach above 90%.