Dynamic releasing of biological cells at high speed using parallel mechanism to control adhesion forces

In this paper, a dynamic releasing method for high-speed biological cell manipulation is proposed. A compact parallel mechanism, used for grasping and releasing microob-jects, was utilized for generating controllable vibration to overcome the strong adhesion forces between the end effector and the manipulated object. To reach the required acceleration of the end effector, which is necessary for the detachment of the target object, vibration in the end effector is generated by applying sinusoidal voltage to the PZT actuator of the parallel mechanism. For the necessary acceleration, we focus on the frequency of the vibration, while keeping the amplitude of the PZT actuator vibration small (14 nm) to achieve precise positioning. Releasing of microbeads and biological cells is conducted and results are compared for the first time. The effect of the air and liquid environments are also investigated. Successful releasing (97.5%) of biological cells proves that the proposed active releasing method is an appropriate solution for the adhered biological cells during the releasing task.