Study On Manipulation Of Particles By Electrokinetic Microfluidic Technology

This article was first report a hybrid electrokinetic microfluidics technology to isolate and trap particles. It can produce a variety of electrokinetics in high conductivity fluids through the microelectrode processed in the chip channel. And based on the innate structural and electrical properties of particles to concentrate and capture, or isolate them from other particles in solution. A polydimethylsiloxane (PDMS)/glass microfluidic chip consisting of a three-layer sandwich structure and a three-parallel micro-electrode system was fabricated for the separation of particles in high conductivity solution by electric field that produced by alternating current. The principle of electrokinetics of particles directional movement was investigated in the experiment.Currently, the separation of different size particles in high conductivity solutions has not been researched systematically. Since the density and size of polystyrene (PS) microspheres are similar with cells, PS can be used as the replacement of cells of different kinds and sizes. In this study, the PS microspheres with different sizes and different electrical properties were used as the research object firstly. With carboxyl-PS bead, for example, the results showed that when the applied voltage was 14 V at 100 kHz, the separation efficiency for the 10 μm and 25 μm polystyrene microspheres was the best. Similarly, with a voltage of 10 V at 2 MHz, the separation efficiency for the 5 μm and 25 μm polystyrene microspheres could achieve the highest. Meanwhile,11 V at 1 MHz was used for the quick and efficient separation of 5 μm,10 μm and 25 μm polystyrene microspheres, the separation of PS microspheres with different electrical properties was achieved with an efficiency of above 90%. At the same time, the formation of the laminar region in the middle of the electrode gap played a key role in the microsphere separation. And the study of the laws of electrokinetics manipulation on the targets with different sizes in high conductivity media has important significance for ultimately achieving the efficient electrokinetic manipulation of biological samples.Circulating tumor cells (CTCs), the cancer cells shed by solid tumors into the peripheral blood of cancer patients, can cause distant metastasis and tumor recurrence which are the main causes of death of malignant tumor. Thus, the capture and detection of cancer cells in the peripheral blood have great clinical values. Based on the conditions of PS microspheres separation, the separation of blood cells and breast cancer cells was studied and discussed. The results showed that the phenomenons of cells separation and microspheres separation were consistent, the PS microspheres can be used as the replacement of cells. The conditions for cells separation were also studied, the optimum conditions for cancer cells and blood cells separation was 15 V at 300 kHz with 1.0 V DC offset. Meanwhile, cells size, innate structural and electrical properties were also have a major impact on cell separation.