Biological Cell Injection Using an Autonomous MicroRobotic System

Recent advances in microbiology, such as cloning, demonstrate that increasingly complex micromanipulation strategies are required for manipulating individual biological cells. In this paper, we present a microrobotic system capable of conducting automatic embryo pronuclei DNA injection (cell injection). Conventionally, cell injection has been conducted manually, however, long training, low success rates from poor reproducibility in manual operations, and contamination all call for the elimination of direct human involvement. To automate cell injections, a microrobotic system is developed that is capable of performing automatic embryo pronuclei DNA injection autonomously through a hybrid visual servoing control scheme. A Hough transform is used to detect the nuclei of embryos. Sum-ofsquared-differences optical flow is used to track injection pipette motion, and auto focusing is implemented to determine the relative depth of subcellular structures. A hybrid control scheme is developed to fulfill the cell injection task. Upon the completion of injection, the DNA injected embryos are transferred into a pseudo-pregnant foster female mouse to reproduce transgenic mice for cancer studies. The experimental result shows that the injection success rate is 100%. KEY WORDS—microrobotic system, cell injection, visual servoing, position control