Development Of Micro-nano Devices For Automated Microinjection System

An important method in the field of life science is microinjection.However,this technique is labor intensive,and requires the operator has a high degree of technical proficiency.The operator spends a great deal of time performing the micromanipulation and microinjection of a single cell under a microscope.The introduction of robot technology into this traditional field of Biotechnology increased injection efficiency and improved the success rate while reducing the amount of labor required.In order to further improve the efficiency and the success rate of the robotic system,the design and fabrication of micro-nano devices for this use are presented in this paper.First,we introduce the characteristics of the biological cell microinjection system and the injection object.A detailed description of the overall design ideas and the components of the system are given according to the particularity of the biological cell.Subsequently,we designed and fabricated a novel force sensor with integrated cell fixation device.Based on the traditional cantilever beam structure,we developed a new symmetrical structure that reduces damage to cells during the microinjection process.A transparent soft cell-fixing device based on PDMS material was integrated in the middle position of the piezoelectric beam.In addition,the sensor is calibrated and validated by an actual cell microinjection experiment.Finally,we propose a new type of cell immobilization device to optimize the fixation of the embryo via adhesion of the material surface to the zebrafish embryos.Using finite element software,we calculated the optimal morphology for maximum contact force between the embryo and the PDMS surface.After surface morphology was obtained by dry etching process,the surface adhesion force of PDMS was further increased by coated poly lysine protein.PDMS surface optical images and SEM showed that the surface morphology of PDMS was adequate,and the results of the contact angle test revealed that the PDMS surface was hydrophobic which is conducive to cell adhesion.Finally,a confirmation experiment was performed.The automated injection of zebrafish embryos verified that the cell fixation device significantly increased the puncture success rate when compared to the common glass slide,which is used for a microinjection automation system.