Study Of Cell Lysis Microfluidic Chip System Based On MEMS Technology

The purpose of cell lysis is to break primary samples and to obtain inner contents (such as protein, DNA, RNA). Microfluidic chip is indispensable for the majority of studies on cellular reaction and detection. In recent years, electronic ways of cell lysis have been paid more attention by researchers and the number of relative reports is rising gradually. Compared with chemical ways and pyrogenation, electronic ways greatly simplify the purifying steps and don't change the protein properties. And its micromation can be conveniently integrated into other biochip samples.Based on Micro-Electro-Mechanical Systems (abbreviation MEMS), a new microfluidic chips system for cell lysis under low voltage is designed and made in this thesis. It is used for the pretreatment in microfluidic system and this sets the base for later chemical and biological research and analysis. In this thesis the new system is made with the standard light-sensitive lacquer method of stripping technology and Ti/Pt microelectrodes on glass substrate. High field intensity can be obtained by pulsed voltage exerted by 6 pairs of microelectrodes. Meantime impulse signal generators especially for cell lysis is designed. It is composed of C8051F020 singlechip computer and applied circuit and imitated output circuit. This generator can justify impulse width, impulse cycle and impulse voltage extent. The new microfluidic chips system also included a cell lysis detecting effect system.With charge coupled device, the detecting system transports the collected cell images to computers and count cells. Cell lysis rate can be calculated through image processing technology. With 8-connected boundary track and grads hough transform to count cells, the result shows that 8-connected boundary track is better and the effect is also better for non-conglutination cell images. But it matters greatly if there exists conglutination in images. This thesis put forward calculating cells with grads hough transform automatically. Grads hough transform is faster in calculating based on standard grads hough transform. The results shows that this method is more accurate than 8-connected boundary track in calculating. BHK21 and C2C12 are respectively used in the cell lysis experiments to test the chip. They are observed through inverted microscope. The observing result shows that impulse electrical field made these two kinds of cells completely broken and extracted DNA from broken cells successfully.Since the distance between electrodes are measured by micron, the voltage needed for cell lysis declines to 3v. The experiment also shows that there is subtle difference between the needed voltage and cell lysis rate under the effect of different impulse signals. Cell lysis rate is relative with impulse width, impulse voltage and electrical conductivity of cell suspending liquid. Researches show that the semi-closed passage between clean polymethyl methacrylate and chips can effectively prevent the production of bubbles. The production of bubbles is also relative with electrical conductivity of cell suspending liquid.In brief, this cell lysis microfluidic chips can break cells under a low voltage at a high breaking rate. It can be conveniently integrated into microfluidic systems or chip experiments for the pretreatment of samples. This system also has advantages, such as low impulse voltage, low cost and micromation etc.