Metachronal patterns by magnetically-programmable artificial cilia surfaces for low Reynolds number fluid transport and mixing

Zhang, Rongjing; Toonder, Jaap M.J. den; Onck, Patrick

doi:10.1039/d1sm01680f

Cited by 12 publications

(14 citation statements)

References 64 publications

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“…5B (ii). Such enhancement to fluid transportation by producing metachronal waves in the array direction is also observed in cilia arrays at low Reynolds numbers through numerical investigation ( 33 ).…”

Section: Resultsmentioning

confidence: 74%

Soft-robotic ciliated epidermis for reconfigurable coordinated fluid manipulation

et al. 2022

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The fluid manipulation capabilities of current artificial cilia are severely handicapped by the inability to reconfigure near-surface flow on various static or dynamically deforming three-dimensional (3D) substrates. To overcome this challenge, we propose an electrically driven soft-robotic ciliated epidermis with multiple independently controlled polypyrrole bending actuators. The beating kinematics and the coordination of multiple actuators can be dynamically reconfigured to control the strength and direction of fluid transportation. We achieve fluid transportation along and perpendicular to the beating directions of the actuator arrays, and toward or away from the substrate. The ciliated epidermises are bendable and stretchable and can be deployed on various static or dynamically deforming 3D surfaces. They enable previously difficult to obtain fluid manipulation functionalities, such as transporting fluid in tubular structures or enhancing fluid transportation near dynamically bending and expanding surfaces.

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Section: Resultsmentioning

confidence: 74%

Soft-robotic ciliated epidermis for reconfigurable coordinated fluid manipulation

et al. 2022

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“…Figure 6A shows that both synchronous and dexioplectic motion could generate translational flows while laeoplectic motion only induced local chaotic flows. This is probably caused by the so-called shielding effect of neighboring cilia: The flow induced by each cilium is obstructed by the neighboring cilia ( 20 , 24 , 63 ). The F-MAC with a laeoplectic metachrony shows larger intercilia shielding effect, which leads to local chaotic flows indicated by the chaotic movement of the tracer particles ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The magnetic couples τ were due to the MAC magnetization m and the externally applied rotating magnetic field ( B ) by using τ = m × B . More details on the numerical model can be found in our previous work ( 54 , 63 ). The geometry and the magnetic and mechanical properties of the MAC were taken directly from the experimental results.…”

Section: Methodsmentioning

confidence: 99%

3D-printed micrometer-scale wireless magnetic cilia with metachronal programmability

Zhang

Meng

et al. 2023

Sci. Adv.

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Biological cilia play essential roles in self-propulsion, food capture, and cell transportation by performing coordinated metachronal motions. Experimental studies to emulate the biological cilia metachronal coordination are challenging at the micrometer length scale because of current limitations in fabrication methods and materials. We report on the creation of wirelessly actuated magnetic artificial cilia with biocompatibility and metachronal programmability at the micrometer length scale. Each cilium is fabricated by direct laser printing a silk fibroin hydrogel beam affixed to a hard magnetic FePt Janus microparticle. The 3D-printed cilia show stable actuation performance, high temperature resistance, and high mechanical endurance. Programmable metachronal coordination can be achieved by programming the orientation of the identically magnetized FePt Janus microparticles, which enables the generation of versatile microfluidic patterns. Our platform offers an unprecedented solution to create bioinspired microcilia for programmable microfluidic systems, biomedical engineering, and biocompatible implants.

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“…In Stokes flow conditions (), recent studies have identified a ciliary ‘shielding effect’ in which the flow generated by a beating cilium is obstructed by adjacent cilia (Khaderi, Den Toonder & Onck 2011; Milana et al. 2020; Zhang, den Toonder & Onck 2021, 2022). This effect is present throughout the entire beating cycle, but it is especially pronounced during the recovery stroke, leading to an overall increase in net flow.…”

Section: Resultsmentioning

confidence: 99%

A new propulsion enhancement mechanism in metachronal rowing at intermediate Reynolds numbers

Lionetti,

Lou,

Herrera-Amaya

et al. 2023

J. Fluid Mech.

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Metachronal rowing is a biological propulsion mechanism employed by many swimming invertebrates (e.g. copepods, ctenophores, krill and shrimp). Animals that swim using this mechanism feature rows of appendages that oscillate in a coordinated wave. In this study, we used observations of a swimming ctenophore (comb jelly) to examine the hydrodynamic performance and vortex dynamics associated with metachronal rowing. We first reconstructed the beating kinematics of ctenophore appendages based on a high-speed video of a metachronally coordinated row. Following the reconstruction, two numerical models were developed and simulated using an in-house immersed-boundary-method-based computational fluid dynamics solver. The two models included the original geometry (16 appendages in a row) and a sparse geometry (8 appendages, formed by removing every other appendage along the row). We found that appendage tip vortex interactions contribute to hydrodynamic performance via a vortex-weakening mechanism. Through this mechanism, appendage tip vortices are significantly weakened during the drag-producing recovery stroke. As a result, the swimming ctenophore produces less overall drag, and its thrust-to-power ratio is significantly improved (up to 55.0 % compared with the sparse model). Our parametric study indicated that such a propulsion enhancement mechanism is less effective at higher Reynolds numbers. Simulations were also used to investigate the effects of substrate curvature on the unsteady hydrodynamics. Our results illustrated that, compared with a flat substrate, arranging appendages on a curved substrate can boost the overall thrust generation by up to 29.5 %. These findings provide new insights into the fluid dynamic principles of propulsion enhancement underlying metachronal rowing.

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Metachronal patterns by magnetically-programmable artificial cilia surfaces for low Reynolds number fluid transport and mixing

Abstract: Motile cilia can produce net fluid flows at low Reynolds number because of their asymmetric motion and metachrony of collective beating. Mimicking this with artificial cilia can find application in...

Cited by 12 publications

References 64 publications

Soft-robotic ciliated epidermis for reconfigurable coordinated fluid manipulation

Soft-robotic ciliated epidermis for reconfigurable coordinated fluid manipulation

3D-printed micrometer-scale wireless magnetic cilia with metachronal programmability

A new propulsion enhancement mechanism in metachronal rowing at intermediate Reynolds numbers

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