Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

Integrative actuators and sensors within a single active device offer compelling capabilities for developing robotics, prosthetic limbs, and minimally invasive surgical tools. But instrumenting these devices at the microscale is constrained by current manufacturing technologies.   Now, a team of researchers has developed a flexible polymer-based actuatable fiber which is capable of being integrated with smart materials and biosensing composite materials. The technology may lead to technological advancements in soft and flexible robotic fields, which could open possibilities for achieving closed-loop control for high-precision operations.   Details of their research were published in ACS Applied Engineering Materials on January 23, 2023. Figure: Active fiber fabricated by the thermal drawing. (Credit: Sato et al.)   Dr. Yuanyuan Guo, who is an associate professor at Tohoku University’s Frontier Research Institute for Interdisciplinary Sciences (FRIS), led the team. “Our microscale fiber, integrated with actuating and sensing functions, could enable the use of smart catheters,” says Guo.   The team produced the fiber by applying the preform-to-fiber thermal drawing process. The telecommunication industry has employed thermal drawing to produce optical fibers and, more recently, to fabricate multi-material and multifunctional fibers for biomedical applications. Although many important functions, such as electrodes, optics, and channels, can be incorporated within fibers, they are limited to passive modalities.   To deliver a workaround to this limitation, the team embedded shape-memory alloy (SMA) wires. The shape-memory effect of the SMA’s enabled fibers with high mechanical actuation.   Additionally, they integrated the fiber with carbon-based composite materials to enable biochemical sensing. The sensors were capable of intrinsically high sensitivity towards electroactive molecules. Utilizing a bifurcated vessel model, the team also succeeded in using the actuatable fiber sensor to approach branched vessels and capture localized chemical information for diagnostic purposes.   Looking ahead, Guo and her team hope to improve the fiber’s freedom of movement. Publication Details Yuichi Sato, Yuanyuan Guo* (*corresponding author) “Shape-memory-alloys enabled actuatable fiber sensors via the preform-to-fiber fabrication” ACS Applied Engineering Materials DOI: 10.1021/acsaenm.2c00226 https://doi.org/10.1021/acsaenm.2c00226 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/navigating_complex_biological_systems_with_smart_fibers.html

Biophysicists in Japan have found ways to make and manipulate capsule-like DNA structures that could be used in the development of artificial molecular systems. Such systems could function, for example, inside the human body. The study was a collaboration between Yusuke Sato of FRIS, Tohoku University and Masahiro Takinoue of the Tokyo Institute of Technology (Tokyo Tech), and the findings were published in the JACS Au.   To make the capsules, the researchers first created two different types of DNA nanostructures. Each type was made using three single-stranded DNA molecules with sticky bits at their ends. Due to differences in their DNA sequences, only similar nanostructures stuck together when the two types were mixed.   Sato and Takinoue then combined the nanostructures in solution with an oily mixture of charged and non-charged molecules. The mixture was first heated and then cooled, and finally examined under a microscope.   The researchers found that water-in-oil droplets had formed, with the DNA nanostructures accumulating at the water-oil interface. The nanostructures came together in different kinds of patch-like patterns, depending on the concentration of each type relative to the other.   The scientists also found that the DNA nanostructures agglomerated in a more homogeneous way when an extra X-shaped DNA nanostructure was added to the mix to connect the two types together.   This worked just as well inside lipid vesicles as in water-in-oil droplets. Sato and Takinoue were also able to separate the DNA capsules from the droplets and vesicles without losing their capsule-like shapes. Finally, they were able to open the capsules and degrade them using specific enzymes.   The findings demonstrate an approach for constructing and modifying DNA capsules that could have a variety of different functions and purposes. For example, they could be used to carry substances to specific target organs, releasing their cargo when exposed to certain enzymes. They could also be made mobile by using DNA nanostructures that can be manipulated to alter the shapes of the capsules. Or they could be modified with proteins or DNA-based molecular devices to make functional compartmental structures, like cellular membranes.   “We believe that functional capsules made from DNA, like the ones we have designed, could provide a new approach for developing capsular structures for artificial cell studies and molecular robotics,” say Sato and Takinoue.   The team will next work on inserting different types of cargo into the capsules, including DNA information processors, and releasing them in response to specific stimuli.   The DNA microcapsules with patterns made of sequence-designed DNA nanostructures. Publication Details Yusuke Sato, Masahiro Takinoue JACS Au "Capsule-like DNA hydrogels with patterns formed by lateral phase separation of DNA nanostructures" DOI: 10.1021/jacsau.1c00450 https://doi.org/10.1021/jacsau.1c00450 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/changing_patters_dna_microcapsules.html Tokyo Institute of Technology https://www.titech.ac.jp/english/news/2021/062646

