19.10.2018

High level research at the nanoscale

The Nanoscience Center (NSC) hosts more than hundred researchers with a background in biology, chemistry or physics. The strength of NSC is that there are people from all areas, from practical biologists to theoretical physicists. In addition to experimental work, substantial effort is invested in the theoretical and computational study of nanosystems.

2018

Molecular memory can be used to increase the memory capacity of hard disksyksittäismolekyylimagneetti-Mansikkamäki.jpg

Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized. The results may be used in the future to massively increase the storage capacity of hard disks without increasing their physical size. Single-molecule magnets are molecules capable of remembering the direction of a magnetic field that has been applied to them over relatively long periods of time once the magnetic field is switched off. Thus, one can “write” information into molecules. Single-molecule magnets have potential applications, for example, as high-density digital storage media and as parts of microprocessors in quantum computers. Practical applications have, however, been greatly hindered by the fact that single-molecule magnets are operational only at extremely low temperatures. Their intrinsic memory properties often vanish if they are heated more than a few degrees above absolute zero (–273°C); therefore, single-molecule magnets can be only studied under laboratory conditions by cooling them with liquid helium.

Fu-Sheng Guo, Benjamin M. Day, Yan-Cong Chen, Ming-Liang Tong, Akseli Mansikkamäki, and Richard A. Layfield. Magnetic hysteresis up to 80 K in a dysprosium metallocene single-molecule magnet. Science, 2018. 

DNA-nanoparticle actuator enabling optical monitoring of nanoscale movements induced by electric field

Highlight_Toppari.jpgOver the past decades, nanoactuators for detection or probing of different biomolecules have attracted vast interest for example in the fields of biomedical, food and environmental industry. To provide more versatile tools for active molecular control in nanometer scale, researchers from the NSC in the University of Jyväskylä, University of Tampere, and BioNavis Ltd have devised a nanoactuator scheme, where gold nanoparticle (AuNP) tethered on a conducting surface is moved reversibly using electric fields, while monitoring its position optically via changes of its plasmon resonance. Forces induced by the AuNP motion on the molecule anchoring the nanoparticle, can be used to change and study its conformation. The research was published in Nanoscale.

K. Tapio, D. Shaoa, S. Auer, J. Tuppurainen, M. Ahlskog, V. P. Hytönen, J. J. Toppari, "DNA-nanoparticle actuator enabling optical monitoring of nanoscale movements induced by electric field", Nanoscale (2018) and JYU press release

Magic shells of electrons and atoms seen in nanoparticle synthesis for the first time

hannu.pngA collaboration between cluster chemists in Xiamen University and computational nanoscientists in the NSC has revealed a new breakthrough in understanding of formation of nanometer-sized noble metal nanoparticles in chemical synthesis.

The mechanisms that affect nucleation and growth in chemical synthesis of metal nanoparticles have been debated for decades. On one hand, additional stability for very small particles may arise from special effects in their electronic structure, if the electron count of the nanoparticle is “just right” to fill the quantum states up to a certain “magic” number, akin to filling a given angular momentum quantum shell of electrons in ordinary atoms. For this reason, these specially stable small nanoparticles are often called as “superatoms”. On the other hand, large nanoparticles are thought to be stabilized when the atom count in the particle is “just right” to complete a certain pattern of atomic packing, e.g., an atom shell in the icosahedral packing. Now, for the first time, both these stabilization mechanisms are directly seen in the same synthesis of nanoparticles that are made of gold and silver atoms. The experimental work in Xiamen University produced two very different-sized metal nanoparticles that co-crystallized in the same single crystal and their atomic structures were solved by X-ray diffraction. The computational analysis of the results done at NSC in the group of Acad. Prof. Hannu Häkkinen showed that the smaller particle (45 metal atoms) is stabilized by electron-shell-closure while the larger particle (267 metal atoms) is stabilized by packing of atoms in the icosahedral symmetry. The work was published in Nature Communications.

