Technical And Experimental Research On Micromanipulation And Microinjection For Automatic Cell Injection

In the domain of biology, medical treatment and so on, cell injection plays a more and more important role. But there are many deficiencies of manual or semi-automatic manipulation, including low experimental efficiency, difficulty of injection volume control and so on. It is an important subject of cell engineering and mechanical engineering to research a cell injection technology, with the characters of high automation and precise control of microinjection volume.Invented and patented by micro-system lab of Nanjing University of Science and Technology, Digitalization of Micro-Fluids is the most important research production lately. With the equivalent of informationization, digital energy transmission and solid movement, the field of the digital matter transportation is exploited by Micro-Fluidic Digitalization technology, which is greatly significant for the development of microsystem research and technology. Base on the Digitalization of Micro-Fluids, the technologies of micro-manipulation and microinjection is presented for automatic cell injection in this paper. The technologies include cell auto-feeding, position and attitude adjusting, digital piercing and withdrawing micropipette and digital microinjection. Considering the aspects of manipulation mechanism, method and device, confirmed and applied experiment, and so on, a novel system structure and the pivotal technologies of automatic cell injection is presented as follow.A novel cell injection system structure with divided manipulators is brought forward. The task and operating method of every single manipulator is simplified. The performance demand of components, including micro image test, servocontrol and so on, is reduce. The manipulating ability of micro part position and attitude is enhanced. The novel cell injection system structure lays a foundation for the automatic cell injection system.By the drive of micro-fluidic digital technology, the prototype of cell auto-feeder is developed. With characteristics of auto-count, auto-separation and real time control, the prototype can transport appointed for different size cell.Based on coupling control of mechanical motion and flow field, an automatable adjusting technology for cellular position and attitude is proposed. The manipulating mechanism of adjusting technology for cell position and attitude is primarily analyzed with the control of cell culture medium. The engineering model of manipulated cell and control model of submerged jet is founded. With end-actuator of micro-holding pipette, an individual cell manipulation system is developed for cell position and attitude adjusting. Precise control for 3D position and 3 D-O-F attitude is achieved.With the structure character of front- and back- end double support, a novel impact micro motion drive principle is proposed. The principle dynamical model is established. Compared with traditional inertial micro motion principle, the transverse vibration, caused by center mass motion, is removed. Step length and motion direction can be adjusted real timely. Working stability is improved and motion travel is unrestricted.A novel micro-injector is presented with function of digital piercing and withdrawing micropipette, digital microinjection. Confirmed by performance experiment of motion and injection, the micro-injector motion precision is high, coming to nanometer. Experimenatal efficiency of cell membrane pierces reachs 149 cells per hour. The instantaneous speed is rapid. The working process is real time controllable with characteristics of rhythmic injection time and standardized injection volume, while the drive pulse is controllable artificially. The amount of microinjection may reach an ultra high resolution of the order of femtoliters.Taking mouse oocyte as experimental object, automatic cell injection experiment is carried with experimental efficency of 12 cells per hour. By experimental confirmation, the automatic cell injection scheme, which is based on manipulation of cell auto-feeding, position and attitude adjusting, digital piercing and withdrawing micropipette, digital microinjection, is feasible. The automation of cell injection is enhanced by system structure with divided manipulators.