Autonomous navigation of shape-shifting microswimmers

Dou, Yong; Bishop, Kyle J. M.

doi:10.1103/physrevresearch.1.032030

Cited by 11 publications

(14 citation statements)

References 31 publications

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“…Although progress on reconfigurable robots at the sub-millimeter scale has been made [19][20][21][22][23] , downscaling these concepts to the colloidal level demands alternative fabrication and design. Shape-shifting colloidal clusters reconfiguring along a predefined pathway in response to local stimuli 24 would combine both characteristics, with high potential toward the vision of realizing adaptive artificial microswimmers. Here, we present an approach to fabricate reconfigurable microswimmers relying on a simple combination of standard "hard" particles with soft responsive colloids.…”

mentioning

confidence: 99%

Reconfigurable artificial microswimmers with internal feedback

et al. 2021

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Self-propelling microparticles are often proposed as synthetic models for biological microswimmers, yet they lack the internally regulated adaptation of their biological counterparts. Conversely, adaptation can be encoded in larger-scale soft-robotic devices but remains elusive to transfer to the colloidal scale. Here, we create responsive microswimmers, powered by electro-hydrodynamic flows, which can adapt their motility via internal reconfiguration. Using sequential capillary assembly, we fabricate deterministic colloidal clusters comprising soft thermo-responsive microgels and light-absorbing particles. Light absorption induces preferential local heating and triggers the volume phase transition of the microgels, leading to an adaptation of the clusters’ motility, which is orthogonal to their propulsion scheme. We rationalize this response via the coupling between self-propulsion and variations of particle shape and dielectric properties upon heating. Harnessing such coupling allows for strategies to achieve local dynamical control with simple illumination patterns, revealing exciting opportunities for developing tactic active materials.

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mentioning

confidence: 99%

Reconfigurable artificial microswimmers with internal feedback

et al. 2021

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“…An alternative strategy has been proposed based on the shape transformations of stimuli–responsive materials in response to changes in the concentration of a chemical. [ 117 ] This strategy has been experimentally realized using geometrically and compositionally asymmetric colloids containing polystyrene particles and thermoresponsive microgels. [ 118 ]…”

Section: Harnessing Fluid–structure Interactionsmentioning

confidence: 99%

On‐Board Mechanical Control Systems for Untethered Microrobots

Dolev

Kaynak

Sakar

2021

Advanced Intelligent Systems

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An autonomous robot perceives its environment, makes decisions based on acquired information and programmed routines, and then actuates a movement or performs a manipulation task within that environment. The idea of microrobotics is primarily based on teleoperated mobile micromachines equipped with manipulation capabilities such as actuated grippers and drug‐loaded reservoirs. Due to miniaturization challenges, the majority of these micromachines are wirelessly actuated using magnetic fields or acoustic waves. A step toward complete autonomy is the development of on‐board control systems that directly transduce environmental stimuli such as heat and pressure into actuation, without going through the perception and computation cycles. Following the analogy of the central nervous system for the architecture of conventional autonomous robots, the next‐generation microrobots are expected to possess reflexes that would allow them to autonomously navigate inside structured microenvironments and perform targeted and triggered operations. Herein, the construction of on‐board control systems using stimuli–responsive materials, nonlinear mechanical mechanisms, and fluid–structure interactions is described. Recent advances in macroscale soft robotics and mechanical metamaterials are highlighted with the hope that they inspire solutions for microrobotics.

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“…Even if the implementation of these concepts is rapidly becoming more frequent at the macroscopic scale [3,4,5], its extension to the (sub)-micrometric or colloidal scale still presents significant challenges. Current microscale systems focus on self-propelling particles, aka artificial microswimmers or active colloids.…”

Section: Introductionmentioning

confidence: 99%

“…This kind of motility is at the core of the current and future applications of microswimmers to act as delivery vehicles [6,7,8,9], active mixers [10], or remediation agents [11,12] , to name a few. Crucially, self-propulsion is enabled by the fact that active colloids have an intrinsic asymmetry in their geometrical or compositional properties, which defines the directionality of their motion [13,5]. However, this asymmetry is typically fixed during synthesis and fabrication [14], implying that synthetic microswimmers only have one internal state, and that propulsion is regulated by controlling the energy input.…”

Section: Introductionmentioning

confidence: 99%

Self-propelling colloidal finite state machines

van Kesteren,

Alvarez,

Arrese-Igor

et al. 2022

Preprint

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Endowing materials with physical intelligence holds the key for a progress leap in robotic systems. In spite of the growing success for macroscopic devices, transferring these concepts to the microscale presents several challenges connected to the lack of suitable fabrication and design techniques, and of internal response schemes that connect the materials' properties to the function of an autonomous unit. Here, we realize self-propelling colloidal clusters which behave as simple finite state machines, i.e. systems built to possess a finite number of internal states connected by reversible transitions and associated to distinct functions. We produce these units via capillary assembly combining hard polystyrene colloids with two different types of thermo-responsive microgels. The clusters, actuated by spatially uniform AC electric fields, adapt their shape and dielectric properties, and consequently their propulsion, via reversible temperature-induced transitions controlled by light. The different transition temperatures for the two microgels enable three distinct dynamical states corresponding to three illumination intensity levels. The sequential reconfiguration of the microgels affects the velocity and shape of the active trajectories according to a pathway defined by tailoring the clusters' geometry during assembly. The demonstration of these simple systems indicates an exciting route to build more complex units with broader reconfiguration schemes and multiple responses towards the realization of autonomous systems with physical intelligence at the colloidal scale.

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Autonomous navigation of shape-shifting microswimmers

Cited by 11 publications

References 31 publications

Reconfigurable artificial microswimmers with internal feedback

Reconfigurable artificial microswimmers with internal feedback

On‐Board Mechanical Control Systems for Untethered Microrobots

Self-propelling colloidal finite state machines

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