EINE INITIATIVE DER UNIVERSITÄT BASEL UND DES KANTONS AARGAU SNI update October 2016 10 years prised me with an amazing program achieved using SNI as well as with many old friends and atomic force EINE INITIATIVE DER UNIVERSITÄT BASEL UND DES KANTONS AARGAU colleagues from Switzerland and microscopes (AFMs). other countries. However, it was also Christoph Gerber, Carl a successful occasion from a scien- Quate and Gerd Binnig have just tific point of view. For that, I would received the Kavli Prize for their in- like once again to extend my sincere vention of AFM. Right on cue, in the thanks to everyone who helped orga- last few months we have seen several nizing the colloqium and came along. papers of SNI members accepted for publication where AFM played a key Michel Calame was one of organizers role. Thanks to many press releases of this event. Now it is my turn to con- we have issued on the subject, we gratulate him! From October, Michel have been able to secure coverage of Dear colleagues, will be heading up a group at Empa in these successes by a wide range of Once again, a great deal has happened Dübendorf that is looking at nanoscale media. since we last reported on our activities transport phenomena. Over the last in the last “SNI update”. In September, few years here at the SNI, Michel has I hope you enjoy this issue and look we came together for a highly inter- done tremendous work on setting up forward to the SNI’s next big event – esting annual meeting at Lenzerheide. the PhD School and has led an out- our 10th anniversary celebrations at I was pleased to hear about the prog- standing scientific team. On behalf of the end of October. ress being made by exciting research the whole SNI, I would like to thank in a wide range of fields and to see how him for his commitment and support. Kind regards, well our doctoral students presented We wish him all the best in his new themselves. I, too, was again able to role and hope to continue working learn a great deal. together closely in the future. th The colloquium held to mark my 60 On the scientific front, the last SNI Director, University of Basel birthday was a very special occasion few weeks at the SNI have been for me, of course. The organizers sur- marked by some remarkable results 2 In another study, copper rather than Cover story silver functioned as the catalyst. Starting with a molecule in which three benzene rings were bound Solving riddles with the AFM together by triple bonds, chemical reactions took place on a copper On September 6 this year, Professor Christoph Gerber, Pro- surface, leading via several steps fessor Carl Quate and Dr Gerd Binnig received the Kavli to the production of new aromatic Prize in Nanoscience. The formal ceremony took place in hydrocarbon compounds that had never previously been synthesized Oslo, in the presence of Crown Prince Haakon of Norway, in solution. Comparative computer and recognized the prizewinners’ invention and develop- calculations yielded the precise mo- ment of the atomic force microscope (AFM) 30 years ago. lecular structure of the compounds, Since then, the AFM has become an important tool for which perfectly matched the micro- nanoscience research, with a wide range of uses. This is scopic images. reflected in some of the publications by SNI members that Measuring the tiniest forces have appeared in recent weeks in prestigious scientific Using atomic force microscopy, journals such as “Nature”. scientists from Ernst Meyer’s and Professor Thomas Jung’s group have succeeded for the first time in mea- Observing chemical reactions suring the very weak Van der Waals In the last few weeks and months, scientists working with Professor Ernst forces between individual atoms. To Meyer and Dr Shigeki Kawai have published papers describing their use of do this, they fixed noble gas atoms a high-resolution atomic force microscope with a carbon monoxide tip to in a molecular network and evalu- track and understand chemical reactions. They have been able, for example, ated the interactions with a single to watch a silver catalyst at work for the first time. During the so-called Ull- xenon atom placed on the tip of a mann reaction, silver atoms catalyze the bond between two carbon atoms. cantilever in the atomic force micro- The researchers’ observations allowed them not only to work out how the scope. As expected, the forces were reaction takes place, but also to calculate the energy turnover involved. This dependent on the distance between may make it possible to find ways of optimizing this long-established and the two atoms, but sometimes they often implemented reaction. were significantly greater than the- oretical calculations had suggested. The intermediate product of the Ullmann reaction with the silver catalyst Rare gas atoms deposited on a mo- (silver) between the carbon rings (black) and sulfur atoms (yellow) curves lecular network are investigated like a bridge over the silver surface. with a probing tip, which is deco- rated with a xenon atom. The mea- surements give information about the weak van der Waals forces between these individual atoms. 