Acoustofluidic micromixer on lab-on-a-foil devices

In this paper, off-the-shelf materials such as polyethylene terephthalate films and double-sided tapes are applied to create lab-on-a-foil microfluidic devices via a cutting plotter. Microstructures termed defended oscillating membrane equipped structures (DOMES) are integrated in the microchannels. These dome-shaped pore-containing DOMES are created above a through hole on the films using two-photon polymerization. As the bottom side of the air-liquid interfaces trapped in DOMES' pores is always facing ambient air, bubble instability that compromises acoustofluidic performance in conventional cases is alleviated or avoided. The acoustically induced flow is observed to be stronger with increasing pore size on DOMES. An acoustofluidic micromixer is proposed to further investigate the capabilities of DOMES, and it is the first time active micromixer is achieved on lab-on-a-foil devices, with good performance competitive to reported microfluidic mixers.