Biological cilia have exquisitely organized dynamic ultrafine
structures
with submicron diameters and exceptional aspect ratios, which are
self-assembled with ciliary proteins. However, the construction of
artificial cilia with size and dynamic functions comparable to biological
cilia remains highly challenging. Here, we propose a self-assembly
technique that generates magnetoresponsive artificial cilia with a
highly ordered 3D structural arrangement using vapor-phase magnetic
particles of varying sizes and shapes. We demonstrate that both monodispersed
Fe3O4 nanoparticles and Fe microparticles can
be assembled layer-by-layer vertically in patterned magnetic fields,
generating both “nanoscale” or “microscale”
artificial cilia, respectively. The resulting cilia display several
structural features, such as diameters of single particle resolution,
controllable diameters and lengths spanning from nanometers to micrometers,
and accurate positioning. We further demonstrate that both the magnetic
nanocilia and microcilia can dynamically and immediately actuate in
response to modulated magnetic fields while providing different stroke
ranges and actuation torques. Our strategy provides new possibilities
for constructing artificial nano- and microcilia with controlled 3D
morphology and dynamic field responsiveness using magnetic particles
of varied sizes and shapes.