Automated Micropipette Aspiration and Positioning with an Auxiliary Micropipette

Micropipette aspiration of single cells is widely used in cell manipulation. In this paper, an automated micropipette aspiration and positioning method is proposed with an auxiliary micropipette. The flow field provided by the auxiliary micropipette reduces the adhesion between the microbead and the bottom of the petri dish, which seriously affects the stability of the aspiration process. The position information of the micropipette tip and the microbead, extracted via image processing, is used as feedback of closed-loop control. A dynamic model of the motion of the microbead in the micropipette is established based on pneumatic pump, and a sliding mode controller is designed on this basis. The experimental results show that the proposed method has faster stability time, smaller steady-state error and higher success rate compared with the traditional aspiration method without the auxiliary micropipette.