In a review article published recently in the MDPI journal materials, the architecture and characteristics of common graphene-based nanomaterials (GBNs) were discussed, as well as the advances in the production of GBNs in engineering of soft tissues (including skin, blood vessel, muscular, and neural tissues).
Miniaturization lies at the heart of countless technological advances. It is undeniable that as devices and their building blocks get smaller, we manage to unlock new functionalities and come up with unprecedented applications. However, with more and more scientists delving into materials with structures on the atomic scale, the gaps in our current understanding of nanomaterial physics are becoming more prominent.
For instance, the nanomaterial's surface represents one such knowledge gap. This is because the influence of surface quantum effects becomes much more apparent when the surface-to-volume ratio of a material is high. In nanoelectromechanical systems (NEMS), a current hot topic in research, the physical properties of the nanomaterials greatly differ from their bulk counterparts when their size is reduced to a few atoms. A solid understanding of the mechanical properties of nanowires and nanocontacts—integral components of NEMS—is essential for advancing this technology. But, measuring them has proven a challenging task.
A major research challenge in the field of nanotechnology is finding efficient ways to control light, an ability essential for high-resolution imaging, biosensors and cell phones. Because light is an electromagnetic wave that carries no charge itself, it is difficult to manipulate with voltage or an external magnetic field. To solve this challenge, engineers have found indirect ways to manipulate light using properties of the materials from which light reflects. However, the challenge becomes even more difficult on the nanoscale, as materials behave differently in atomically thin states.
Deep Jariwala, Assistant Professor in Electrical and Systems Engineering, and colleagues have discovered a magnetic property in antiferromagnetic materials that allows for the manipulation of light on the nanoscale, and simultaneously links the semiconductor material to magnetism, a gap that scientists have been trying to bridge for decades. They described their findings in a recent study published in Nature Photonics.
Collaborating with Liang Wu, Assistant Professor in the Department of Physics and Astronomy in Penn's School of Arts and Sciences, along with graduate students Huiqin Zhang, a doctoral student in Jariwala's lab, and Zhuoliang Ni, a doctoral student in Wu's lab, the researchers describe the magnetic property of FePS3, an antiferromagnetic semiconductor material. Christopher Stevens and Joshua Hendrickson of the Air Force Research Laboratory and KBR, Inc. in Ohio, as well as Aofeng Bai and Frank Peiris at Kenyon College in Ohio also contributed to this work.
From designing new biomaterials to novel photonic devices, new materials built through a process called bottom-up nanofabrication, or self-assembly, are opening up pathways to new technologies with properties tuned at the nanoscale. However, to fully unlock the potential of these new materials, researchers need to "see" into their tiny creations so that they can control the design and fabrication in order to enable the material's desired properties.
This has been a complex challenge that researchers from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and Columbia University have overcome for the first time, imaging the inside of a novel material self-assembled from nanoparticles with seven nanometer resolution, about 1/100,000 of the width of a human hair. In a new paper published on April 7, 2022, in Science, the researchers showcase the power of their new high-resolution X-ray imaging technique to reveal the inner structure of the nanomaterial.
In a discovery that could speed research into next-generation electronics and LED devices, a University of Michigan research team has developed the first reliable, scalable method for growing single layers of hexagonal boron nitride on graphene.
The process, which can produce large sheets of high-quality hBN with the widely used molecular-beam epitaxy process, is detailed in a study in Advanced Materials.
Graphene-hBN structures can power LEDs that generate deep-UV light, which is impossible in today's LEDs, said Zetian Mi, U-M professor of electrical engineering and computer science and a corresponding author of the study. Deep-UV LEDs could drive smaller size and greater efficiency in a variety of devices including lasers and air purifiers.
"The technology used to generate deep-UV light today is mercury-xenon lamps, which are hot, bulky, inefficient and contain toxic materials," Mi said. "If we can generate that light with LEDs, we could see an efficiency revolution in UV devices similar to what we saw when LED light bulbs replaced incandescents."
