Research Of Anti-Magnetic Micro-Manipulation Based On MEMS

Most of the substances in nature have weak diamagnetic properties, when these materials are put in the magnetic field, they will be suffered an anti-magnetic force afforded by the magnetic field. The materials can be stabilized suspension at a point in space where the gravity is equivalent to anti-magnetic force. The project utilizes the diamagnetic properties of most of the materials, combined with MEMS technology, using the magneto-Archimedes effect, to achieve the capture and manipulation of the biological particles in chips with the unique "anti-magnetic tweezers trap".Firstly, the current biological micro-manipulation techniques have been described, the principle, advantages and disadvantages of different biological micro-manipulation techniques were compared. Then the category, principle and implementation method of the diamagnetic levitation technology were introduced. Combined anti-magnetic levitation technology based on magneto-Archimedes effect with MEMS technology, a novel anti-magnetic micro-manipulation techniques was proposed, and the principle of the realization of the micro-manipulation techniques and chip implementations are introduced in detail.The analysis of anti-magnetic force is the difficulty in anti-magnetic levitation technology. In the third chapter, the analysis of electromagnetic field in the anti-magnetic levitation system was introduced in detail, using electromagnetic theory derived equations of the electromagnetic vector, electromagnetic force and electromagnetic torque, provided a theoretical basis for the solution of the anti-magnetic force.In order to achieve the micro-manipulation of micro/nano scale particles preferable, in the fourth chapter, we first studied the suspension and separation of soybean, green beans, and other seeds at the macro dimensions, studied the ratio of paramagnetic GdCl3 solution, structure of the permanent magnet construction, and utilized the Maxwell 3D(Ansoft corporation) software to simulate the magnetic field distribution of the composite of the permanent magnet when seed levitation, the status of the anti-magnetic force in different locations were also simulated.According to the position change of the magnetic source and position fixed of the magnetic source, designed three manipulation experiment of micro-micron scale particle: One particles capture experiment based on Ni magnetized using permanent magnets. Another is based on the mobile platform to mobile permanent magnet to change the magnetic field distribution, thus achieving particle manipulation. The last one is mainly based on MEMS technology, to make coil array in chip, at different time electrify different direct current to coil array, to change the magnetic field distribution inside the chip through the principle of electromagnetic induction, thus achieving particle micro-manipulation. Chapters fifth and sixth are presented the realization, chips structure and process steps of the three micro-manipulation experiments respectively and also simulated the magnetic field distribution using Maxwell software under these two experiments.Experiments show that the anti-magnetic micro-manipulation techniques based on MEMS can achieve the micro-manipulation of the biological particles, such as capture, separation, and has its own unique advantages, is expected to become a new type of micro-manipulation techniques.