Indirect pushing based automated micromanipulation of biological cells using optical tweezers

In this paper, we introduce an indirect pushing based technique for automated micromanipulation of biological cells. Indirect pushing can be viewed as nonprehensile robotic manipulation. We propose a bead formation composed of two inert, optically-trapped glass beads, where one of the beads pushes the other freely diffusing intermediate bead to indirectly manipulate a given cell. Some cells can undergo significant changes in their behaviors as a result of direct exposure to a laser beam. Indirect pushing eliminates this problem by minimizing the exposure of the cell to the laser beam. We report an automated feedback planning algorithm that combines three motion maneuvers, namely, push, align, and backup for micromanipulation of cells. We have developed a simulation model of indirect pushing dynamics and also identified parameters of measurement noise using physical experiments. We present an optimization based approach for automated tuning of planner parameters to enhance its robustness. Finally, we have tested the developed planner using our optical tweezers physical setup and carried out a detailed analysis of the experimental results. The developed approach can be utilized in biological experiments for studying collective cell migration by accurately arranging the cells in arrays without exposing them to a laser beam. ∗All correspondence should be addressed to [email protected].