According to an article to be published by New Scientist on February 28, First robot moved by muscle power, a microrobot half the width of a human hair has been powered by living rat heart muscle. "It is the first time muscle tissue has been used to propel a micromachine." Carlos Montemagno, from the University of California at Los Angeles, who created the 'musclebot', wants to use the technology to help paralyzed people to breathe without a ventilator. And NASA, who helped funding the research, hopes that battalions of these 'musclebots' could one day help maintain spacecraft by plugging holes made by micrometeorites.
How works this device, which is an arch of silicon 50 micrometres wide?
The UCLA team's breakthrough is to have developed an automated way of anchoring muscle tissue to a substance like silicon. The team carved an arch-shaped skeleton from a wafer of silicon using automated microchip manufacturing equipment, and coated it with an etchable polymer. They then etched away the coating on the underside of the arch and deposited a gold film there. This acts as an adherent for the muscle cells. To grow the muscle, the skeleton was placed in a Petri dish containing rat cardiac muscle cells in a glucose culture medium. Over three days, the muscle cells grew into muscle fibres that attached themselves to the gold underside, forming a cable of cardiac muscle running the length of the arch.
During this process, the arch was held in place by a restraining beam. When this was removed the musclebot immediately started crawling at speeds up to 40 micrometres per second. The geometry of the musclebot ensures that its flexing pushes it in one direction, rather than simply contracting and relaxing on the spot.
For more information, you can read the report that Montemagno wrote for the NASA's Institute for Advanced Concepts Funded Studies, Directed Application of Nanobiotechnology for the Development of Autonomous Biobots.
||Here is an image of myotubes used for earlier versions of these biobots (Credit: Carlos Montemagno).|
||And here is another image of an isolated myotube (arrow) which exhibited spontaneous shortening (Credit: Carlos Montemagno).|
When will we see these 'musclebots' helping people and repairing spacecrafts? Not anytime soon.
[Montemagno] stresses that such applications are several decades away. "The issue of all of the microbots talking to one another hasn't even been addressed," he stresses. Or, indeed, how they would be fuelled. Watch out for the sugar-coated space station.
Source: Anil Ananthaswamy, New Scientist, via EurekAlert!, February 25, 2004