3 Evidence of exotic particles Development brings new Scientists from the SNI and the Department of Physics at Basel are using applications atomic force microscopy not only to study and understand chemical pro- Christoph Gerber and his colleagues cesses: With the different microscopes available, which can be used in a laid the foundations for this and variety of ways, it is also possible to observe physical phenomena in the many other research studies 30 most precise detail. Professor Ernst Meyer’s group and the theoretical phys- years ago. Since then, there has icists grouped with Professor Jelena Klinovaja and Professor Daniel Loss are been ongoing development of AFM, working together using AFM to find experimental proof of the existence of and today it can be used in a huge so-called Majorana fermions, which are also their own anti-particles. These variety of ways. For example, Pro- exotic particles were first described around 75 years ago by the physicist fessor Patrick Maletinsky is placing Ettore Majorana. Interest in them has grown hugely since then, as they diamonds with nitrogen-vacancy may have a role to play in producing a quantum computer. The Majoranas centers in atomic force microscopes are already well described in theoretical terms. However, studying them as quantum sensors, enabling him to and finding experimental proof of their existence has proved difficult, as generate images of magnetic fields they always occur in pairs, but usually combine to form a normal electron. in superconductors at a resolution Very ingenious combinations and arrangements of different materials are not yet seen. In a recent issue of therefore needed to produce two Majoranas and keep them apart. “Nature Nanotechnology”, Maletin- sky’s team describe their success in Cancer diagnosis using this new kind of AFM for the AFM employs cantilevers equipped with a sharp tip to scan samples. The first time in cryogenic conditions, inventor of AFM Christoph Gerber is now using these cantilevers for diag- at temperatures of around 4 Kelvin nostic purposes. Gerber’s team coats the cantilevers with different mole- (-269,15 °C). With it, they were able cules, depending on what is needed. In a study published recently in “Nano to image magnetic stray fields of Letters”, he presents the use of cantilevers in initial clinical trials to help vortices in a high-temperature su- treat malignant melanoma. perconductor with unprecedented precision. To do this, Gerber’s team coats the cantilevers with a recognition sequence for a gene mutation exhibited by 50 percent of all patients with malignant Argovia Professor Martino Poggio is melanoma. RNA is then isolated from patients’ tissue samples and applied also working to develop a new type to the cantilevers. If the genetic change is present, the RNA binds to the of AFM, as he describes in “Nature recognition sequence on the cantilever. The resulting surface stress causes Nanotechnology”. To do so, Poggio’s team are using nanowires as tiny sensors, which allows them – un- like with traditional devices— to measure both the magnitude and the direction of forces. Here the researchers are able to exploit the special mechanical properties of the nanowires, which vibrate at rough- ly the same frequency along two axes at right angles to each other. Using AFM, the scientists measure the changes in vibration that are The cantilever on the left bears the recognition sequence for the target triggered by different forces. They mutation. If this is present in the sample being tested, the corresponding therefore use the nanowires as segment of RNA binds to the cantilever, causing the latter to bend. This can tiny mechanical compass needles be measured, providing clear evidence that the genetic change is present. indicating both the direction and the magnitude of the surrounding forces. this to bend, providing the scientists with a clear signal that indicates the presence of the mutation. As a potential treatment is available for patients These are just some examples of who exhibit this genetic change, a quick and inexpensive test of this kind research results involving AFM is highly valuable. that have been published by SNI 4 members in recent months. “Since AFM was invented, around 350,000 pub- lications have appeared about it,” Christoph Gerber notes. “And it will be Nano Image fascinating to see how the technology continues to evolve.” Award 2016 This year`s submissions for the Nano Image Award have again shown how beautiful the nano- world can be.