J. Yan, S. Malola, C. Hu, J. Peng, B. Dittrich, B.K. Teo, H. Häkkinen, L. Zheng and N. Zheng, "Co-crystallization of atomically precise metal nanoparticles driven by magic atomic and electronic shells", Nature Comm (2018)

New information to understand regulation of muscle function in muscle dystrophy patients

ylanne-electronmicroscope.pngIn multicellular organism cell adhesion to other cells and to the extracellular matrix is very tightly regulated. Depending on the tissue, the attachment structures are adjusted to tolerate various pulling forces and sometimes the attachments are opened and reorganized. For force tolerance adhesion proteins in the cellular membrane need to be connected to intracellular structural elements, the cytoskeleton, and this connection is the key regulatory point. The research groups of Professor Jari Ylänne from Department of Biological and Environmental Science at the University of Jyväskylä and Professor Nick H. Brown from Department of Physiology, Development and Neuroscience at the University of Cambridge have studies for several years so called mechanosensor proteins, whose function change according to pulling force. The research is important for the basic understanding of regulation of muscle function for instance in muscle dystrophy patients and muscle adaptation to physical activity and sports.

H.J. Green, A.G.M. Griffiths, J. Ylänne, and N.H. Brown, "Novel functions for integrin-associated proteins revealed by analysis of myofibril attachment in Drosophila", eLife 7, e35783 (2018) and JYU press release

Real-space imaging with pattern recognition of a ligand-protected Ag374 nanocluster at sub-molecular resolution

Highlight_Hakkinen.jpegHigh-resolution imaging of nanoparticlesurface structures is now possible. Using scanning tunnelling microscopy (STM), extremely high resolution imaging of the molecule-covered surface structures of silver nanoparticles is possible, even down to the recognition of individual parts of the molecules protecting the surface. This was the finding of joint research between China and Finland, led in Finland by Academy Professor Hannu Häkkinen of the University of Jyväskylä. The research was recently published in the prestigious Nature Communications series and the publication was selected by the journal editors to the journal’s monthly collection of highlighted papers.

Q. Zhou, S. Kaappa, S. Malola, H. Lu, D. Guan, Y. Li, H. Wang, Z. Xie, Z. Ma, H. Häkkinen, N. Zheng. X. Yang, and Lansun Zheng, "Real-space imaging with pattern recognition of a ligand-protected Ag374 nanocluster at sub-molecular resolution" Nature Comm 9, 2948 (2018), JYU press release, and AKA press release

Stabilized entanglement of massive mechanical oscillators

Highlight_Massel.jpegResearchers at the University of Jyväskylä (Finland) participated in an international collaboration with research groups from Aalto University (Finland), UNSW (Australia) and University of Chicago (United States) and showed that it is possible to create an entangled state for the dynamics of two mechanical objects each constituted by 1012 (1 followed by twelve zeroes) atoms! This allowed them to demonstrate how some of the most counterintuitive predictions of quantum mechanics can be verified in nearly-macroscopic objects. The research was published in Nature.

C. F. Ockeloen-Korppi, E. Damskägg, J. M. Pirkkalainen, M. Asjad, A. A. Clerk, F. Massel, M. J. Woolley, and M. A. Sillanpää, Nature 556, 478 (2018)

From symmetry breaking to unraveling the origin of the chirality of ligated Au13Cu2 nanoclusters

Highlight_Hakkinen2.jpegThis collaborative work between NSC (Acad. Prof. Häkkinen) and Xiamen University (Prof. Nanfeng Zheng) demonstrates a new method to synthesize and characterize optically pure ultra-small chiral Au-Cu clusters protected by pyridinethiols and chiral diphosphines. DFT calculations done at the NSC reveal the details of the origin of the chiral optical response of these nanomaterials, which resist racemization up to 70 C making them potentially interesting materials for enantioselective catalysis. The research was published in Angewandte Chemie.

