Capturing, carrying, and releasing of micro-objects by AC-electroweting-actuated oscillating bubbles

This paper reports a new principle of object manipulation along with experimental proofs. It is found that air bubbles oscillated by AC electrowetting capture neighboring objects. The capturing strength is proportional to the oscillation amplitude that can be controlled by the amplitude and frequency of electrowetting signal. Using microfabricated-testing chips, it is demonstrated that oscillating mobile bubbles capture, carry, and release neighboring objects on a chip. Switching operations between capturing and releasing is done simply by changing the frequency of electrowetting signal while electrowetting is on. This new manipulation method may provide an efficient tool for handling millimeter- as well as micron-sized objects such as biological cells and embryos cells.