Metachronal motion of miniaturized magnetic artificial cilia generates microfluidic flow

Biological cilia are often found to exhibit out-of-phase collective metachronal motion. Inspired by nature, we have developed magnetic artificial cilia (MAC) that perform metachronal motion even though all cilia are identical and without using any translating magnets, which are approaches previously used to realize metachrony but difficult to miniaturize. Our approach is to integrate a magnetic substructure underneath the MAC, which locally modifies the applied uniform magnetic field. We show that the induced fluid flow depends on the direction of the metachronal wave. Our method is suitable for miniaturized MAC, enabling pumping by magnetic artificial cilia in small-scale microfluidic chips.