A Pumpless Mixer for Efficient Capturing of Small Particles Utilizing Vibration-Induced Flow

We demonstrated the applicability of the vibration-induced flow, in which a mean flow is induced around a micro-pillar by applying small circulating vibration (Figure 1), for capturing small particles by larger capture beads. The current approach is advantageous in handling a small amount of liquid of down to several $\mu \mathrm{L}$ because it does not require an external pump. A set of capturing experiments implemented with a simple cylindrical pillar showed that the capturing-rate of small particles depends on the vibration parameters. Since the binding energy (affinity) of biological samples is often weak, there exists the optimal condition to achieve a high capturing rate.