A novel on-chip micromanipulation method using a microbubble for single cell manipulation and characterization

A novel on-chip micromanipulation method has been developed where a gaseous microbubble is applied to physically manipulate micro-objects in an aqueous medium through optical and acoustical excitations. This micromanipulation concept is experimentally verified: bubble manipulation (generating and transporting operations) and micro-object manipulation (capturing, carrying, and releasing operations). Optically induced microbubble generation is firstly tested for different optical powers in a microfluidic chip with an amorphous silicon layer as an optically absorbent material. And microbubble transportation is also demonstrated using optically induced thermocapillary effects. Micro-object manipulation is separately demonstrated using a gaseous microbubble (300 μm dia.) with glass beads (100 μm dia.) in an aqueous medium. When the microbubble is acoustically excited by a piezoactuator attached on the bottom of a chip, it oscillates and simultaneously captures the neighboring glass beads owing to the oscillating bubble induced radiation forces. Finally, the manipulation of a single glass bead (100 μm dia.) using a microbubble (300 μm dia.) is successfully achieved with integration of optical and acoustical excitations. This novel micromanipulation technique may be an efficient tool for single cell manipulation and characterization in a microfluidic chip.