Acoustofluidic micromixer on lab-on-a-foil devices

In this paper, off-the-shelf materials 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 structure (DOMES) are integrated in the microchannels, and it is created above a through hole on the films using two-photon polymerization. As the bottom side of air-liquid interfaces trapped by multiple pores on DOMES is always facing ambient air, bubble instability that compromises acoustofluidic performance in conventional cases can be 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 devices.