Programming magnetic anisotropy in polymeric microactuators

Kim, Jiyun; Chung, Siu-Wah; Choi, Sung-Eun; Lee, Howon; Kim, Junhoi; Kwon, Sunghoon

doi:10.1038/nmat3090

Cited by 451 publications

(407 citation statements)

References 30 publications

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“…hape-programmable matter refers to active materials that can be controlled by heat (1)(2)(3)(4)(5), light (6,7), chemicals (8)(9)(10)(11)(12)(13), pressure (14,15), electric fields (16,17), or magnetic fields (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33) to generate desired folding or bending. As these materials can reshape their geometries to achieve desired time-varying shapes, they have the potential to create mechanical functionalities beyond those of traditional machines (1,15).…”

mentioning

confidence: 99%

Shape-programmable magnetic soft matter

Lum

Zhou

Dong

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

475

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Shape-programmable matter is a class of active materials whose geometry can be controlled to potentially achieve mechanical functionalities beyond those of traditional machines. Among these materials, magnetically actuated matter is particularly promising for achieving complex time-varying shapes at small scale (overall dimensions smaller than 1 cm). However, previous work can only program these materials for limited applications, as they rely solely on human intuition to approximate the required magnetization profile and actuating magnetic fields for their materials. Here, we propose a universal programming methodology that can automatically generate the required magnetization profile and actuating fields for soft matter to achieve new time-varying shapes. The universality of the proposed method can therefore inspire a vast number of miniature soft devices that are critical in robotics, smart engineering surfaces and materials, and biomedical devices. Our proposed method includes theoretical formulations, computational strategies, and fabrication procedures for programming magnetic soft matter. The presented theory and computational method are universal for programming 2D or 3D time-varying shapes, whereas the fabrication technique is generic only for creating planar beams. Based on the proposed programming method, we created a jellyfish-like robot, a spermatozoid-like undulating swimmer, and an artificial cilium that could mimic the complex beating patterns of its biological counterpart.programmable matter | multifunctional materials | soft robots | magnetic actuation | miniature devices S hape-programmable matter refers to active materials that can be controlled by heat (1-5), light (6, 7), chemicals (8-13), pressure (14, 15), electric fields (16, 17), or magnetic fields (18-33) to generate desired folding or bending. As these materials can reshape their geometries to achieve desired time-varying shapes, they have the potential to create mechanical functionalities beyond those of traditional machines (1, 15). The functionalities of shape-programmable materials are especially appealing for miniature devices whose overall dimensions are smaller than 1 cm as these materials could significantly augment their locomotion and manipulation capabilities. The development of highly functional miniature devices is enticing because, despite having only simple rigid-body motions (34-36) and gripping capabilities (37), existing miniature devices have already been used across a wide range of applications pertaining to microfluidics (38, 39), microfactories (40, 41), bioengineering (42, 43), and health care (35, 44).Among shape-programmable matter, the magnetically actuated materials are particularly promising for creating complex timevarying shapes at small scales because their control inputs, in the form of magnetic fields, can be specified not only in magnitude but also in their direction and spatial gradients. Furthermore, as they can be fabricated with a continuum magnetization profile, m, along their bodies, these magne...

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mentioning

confidence: 99%

Shape-programmable magnetic soft matter

Lum

Zhou

Dong

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

475

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“…A daptive soft matter, such as responsive gels, elastomers, shape memory and electro-active polymers, is attracting burgeoning interest in material science, engineering, medicine and biology [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Fast and robust responsiveness coupled with large-scale displacement are eagerly sought after 18 , which have been the defining feature of biological actuators but missing from synthetic counterparts [19][20][21][22][23][24] .…”

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confidence: 99%

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

et al. 2014

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Fast actuation speed, large-shape deformation and robust responsiveness are critical to synthetic soft actuators. A simultaneous optimization of all these aspects without trade-offs remains unresolved. Here we describe porous polymer actuators that bend in response to acetone vapour (24 kPa, 20°C) at a speed of an order of magnitude faster than the state-ofthe-art, coupled with a large-scale locomotion. They are meanwhile multi-responsive towards a variety of organic vapours in both the dry and wet states, thus distinctive from the traditional gel actuation systems that become inactive when dried. The actuator is easy-tomake and survives even after hydrothermal processing (200°C, 24 h) and pressing-pressure (100 MPa) treatments. In addition, the beneficial responsiveness is transferable, being able to turn 'inert' objects into actuators through surface coating. This advanced actuator arises from the unique combination of porous morphology, gradient structure and the interaction between solvent molecules and actuator materials.

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“…In order to create an effective magnetic torque for rotation, introduction of a magnetization axis perpendicular to the helical axis was necessary, which was accomplished by the alignment and entrapment of the magnetic nanoparticles under uniform magnetic field during the fabrication process ( Fig. 1c, d) (38).…”

Section: Design Fabrication and Mobility Of Microswimmersmentioning

confidence: 99%

3D-Printed Biodegradable Microswimmer for Drug Delivery and Targeted Cell Labeling

Ceylan

Yasa

Yaşa

et al. 2018

Preprint

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Miniaturization of interventional medical devices can leverage minimally invasive technologiesby enabling operational resolution at cellular length scales with high precision and repeatability.Untethered micron-scale mobile robots can realize this by navigating and performing in hard-toreach, confined and delicate inner body sites. However, such a complex task requires an integrated design and engineering strategy, where powering, control, environmental sensing, medical functionality and biodegradability need to be considered altogether. The present study reports a hydrogel-based, biodegradable microrobotic swimmer, which is responsive to the changes in its microenvironment for theranostic cargo delivery and release tasks. We design a double-helical magnetic microswimmer of 20 µm length, which is 3D-printed with complex geometrical and compositional features. At normal physiological concentrations, matrix metalloproteinase-2 (MMP-2) enzyme can entirely degrade the microswimmer body in 118 h to solubilized non-toxic products. The microswimmer can respond to the pathological concentrations of MMP-2 by swelling and thereby accelerating the release kinetics of the drug payload. Anti-ErbB 2 antibodytagged magnetic nanoparticles released from the degraded microswimmers serve for targeted labeling of SKBR3 breast cancer cells to realize the potential of medical imaging of local tissue sites following the therapeutic intervention. These results represent a leap forward toward clinical medical microrobots that are capable of sensing, responding to the local pathological information, and performing specific therapeutic and diagnostic tasks as orderly executed operations using their smart composite material architectures.

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Programming magnetic anisotropy in polymeric microactuators

Cited by 451 publications

References 30 publications

Shape-programmable magnetic soft matter

Shape-programmable magnetic soft matter

An instant multi-responsive porous polymer actuator driven by solvent molecule sorption

3D-Printed Biodegradable Microswimmer for Drug Delivery and Targeted Cell Labeling

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