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MADISON -- While the shiny material of pearls and abalone shells has long been prized for its iridescence and aesthetic value in jewelry and decorations, scientists admire mother-of-pearl for other physical properties as well. Also called nacre ("NAY-ker"), mother-of-pearl is 3,000 times more fracture-resistant than the mineral it is made of, aragonite, says Pupa Gilbert, a physicist at the University of Wisconsin-Madison. "You can go over it with a truck and not break it - you will crumble the outside [of the shell] but not the [nacre] inside. And we don't understand how it forms - that's why it's so...

In the nanoworld, three square millimeters is pretty big territory A droplet of liquid and a few seconds are all that researchers need to produce neatly spaced ridges of molecules that cover a huge area--at least by the standards of nanotechnology. In a feat of so-called self-assembly, a group reports that disk-shaped molecules can stack themselves by the millions into lines of up to a millimeter in length and covering several square millimeters. The process might help ease the fabrication of sensors such as liquid crystal displays (LCDs) that register the presence of offending chemicals. "You just drop a droplet...

Scientists have created a robot that can replicate itself in minutes. The team behind the machine says the experiment shows that self- reproduction is not unique to living organisms The researchers add that the ability could be harnessed to drive major advances in nanotechnology, the science of the very small, and may even lead to space colonization by robots. Developed by researchers at Cornell University in Ithaca, New York, the machine was constructed from cube-shaped robotic units (modules) that functioned independently. A four-module robot could assemble an exact replica of itself in just two and a half minutes. Writing for...

Humans do it, bacteria do it, even viruses do it: they make copies of themselves. Now US researchers have built a flexible robot that can perform the same trick. It's not the first self-replicating robot ever built, says Hod Lipson of Cornell University, who led the study. But previous machines with the capacity for copying themselves have been very simple, often spreading out in only two dimensions. And more complex devices existed only in computer simulations, not reality. Lipson's robot, which is made of four cubes stacked on top of each other, has a flexible, three-dimensional design. "There is a...

Nano-transistor self-assembles using biology A functional electronic nano-device has been manufactured using biological self-assembly for the first time. Israeli scientists harnessed the construction capabilities of DNA and the electronic properties of carbon nanotubes to create the self-assembling nano-transistor. The work has been greeted as "outstanding" and "spectacular" by nanotechnology experts. The push to shrink electronic circuits to ever smaller dimensions is relentless. Carbon nanotubes, which have remarkable electronic properties and only about one nanometre in diameter, have been touted as a highly promising material to help drive miniaturisation. But manufacturing nano-scale transistors has proved both time-consuming and labour-intensive. The team,...