• Name

Swimming microbots

• What is the item

Swimming microbots that can change direction

• What Horizon is it on

Fifth Horizon

• Explanation of the item 

newscientist.com reported on February 16, 2011:

Tiny microbots swimming through liquid invariably conjures up images of Isaac Asimov's sci-fi classic Fantastic Voyage.

But while microbots exist, and they can be made to swim, it's getting them to change direction that has been tricky so far - a bit of an issue if you're even planning on sticking them in a human body, for instance.

Now a system used to propel swimming microbots without the need for on-board fuel has brought this idea one step closer. Researchers at North Carolina State University have coaxed their bots to perform U-turns on command.

The microbot, a mere 1.3 millimetres long, is essentially a diode - an electrical element that only allows current to pass in one direction. The diode is exposed to an alternating electric field, which induces a voltage across it, creating an electric dipole. This dipole pushes on ions in the water, driving them backward and propelling the microbot forward.  

In order to make the bot turn, the group added a DC element to the field, modifying the initial AC field. Rachita Sharma and Orlin Velev believe that the DC field changes the distribution of the ions near the diode, and the torque they exert on the electric dipole causes the microbot to rotate. Once the microbot completed its 180-degree turn, the researchers turned off the DC field, and the microbot swam off in the other direction.

Miniaturisation will be vital if the robots are ever to navigate human bodies., like in Fantastic Voyage. The group is also investigating "yeast-boats", which use metabolic reactions to motor through glucose or hydrogen peroxide solutions. A similar vehicle may one day carry a molecular doctor on board to make a diagnosis - or dock with diseased tissue to deliver ashipment of drugs.

This work is to be presented on 25 March at a meeting of the American Physical Society.

http://www.newscientist.com/blogs/onepercent/2011/02/making-microbots-swim-using-el.html

• Photos or Videos (if available)

• Issues

http://www.newscientist.com/blogs/onepercent/2011/02/making-microbots-swim-using-el.html

• Sources

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