A magnetically driven micromanipulator incorporated with a bubble for bio/micro-object manipulation

This paper presents a magnetically driven micromanipulator for bio/micro-object manipulation in a microfluidic chip. The proposed micromanipulator mainly consists of a compressible bubble for a gripping tool and twin permanent magnets for 2-D propulsion in an aqueous medium. First, the two-dimensional motion controls of the micromanipulator - horizontal, vertical, and rotational motions - are demonstrated by using an external magnetic controller attached beneath the bottom of a chip owing to the interaction forces induced by twin magnets installed inside the micromanipulator and controller. Second, the micro-object manipulation is separately tested with glass beads (100 μm diameter) and a steel ball (600 μm diameter) using an acoustically oscillating bubble. When a bubble is acoustically excited by a piezoactuator around its natural frequency, the radiation force generated from it pulls and grasps neighboring objects. Finally, the manipulation of a steel ball (600 μm diameter) on a chip is achieved by the micromanipulator incorporated with the acoustic excitation. This micromanipulation technique can be applied to various potential applications such as single cell manipulation, micro devices assembly, etc. with minimizing the contact damage by applying a compressible bubble for a gripping tool as a human hand with maintaining high throughput and repeatability.