Scientists have tied molecules
into the tightest knot ever achieved - a breakthrough that may pave the way for
a new generation of light, super-strong, and flexible materials.
Researchers from the University of Manchester in the UK developed a way
to braid multiple molecular strands, enabling tighter and more complex knots to
be made than has previously been possible.
The breakthrough knot has eight
crossings in a 192-atom closed loop which is about 20 nanometres long.
Being able to make different types of
molecular knots means that scientists should be able to probe how knotting
affects strength and elasticity of materials, which in turn will enable them to
weave polymer strands to generate new types of materials.
“Tying knots is a process similar to
weaving, so the techniques being developed to tie knots in molecules should
also be applicable to the weaving of molecular strands,” said David Leigh, a
Professor at the University of Manchester.
“For example, bullet-proof vests and
body armours are made of kevlar, a plastic that consists of rigid molecular
rods aligned in a parallel structure. However, interweaving polymer strands
have the potential to create much tougher, lighter, and more flexible materials
in the same way that weaving threads does in our everyday world,” said Leigh.
“Some polymers, such as spider silk,
can be twice as strong as steel, so braiding polymer strands may lead to new
generations of light, super-strong and flexible materials for fabrication and construction,”
he said.
“We ‘tied' the molecular knot using a technique called ‘self-assembly',
in which molecular strands are woven around metal ions, forming crossing points
in the right places just like in knitting - and the ends of the strands were
then fused together by a chemical catalyst to close the loop and form the
complete knot,” said Leigh.
“The eight-crossings molecular knot is the most complex regular woven
molecule yet made by scientists,” he said.
Source: DNA-16th January,2017
