The research group led by Professor Yuichi Ikuhara (also appointed as a professor at Tokyo University), Associate Professor Zhongchang Wang and Assistant Professor Chunlin Chen at the Advanced Institute for Materials Research, Tohoku University (AIMR), in collaboration with Group Leader Takashi Taniguchi at the National Institute for Materials Science (NIMS) and Japan Fine Ceramics Center (JFCC), succeeded for the first time in identifying the atomic structure and bonding mechanism in coherent interfaces between diamond, the hardest known material, and cubic boron nitride, the second hardest, using a state-of-the-art super-high-resolution scanning transmission electron microscope and first-principles calculation. 
(a and b) HAADF STEM images of c-BN/diamond interface viewed in direction parallel to [1-10] zone axis, (a) coherent area without defects, (b) area with defects, (c and d) HAADF STEM images of c-BN/diamond interface viewed in direction parallel to [11-2] zone axis, (c) area without defects, and (d) area with defects. Partial dislocations are observable. By comparing (c) and (d), a Burgers vector, which characterizes partial dislocations, of 1/4<1-10> was determined. All scale bars are 0.5 nm in length. The research group has attempted to develop new functional materials by focusing on lattice defects in crystals, namely dislocation, grain boundaries and interfaces, analyzing their atomic structures, and controlling lattice defects. Through the concurrent use of atomic-resolution scanning transmission electron microscopy, for which technological breakthroughs were achieved in recent years, and extensive theoretical calculation based on first principles, the group revealed that in coherent interfaces between diamond and cubic boron nitride, carbon and boron are bonded to each other, and the type of crystal defect called dislocation has a characteristic structure. In the future, these findings may be applicable to designing new devices using materials with improved properties resulting from controlling the formation of such defect structures, designing new devices incorporating lattice defect structures, and research and development of novel functional materials. This study was published in the online version of the UK scientific journal ("Misfit accommodation mechanism at the heterointerface between diamond and cubic boron nitride").
(a and b) HAADF STEM images of c-BN/diamond interface viewed in direction parallel to [1-10] zone axis, (a) coherent area without defects, (b) area with defects, (c and d) HAADF STEM images of c-BN/diamond interface viewed in direction parallel to [11-2] zone axis, (c) area without defects, and (d) area with defects. Partial dislocations are observable. By comparing (c) and (d), a Burgers vector, which characterizes partial dislocations, of 1/4<1-10> was determined. All scale bars are 0.5 nm in length. The research group has attempted to develop new functional materials by focusing on lattice defects in crystals, namely dislocation, grain boundaries and interfaces, analyzing their atomic structures, and controlling lattice defects. Through the concurrent use of atomic-resolution scanning transmission electron microscopy, for which technological breakthroughs were achieved in recent years, and extensive theoretical calculation based on first principles, the group revealed that in coherent interfaces between diamond and cubic boron nitride, carbon and boron are bonded to each other, and the type of crystal defect called dislocation has a characteristic structure. In the future, these findings may be applicable to designing new devices using materials with improved properties resulting from controlling the formation of such defect structures, designing new devices incorporating lattice defect structures, and research and development of novel functional materials. This study was published in the online version of the UK scientific journal ("Misfit accommodation mechanism at the heterointerface between diamond and cubic boron nitride").
This illustration depicts phonons "tunneling" from one lattice of sodium chloride to another. New research shows that phonons can reach across a gap as small as a nanometer, “tunneling” from one material to another to enhance heat transport. (Illustration: Jose-Luis Olivares/MIT) Phonons represent units of energy produced by vibrating atoms in a crystal lattice. For example, a single crystal of table salt contains atoms of sodium and chloride, arranged in a lattice pattern. Together, the atoms vibrate, creating mechanical waves that can transport heat across the lattice. Normally these waves, or phonons, are only able to carry heat within, and not between, materials. However, the new research shows that phonons can reach across a gap as small as a nanometer, “tunneling” from one material to another to enhance heat transport. The researchers believe that phonon tunneling explains the physical mechanics of energy transport at this scale, which cannot be clearly attributed to either conduction or radiation. “This is right in the regime where the language of conduction and radiation is blurred,” says Vazrik Chiloyan, an MIT graduate student in mechanical engineering. “We’re trying to come up with a clear picture of what the physics are in this regime. Now we’ve brought information together to demonstrate tunneling is, in fact, what’s going on for the heat-transfer picture.” Chiloyan and Gang Chen, the Carl Richard Soderberg Professor of Power Engineering and head of MIT’s Department of Mechanical Engineering, publish their results this week in . Clearing the thermal picture In the past few decades, researchers have attempted to define heat transport across ever-smaller distances. Several groups, including Chen’s, have experimentally measured heat flow by thermal radiation across gaps as small as tens of nanometers. However, as experiments move to even smaller spacing, researchers have questioned the validity of current theories: Existing models have largely been based on theories for thermal radiation that Chiloyan says “smeared out the atomic detail,” oversimplifying the flow of heat from atom to atom. In contrast, there exists a theory for heat conduction — known as Green’s functions — that describes heat flow at the atomic level for materials in contact. The theory allows researchers to calculate the frequency of vibrations that can travel across the interface between two materials. “But with Green’s functions, atom-to-atom interactions tend to drop off after a few neighbors. … You’d artificially predict zero heat transfer after a few atom separations,” Chiloyan says. “To actually predict heat transfer across the gap, you have to include long-range, electromagnetic forces.” Typically, electromagnetic forces can be described by Maxwell’s equations — a set of four fundamental equations that outline the behavior of electricity and magnetism. To explain heat transfer at the microscopic scale, however, Chiloyan and Chen had to dig up the lesser-known form known as microscopic Maxwell’s equations. “Most people probably don’t know there exists a microscopic Maxwell’s equation, and we had to go to that level to bridge the atomic picture,” Chen says. Bridging the gap The team developed a model of heat transport, based on both Green’s functions and microscopic Maxwell’s equations. The researchers used the model to predict heat flow between two lattices of sodium chloride, or table salt, separated by a nanometer-wide gap. With the model, Chiloyan and Chen were able to calculate and sum up the electromagnetic fields emitted by individual atoms, based on their positions and forces within each lattice. While atomic vibrations, or phonons, typically cannot transport heat across distances larger than a few atoms, the team found that the atoms’ summed electromagnetic force can create a “bridge” for phonons to cross. When they modeled heat flow between two sodium chloride lattices, the researchers found that heat flowed from one lattice to the other via phonon tunneling, at gaps of one nanometer and smaller. At sub-nanometer gaps “is a regime where we lack proper language,” Chen says. “Now we’ve developed a framework to explain this fundamental transition, bridging that gap.”
