Manchester scientists tie the tightest knot ever achieved

January 12, 2017
The X-ray crystal structure of a 192-atom-loop molecular 819 knot featuring iron ions (shown in purple), oxygen atoms (red), nitrogen atoms (dark blue), carbon atoms (shown in metallic grey, with one of the building blocks shown in light blue) and a single chloride ion (green) at the center of the structure. Credit: Robert W. McGregor (mcgregorfineart.com).

Scientists at The University of Manchester have produced the most tightly knotted physical structure ever known - a scientific achievement which has the potential to create a new generation of advanced materials.

The University of Manchester researchers, led by Professor David Leigh in Manchester's School of Chemistry, have developed a way of braiding 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 (ie 20 millionths of a millimeter).

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 will enable them to weave polymer strands to generate new types of materials.

Professor David Leigh said: "Tying knots is a similar process to weaving so the techniques being developed to tie knots in molecules should also be applicable to the weaving of molecular strands.

"For example, bullet-proof vests and body armour 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.

The video will load shortly
The X-ray crystal structure of a 192-atom-loop molecular 819 knot featuring iron ions (shown in purple), oxygen atoms (red), nitrogen atoms (dark blue), carbon atoms (shown in metallic grey, with one of the building blocks shown in light blue) and a single chloride ion (green) at the center of the structure. Credit: Robert W. McGregor (mcgregorfineart.com).

"Some polymers, such as spider silk, can be twice as strong as steel so braiding may lead to new generations of light, super-strong and flexible for fabrication and construction."

Professor David Leigh said he and his team were delighted to have achieved this scientific landmark.

He explained the process behind their success: "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.

X-ray crystal structure of a molecular knot with eight crossings. Credit: Jean-Francois Lemonnier, University of Manchester

"The eight-crossings molecular knot is the most complex regular woven molecule yet made by scientists."

The research breakthrough will be published in the prestigious journal Science on 13 January 2017 in a paper entitled: 'Braiding a molecular knot with eight crossings'

Explore further: Tying molecules in knots

More information: "Braiding a molecular knot with eight crossings," Science, science.sciencemag.org/cgi/doi/10.1126/science.aal1619

Related Stories

Tying molecules in knots

November 7, 2011

A new generation of lighter, stronger plastics could be produced using an intricate chemical process devised by scientists.

The secret life of knots

June 10, 2013

Nanotechnologies require a detailed knowledge of the molecular state. For instance, it is useful to know when and how a generic polymer, a long chain of polymers (chain of beads), knots. The study of molecular entanglement ...

A revolution in knot theory

November 10, 2011

In the 19th century, Lord Kelvin made the inspired guess that elements are knots in the "ether". Hydrogen would be one kind of knot, oxygen a different kind of knot---and so forth throughout the periodic table of elements. ...

New star-shaped molecule breakthrough

September 22, 2014

(Phys.org) —Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created.

Recommended for you

Sea sponges stay put with anchors that bend but don't break

June 22, 2017

Sea sponges known as Venus' flower baskets remain fixed to the sea floor with nothing more than an array of thin, hair-like anchors made essentially of glass. It's an important job, and new research suggests that it's the ...

Custom-built molecule shows promise as anti-cancer therapy

June 22, 2017

Scientists at the University of Bath funded by Cancer Research UK have custom-built a molecule which stops breast cancer cells from multiplying in laboratory trials, and hope it will eventually lead to a treatment for the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.