Analysis of the micropipette insertion mechanism into Human Liver Bud Organoids and its experimental verification

Abstract

The development of a cell isolation tool that can get a neutrophil from human blood vessels within Human Liver Bud Organoid (HLBO) transplanted into the mouse brain is desired. The conditions for inserting a cell isolation tool into HLBO from mouse Cranial Window must be clarified. We made an assumption that the success or failure of inserting a micropipette into biological tissue was determined by multiple factors, such as the mechanical properties of the object to be inserted, the shape of micropipette tip, and the impulse during insertion. To characterize the performance of the micropipette insertion, we fabricated an artificial transparent gel tissue whose mechanical properties were similar to those of living organoid tissues. Then, the mechanical interaction between the micropipette and the gel before and after insertion was evaluated using the piezoelectric impact drive mechanism (IDM). The micropipette fabricated of a thin-walled glass capillary was fixed and driven by the IDM. We used high-speed vision to analyze movements such as the average impact force and speed during micropipette insertion. The results suggested that there might be a certain threshold for the impulsive force generated at the pipette tip with respect to the success or failure of insertion and the selection of an appropriate pipette tip shape were effective for insertion.