Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Micro-Swimmer Robots Could Deliver Cargo & Drugs

07.08.2012
When you’re just a few microns long, swimming can be difficult. At that size scale, the viscosity of water is more like that of honey, and momentum can’t be relied upon to maintain forward motion.

Microorganisms, of course, have evolved ways to swim in spite of these challenges, but tiny robots haven’t quite caught up. Now a team of researchers at the Georgia Institute of Technology has used complex computational models to design swimming micro-robots that could overcome these challenges to carry cargo and navigate in response to stimuli such as light.

When they’re actually built some day, these simple micro-swimmers could rely on volume changes in unique materials known as hydrogels to move tiny flaps that will propel the robots. The micro-devices could be used in drug delivery, lab-on-a-chip microfluidic systems – and even as micro-construction robots working in swarms.

The simple micro-swimmers were described July 23 in the online advance edition of the journal Soft Matter, published by the Royal Society of Chemistry in the United Kingdom.

“We believe that our simulations will give experimentalists a reason to pursue development of these micro-swimmers to go beyond what is available now,” said Alexander Alexeev, an assistant professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “We wanted to demonstrate the principle of how robots this small could move by determining what is important and what would need to be used to build a real system.”

The simple swimmer designed by Alexeev and collaborators Hassan Masoud and Benjamin Bingham consists of a responsive gel body about ten microns long with two propulsive flaps attached to opposite sides. A steering flap sensitive to specific stimuli would be located at the front of the swimmer.

The responsive gel body would undergo periodic expansions and contractions triggered by oscillatory chemical reactions, oscillating magnetic or electric fields, or by cycles of temperature change. These expansions and contractions – the chemical swelling and de-swelling of the material – would create a beating motion in the rigid propulsive flaps attached to each side of the micro-swimmer. Combined with the movement of the gel body, the beating motion would move the micro-swimmer forward.

The trajectory of the micro-swimmer would be controlled by a flexible steering flap on its front. The flap would be made of a material that deforms based on changes in light intensity, temperature or magnetic field.

“The combination of these flaps and the oscillating body creates a very nice motion that we believe can be used to propel the swimmer,” said Alexeev. “To build a device that is autonomous and self-propelling at the micron-scale, we cannot build a tiny submarine. We have to keep it simple.”

Key to the operation of the micro-swimmer would be the latest generation of hydrogels, materials whose volume changes in a cyclical way. The hydrogels would serve as “chemical engines” to provide the motion needed to move the device’s propulsive flaps. Such materials currently exist and are being improved upon for other applications.

“We are using the state-of-the art in materials science, changing the properties of the material,” explained Masoud, a Ph.D. candidate in the School of Mechanical Engineering. “We have combined the materials with the principles of hydrodynamics at the small scale to develop this new swimmer.”

As part of their modeling, the researchers examined the effects of flaps of different sizes and properties. They also studied how flexible the micro-swimmer’s body needed to be to produce the kind of movement needed for swimming.

“You can’t swim at the small scale in the same way you swim at the large scale,” Alexeev said. “There is no inertia, which is how you keep moving at the large scale. What happens at the small scale is counter-intuitive to what you expect at the large scale.”

The computational fluid modeling the researchers used allowed them to study a wide range of parameters in materials, oscillation rates and flexibility. What they learned, Alexeev said, will give experimentalists a starting point for actually building prototypes of the flexible gel robots.

“We have captured the solid mechanics of the periodically-oscillating body, the fluid dynamics of moving through the viscous liquid, and the coupling between the two,” he said. “From a computational fluid dynamics standpoint, it’s not an easy problem to model at this scale.”

Ultimately, the researchers hope to work with an experimental team to actually build the micro-swimmers. Combining their theoretical work with actual experiments could be a powerful approach to building robots on this size scale.

“This is a simulation that we hope to see in real life one day,” Alexeev said. “We have learned how experimentalists can pursue fabrication of these devices without extensive trial-and-error. We can use the simulations to look inside what will happen by using the laws of physics to explain it.”

The researchers envision groups of micro-swimmers carrying cargo through microfluidic chips or other devices. Swarms of them could one day work together as tiny construction robots moving materials to desired locations for assembly.

But the micro-swimmers won’t win any Olympic competitions. Alexeev estimates that their top speed could be on the order of a few micrometers per second – which should be enough to accomplish their mission.

“If your body is micrometers in size, that kind of speed is really not too bad,” he said. “The swimming speed will be rather slow, but at that size scale, you don’t really need to go very fast since you only need to go short distances.”

Citation: Hassan Masoud, Benjamin I. Bingham and Alexander Alexeev, Soft Matter, 2012, Advance Article. DOI: 10.1039/C2SM25898F.

Research News & Publications Office
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 309
Atlanta, Georgia 30308 USA
Media Relations Contact: John Toon (404-894-6986)(jtoon@gatech.edu).
Writer: John Toon

John Toon | Newswise Science News
Further information:
http://www.gatech.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>