Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > ETH Zurich researchers copy bacteria

Artificial bacterial flagella are about half as long as the thickness of a human hair. They can swim at a speed of up to one body length per second. This means that they already resemble their natural role models very closely. (Image: Institute of Robotics and Intelligent Systems/ETH Zurich)
Artificial bacterial flagella are about half as long as the thickness of a human hair. They can swim at a speed of up to one body length per second. This means that they already resemble their natural role models very closely. (Image: Institute of Robotics and Intelligent Systems/ETH Zurich)

Abstract:
For the first time, ETH Zurich researchers have built micro-robots as small as bacteria. Their purpose is to help cure human beings.

ETH Zurich researchers copy bacteria

Zurich, Switzerland | Posted on April 15th, 2009

They look like spirals with tiny heads, and screw through the liquid like miniature corkscrews. When moving, they resemble rather ungainly bacteria with long whip-like tails. They can only be observed under a microscope because, at a total length of 25 to 60 Ám, they are almost as small as natural flagellated bacteria. Most are between 5 and 15 Ám long, a few are more than 20 Ám.
Mimicking nature

The tiny spiral-shaped, nature-mimicking lookalikes of E. coli and similar bacteria. are called "Artificial Bacterial Flagella" (ABFs), the "flagella" referring to their whip-like tails. They were invented, manufactured and enabled to swim in a controllable way by researchers in the group led by Bradley Nelson, Professor at the Institute of Robotics and Intelligent Systems at ETH Zurich. In contrast to their natural role model, some of which cause diseases, the ABFs are intended to help cure diseases in the future.

The practical realization of these artificial bacteria, the smallest yet created, with a rigid flagellum and external actuation, was made possible mainly by the self-scrolling technique from which the spiral-shaped ABFs are constructed. ABFs are fabricated by vapor-depositing several ultra-thin layers of the elements indium, gallium, arsenic and chromium onto a substrate in a particular sequence. They are then patterned from it by means of lithography and etching. This forms super-thin, very long narrow ribbons that curl themselves into a spiral shape as soon as they are detached from the substrate, because of the unequal molecular lattice structures of the various layers. Depending on the deposited layer thickness and composition, a spiral is formed with different sizes which can be precisely defined by the researchers. Nelson says, "We can specify not only how small the spiral is, but even the scrolling direction of the ribbon that forms the spiral."

External propulsion via magnetic field

Even before releasing the ribbon that will afterwards form the artificial flagellum, a kind of head for the mini-robot is attached to one of its ends. It consists of a chromium-nickel-gold tri-layer film, also vapor-deposited. Nickel is soft-magnetic, in contrast to the other materials used, which are non-magnetic. Nelson explains that, "This tiny magnetic head enables the ABF to move in a specific way in a magnetic field." The spiral-shaped ABF swim through the liquid and its movements can be observed and recorded under a microscope.

With the software developed by the group, the ABF can be steered to a specific target by tuning the strength and direction of the rotating magnetic field which is generated by several coils. The ABFs can move forwards and backwards, upwards and downwards, and can also rotate in all directions. Brad Nelson says "There's a lot of physics and mathematics behind the software." The ABFs do not need energy of their own to swim, nor do they have any moving parts. The only decisive thing is the magnetic field, towards which the tiny head constantly tries to orientate itself and in whose direction it moves. The ABFs currently swim at a speed of up to 20 Ám, i.e. up to one body length, per second. Nelson expects that it will be possible to increase the speed to more than 100 Ám per second. For comparison: E. coli swims at 30 Ám per second.
Possible applications in medicine

The ABFs have been designed for biomedical applications. For example, they could carry medicines to predetermined targets in the body, remove plaque deposits in the arteries or help biologists to modify cellular structures that are too small for direct manipulation by researchers. In initial experiments, the ETH Zurich researchers have already made the ABFs carry around polystyrene micro-spheres.

At the moment, however, the group is still carrying out basic research. Further investigations will be needed before there can be any practical applications. Nelson explains that, "For applications in the human body, it would first of all be necessary to steer the ABFs precisely, track their route without optical monitoring and guarantee their localization at all times." If ABFs are to deliver drugs, they would first of all have to be functionalized in a fe

####

For more information, please click here

Contacts:
ETH Zurich
Editorial Office
HG F 41
Raemistrasse 101
8092 Zurich
SWITZERLAND

Fax +41 44 632 17 16

Copyright © ETH Zurich

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Molecular Machines

Biophysics -- lighting up DNA-based nanostructures April 25th, 2018

Tiny nanomachine successfully completes test drive: Researchers at the University of Bonn and the research institute Caesar build a one-wheeled vehicle out of DNA rings April 11th, 2018

Piecework at the nano assembly line: Electric fields drive nano-motors a 100,000 times faster than previous methods January 22nd, 2018

'Gyroscope' molecules form crystal that's both solid and full of motion: New type of molecular machine designed by UCLA researchers could have wide-ranging applications in technology and science January 16th, 2018

Nanomedicine

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication July 13th, 2018

UMBC researchers develop nanoparticles to reduce internal bleeding caused by blast trauma July 13th, 2018

Researchers identify cost-cutting option in treating nail fungus with nanotechnology: GW researcher Adam Friedman, M.D., studied the potential use of nitric oxide-releasing nanoparticles to improve onychomycosis treatment July 11th, 2018

New sensor technology enables super-sensitive live monitoring of human biomolecules July 3rd, 2018

Discoveries

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits July 16th, 2018

Announcements

The relationship between charge density waves and superconductivity? It's complicated July 19th, 2018

Sirrus's Issued Patent Portfolio Continues To Accelerate July 18th, 2018

FEFU scientists reported on toxicity of carbon and silicon nanotubes and carbon nanofibers: Nanoparticles with a wide range of applying, including medicine, damage cells of microalgae Heterosigma akashivo badly. July 18th, 2018

In borophene, boundaries are no barrier: Rice U., Northwestern researchers make and test atom-thick boron's unique domains July 17th, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project