The Universe is filled with energetic particles, such as X rays, gamma rays, and neutrinos. However, most of the high-energy cosmic particles’ origins remain unexplained.   Now, an international research team led by Dr. Shigeo S. Kimura, a researcher at FRIS (Toma Group) of Tohoku University, has proposed a scenario that explains these; black holes with low activity act as major factories of high-energy cosmic particles.   Details of their research were published in the journal Nature Communications.   Gamma rays are high-energy photons that are many orders of magnitude more energetic than visible light. Space satellites have detected cosmic gamma rays with energies of megaelectron to gigaelectron volts.   Neutrinos are subatomic particles whose mass is nearly zero. They rarely interact with ordinary matter. Researchers at the IceCube neutrino observatory have also measured high-energy cosmic neutrinos.   Both gamma rays and neutrinos should be created by powerful cosmic-ray accelerators or surrounding environments in the Universe. However, their origins are still unknown. It is widely believed that active supermassive black holes (so-called active galactic nuclei), especially those with powerful jets, are the most promising emitters of high-energy gamma rays and neutrinos. However, recent studies have revealed that they do not explain the observed gamma rays and neutrinos, suggesting that other source classes are necessary.   The new model shows that not only active black holes but also non-active, "mellow" ones are important, acting as gamma-ray and neutrino factories.   All galaxies are expected to contain supermassive black holes at their centers. When matter falls into a black hole, a huge amount of gravitational energy is released. This process heats the gas, forming high-temperature plasma. The temperature can reach as high as tens of billions of Celsius degrees for low-accreting black holes because of inefficient cooling, and the plasma can generate gamma rays in the megaelectron volt range.   Such mellow black holes are dim as individual objects, but they are numerous in the Universe. The research team found that the resulting gamma rays from low-accreting supermassive black holes may contribute significantly to the observed gamma rays in the megaelectron volt range.   In the plasma, protons can be accelerated to energies roughly 10,000 times higher than those achieved by the Large Hadron Collider -- the largest human-made particle accelerator. The sped-up protons produce high-energy neutrinos through interactions with matter and radiation, which can account for the higher-energy part of the cosmic neutrino data. This picture can be applied to active black holes as demonstrated by previous research. The supermassive black holes including both active and non-active galactic nuclei can explain a large fraction of the observed IceCube neutrinos in a wide energy range.   Future multi-messenger observational programs are crucial to identify the origin of cosmic high-energy particles. The proposed scenario predicts gamma-ray counterparts in the megaelectron volt range to the neutrino sources. Most of the existing gamma-ray detectors are not tuned to detect them; but future gamma-ray experiments, together with next-generation neutrino experiments, will be able to detect the multi-messenger signals. Schematic picture of mellow supermassive black holes. Hot plasma is formed around a supermassive black hole. Electrons are heated up to ultrahigh temperature, which emits gamma-rays efficiently. Protons are accelerated to high energies, and they emit neutrinos. (Credit: Shigeo S. Kimura) Publication Details Shigeo S. Kimura, Kohta Murase, Péter Mészáros Nature Communications "Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos" DOI: 10.1038/s41467-021-25111-7 https://doi.org/10.1038/s41467-021-25111-7 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/gamma_rays_neutrinos_mellow_supermassive_black_holes.html Graduate School of Science, Tohoku University https://www.sci.tohoku.ac.jp/english/news/20210921-11746.html The Pennsylvania State University https://news.psu.edu/story/669728/2021/09/23/research/gamma-rays-and-neutrinos-mellow-supermassive-black-holes