AZoNano speaks with Graphmatech, a Swedish-based company about their approach to making graphene more industrially accessible to unleash this wonder material's full potential. Here, we discuss their graphene hybrid, Aros Graphene®, and the challenges around graphene integration, and how sustainability has shaped their business practice.
Scientists have demonstrated a new material that conducts heat 150% more efficiently than conventional materials used in advanced chip technologies.
The device—an ultrathin silicon nanowire—could enable smaller, faster microelectronics with a heat-transfer-efficiency that surpasses current technologies. Electronic devices powered by microchips that efficiently dissipate heat would in turn consume less energy—an improvement that could help mitigate the consumption of energy produced by burning carbon-rich fossil fuels that have contributed to global warming.
"By overcoming silicon's natural limitations in its capacity to conduct heat, our discovery tackles a hurdle in microchip engineering," said Junqiao Wu, the scientist who led the Physical Review Letters study reporting the new device. Wu is a faculty scientist in the Materials Sciences Division and professor of materials science and engineering at UC Berkeley.
The utilization of thin carbon layers in Si/C architectures promises improved ion/charge kinetics, although structural stability is still a concern due to the aggregation of Si nanoparticles (SiNPs).
Promising New Materials Mimic Muscle Structure and Function by Matthew Carroll
June 3, 2022
Introduction:
(Phys.org) Inspired by the structure of muscles, an innovative new strategy for creating fiber actuators could lead to advances in robotics, prosthetics, and smart clothing, according to a Penn State led team of scientists who discovered the process.
"Actuators are any material that will change or deform under any external stimuli, like parts of a machine that will contract, bend or expand," said Robert Hickey, assistant professor of materials science and engineering at Penn State. "And for technologies like robotics, we need to develop soft, lightweight versions of these materials that can basically act as artificial muscles. Our work is really about finding a new way to do this."
The team developed a two-step process to make fiber actuators that mimic the structure of muscle fibers and that excel in several aspects compared to other current actuators, including in efficiency, actuation strain and mechanical properties. They reported their findings today (June 2) in the journal Nature Nanotechnology.
"This is a big field and there's a lot of exciting research out there, but it has been really focused on engineering materials to optimize properties," Hickey said. "What makes our work exciting is we really focus on the connection between chemistry, structure and property."
New Study Suggests DNA Nanotech Safe for Medical Use June 14, 2022
Introduction:
(EurekAlert) COLUMBUS, Ohio – Advances in nanotechnology have made it possible to fabricate structures out of DNA for use in biomedical applications like delivering drugs or creating vaccines, but new research in mice investigates the safety of the technology.
Using a technique called DNA Origami (DO) – a process which involves folding complementary strands of DNA into double helixes over and over again – scientists can construct a variety of tiny devices with complex shapes that could be injected in the body to deliver medicines or perform other tasks. But because this technology is still relatively new, scientists have been divided on whether nanostructures could cause dangerous immune responses or be toxic in other ways in animal systems.
Now, a team of researchers from The Ohio State University has taken an initial step toward answering that question. The study, published in the journal Small (https://onlinelibrary.wiley.com/doi/ful ... .202108063), found that while high amounts of these DNA devices can cause a slight immune response, it isn’t marked enough to be dangerous. Their findings also suggest that different shapes may be more conducive to different therapeutic applications.
“DNA is unbelievable in terms of construction and how it's able to be manipulated and designed to form nano-robots in a very coordinated manner,” said Christopher Lucas, lead author of the study and a research scientist in mechanical and aerospace engineering at Ohio State. “We believe this technology, which has an incredible amount of potential, can be used to diagnose, treat and prevent disease.”
If you've ever swallowed the same round tablet in hopes of curing everything from stomach cramps to headaches, you already know that medicines aren't always designed to treat precise pain points. While over-the-counter pills have cured many ailments for decades, biomedical researchers have only recently begun exploring ways to improve targeted drug delivery when treating more complicated medical conditions, like cardiovascular disease or cancer.
