Artificial cilia fabricated using magnetic fiber drawing generate substantial fluid flow

Wang, Ye; Gao, Yuan; Wyss, Hans M.; Anderson, Patrick Patrick; Toonder, Jaap M.J. den

doi:10.1007/s10404-014-1425-8

Cited by 46 publications

(66 citation statements)

References 18 publications

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“…There are two explanations for this trend based on dynamics effects. First, viscous forces acting on cilia increase with higher actuation speeds, as also reported for magnetic beating cilia . This effect is described by a dimensionless parameter called Sperm number, defined as the ratio between the viscous forces and the elasticity of the cilium.…”

Section: Flow Field Measurementsmentioning

confidence: 62%

Artificial Soft Cilia with Asymmetric Beating Patterns for Biomimetic Low‐Reynolds‐Number Fluid Propulsion

Milana

Gorissen

Peerlinck

et al. 2019

Adv Funct Materials

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In nature, liquid propulsion in low-Reynolds-number regimes is often achieved by arrays of beating cilia with various forms of motion asymmetry. In particular, spatial asymmetry, where the cilia follow a different trajectory in their effective and recovery strokes, is an efficient way of generating flow in low Reynolds regimes. However, this type of asymmetry is difficult to mimic and control artificially. In this paper, an artificial soft cilium that comprises two pneumatic actuators that can be controlled individually is developed. These two independent degrees of freedom allow for the first time adjustment and study of spatial asymmetry in the cilium's beating pattern. Using low-Reynolds-number flow measurements, it is confirmed that spatial asymmetry allows for the generation of fluid propulsion. These twodegree-of-freedom soft cilia provide a platform to study ciliary fluid transport mechanisms and to mimic biologic viscous propulsion.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201900462. of a single cilium as well as for whole cilia arrays. For a single cilium, orientational, temporal, and spatial asymmetry can be distinguished, [6] where the latter has the highest impact on low Reynolds fluid propulsion. Spatial asymmetry, where the cilium tip describes a different path during the effective and recovery stroke, is quantified by the swept area; the larger the area, the higher the net flow. [7] At the array level, an additional type of asymmetry has been observed, metachronal asymmetry, which is characterized by a phase difference between neighboring cilia [8] that gives rise to a global wave-like movement.With the development of microsystem technology, artificial cilia can now be fabricated and are foreseen to find applications in microrobotic devices, such as microswimmers, [9,10] microsensors, [11] micropumps, [12][13][14] and micromixers. [15][16][17][18] The vast majority of artificial cilia consist of microactuators that are incorporated in silicone rubber pillars or plate-like flexible structures in order to mimic the biological hair-like design. Current actuation methods include electric fields, [15] magnetic fields, [19][20][21][22][23] vibrations, [24,25] mechanical forces, [26] or pressurized fluids. [27,28] However, asymmetric motion remains the most challenging feature to mimic in artificial cilia systems. In nature, nonreciprocal beating is achieved by a change in bending stiffness between the effective and recovery stroke: [29] A higher stiffness is observed during the fast effective stroke, where the cilium does not deform significantly, whereas in the slower recovery phase the cilium has a lower stiffness and tends to be deformed by the drag forces. To mimic such an asymmetric motion, the artificial cilium needs at least two deformation modes that need to be sequentially addressed. This can be achieved through elastic instabilities, [7] the interaction between elastic, viscous, and actuation forces, [26,30] or a multise...

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Section: Flow Field Measurementsmentioning

confidence: 62%

Artificial Soft Cilia with Asymmetric Beating Patterns for Biomimetic Low‐Reynolds‐Number Fluid Propulsion

Milana

Gorissen

Peerlinck

et al. 2019

Adv Funct Materials

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“…9). A somewhat related, also template-free, fiber-drawing technique for fabricating magnetic cilia with high aspect ratios has recently been presented by Wang et al [34]. Their cilia are able to generate net flow velocities up to 70 lm/s in a closed-loop design.…”

Section: Pdms Composite Actuatorsmentioning

confidence: 99%

Stimulus-active polymer actuators for next-generation microfluidic devices

Hilber

2016

Appl. Phys. A

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Microfluidic devices have not yet evolved into commercial off-the-shelf products. Although highly integrated microfluidic structures, also known as lab-on-a-chip (LOC) and micrototal-analysis-system (lTAS) devices, have consistently been predicted to revolutionize biomedical assays and chemical synthesis, they have not entered the market as expected. Studies have identified a lack of standardization and integration as the main obstacles to commercial breakthrough. Soft microfluidics, the utilization of a broad spectrum of soft materials (i.e., polymers) for realization of microfluidic components, will make a significant contribution to the proclaimed growth of the LOC market. Recent advances in polymer science developing novel stimulus-active soft-matter materials may further increase the popularity and spreading of soft microfluidics. Stimulus-active polymers and composite materials change shape or exert mechanical force on surrounding fluids in response to electric, magnetic, light, thermal, or water/solvent stimuli. Specifically devised actuators based on these materials may have the potential to facilitate integration significantly and hence increase the operational advantage for the end-user while retaining costeffectiveness and ease of fabrication. This review gives an overview of available actuation concepts that are based on functional polymers and points out promising concepts and trends that may have the potential to promote the commercial success of microfluidics.

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“…Despite practical advantages of passive manipulation of particles (Kang et al 2009), for several applications more control is required and an active manipulation is desired. Researchers have used different actuation mechanisms to displace and transport rigid and deformable particles like electrostatics (den Toonder et al 2008;Khatavkar et al 2007), magnetics (Zhang et al 2019;Wang et al 2013Wang et al , 2015Wang et al , 2016 and light (van Oosten et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Head-on collision of Newtonian drops in a viscoelastic medium

Mitrias

Hulsen

Anderson

2019

Microfluid Nanofluid

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Depending on the application, one needs to either stabilize or destabilize the interfacial properties of an emulsion. An aspect of the dynamics that governs the stability of emulsions in general is the drainage time of the film that is formed when two drops collide. In this work, we study the effect that viscoelasticity of the matrix fluid has on this drainage time of two Newtonian drops that perform a head-on collision under an applied macroscopic extensional rate. For the modeling of the viscoelastic matrix material, the Giesekus model is chosen. A cylindrical coordinate system is applied with imposed axisymmetry and the resulting equations are solved using fully resolved numerical simulations employing a finite element discretization. Our results show that viscoelasticity reduces the drainage time, which is a combined effect of three different stages.

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Artificial cilia fabricated using magnetic fiber drawing generate substantial fluid flow

Cited by 46 publications

References 18 publications

Artificial Soft Cilia with Asymmetric Beating Patterns for Biomimetic Low‐Reynolds‐Number Fluid Propulsion

Artificial Soft Cilia with Asymmetric Beating Patterns for Biomimetic Low‐Reynolds‐Number Fluid Propulsion

Stimulus-active polymer actuators for next-generation microfluidic devices

Head-on collision of Newtonian drops in a viscoelastic medium

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