Inspired by the structure and properties of natural cilia, we focused on a
facile template-free approach to prepare magnetic artificial cilia grown on the substrate
(glass, PDMS, or others). In an applied magnetic field, the cilia formed spontaneously and
immediately from magnetic nanoparticles and elastomeric polymer in a liquid solvent by
bottom-up self-assembly. The length of prepared cilia could be in the scale of millimeter
and reach a high aspect ratio of even over 100. We studied the effect of the magnetic
strength applied and the size of nanoparticles to get tunable scale of cilia. The cilia show
reversibly bending in an external magnetic field and this bending actuation gave some
important functions: to transport macroscopic nonmagnetic materials on the cilia and to
mix liquids.
