Wednesday August 9 3:43 PM ET DNA Motors Promise Faster, Smaller Electronics Reuters
Photo By Bill Rosato LONDON (Reuters) - An international team of scientists said
Wednesday it had made the world's first DNA motors, paving the way for molecular
electronic circuits thousands of times faster and smaller than silicon chips.
``You would have much smaller and faster computers. For the same surface area
you could fit in some 10,000 times more components and you could make three dimensional
arrangements,'' Bernard Yurke, from Bell Labs, the research and development arm
of Lucent Technologies, told Reuters. DNA, or deoxyribonucleic acid, is the genetic
material inside the nucleus of a cell that carries instructions for making living
things. The DNA motors, which assemble themselves, pave the way for the development
of minute electronic systems composed of molecular switches and other elements
which could be produced by mixing the components in a test-tube, Yurke and Andrew
Turberfield, a physicist at the University of Oxford, said. Single-strands of
DNA will only bind to other DNA strands that have a complementary sequence of
molecules on their surface to form the stable double-stranded helix. Hence a DNA
``tweezer'' was assembled by the simple expedient of mixing three specially designed
single strands of DNA in a test-tube. Each single strand then found its complementary
partner and attached itself to it forming a V-shaped structure 100,000 times smaller
than the head of a pin, the scientists said in the journal Nature. Tweezer Is
Forerunner To Molecular Computers Turberfield described how the ``tweezer'' knowledge
could pave the way for molecular electronic circuits. ``The idea is that you add
DNA tags to each molecular component -- then you mix them in a pot, complementary
tags find each other and an ordered, designed device assembles itself,'' Turberfield,
who spent a sabbatical year at Bell Labs, said. The DNA ``tweezers'' can open
and close by using a ``fuel'' strand which binds to the single-stranded DNA dangling
from the ends of the arms of the tweezers and zips them closed. The scientists
also engineered a removal strand that pulls the ``fuel'' strand away from the
``tweezers'' and opens them. At the moment the only two things standing in the
way of the production of molecular devices with practical applications were the
technology to assemble molecular components, which the ''tweezers'' knowledge
should overcome, and molecules that act as transistors, Yurke said. Researchers
have already created molecular wires, logic gates (a building block of computers)
and switches, which could be hooked up to make a working computer a fraction of
the size of ones based on silicon chips. The development of molecular circuits
was essential, Turberfield said. ``Something has to be done to revolutionize electronic
circuit assembly because conventional processes are going to run into a brick
wall within the next 10 to 20 years,'' he said.