In situ generation of biofunctionalized graphene. A) Schematic representation of the process. Ultrasound waves are applied as a source of mechanical force that brakes and exfoliates the starting material (graphite). Subsequently, the hydrophobic region of the amphiphilic protein hydrophobin Vmh2 is spontaneously adsorbed onto the laminated material (which is also hydrophobic) stabilizing and functionalizing the exfoliated material. B) Raman spectra of the starting material (graphite crystallites). C) Raman spectra of the generated material (biofunctionalized few-layer graphene flake). (© Wiley) The production of defect-free graphene and its biological interfacing are crucial requirements for the biomedical exploitation of graphene. Researchers from the ICN2 have designed a new method for the in situ production of biofunctionalised few-layer defect-free microsheets of this promising nanomaterial. The new method has been developed by the ICN2 Nanobioelectronics and Biosensors Group, led by ICREA Research Prof Arben Merkoçi, in collaboration with the Department of Chemical Sciences from University of Naples “Federico II”, led by Prof. Paola Giardina. The first authors of this research are Alfredo M. Gravagnuolo and Dr Eden Morales. The results have been published today in ("In Situ Production of Biofunctionalized Few-Layer Defect-Free Microsheets of Graphene"). In the study, Prof Merkoçi’s Group offers a promising approach that consists in the exfoliation of low cost graphite using ultrasonic waves in synergy with a peculiar surface active and self-assembling protein. Such protein, called Vmh2 hydrophobin, is extracted from the mycelium of the edible fungus Pleurotus ostreatus (commonly known as “oyster mushroom"). The described phenomenon occurs in the liquid phase and allows obtaining bio-hybrid micro-sheets of high quality graphene. As a potentially scalable approach, this method could enable massive production of biofunctionalised graphene, which could be a valuable material for the upcoming diffusion of new nano-biotechnologies in the global bio-medical market. The obtained product is likely to prove valuable for the emerging applications of graphene in the biotechnological field including nanomedicine, sensing and bioelectronics technologies besides others.
Fluorescent nanoparticles in cells. Entering the body, the nanoparticles of certain substances may accumulate in the tumor cells, “ignoring” the healthy ones. It’s possible to attach the molecules of drugs or diagnostic agents to such nanoparticles to find cancer cells and destroy them without damaging the other cells in the body. For this purpose, researchers use nanoparticles of gold and ferromagnetic materials, heating them with high frequency electric currentsso that they kill cancer cells from the inside. One of the most promising types of nanoparticles for diagnosing and treating cancer is so-called upconversion nanoparticles (UCNPs). They convert near-infrared radiation, which can penetrate deep into human tissue, in visible light, making it possible to detect cancerous cells in body tissues, change them and monitor the progress of treatment. UCNP scan be configured so that they will release drugs with the help of light. 
Different types of coating for upconversion nanoparticles. However, before developing therapeutic methods based on the use of nanoparticles, it must be determined whether they can cause any harm to healthy cells or not – that is the subject of the research done by Elena Petersen and Inna Trusova of MIPT and their colleagues from Moscow, Nizhny Novgorod, Australia and the Netherlands. “Despite the fact that there’re a large number of studies on the cytotoxicity of UCNPs, all of them are circumstantial in a way, because the study of this problem was peripheral for their authors,” says Petersen, the head of the Laboratory of Cellular and Molecular Technologies at MIPT. “We’ve done the first systematic study of the effects of nanoparticles on cells.” The researchers studied the properties of one of the most common types of UCNPs, which is derived from sodium yttrium fluoride (Na[YF4]) doped with the rare-earth elements erbium and ytterbium. The group tested how these nanoparticles are absorbed by fibroblasts (the cells of human connective tissue)and keratinocytes (epidermal cells), and studied how nanoparticles affect these cells’ viability. The results show that the cytotoxicity of UCNPs depends on the cell type. They are not toxic for dermal fibroblasts and slightly toxic for keratinocytes. However, the toxicity for keratinocytes depends on the concentration of the nanoparticles, meaning that these cells can be used as a biological indicator for evaluating the safety of different types of UCNPs. In addition to the “naked” nanoparticles, there searchers tested several modifications of polymer-coated nanoparticles. In these cases, the difference between the response of fibroblasts and keratinocytes was even higher, for example, the particles coated with polyethylenimine interfered with the intracellular metabolism of the keratinocytes, but had no effect on the fibroblasts. The group identified the types of polymer coating that made the nanoparticles as safe as possible. “This study is an important step towards beginning to use UCNPs to diagnose and treat skin cancer and other skin diseases,” says Petersen. According to her, there are already studies of the use of nanoparticles for the treatment of skin diseases, but to utilize them on a large scale it is necessary to prove that they are safe and efficient.