Scientists recently reached a biological computing milestone set by the simplest creatures millions of years ago.
A team at the Technion-Israel Institute of Technology manufactured a nanoscale transistor that self-assembles at room temperature using proteins - an achievement quite new to our petroleum-based economy but rooted in the very molecules of life.
The New Scientist reported that the nanodevice was constructed by the DNA of Escherichia coli, or E. coli - bacteria that live in the human digestive tract. While E. coli is known as a bane of those with compromised immune systems, it is the boon of the scientific community because of its willingness to create the proteins of other organisms.
The team, led by physicist Erez Braun, began creation of the transistor by coating a part of a long DNA molecule with E. coli proteins. The scientists then coated graphite nanotubes with antibodies and added them to the DNA-E.coli complex, causing the proteins to bind together.
A silver ion solution was added, causing the ions to attach to the phosphates on the DNA where no protein was yet present. The addition of aldehyde reduced the silver ions to metal and gold was bound to the silver. The product was a nanoscale carbon device with a tiny silver and gold wire conductor.
The full use of the device remains to be seen, but the ability of the device to self-assemble is a big step towards room-temperature materials manufacturing.
Just ask your local eight-legged residents about self-assembly. The orb weaver spider "Nephila clavipes" is the focus of study in a Seattle laboratory for the proteins it manufactures in its tiny belly.
The animal is able to mix six different silks in separate glands at once, producing materials that, ounce to ounce, are five times stronger than steel and able to absorb five times as much impact as Kevlar. The spider silk is able to stretch up to 40 longer than its original length and bounce back, much better than any nylon we have manufactured.
According to the New Scientist, French scientists also have become master weavers. Rather than silk, the scientists have woven carbon nanotubes into long threads in research for strong and lightweight fabrics.
The ends of the tubes are closed with carbon hemispheres and are stronger than steel, yet still weaker than iron. The bonus of carbon is its conductivity. The nanotubes are chemically treated and lined up, glued together end to end. But as with silk, nature is still far ahead of human science in adhesive manufacture.
"Mytilus edulis," a marine mollusk with two shells that's similar to a clam, has the means to produce a waterproof adhesive compound in its foot - not a small feat in the least. The mussels, residents of the tidal zone, produce an adhesive to keep it anchored to the turbulent surfaces where it feeds.
Like humans, the creature has to clean the surface it lives on, or prime it, before it lays down the adhesive. Unlike humans, the mussel is able to squeeze out water before it applies the adhesive.
And the tiny mollusk can produce the adhesive at room temperature in the water. Not even duct tape can beat that, but maybe E. coli will soon prove us wrong and produce an adhesive to fix aircraft using tiny, self-assembling proteins from a seafood foot, step by nanostep.
Audra Baker is a journalism and biology senior stuck on spiders and seafood. Net her at audra.baker@asu.edu.
