w 12 | ive from the Labs cnrsI InternatIonal magazIne L Nanotechnology Anano-machineclusterproducingcoordinatedcontraction andextensionmovementsbringsusclosertomimickinghumanmuscle. CNRS Team Strasbourg Flexes Muscles rtists, with major applications at EPRO bonds, strong but dynamic. This techni-repeated units) linked by supramolecularcal trick allows better incorporation ofthe machines within the long andcomplex polymer chains. SimultaneousWITHPERMISSIONpolymers (compounds made up of.dCEduA.-uklFor the first time, chemists fromeeeproducing muscle movementsis a challenging issue for scienlIufBYstake. the ICS1 have synthesized an assembly .KG response from the nano-machines wasA O of nano-machines capable of muscle H triggered by changing the pH of the envi- fiber-like motion,2 a breakthrough G ronment, causing the entire chain toMB validated experimentally by physicists q contraction (left) and extension (right) of a telescopic ERLAG contract or extend. While each nano- from the MSC.3 polymer chain (center) made up of thousands of nano- y-VCH machine can only move one nanometermachines.ILEor so, the movement of the whole chain is-Living organisms consist of molecu lar machines where groups of molecules like proteins control sets of nano-machines in time and space.© amplified by 10,000, covering about 10 key biological tasks including muscle contraction. It is the joint The puzzle has now been solved. The micrometers. This echoes the model of action of these tiny molecules that extends their scope. This is ICS’s biomimetic feat began with a 13- the myosin/actin-driven sarcomere in the case of protein nano-machines in muscle tissue: individual step synthesis to produce a target nano- muscle fiber. The finding was verified by myosin proteins can only move a few nanometers along actin machine: “a basic molecule coded to measurements taken via light and neu- filaments, but grouped by the thousands in a sarcomere (the contract and expand,” explains team tron scattering experiments run by Eric basic muscle unit), their concerted movement can cover one leader Nicolas Giuseppone. The next ob- Buhler’s team at the MSC. micrometer, allowing muscle contraction on a normal scale. jective was to create “a big enough as- This polymer chain breakthrough Inspired by nature, chemists have artificially synthesized nano- sembly to trace movement.” About 3000 represents an important first step towards machines since the 1960s, but have never been able to coordinate molecules were joined together to form a range of long-term applications. These Astronomy Exoplanet Closest to Earth BYeddydelcher yetthenewplanetorbitstoocloseto planet’sgravitationalpull.Thesechang- itsparentstarforwater,ifpresent,tobe es,oflessthan2km/h,werepickedup w liquid,andthereforedoesnotqualifyas usingtheHARPS3instrumentonthe3.6 A team of European astronomers has just detected a planetwithamass an Earth twin—i.e., a planet similar to meter telescope at the ESO’s La Silla similartothatofEarth,orbitingAlpha Earthinsizeandmass,andorbitingina ObservatoryinChile.WhileHARPSoffers CentauriB.1 star’shabitablezone.“Itisanimportant thehighestaccuracyavailableforradial NotonlyisAlphaCentauriBb—the discoverynonetheless,as80%oflight velocitymeasurements,itdoeshaveits “b”designatingthefirstplanetfoundin planetsarepartofmulti-planetarysys- limitations.“Wecanonlyobservevery Paris orbit—thelightestplanetfoundtodate tems.Sothereisagoodprobabilitywe brightstarssuchasAlphaCentauri,and around a Sun-like star, it is also the willfindEarthtwincandidatesinthat stilllacktheprecisionrequiredtofind closest to our Solar System. Alpha area,”explainsFrançoisBouchyfromthe Earthtwins,”explainsBouchy.Thearrival Centauri B is 4.3 light years away, a IAP,2whoparticipatedinthestudy. of the high-precision spectrographs relatively short distance considering TheteamfoundAlphaCentauriBbby ESPRESSO4 and SPIRou5 in late 2016, that our galaxy stretches over some detectingtinychangesinitsparentstar’s shouldmakeitpossibletodiscoverEarth 100,000lightyears. radial velocity, caused by the orbiting twinswithinthenext10years.
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