Nano-machines Achieve Huge Mechanical Breakthrough

Scientists have built molecules that can, for the first time ever,move larger-than-atom-sized objects. Constructing molecular machinescapable of performing relatively large-scale mechanical tasks has neverbeen achieved before.

Now, in an unprecedented breakthrough, chemists at EdinburghUniversity have used light to stimulate man-made molecules to propelsmall droplets of liquid across flat surfaces and even up 12°slopes against the force of gravity. This is equivalent to tinymovements in a conventional machine raising objects to over twice theheight of the world's tallest building.

This significant step could eventually lead to the developmentof artificial muscles that use molecular 'nano'-machines of this kindto help perform physical tasks. Nano-machines could also be used in'smart' materials that change their properties (e.g. volume, viscosity,conductivity) in response to a stimulus. They could even control themovement of drugs around the body to the exact point where they areneeded.

The research has been funded by the Engineering and PhysicalSciences Research Council (EPSRC), and has also involved scientists inItaly and the Netherlands. David Leigh, Forbes Professor of OrganicChemistry and EPSRC Senior Research Fellow, leads the EdinburghUniversity team.

David Leigh and his colleagues have achieved theirbreakthrough by harnessing a natural biological mechanism called'Brownian motion' (the random movement of molecules caused bycollisions with molecules around them). This has involved controlling(or 'biasing') Brownian motion so that molecule movements are no longercompletely random.

The team has developed a way of covering a gold surface withspecially engineered molecules. When stimulated by ultra-violet light,the components of these molecules change position (this is because achemical reaction takes place in one part of the molecule that causesit to repel another part). These changes in position dramatically alterthe surface tension of a droplet of liquid placed on the gold surfaceand in this way produce enough energy to move the droplet a distance ofup to a millimetre. It may be the tiniest of movements but in theemerging discipline of nanotechnology this represents a gianttechnological leap forward.

David Leigh says: "Nature uses molecules as motors andmachines in all kinds of biological and chemical processes. Althoughman's understanding of how to build and control molecular machines isstill at an early stage, nanoscale science and engineering could have alife-enhancing impact on human society comparable in extent to that ofelectricity, the steam engine, the transistor and the Internet."

David Leigh will be discussing his work and showing videos ofdroplet movement during his talk at the Festival on 7th September. Adetailed report has also been published in the latest edition of Nature Materials ('Nanoshuttles move droplets uphill'; Vol. 4, pp.704-710, 2005).

Notes

Nanotechnology involves manipulating materials on a very smallscale to build microscopic machines. The prefix 'nano' in'nanotechnology' means one thousand-millionth (10-9). A nanometre, forexample, is one thousand-millionth of a metre.

This year's BA (British Association for the Advancement ofScience) Festival of Science takes place in Dublin from 3rd -10thSeptember. The event is one of the UK's biggest science festivals andattracts around 400 of the best scientists and science communicatorsfrom home and abroad who reveal the latest developments in research toa general audience. For more information visit www.the-ba.net.

Professor David Leigh will be talking about "Tooling Up for theNanoworld: The Magic of Molecular Machines" from 14.00 to 16.00 on 7thSeptember at Joly LT, Hamilton Building. Professor Leigh will also betaking part in a press conference at 09.00 on 7th September where hewill be discussing his work. Professor Amilra de Silva of Queen'sUniversity Belfast, with whom Professor Leigh has worked extensively inthe past, will be talking about "Luminescent Molecules as InformationProcessors" on the same day and will also be taking part in the samepress conference.

The Engineering and Physical Sciences Research Council (EPSRC)is the UK's main agency for funding research in engineering and thephysical sciences. The EPSRC invests more than £500million a year in research and postgraduate training, to help thenation handle the next generation of technological change. The areascovered range from information technology to structural engineering,and mathematics to materials science. This research forms the basis forfuture economic development in the UK and improvements for everyone'shealth, lifestyle and culture. EPSRC also actively promotes publicawareness of science and engineering. EPSRC works alongside otherResearch Councils with responsibility for other areas of research. TheResearch Councils work collectively on issues of common concern viaResearch Councils UK. Website address for more information on EPSRC: www.epsrc.ac.uk/