Assistant Professor Fumihiro Kaneda has received “2021 OSA Outstanding Reviewer.” This award is given annually by The Optical Society (OSA) to commend the top reviewers for their outstanding peer review efforts over the past year.   Date: August 2020 Given to: Assistant Professor Fumihiro Kaneda in FRIS and RIEC Prize: 2021 OSA Outstanding Reviewer Given for: top reviewers for their outstanding peer review efforts to OSA journals Given by: The Optical Society (OSA) Reference: https://www.osapublishing.org/reviewer/?page=outstanding_reviewers

Magnesium rechargeable batteries (MRBs), where high-capacity Mg metal is used as the anode material, are promising candidates for next-generation batteries due to their energy density, safety, and cost. However, the lack of high-performance cathode materials impedes their development.   Like their lithium-ion counterparts, transition metal oxides are the staple cathode materials in MRBs. Yet the slow diffusion of Mg ions inside the oxides poses a serious problem. To overcome this, some researchers have explored sulfur-based materials. But sulfur-based cathodes for MRBs have severe limitations: low electronic conductivity, sluggish Mg diffusion in solid Mg-S compounds, and dissolubility of polysulfides into electrolytes, which results in low-rate capability and poor cyclability.   Now, a research team that included Tohoku University's Dr. Shimokawa and Professor Ichitsubo has developed liquid-sulfur/sulfide composite cathodes enabling high-rate magnesium batteries. Their paper has been published in the Journal of Materials Chemistry A.   The liquid-sulfur/sulfide composite materials can be spontaneously fabricated by electrochemically oxidizing metal sulfides, such as iron sulfide, in an ionic liquid electrolyte at 150. The composite material showed high performance in capacity, potential, cyclability, and rate capability.   The researchers achieved the discharge capacity of ~900 mAh/g at a high current density of 1246 mA/g based on the mass of active sulfur. In addition, they revealed that the discharge potential was enhanced by utilizing non-equilibrium sulfur formed by fast charging processes.   This material allowed for a stable cathode performance at 150 for more than 50 cycles. Such a high cyclability could be attributed to the following points: high structural reversibility of the liquid state active material, low solubility of polysulfides into the ionic liquid electrolyte, and high utilization ratio of sulfur due to its adhesion to conductive sulfide particles that form a porous morphology during the synthesis of the composite materials.   Schematic illustration showing the concept of this work. Liquid-sulfur/sulfide composite materials fabricated by electrochemical oxidation of metal sulfides can work as high-performance cathode materials for magnesium rechargeable batteries. (Credit: Kohei Shimokawa)   Despite the researchers' progress, several problems remain. "We need electrolytes that are compatible with both the cathode and anode materials because the ionic liquid used in this work passivates the Mg-metal anode," said Shimokawa. "In the future, it is important to develop new electrochemically stable electrolytes to make MRBs more practical for widespread use."   Although MRBs are still in the development stage, the research team is hopeful their work provides a new way to utilize liquid sulfur as high-rate cathode materials for MRBs. "This would boost the improvement of sulfur-based materials for achieving high-performance next-generation batteries," added Shimokawa. Publication Details Kohei Shimokawa, Takuya Furuhashi, Tomoya Kawaguchi, Won-Young Park, Takeshi Wada, Hajime Matsumoto, Hidemi Kato, Tetsu Ichitsubo Journal of Materials Chemistry A "Electrochemically Synthesized Liquid-Sulfur/Sulfide Composite Materials for High-Rate Magnesium Battery Cathodes" DOI: 10.1039/d1ta03464b https://doi.org/10.1039/d1ta03464b Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/high_rate_magnesium_rechargeable_batteries.html Institute for Materials Research, Tohoku University http://www.imr.tohoku.ac.jp/en/news/results/detail---id-1349.html

