Robotic Cardinal Vein Microinjection of Zebrafish Larvae Based on 3D Positioning

Zebrafish (Danio Rerio) larvae have long been an important model organism for biomedicine and drug discovery. It is difficult to deliver the external materials into the circulatory system by conventional exposing administration, while vein microinjection is more efficient but more challenging. In this paper, a robotic cardinal vein microinjection system was presented for zebrafish larvae. The key points of injection pipette during penetration were analyzed, and their 3D positions were identified online by combining motion analysis and visual calibration. 3D path planning of the pipette tip was designed automatedly before injection. The injection system was evaluated by injecting green fluorescent microspheres into 20 zebrafish larvae. The experiment results show that the fluorescent microspheres spread rapidly in the blood circulation system after injection, achieving a success rate of 85.0% and a survival rate of 94.1%. The superior performance provided by the system will significantly facilitate tumor xenografts and canner studies on zebrafish.