Research Of Low Voltage Cell Electrofusion Chip And System Based On MEMS

Compared with traditional cell fusion technologies, cell electrofusion technology has many advantages in terms of precise control, biodegradable, high efficiency, more widely usage and lower sample consumption etc. It has significant value and already been widely applied in monoclonal antibody preparation, mammalian animal cloning, gene engineering research, cancer vaccine, new species cultivation and other related biotechnology fields.Traditional cell fusion technique requires large distance between electrodes, high amplitude pulse signal generated by function generator for cell electroporation. And it has shortcomings in big volume and safety problem. With the development of MEMS(Micro-Electro-Mechanical System) technology, cell electrofusion research,which based on Microchip system, has attracted many researchers and related reports. However, the research about fusion automation and supporting low voltage device of electrofusion reported less. Using MEMS technology to design fusion chips will reduce spacing to micron level, substantially reduce the voltage of cell electroporation, and improve safety and reliability.Based on MEMS, a new project for cell automation sample and fusion is discussed in the thesis. And a low voltage cell fusion system was applied. We applied microelectrode chips as experimental platform to achieve cell electrofusion and lysis under self-designed multi-system. It provides a solution for future micromation of cell electrofusion system.Cell clusters and the electroporation of cell membrane are the basis of cell fusion. This paper has studied the theory of cell dielectrophoresis and electroporation of cell membrane first. Then based on the theory, we researched the frequency-voltage relationship between cell membrane voltage and electric fusion signals. The electrical characteristics of cells have great influence on the efficiency of cell fusion. And with the application of simulation software Multisim, which studied the frequency response of the electrical models of cells with three and five layers, we conclude that cell membrane has the characteristics of low-pass filtering, the nuclear membrane has a band-pass filtering and they coincide with each other in band. Fixed the3-layer cell electrical model in inductance characteristic, whose results provided the solution for the cell fusion. Electrode shape of cell fusion chips has greatly influenced the electric-field distribution, high-throughput, and the ratio of cell fusion. This article applied finite element analysis software-ANSYS to simulate electric field distribution of four different shape electrodes. We conclude that the staggered type semicircle dentate electrode structure, has a wider effective electric field distribution, compared with the square dentate electrode structure, uniform electric field gradient is more suitable for cell fusion and separation, it is the first selection of electrode design. The Platinum/titanium microelectrode chip has been made on glass substrate by lift-off process according to simulation result. Based on the signals sources requirements of cell electrofusion, the shortcomings of the existing cell fusion device, and combined with the similarities between cell lysis and cell fusion system, we successfully intergrated the cell lysis and fusion, which means we designed a new cell manipulation system based on microelectrode chip.The system is of multi-function and high precision, and it can be used for fusing and lysing cell. From the perspective of microfluidic cell electrofusion chip automation integration, and based on the theory of dielectric breakdown and the electroosmosis driven, we put forward the program by applying the two methods into cell electro-fusion sample. Based on the COMSOL simulation, we manufactured a symmetrical cross type microfluidic dielectric breakdown sample chip which has clearance obstruct, and completed sample experiments. Furthermore, during cell fusion experiment we found that Joule heat and electrode hydrolysis rate were not only proportional to the size of the electric field intensity, pulse width, but to the pulse duty ratio, there were an optimal value between them. This conclusion is supplementary explanation of the traditional theory.According to the electric field distribution and signal required for electrofusion, we respectively designed a low voltage cell electrofusion microelectrode chip and a cell manipulation system which integrated multi-function. This system also has advantages in terms of low fusion voltage, low cost, easy operation and micromation etc. Moreover, this thesis introduced a new idea of automation cell electrofuion chip laboratory, and verified the feasibility of the scheme by experiments. It set up a foundation for the development of high efficiency, antomation and intelligentize of cell electrofusion chip.