On-Chip Automatic Trapping and Rotating for Zebrafish Embryo Injection

Zebrafish embryo injection is often required in biomedical research using zebrafish. In the injecting operation, trapping and rotating the zebrafish embryo to achieve a proper posture is essential for the high success rate. We proposed an on-chip platform capable of efficient and automatic trapping and rotating for the injection of zebrafish embryos. A low-cost 3D-printed microchannel is designed to trap zebrafish embryos into the cavity array. The blind-hole design at each cavity can generate microbubbles, and the bubbles exposed to the acoustic wave with a specific frequency can trap and rotate the zebrafish embryos. The progress, including trapping and rotating, can be monitored and executed automatically with computer vision assistance. Experimental results show that we realized on-chip trapping and rotating operations successfully. The success rate of trapping zebrafish embryos was up to 99%, and the time of trapping a single embryo was as low as 0.2 s. Embryo rotation could be achieved by two different modes, including continuous rotation and intermittent rotation. The accuracy and maximal velocity of rotating the embryo reached 5° and 3.5 r/s, respectively. Thus, we believe the proposed efficient automatic on-chip trapping and rotating platform could support the zebrafish embryo injection well.