Study Of Cell Enrichment Process By Dielectrophrosis On Microchip

Dielectrophoresis on microchip is based on the dielectrophoresis separation principle and Micro Electronic Mechanical System (MEMS) fabrication technique, which is a powerful tool for high efficiency separation and manipulation of biochemical samples. As a non-invasive cell manipulation technique, microchip dielectrophoresis has many advantages, such as high performance, high resolution, low pollution and more samples information. For these reasons, this technique has significant research meaning and potential practical value in biochemical samples analysis, especially in cell analysis.The developing level of microchip dielectrophoresis in cell analysis was summarized in this paper. Four kinds of simplified dielectrophoresis microchips were designed and manufactured based on the separation principle of dielectrophoresis and the fabrication technology of microchip. Meanwhile, a preliminary study of cell enrichment process was demonstrated on simplified dielectrophoresis microchips. The influence of microchip materials on cell enrichment process and microchip fabrication was discussed, and finally the glass-PDMS composite chip structure was selected and performed chip making.DEP microchip with interdigitated arrayed electrodes was designed, at the same time, Conventorware finite element analysis software was used to optimize DEP microchip structure parameters and dielectrophoresis enrichment process. The optimum chip structure parameters were the electrode width and interval 30μm, the micro-channel height 30μm, and the optimum DEP manipulation voltage is 10V.DEP microchip and SU-8 anode film were fabricated using the standard making process. CCD microscopic imaging apparatus and MEMS measuring & operating system were used to characterize electrode dimension, the flatness of glass substrate as well as the depth-width ratio of SU-8 anode film. An integrated dielectrophoresis microchip system was constructed, which was consisted of high-frequency low-voltage signal generating system, DEP microchip with interdigitated arrayed electrodes and CCD microscope imaging detection system.Different types DEP positioning enrichment of the red blood cells and colon cancer cells were achieved on the constructed system. The dielectrophoresis enrichment and manipulation parameters were optimized according to the peak value of applied AC signal and its frequency, as well as the type and composition of buffer solution. With the optimized operation parameters of the AC signal peak value was set to 5V, the frequency of AC signal range from 20MHz to 1MHz. The study demonstrated that enrichment efficiency of DEP was controlled by the AC signal peak value and the types of dielectrophoresis were determined by the frequency of AC signal and composition of buffer solution. Enrichment efficiency of positive and negative DEP to colon cancer cells respectively reached 87.2% and 84.8% on the constructed system.