Thursday May 13, 2004

Tiny Feet and Giant Steps

In the news...

Our cats are great spider spotters. We'll walk into a room and notice a cat, staring intently at the ceiling. We look up... and there's a spider, in the middle of the ceiling, equidistant from the four walls. How did he get up there? How does he stay up there?

For the first time, scientists have measured exactly how that spider sticks to the ceiling and also how strong the adhesion force is.

A team from Germany and Switzerland have made the first detailed examinations of a jumping spider's 'foot' and have discovered that a molecular force sticks the spider to almost anything. The force is so strong that these spiders could carry over 170 times their own body weight while standing on the ceiling.

[cf. Institute of Physics press release PR29(04). ]

The paper, Getting a grip on spider attachment: an AFM approach to microstructure adhesion in arthropods, by Antonia Kesel, Andrew Martin and Tobias Seidl, was published on 19 April 2004, in the Institute of Physics journal Smart Materials and Structures. I like the title :-)

If you think the itsy bitsy spider has itsy bitsy feet, think again. Scientists have created a "microscopic walking robot", just 10 nanometers long and made out of DNA.

A New York University team created the robot using DNA legs that move along a footpath, which is also based on DNA.

The legs move by detaching themselves from the footpath, moving along it and then reattaching themselves, New Scientist reports.

DNA is an ideal material to build the robot from, because DNA chains easily pair up.

By re-ordering the sequence of base pairs that make up the DNA strand, the scientists were able to control where each strand attached.

"What we've done is to build a sidewalk to accommodate one step and we've demonstrated quantitatively that [the robot] can take a second step," Professor Nadrian Seeman, of New York University, told BBC News Online.

[ cf BBC News Online ]

Could a spiderbot made of DNA walk on the ceiling?

Tiny Feet and Giant Steps ( in category In The News ) - posted at Thu, 13 May, 19:38 Pacific | «e»