All-Purpose Magnetic Micromanipulation System with Two Modes: Chopstick-Like Two-Finger Microhand and Hydrodynamic Tweezer

In the last two decades, the micromanipulation technique has been widely utilized in industrial and biological fields. However, existing micromanipulation methods can hardly meet all the demands in both fields. In this paper, we present an all-purpose magnetically driven micromanipulation system with designed contact and non-contact modes for numerous industrial and biological applications, respectively. In the system, a micropipette containing the ferromagnetic beads driven by the magnetic field presents high-precision and high-speed motions. With another micropipette, this two-finger microhand can efficiently perform the chopstick-like grasp motion by physical contact. The vibration-based active release relying on the high-speed motion can help release the targets adhering to the end-effector. Besides, local whirling flow surrounding the micropipette induced by high-speed circular motion can trap, transport, and rotate micro-targets without contact like a hydrodynamic tweezer to operate micro bio-targets without any damages. In experiments, microbeads are grasped and released efficiently in the desired positions using the chopstick-like two-finger microhand mode, and the arrays of a hexagon and "T MECH" have been assembled. The hydrodynamic tweezer mode is adopted to trap, transport, and rotate the microbeads and further applied in the operations of the mouse egg cells. We believe the proposed magnetic micromanipulation system, as an all-purpose tool at the microscale, holds great potential in industrial and biological applications.