Surface swimmers, harnessing the interface to self-propel

Grosjean, Galien; Hubert, Maxime; Collard, Ylona; Pillitteri, Salvatore; Vandewalle, Nicolas

doi:10.1140/epje/i2018-11747-y

Cited by 29 publications

(21 citation statements)

References 74 publications

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“…The locomotion of swimmers at small scales has been an active area of research in recent years [1], with a variety of microswimmer models being proposed, both experimental [2][3][4][5][6][7][8][9][10][11] and theoretical [12][13][14][15][16][17][18][19][20][21]. A number of these models aims at understanding the propulsion mechanisms of small organisms such as bacteria or algae cells, or at designing artificial microswimmers.…”

Section: Introductionmentioning

confidence: 99%

A general perturbative approach for bead-based microswimmers reveals rich self-propulsion phenomena

et al. 2019

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Studies of model microswimmers have significantly contributed to the understanding of the principles of self-propulsion we have today. However, only a small number of microswimmer types have been amenable to analytic modeling, and further development of such approaches is necessary to identify the key features of these active systems. Here we present a general perturbative calculation scheme for swimmers composed of beads interacting by harmonic potentials and via hydrodynamics, driven by an arbitrary force protocol. The approach can be used with mobility matrices of arbitrary accuracy, and we illustrate it with the Oseen and Rotne-Prager approximations. We validate our approach by using 3 bead assemblies and comparing the results with the numerically obtained full-solutions of the governing equations of motion, as well as with existing analytic models for the linear and the triangular swimmer geometry. While recovering the relation between the force and swimming velocity, our detailed analysis and the controlled level of approximation allow us to find qualitative differences already in the far field flow of the devices. Consequently, we are able to identify a behavior of the swimmer that is richer than predicted in previous models. Given its generality, the framework can be applied to any swimmer geometry, driving protocol and bead interactions, as well as in problems involving many swimmers.Despite its immense usefulness, this model suffers from the constriction of all internal degrees of freedom by the swimming stroke, namely the internal dynamical behavior of the swimmer cannot react to its surrounding. This was overcome by replacing the arms with springs and prescribing the forces acting on the beads rather than the stroke itself [28,20]. Importantly, the responsive elastic degree of freedom, which is typically associated with the swimmer design, but which could also be in the fluid, is responsible for several interesting phenomena. For example, it is the source of the optimal driving frequency in the overdamped regime [29] and it promotes swimming based on the minimization of drag or enhancement of hydrodynamic interactions [20]. Furthermore, it is also responsible for the existence of a viscosity maximising the swimming velocity [30] and synchronization effects of the stroke [20]. Similar findings have been reported in investigations of bead-based swimmers in a visco-elastic fluid [31,32]. Recently, an altered version of the bead-spring model has been proposed, where the swimmer was driven by periodic changes in the equilibrium lengths of the springs [33,34].The boundedness of the linear swimmer to one dimension is broken in a triangular swimmer geometry, allowing for translational as well as rotational motion [35,14,16]. This geometry has also been used to model Chlamydomonas reinhardtii and investigate in particular the synchronization between the beating of its two flagella [18,36,19]. Experimentally, a triangular swimmer with intrinsic elasticity has been realized by placing ferromagnetic beads subject...

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Section: Introductionmentioning

confidence: 99%

A general perturbative approach for bead-based microswimmers reveals rich self-propulsion phenomena

et al. 2019

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“…In the first approach, the fluid membranes respond linearly to the synchronous or asynchronous spinning motion of the confined nanowires, perturbing at the same time the fluid outside in a controlled manner. The field induced rotation is rectified into translational motion only in the proximity of an interface, condition that is fulfilled in most of the systems of application . The vesicles reach velocities larger than the ones measured when they are loaded with superparamagnetic spherical particles.…”

Section: Resultsmentioning

confidence: 98%

Giant Vesicles with Encapsulated Magnetic Nanowires as Versatile Carriers, Transported via Rotating and Nonhomogeneous Magnetic Fields

Mateos‐Maroto

Ortega

Rubio

et al. 2019

Part & Part Syst Charact

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Two real‐time methods to transport magnetic nanowires confined in giant hybrid vesicles upon the application of different strategies are studied. The microscale carriers are either magnetically guided through the viscous medium by a nonhomogenous field or advected by precisely monitored hydrodynamic flows. The slender geometry of the magnetic component enables the application of large torques, the in situ characterization of the rotational dynamics, as well as the guided propulsion via the continuous thrust of the nanowire tip on the confining bilayer. The flexibility of the vesicles, required to deform along the steering direction during passage through microscale openings, is enhanced via the adsorption of nonionic surfactants on the lipid membrane. The resulting integrated system is an excellent candidate to transport colloidal cargos or fluid amounts of some picoliters in microfluidic platforms, even in physiological environments, since it combines the maneuverability of propelled microscopic systems and the protection conferred by the vesicle.

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“…Care must be taken when implementing LBM with MD because compliant springs can cause translation of the membrane due to inplane stretching. This mechanism has been observed in systems of a few colloids [33]. Therefore, the stiffness of the springs must be large enough to eliminate this effect for an inextensible membrane model requiring the use of a smaller simulation timestep.…”

Section: Hydrodynamic Effects On "Wobbling" Membranesmentioning

confidence: 95%

Locomotion of magnetoelastic membranes in viscous fluids

Brisbois,

de la Cruz

2021

Preprint

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The development of multifunctional and biocompatible microrobots for biomedical applications relies on achieving locomotion through viscous fluids. Here, we describe a framework for swimming in homogeneous magnetoelastic membranes composed of superparamagnetic particles. By solving the equations of motion, we find the dynamical modes of circular membranes in precessing magnetic fields, which are found to actuate in or out of synchronization with a magnetic field precessing above or below a critical precession frequency, ωc, respectively. For frequencies larger than ωc, synchronized rotational and radial waves propagate on the membrane. These waves give rise to locomotion in an incompressible fluid at low Reynolds number using the lattice Boltzmann approach. Non-reciprocal motion resulting in swimming is achieved by breaking the morphological symmetry of the membrane, attained via truncation of a circular segment. The membrane translation can be adapted to a predetermined path by programming the external magnetic field. Our results lay the foundation for achieving directed motion in thin, homogeneous magnetoelastic membranes with a diverse array of geometries.

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Surface swimmers, harnessing the interface to self-propel

Cited by 29 publications

References 74 publications

A general perturbative approach for bead-based microswimmers reveals rich self-propulsion phenomena

A general perturbative approach for bead-based microswimmers reveals rich self-propulsion phenomena

Giant Vesicles with Encapsulated Magnetic Nanowires as Versatile Carriers, Transported via Rotating and Nonhomogeneous Magnetic Fields

Locomotion of magnetoelastic membranes in viscous fluids

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