A microphysiological system (MPS), also known as an organ-on-a-chip, is a 3D organ construct using human cells that help reveal how organs respond to drugs and environmental stimuli. Now, Tohoku University researchers have developed a new analytical method that visualizes cell functions in MPS using scanning probe microscopy (SPM).   SPM differs from optical microscopy since it employs fine probe scanning over a sample surface and then exploits the local interactions between the probe and the surface. The biggest advantage of SPM over conventional microscopy is that physical and chemical conditions can be acquired rapidly and as a high-resolution image.   In this study, SPMs evaluated a vascular model (vasculature-on-a-chip) by scanning electrochemical microscopy (SECM) and scanning ion conductance microscopy (SICM). Using these SPMs, the researchers quantified the permeability and topographical information of the vasculature-on-a-chip. "MPS shows potential to recapitulate the physiology and functions of their counterparts in the human body. Most research on this topic has focused on the construction of biomimetic organ models. Today, there is an increasing interest in developing sensing systems for MPS" said first author Yuji Nashimoto at Tohoku University.   Some have touted electrochemical sensors to monitor MPS. However, most electrochemical sensors cannot acquire the spatial information of cell functions in MPS because they have only one sensor per one analyte. In contrast, SPM provides spatial information about cell functions rapidly.   "Our research group has developed various electrochemical imaging tools, SPMs and electrochemical arrays," explained corresponding author Hitoshi Shiku. Endothelial functions (permeability and topography) in a microphysiological system (MPS) are electrochemically visualized using scanning probe microscopies (SPMs). The analytical system is a new means to evaluate MPS or organ-on-a-chip (OoC). Publication Details Yuji Nashimoto, Minori Abe, Ryota Fujii, Noriko Taira, Hiroki Ida, Yasufumi Takahashi, Kosuke Ino, Javier Ramon Azcon, Hitoshi Shiku Advanced Healthcare Materials "Topography and Permeability Analyses of Vasculature-on-a-Chip using Scanning Probe Microscopies" DOI: 10.1002/adhm.202101186 https://doi.org/10.1002/adhm.202101186 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/new_imaging_tool_microphysiological_system.html

[Venue] ONLINE – Zoom   The 24th FRIS Seminar / TI-FRIS Lecture Course on Academic Impact “What is Research Impact? / Creating a High Research Impact Plan” at 10:00-15:00 on 23rd Aug. 2021 To register: https://forms.gle/YYR1Lbr7rdxo3BYc7 Deadline for registration: 12:00(noon) on 17th Aug. 2021   Lecturer: Dr. Rintaro OHNO, Senior Assistant Professor, Strategic Planning Office, Tohoku University Lecture title:    “What is Research Impact?” (for Introductory Session)   “Creating a High Research Impact Plan” (for Practical Session) Language: English (Japanese is also partially used.)   Contents of the lecture: [Introductory Session] How research impact is perceived from the perspective of university management is explained along with various data. [Practical Session] We will discuss what measures can be taken in the process of conducting academic research to make it a high impact. Before the lecture, participants will be presented with a specific theme of the discussion and asked to make preliminary considerations.   Contact: Dr. Suzuki or Dr. Fujiwara, research administrators of FRIS ura*fris.tohoku.ac.jp (please replace * with @.)  

Downsizing particles into the extreme of single atoms can maximize the utilization efficiency of elements and bring about new chemical properties. For this reason, catalysts in the form of single atoms, termed single-atom catalysts, have been widely explored in recent years to improve the efficiency and selectivity of catalytic reactions.   A joint team consisting of assistant professor Jiuhui Han at FRIS, Professor Pan Liu at Shanghai Jiao Tong University (China), and Professor Mingwei Chen at Johns Hopkins University (US) has developed a single-atom catalyst of 3D nanoporous graphene co-anchored with nickel and copper atoms. Due to the synergistic effect of the Cu and Ni single atoms in a nitrogen-doped graphene matrix, this material exhibits exceptional catalytic activity toward the oxygen reduction reaction (ORR). The rechargeable Zinc-air batteries using this single-atom catalyst as the air electrode show excellent energy efficiency, large power density, and high cycling stability. This study may pave an efficient avenue of designing highly durable single-atom ORR catalysts for metal-air batteries. This work was published in Nanoscale on June 28, 2021. Publication Details Yongtai Cheng, Haofei Wu, Jiuhui Han, Siying Zhong, Senhe Huang, Shufen Chu, Shuangxi Song, Kolan Madhav Reddy, Xiaodong Wang, Shao-Yi Wu, Xiaodong Zhuang, Isaac Johnson, Pan Liu, and Mingwei Chen. “Atomic Ni and Cu co-anchored 3D nanoporous graphene as an efficient oxygen reduction electrocatalyst for zinc-air batteries”, Nanosclae, 2021, doi: 10.1039/D1NR01612A https://pubs.rsc.org/en/Content/ArticleLanding/2021/NR/D1NR01612A#!divAbstract

