A Novel Auto-Focusing Algorithm for Automated Cell Immobilization

Automated cell immobilization is a key technology in robotic single cell manipulation. In the existing automation methods of cell immobilization, the microinjection tools (microgripper or micropipette) and the cells need to be manually put into the culture media, and then the microgripper or micropipette is automated to gradually approach the plane in which the center of the cell is located in order to clamp or adsorb the cells to immobilize cell. This paper presents a novel technology that is capable of automatically moving down the gripper into the culture media from the outside air environment, and then precisely clamping a cell in the liquid environment for injection. In the proposed solution, an active window-based auto-focusing algorithm is developed to solve the challenging problem: the image information is lost due to the “viscous effect” taking place when the gripper jaw touches the water surface and enters the culture media. The proposed algorithm are tested and validated by the immobilization experiments of zebrafish embryos using the in-house develop micro-robotic system. The proposed algorithm in this paper can help firmly immobilize cells, significantly improve the automation of micromanipulation, and reduce the working intensity of the labors.