Force characterization of live cells in automated transportation with robot-tweezers manipulation system

Optical trap provides a new and unique tool for manipulation in micro/nano scale and have wide applications in biological fields. Increasing demands for both accuracy and efficiency in cell manipulation highlight the need for automation process that integrates robotics and optical tweezers technologies. A clear understanding of the forces exerted on cells, i.e., trapping and viscous drag forces, is essential to enable automated manipulation using optical tweezers. In this paper, we propose a method to characterize the forces exerted on the live cell moved by optical trap, where the cell is bound to a micro polystyrene bead. Experiment of the cell falling to the focus of the optical trap is performed to show that the proposed force calibration method exhibit better accuracy than the traditional ray-optic numerical method based on the transparent-bead model. Further, automated transportation of the yeast cell is performed to demonstrate the effectiveness in applying the proposed force characterization approach to automated cell manipulation.