| With the development of modern biomedicine technology,micro manipulation for single cell is becoming more and more complex and precise.The motion of the manipulation even can be measured by submicron and nanometer,making a higher requirement to the bio manipulation technology.Therefore,it's important to develop the micro damage cell injector high precise performance for the complex cell "operation".Based on the piezoceramics ultrasonic vibration technology,the piezo-driven cell injector in this paper can penetrate the cell membrane with slight cell damage.The cell injector has 3 important advantages:(1)The new injector has high vibration transmission speed,excellent heat dissipating performance and a long lifetime.(2)Optimized pipette holder can use the bend pipette,making the cell injector more suitable for the traditional manipulation habit.(3)Cell elastic modulus detection function and cell injection function were combined together,making the new process conception of detection and injection be a reality.Finally,the experimental study shows the performance improved a lot compared to the traditional devices.The main research content is as follow:Part one,the state of development about the cell injection technology and assistive technology was introduced.Then,the development status of cell injection device was summarized.And find the micro manipulation technology development trend can be summarized as:"human eye vision replaced by machine vision" and "human hands replaced by mechanical manipulator".Part two,piezoceramics and ultrasonic vibration technology were lucubrated.Then pipette tip's vibration was analyzed by mathematical equations derivation.In cell penetrating mechanism,a new membrane breaking mechanism was presented.The penetrating process was divided and the effect of axial and lateral vibration in different process was studied.The lateral vibration was found can reduce pipette tip's drag in process two.In cell elastic modulus detection,the technology principle used in this paper was stated.Part three,the body of the cell injector was designed and optimized.6061 aluminum alloy was used in new open type piezoceramics package,the new package is lighter than before and the structure has a good heat dissipating performance.The vibration transmission speed is higher than before with the "bow" structure.After optimization,the lightweight pipette holder weight only 1 gram.And it's suitable for the fast copy by 3D printer in future laboratory.In addition,the inapplicability problem of traditional bend pipette with piezoelectric device was solved by the bend holder design.At last the structure was analyzed by FEA tool,the analysis results shows the injector's modal frequency has no effect to the ultrasonic vibration and the minimum lateral vibration of the pipette tip is only 18.5?m at 22KHz.And this can satisfy the cell injection manipulation requirement.Part four,injector test and experimental study were performed for function check and performance research.First,the system was built for the test and experiment requirement,manipulation was assisted by machine vision and micro manipulator.Then,the injector was test in two mediums,result shows the culture medium weaken the vibration partly and the pipette tip's lateral vibration shadow reached the minimum width 20.5?m at 20 KHz.After that,the elastic modulus detect function was test following the manipulation process,result shows the injector can distinguish the different silica gel cube.After that,pig's ovum was used to perform several membrane penetrating experiments,and the damage status was evaluated by comparisons,result shows the new injector's damage is slighter than before.At last,60 cells were divided to 3 groups for survival rate calculating,and finally the survival rate is 98.3%after 24 hours cultivating. |
PDF Full Text Request