Controlled propulsion in viscous fluids of magnetically actuated colloidal doublets

Tierno, Pietro; Güell, Oriol; Sagués, Francesc; Golestanian, Ramin; Pagonabarraga, Ignacio

doi:10.1103/physreve.81.011402

Cited by 49 publications

(51 citation statements)

References 42 publications

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“…[15][16][17][18] After employing "topdown" fabrication processes, the entire 2D patterned mesa is released from the substrate and self-organizes to form a tethered ABF, as shown in Figure 1a,b. The details of the fabrication are reported elsewhere.…”

Section: Maximum Dimensional Speedmentioning

confidence: 99%

“…17,18 The self-scrolling technique used allows the size of the 3D structure to be tuned from the nanometer to millimeter range by adjusting the layer thickness; furthermore, other materials can be integrated into the rolled-up structures. 16,19,20 To untether the ABF from the substrate, micromanipulation is performed to cut, pick, and release the ABF (see Supporting Information). Moreover, the length of the ABF tail can be tailored by micromanipulation as well.…”

Section: Maximum Dimensional Speedmentioning

confidence: 99%

“…The first group includes helical propellers [13,14], as inspired by helical bacterial flagella [11], which propel upon rotation imposed by external magnetic fields. The second group of propellers relies on a surface to break the spatial symmetry and provide one additional degree of freedom to escape the constraints from the scallop theorem, and hence are termed surface walkers [15][16][17][18]. Finally, the third type of propellers, referred to as flexible propellers, exploits the deformation of flexible filaments for propulsion.…”

Section: Introductionmentioning

confidence: 99%

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High-speed propulsion of flexible nanowire motors: Theory and experiments

et al. 2011

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Micro/nano-scale propulsion has attracted considerable recent attention due to its promise for biomedical applications such as targeted drug delivery. In this paper, we report on a new experimental design and theoretical modelling of high-speed fuel-free magnetically-driven propellers which exploit the flexibility of nanowires for propulsion. These readily prepared nanomotors display both high dimensional propulsion velocities (up to ≈ 21µm/s) and dimensionless speeds (in body lengths per revolution) when compared with natural microorganisms and other artificial propellers. Their propulsion characteristics are studied theoretically using an elastohydrodynamic model which takes into account the elasticity of the nanowire and its hydrodynamic interaction with the fluid medium. The critical role of flexibility in this mode of propulsion is illustrated by simple physical arguments, and is quantitatively investigated with the help of an asymptotic analysis for small-amplitude swimming. The theoretical predictions are then compared with experimental measurements and we obtain good agreement. Finally, we demonstrate the operation of these nanomotors in a real biological environment (human serum), emphasizing the robustness of their propulsion performance and their promise for biomedical applications.

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Section: Maximum Dimensional Speedmentioning

confidence: 99%

Section: Maximum Dimensional Speedmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-speed propulsion of flexible nanowire motors: Theory and experiments

et al. 2011

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“…The micro-mutual-dipolar model is demonstrated to be useful for force calculations in dynamic simulations of small clusters of particles for which both accuracy and efficiency are desirable. [5,6], biomedical sensing [7,8], propulsion and transportation in fluids [9,10], and force probes [11,12]. In these applications, the magnetic force between paramagnetic particles must be calculated accurately.…”

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confidence: 99%

Micro-mutual-dipolar model for rapid calculation of forces between paramagnetic colloids

Biswal

2014

Phys. Rev. E

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Typically, the force between paramagnetic particles in a uniform magnetic field is calculated using either dipole-based models or the Maxwell stress tensor combined with Laplace's equation for magnetostatics. Dipolebased models are fast but involve many assumptions, leading to inaccuracies in determining forces for clusters of particles. The Maxwell stress tensor yields an exact force calculation, but solving Laplace's equation is very time consuming. Here, we present a more elaborate dipole-based model: the micro-mutual-dipolar model. Our model has a time complexity that is similar to that of other dipole-based models but is much more accurate especially when used to calculate the force of small aggregates. Using this model, we calculate the force between two paramagnetic spheres in a uniform magnetic field and a circular rotational magnetic field and compare our results with those of other models. The forces for three-particle and ten-particle systems dispersed in two-dimensional (2D) space are examined using the same model. We also apply this model to calculate the force between two paramagnetic disks dispersed in 2D space. The micro-mutual-dipolar model is demonstrated to be useful for force calculations in dynamic simulations of small clusters of particles for which both accuracy and efficiency are desirable. [5,6], biomedical sensing [7,8], propulsion and transportation in fluids [9,10], and force probes [11,12]. In these applications, the magnetic force between paramagnetic particles must be calculated accurately. Typically, dipole-based models, such as the dipolar model (DM) and the mutual-dipolar model (MDM), are used to calculate the force between paramagnetic particles placed in an external magnetic field [2,5,13]. Dipole-based models are usually fast but inaccurate for systems in which particles are close to one another. Such models are inaccurate because they do not consider multipolar effects [14]. The exact force can be calculated by solving a Laplace equation for magnetostatics with multiple boundary and initial conditions and calculating the Maxwell stress tensor for each particle [15]. The solution to the Laplace equation can be analytically approximated by a solid harmonics expansion with the Hobson formula applied to unify the coordinate system [14,16]. This coordinate unification is very computationally expensive and suffers from singularity-related issues [17,18]. A numerical solution to Laplace's equation can be obtained by using a smoothed representation of susceptibility to replace the boundary conditions [17]; this method is referred to as the Laplace equation solver (LES) method. This numerical approach is stable in terms of error propagation but still computationally time consuming.Here, we present a more-sophisticated dipole-based model that considers mutual interactions between dipole moments and multipolar effects. All dipole-based models are based on the fact that a single spherical paramagnetic particle is uniformly magnetized in the presence of a uniform magnetic * Correspondin...

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“…The asymmetric dumbbell geometry was recently proposed as a micro-propeller and microrheometer in viscoelastic fluids in the absence of inertia [23], and as will be discussed below, inertia and viscoelastic fluids lead to effects acting in opposite directions. Note that magnetically actuated asymmetric microdumbbells have been shown to propel in a purely Stokesian framework by Tierno et al [24][25][26]. In this case, the propulsion, which is impossible to achieve in an isotropic medium, is enabled by the presence of a wall which breaks the symmetry of the nearby environment.…”

Section: Introductionmentioning

confidence: 99%

Rotational propulsion enabled by inertia

et al. 2014

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Abstract. The fluid mechanics of small-scale locomotion has recently attracted considerable attention, due to its importance in cell motility and the design of artificial micro-swimmers for biomedical applications. Most studies on the topic consider the ideal limit of zero Reynolds number. In this paper, we investigate a simple propulsion mechanism -an up-down asymmetric dumbbell rotating about its axis of symmetryunable to propel in the absence of inertia in a Newtonian fluid. Inertial forces lead to continuous propulsion for all finite values of the Reynolds number. We study computationally its propulsive characteristics as well as analytically in the small-Reynolds-number limit. We also derive the optimal dumbbell geometry. The direction of propulsion enabled by inertia is opposite to that induced by viscoelasticity.

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Controlled propulsion in viscous fluids of magnetically actuated colloidal doublets

Cited by 49 publications

References 42 publications

High-speed propulsion of flexible nanowire motors: Theory and experiments

High-speed propulsion of flexible nanowire motors: Theory and experiments

Micro-mutual-dipolar model for rapid calculation of forces between paramagnetic colloids

Rotational propulsion enabled by inertia

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