The 5th FRIS-TFC Collaboration Event Departing the Ivory Tower: A workshop on Entrepreneurial Research How to maximize the impact of my research? How to translate the lab work into the market? What does academic entrepreneurship mean? Where should I start if I want to venture out in commercializing my research?    These questions, among others, are pondered by many researchers and academics, especially the young minds who are eager to move their lab technologies into the market.  This workshop is intended to showcase how research can transition from a purely academic endeavour to applications in the real world. Researchers and professionals will introduce their work and describe their career experiences. In addition, it aims to help students and young researchers to plan their career, introduce options for transitioning from academia to industry (and vice versa), and also how to connect their lab research with impactful applications.   *This event will be held mostly in English and partially in Japanese.   Date: July 15, 2021 16:00 – 18:00 (JST) Venue: TOKYO ELECTRON House of Creativity / Online (Zoom)　(Capacity: 500) Registration deadline : Wednesday, July 14, 2021, 16:00 (JST) https://forms.gle/kzHmLEfjJb9jEkRY8   Invited Speakers： Fabien Sorin 　(Associate Professor, Institute of Materials, École Polytechnique Fédérale de Lausanne) Shigeyoshi Yoshida 　(Deputy Director / Specially Appointed Professor, Material Solutions Center, Tohoku University)* This talk will be given in Japanese.   Hosted by: Tohoku Forum for Creativity, Organization for Research Promotion, Tohoku University Frontier Research Institute for Interdisciplinary Sciences, Tohoku University   More details on :  The 5th FRIS-TFC Joint Symposium Web   Contact : Email: tfc_webinar1*grp.tohoku.ac.jp (change * to @)

Supermassive black holes (SMBH) occupy the center of galaxies, with masses ranging from one million to 10 billion solar masses. Some SMBHs are in a bright phase called active galactic nuclei (AGN).   AGNs will eventually burn out since there is a maximum mass limit for SMBHs; scientists have long since pondered when that will be.   Tohoku University's Kohei Ichikawa and his research group may have discovered an AGN towards the end of its life span by accident after catching an AGN signal from the Arp 187 galaxy.   Through observing the radio images in the galaxy using two astronomy observatories – the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Array (VLA) – they found a jet lobe, a hallmark sign of AGN.   However, they noticed no signal from the nucleus, indicating the AGN might indicate the AGN activity might be already silent.   Upon further analysis of the multi-wavelength data, they found all the small scale AGN indicators to be silent, while the large-scale ones were bright. This is because the AGN has recently been quenched within the last 3,000 years.   Once an AGN dies off, smaller-scale AGN features become faint because further photon supplies also shut down. But the large scale ionized gas region is still visible since it takes about 3000 years for photons to arrive at the region's edge. Observing past AGN activity is known as light echoing.   "We used the NASA NuSTAR X-ray satellite, the best tool to observe current AGN activity," said Ichikawa. "It enables non-detection, so we were able to discover that the nucleus is completely dead."   The findings indicate AGN turn-off occurs within a 3000-year time scale, and the nucleus becomes over 1000 times fainter during the last 3000 years.   Ichikawa, who co-authored a paper for the 238 Meeting of the American Astronomical Society, says they will continue to investigate dying AGNs moving forward. "We will search for more dying AGN using a similar method as this study. We will also obtain the high spatial resolution follow-up observations to investigate the gas inflows and outflows, which might clarify how the shut-down of AGN activity has occurred.   The radio band composite image of Arp 187 obtained by VLA and ALMA telescopes (blue: VLA 4.86 GHz, green: VLA 8.44 GHz, red: ALMA 133 GHz). The image shows clear bimodal jet lobes, but the central nucleus (center of the image) is dark or non-detection. (Credit: ALMA (ESO/NAOJ/NRAO), Ichikawa et al.) Presentation Details: Kohei Ichikawa, Junko Ueda, Taiki Kawamuro "Serendipitous Discovery of a Dying Active Galactic Nucleus in Arp 187" 238th Meeting of the American Astronomical Society https://aas.org/meetings/aas238 Press Release: Tohoku University https://www.tohoku.ac.jp/en/press/discovery_of_dying_supermassive_black_hole.html ALMA Project, National Astronomical Observatory of Japan https://alma-telescope.jp/en/news/dyingbh-202106