Robotic Microscopic Vision-Free Cell Transportation Based on Pressure Variation Model Inside Bilayer Micropipette

Cell transportation is a key step in many biological applications. Currently, most cell transportation research relies on microscopic vision feedback, which limits its application at places when a microscopic view is unavailable. For the first time, this paper proposed a robotic microscopic view-free cell transportation method based on pressure variation model inside a self-made bilayer micropipette. The bilayer micropipette, made by inserting a thin micropipette into a thicker one, picks the target cell with the outsider micropipette and holds it with the inner micropipette in cell transportation. To achieve this, the appropriate fluidic forces to pick and place the cell were determined based on force analysis. Then, the appropriate inner diameter of the inner thin micropipette was determined based on the micropipette aspiration model. Further, the pressure variation inside the bilayer micropipette during holding and releasing process were modeled to conduct a robotic microscopic vision-fee cell transportation. Experimental results demonstrated that our system was capable of transporting zebrafish embryos at an average speed of 25 s/cell with a success rate of 90%, with a transportation efficiency comparable to the related methods with microscopic view feedback. Besides, ignorable mechanical harm to the development competence of the zebrafish embryos was confirmed through culturing experiments.
Note to Practitioners
—Cell transportation is an important step in many biomedical researches. Currently, cell transportation usually relies on microscopy for picking up, and releasing cells, limiting its application in special environments without microscopic view feedback. In this paper, a robotic microscopic vision-free cell transportation method is proposed for the first time. In this method, cells are transported within a self-made bilayer micropipette. Pressure variations inside the micropipette are utilized to determine cell picking up and release. This robotic transport method demonstrated a high success rate and low harm to cells in experiments. Our research may contribute to the future development of vision-free and fully automated robotic cell culture techniques. Our research may spike inspiration for future research on microscopic vision-free cell transportation in fully automated cell culture system.