Transportation of Multiple Biological Cells through Saturation-controlled Optical Tweezers in Crowded Microenvironments

Chen, H. ; Wang, C. ; Li, X. ; Sun, D.

Transportation of biological cells has attracted increased attention in bioscience and nanomedicine. Existing approaches to achieve automated multi-cell transportation are generally based on numerous over-strict conditions or assumptions, including static and clean environments, complex theoretical convergence cond itions, omitting tool kinematics, and off-line calibrations. This paper presents a novel approach for the automated transportation of multiple cells by using robotically controlled holographic optical tweezers. First, a swarming controller was developed with easily satisfied convergence conditions. The offset between centers of the cell and optical tweezers was constrained by saturation control to maintain the cells in the optically trapping area. An artificial first-order kinematic model of the tweezers was considered in the controller design to reduce controller oscillation. Second, a solution to the collision avoidance of random-moving obstacles was developed to remove the assumption of static or clean environments. Finally, an automated method based on the drag force model and gradient descent optimization was presented to calibrate cell dynamics online. Experiments on yeast cells were performed to verify the effectiveness of the proposed approach.

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