Programmable metachronal motion of densely packed magnetic artificial cilia

TL;DR

This paper demonstrates the controlled generation of metachronal waves in densely packed magnetic artificial cilia, proving experimentally that such waves can produce significant microfluidic flow without additional asymmetries, advancing biomimetic fluid control.

Contribution

The study introduces a precise micro-molding fabrication method for artificial cilia that can generate and control metachronal waves, providing experimental validation of fluid flow driven solely by metachrony.

Findings

Metachronal waves can generate net fluid flow in dense artificial cilia arrays.

Fluid transport efficiency depends on cilia spacing.

Experimental results align with theoretical predictions of metachronal flow effects.

Abstract

Despite recent advances in artificial cilia technologies, the application of metachrony, which is the collective wavelike motion by cilia moving out-of-phase, has been severely hampered by difficulties in controlling densely packed artificial cilia at micrometer length scales. Moreover, there has been no direct experimental proof yet that a metachronal wave in combination with fully reciprocal ciliary motion can generate significant microfluidic flow on a micrometer scale as theoretically predicted. In this study, using an in-house developed precise micro-molding technique, we have fabricated densely packed magnetic artificial cilia that can generate well-controlled metachronal waves. We studied the effect of pure metachrony on fluid flow by excluding all symmetry-breaking ciliary features. Experimental and simulation results prove that net fluid transport can be generated by metachronal motion alone, and the effectiveness is strongly dependent on cilia spacing. This technique not only offers a biomimetic experimental platform to better understand the mechanisms underlying metachrony, it also opens new pathways towards advanced industrial applications.