World's smallest wedding rings from DNA created

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A just-married German researcher has created the world's smallest wedding rings from DNA strands.

Prof Alexander Heckel and his doctoral student Thorsten Schmidt from the Goethe University interlocked the rings like two links in a chain.

The interlocked rings, known as catenans (after the Latin word for 'chain'), measure just 18 nanometers in size.

Schmidt, who got married during the time he was working on the project, believes that they are probably the world's smallest wedding rings.

The rings are, as opposed to the majority of the DNA nanoarchitechtures that have already been realized, not fixed formations, but freely pivotable.

They are therefore suitable as components of molecular machines or of a molecular motor.

"We still have a long way to go before DNA structures such as the catenan can be used in everyday items, but structures of DNA can, in the near future, be used to arrange and study proteins or other molecules that are too small for a direct manipulation, by means of auto-organization," said Heckel.

The experiment involved creating two C-shaped DNA fragments that were positioned with their open ends pointing away from each other.

The catenan was then created by adding two strands that attach to the ends of the two ring fragments, which are still open.

Since they are much smaller than the wavelengths of visible light, the rings cannot be seen with a standard microscope.

You would have to string together about 4000 such rings to even achieve the diameter of a human hair", said Schmidt.

The discovery is reported in the journal Nano Letters.