94 research outputs found
Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots.
Microorganisms move in challenging environments by periodic changes in body shape. In contrast, current artificial microrobots cannot actively deform, exhibiting at best passive bending under external fields. Here, by taking advantage of the wireless, scalable and spatiotemporally selective capabilities that light allows, we show that soft microrobots consisting of photoactive liquid-crystal elastomers can be driven by structured monochromatic light to perform sophisticated biomimetic motions. We realize continuum yet selectively addressable artificial microswimmers that generate travelling-wave motions to self-propel without external forces or torques, as well as microrobots capable of versatile locomotion behaviours on demand. Both theoretical predictions and experimental results confirm that multiple gaits, mimicking either symplectic or antiplectic metachrony of ciliate protozoa, can be achieved with single microswimmers. The principle of using structured light can be extended to other applications that require microscale actuation with sophisticated spatiotemporal coordination for advanced microrobotic technologies.This work was in part supported by the European Research Council under the ERC Grant agreements 278213 and 291349, and the DFG as part of the project SPP 1726 (microswimmers, FI 1966/1-1). SP acknowledges support by the Max Planck ETH Center for Learning Systems.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nmat456
Light‐Powered Microrobots: Challenges and Opportunities for Hard and Soft Responsive Microswimmers
Worldwide research in microrobotics has exploded in the past two decades,
leading to the development of microrobots propelled in various manners. Despite
significant advances in the field and successful demonstration of a wide range of
applications, microrobots have yet to become the preferred choice outside a
laboratory environment. After introducing available microrobotic propulsion and
control mechanisms, microrobots that are manufactured and powered by light
are focused herein. Referring to pioneering works and recent interesting
examples, light is presented not only as a fabrication tool, by means of twophoton
polymerization direct laser writing, but also as an actuator for microrobots
in both hard and soft stimuli–responsive polymers. In this scenario, a
number of challenges that yet prevent polymeric light-powered microrobots from
reaching their full potential are identified, whereas potential solutions to overcome
said challenges are suggested. As an outlook, a number of real-world
applications that light-powered microrobots should be particularly suited for are
mentioned, together with the advances needed for them to achieve such purposes.
An interdisciplinary approach combining materials science, microfabrication,
photonics, and data science should be conducive to the next generation of
microrobots and will ultimately foster the translation of microrobotic applications
into the real world
Micro/nanoscale magnetic robots for biomedical applications
Magnetic small-scale robots are devices of great potential for the biomedical field because of the several benefits of this method of actuation. Recent work on the development of these devices has seen tremendous innovation and refinement toward ​improved performance for potential clinical applications. This review briefly details recent advancements in small-scale robots used for biomedical applications, covering their design, fabrication, applications, and demonstration of ability, and identifies the gap in studies and the difficulties that have persisted in the optimization of the use of these devices. In addition, alternative biomedical applications are also suggested for some of the technologies that show potential for other functions. This study concludes that although the field of small-scale robot research is highly innovative ​there is need for more concerted efforts to improve functionality and reliability of these devices particularly in clinical applications. Finally, further suggestions are made toward ​the achievement of commercialization for these devices
Design, Actuation, and Functionalization of Untethered Soft Magnetic Robots with Life-Like Motions: A Review
Soft robots have demonstrated superior flexibility and functionality than
conventional rigid robots. These versatile devices can respond to a wide range
of external stimuli (including light, magnetic field, heat, electric field,
etc.), and can perform sophisticated tasks. Notably, soft magnetic robots
exhibit unparalleled advantages among numerous soft robots (such as untethered
control, rapid response, and high safety), and have made remarkable progress in
small-scale manipulation tasks and biomedical applications. Despite the
promising potential, soft magnetic robots are still in their infancy and
require significant advancements in terms of fabrication, design principles,
and functional development to be viable for real-world applications. Recent
progress shows that bionics can serve as an effective tool for developing soft
robots. In light of this, the review is presented with two main goals: (i)
exploring how innovative bioinspired strategies can revolutionize the design
and actuation of soft magnetic robots to realize various life-like motions;
(ii) examining how these bionic systems could benefit practical applications in
small-scale solid/liquid manipulation and therapeutic/diagnostic-related
biomedical fields
The Effect of Flagella Stiffness on the Locomotion of a Multi-Flagellated Robot at Low Reynolds Environment
Microorganisms such as algae and bacteria move in a viscous environment with
extremely low Reynolds (), where the viscous drag dominates the inertial
forces. They have adapted to this environment by developing specialized
features such as whole-body deformations and flexible structures such as
flagella (with various shapes, sizes, and numbers) that break the symmetry
during the motion. In this study, we hypothesize that the changes in the
flexibility of the flagella during a cycle of movement impact locomotion
dynamics of flagellated locomotion. To test our hypothesis, we developed an
autonomous, self-propelled robot with four flexible, multi-segmented flagella
actuated together by a single DC motor. The stiffness of the flagella during