G. Deng, S. Malola, J. Yan, J. Han, P. Yuan, C. Zhao, X. Yuan, S. Lin, Z. Tang, B. K. Teo, H. Häkkinen, N. Zheng, Angew Chem 57, 13, 3421 (2018)

Extinct type of human parvovirus B19 persists in tonsillar B cells

Vihinen-Ranta-image-nsc.docx.jpg

Research groups from the NSC in the University of Jyväskylä and Department of Virology in the University of Helsinki have reported that Parvovirus B19 (B19V) DNA persists lifelong in human tonsillar tissues. The B19V DNA is most frequent and abundant among B cells, and within them they find a B19V genotype that vanished from circulation 440 years ago. The research was published in Nature Communications.

L. Pyöriä, M. Toppinen, E. Mäntylä, L. Hedman, L.M. Aaltonen, M. Vihinen-Ranta, T. Ilmarinen, M. Söderlund-Venermo, K. Hedman, M Perdomo Nature Comm 4, 14930 (2018) and Nature microbiology community

Building miniature optical antennas using DNA as a guide 21519df3-de61-4dfb-9263-402c8bf591a0-2.jpeg

Research groups from the NSC in the University of Jyväskylä and Aalto University (Finland) together with researchers from California Institute of Technology (Caltech, USA) and Aarhus University (iNANO Center, Denmark) have reported a new highly parallel technique to fabricate precise metallic nanostructures with designed plasmonic properties by means of different self-assembled DNA origami shapes. The so-called DALI (DNA-assisted lithography) method has been published in the latest issue of Science Advances.

B. ShenV. LinkoK. TapioS. Pikker, T. LemmaA. GopinathK. V. GothelfM. A. Kostiainen and J. J. Toppari, "Plasmonic nanostructures through DNA-assisted lithographyScience Adv 4, 8978 (2018)

New research opening for atomically thin metal nanostructures45b64cc2-1239-4ea2-81b9-337b0ca5bc47.png

Researchers at the NSC in the University of Jyväskylä predict systematically the properties of atomically thin structures made exclusively from metallic elements. This provides an atlas for two-dimensional elemental metals. The research was published in Physical Review B.

Janne Nevalaita and Pekka Koskinen, "An Atlas of two-dimensional elemental metals", Phys Rev B 97, 035411 (2018)

2017

Helium ions reveal how viruses attack bacteria bakteriofaagit.jpg

An interdisciplinary research consortium from the NSC at University of Jyvaskyla in Finland (group leaders Dr. Lotta-Riina Sundberg and Prof. Ilari Maasilta) has found that bacteria and viruses can be imaged with helium ions in contrast to electrons which are the standard workhorse in nanoscale microscopy. Helium ions, being more massive than electrons, can be focused to a much tighter spot down to the atomic length scales. By measuring the electrons generated by the ion bombardment, an image can be formed from the sample with biological features visible below the nanometer (one billionth of a meter) length. The research was published in Advanced Biosystems.

M. Leppänen, L.-R. Sundberg, E. Laanto, G. Magno de Freitas Almeida, P. Papponen, and I. J. Maasilta, "Imaging Bacterial Colonies and Phage–Bacterium Interaction at Sub-Nanometer Resolution Using Helium-Ion Microscopy", Adv Biosys 1, 1700070 (2017)

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Quantum theory for manipulating nanomagnets 

Researchers at the Department of Physics, Universityof Jyväskylä, Finland, have created a theory that predicts the properties of nanomagnets manipulated with electric currents. This theory is useful for future quantum technologies. The research was published in Physical Review Letters.

P. Virtanen and T. T. Heikkilä,Spin Pumping and Torque Statistics in the Quantum Noise LimitPhy Rev Lett 118, 237701 (2017)

Researchers beat the quantum limit of microwave measurements rumpuwiggle.jpg

Research groups at Aalto University and the University of Jyväskylä have demonstrated a new microwav measurement method that goes to the quantum limit of measurement and beats it. The new method can potentially be used for example in quantum computing and measurement of gravitational waves. The research was published in Physical Review Letters.

C. F. Ockeloen-Korppi, E. Damskägg, J.-M. Pirkkalainen, T. T. Heikkilä, F. Massel, and M. A. Sillanpää, "Noiseless Quantum Measurement and Squeezing of Microwave Fields Utilizing Mechanical Vibrations” Phys Rev Lett 118, 103601 (2017)