the locomotion is controlled via a cable-driven mechanism attached to the
center of the robot. Experimental assessments of the robot's swimming
demonstrate that increasing the flexibility of the flagella during recovery
stroke and reducing the flexibility during power stroke improves the swimming
performance of the robot. Our results give insight into how these
microorganisms manipulate their biological features to propel themselves in low
viscous media and are of great interest to biomedical and research
applications
Bioinspired reorientation strategies for application in micro/nanorobotic control
Engineers have recently been inspired by swimming methodologies of microorganisms in creating micro-/nanorobots for biomedical applications. Future medicine may be revolutionized by the application of these small machines in diagnosing, monitoring, and treating diseases. Studies over the past decade have often concentrated on propulsion generation. However, there are many other challenges to address before the practical use of robots at the micro-/nanoscale. The control and reorientation ability of such robots remain as some of these challenges. This paper reviews the strategies of swimming microorganisms for reorientation, including tumbling, reverse and flick, direction control of helical-path swimmers, by speed modulation, using complex flagella, and the help ofmastigonemes. Then, inspired by direction change in microorganisms,methods for orientation control for microrobots and possible directions for future studies are discussed. Further, the effects of solid boundaries on the swimming trajectories of microorganisms and microrobots are examined. In addition to propulsion systems for artificial microswimmers, swimming microorganisms are promising sources of control methodologies at the micro-/nanoscale
Biohybrid robotics: From the nanoscale to the macroscale
Biohybrid robotics is a field in which biological entities are combined with artificial materials in order to obtain improved performance or features that are difficult to mimic with hand-made materials. Three main level of integration can be envisioned depending on the complexity of the biological entity, ranging from the nanoscale to the macroscale. At the nanoscale, enzymes that catalyze biocompatible reactions can be used as power sources for self-propelled nanoparticles of different geometries and compositions, obtaining rather interesting active matter systems that acquire importance in the biomedical field as drug delivery systems. At the microscale, single enzymes are substituted by complete cells, such as bacteria or spermatozoa, whose self-propelling capabilities can be used to transport cargo and can also be used as drug delivery systems, for in vitro fertilization practices or for biofilm removal. Finally, at the macroscale, the combinations of millions of cells forming tissues can be used to power biorobotic devices or bioactuators by using muscle cells. Both cardiac and skeletal muscle tissue have been part of remarkable examples of untethered biorobots that can crawl or swim due to the contractions of the tissue and current developments aim at the integration of several types of tissue to obtain more realistic biomimetic devices, which could lead to the next generation of hybrid robotics. Tethered bioactuators, however, result in excellent candidates for tissue models for drug screening purposes or the study of muscle myopathies due to their three-dimensional architecture
CeFlowBot:A Biomimetic Flow-Driven Microrobot that Navigates under Magneto-Acoustic Fields
Aquatic organisms within the Cephalopoda family (e.g., octopuses, squids, cuttlefish) exist that draw the surrounding fluid inside their bodies and expel it in a single jet thrust to swim forward. Like cephalopods, several acoustically powered microsystems share a similar process of fluid expulsion which makes them useful as microfluidic pumps in lab-on-a-chip devices. Herein, an array of acoustically resonant bubbles are employed to mimic this pumping phenomenon inside an untethered microrobot called CeFlowBot. CeFlowBot contains an array of vibrating bubbles that pump fluid through its inner body thereby boosting its propulsion. CeFlowBots are later functionalized with magnetic layers and steered under combined influence of magnetic and acoustic fields. Moreover, acoustic power modulation of CeFlowBots is used to grasp nearby objects and release it in the surrounding workspace. The ability of CeFlowBots to navigate remote environments under magneto-acoustic fields and perform targeted manipulation makes such microrobots useful for clinical applications such as targeted drug delivery. Lastly, an ultrasound imaging system is employed to visualize the motion of CeFlowBots which provides means to deploy such microrobots in hard-to-reach environments inaccessible to optical cameras
CeFlowBot:A Biomimetic Flow-Driven Microrobot that Navigates under Magneto-Acoustic Fields
Aquatic organisms within the Cephalopoda family (e.g., octopuses, squids, cuttlefish) exist that draw the surrounding fluid inside their bodies and expel it in a single jet thrust to swim forward. Like cephalopods, several acoustically powered microsystems share a similar process of fluid expulsion which makes them useful as microfluidic pumps in lab-on-a-chip devices. Herein, an array of acoustically resonant bubbles are employed to mimic this pumping phenomenon inside an untethered microrobot called CeFlowBot. CeFlowBot contains an array of vibrating bubbles that pump fluid through its inner body thereby boosting its propulsion. CeFlowBots are later functionalized with magnetic layers and steered under combined influence of magnetic and acoustic fields. Moreover, acoustic power modulation of CeFlowBots is used to grasp nearby objects and release it in the surrounding workspace. The ability of CeFlowBots to navigate remote environments under magneto-acoustic fields and perform targeted manipulation makes such microrobots useful for clinical applications such as targeted drug delivery. Lastly, an ultrasound imaging system is employed to visualize the motion of CeFlowBots which provides means to deploy such microrobots in hard-to-reach environments inaccessible to optical cameras.</p
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