A promising innovation within this burgeoning area of biomedicine is the millirobot. These fingertip-sized robots are poised to become medicine's future lifesavers—to crawl, spin, and swim to enter narrow spaces on their mission to investigate inner workings or dispense medicines.
To develop new drugs and vaccines, detailed knowledge about nature's smallest biological building blocks—biomolecules—is required. Researchers at Chalmers University of Technology, Sweden, are now presenting a groundbreaking microscopy technique that allows proteins, DNA and other tiny biological particles to be studied in their natural state in a completely new way.
A great deal of time and money is required when developing medicines and vaccines. It is therefore crucial to be able to streamline the work by studying how, for example, individual proteins behave and interact with one another. The new microscopy method from Chalmers can enable the most promising candidates to be found at an earlier stage. The technique also has the potential for use in conducting research into the way cells communicate with one another by secreting molecules and other biological nanoparticles. These processes play an important role in our immune response, for example.
Detailed knowledge of nature’s smallest biological building elements — biomolecules — is essential to generating new medications and vaccinations. Researchers at the Chalmers University of Technology in Sweden have developed a revolutionary microscopy approach that allows proteins, DNA, and other small biological particles to be investigated in their natural conditions in an entirely new way.
By turning a traditional lab-based fabrication process upside down, researchers at Duke University have greatly expanded the abilities of light-manipulating metasurfaces while also making them much more robust against the elements.
The combination could allow these quickly maturing devices to be used in a wide range of practical applications, such as cameras that capture images in a broad spectrum of light in a single shutter snap.
The results appear online July 1 in the journal Nano Letters.
Plasmonics is a technology that essentially traps the energy of light in groups of electrons oscillating together on a metal surface. This creates a small but powerful electromagnetic field that interacts with incoming light.
Traditionally, these groups of electrons—called plasmons—have been excited on the surfaces of metal nanocubes. By controlling the size of the nanocubes and their spacing from each other as well as the metal base below, the system can be tuned to absorb specific wavelengths of light.
As our devices get smaller and smaller, the use of molecules as the main components in electronic circuitry is becoming ever more critical. Over the past 10 years, researchers have been trying to use single molecules as conducting wires because of their small scale, distinct electronic characteristics, and high tunability. But in most molecular wires, as the length of the wire increases, the efficiency by which electrons are transmitted across the wire decreases exponentially. This limitation has made it especially challenging to build a long molecular wire—one that is much longer than a nanometer—that actually conducts electricity well.
Columbia researchers announced today that they have built a nanowire that is 2.6 nanometers long, shows an unusual increase in conductance as the wire length increases, and has quasi-metallic properties. Its excellent conductivity holds great promise for the field of molecular electronics, enabling electronic devices to become even tinier. The study is published today in Nature Chemistry.
A research team led by Prof. Meng Guowen from the Institute Solid State Physics, Hefei Institutes of Physical Science (HFIPS) of Chinese Academy of Sciences (CAS), cooperating with Prof. Wei Bingqing of the University of Delaware, Newark, U.S., successfully developed structurally integrated, highly-oriented carbon tube (CT) grids as electrodes of electric double-layer capacitors (EDLCs) to significantly improve in the frequency response performance and the areal and volumetric capacitances at the corresponding frequency. It is expected to be used as a high-performance small-sized alternating current (AC) line-filtering capacitor in electronic circuits, providing the essential materials and technology for the miniaturization and portability of electronic products.
The skin is one of the largest and most accessible organs in the human body, but penetrating its deep layers for medicinal and cosmetic treatments still eludes science.
Although there are some remedies—such as nicotine patches to stop smoking—administered through the skin, this method of treatment is rare since the particles that penetrate must be no larger than 100 nanometers. Creating effective tools using such tiny particles is a great challenge. Because the particles are so small and difficult to see, it is equally challenging to determine their exact location inside the body—information necessary to ensure that they reach intended target tissue. Today such information is obtained through invasive, often painful, biopsies.
A novel approach, developed by researchers at Bar-Ilan University in Israel, provides an innovative solution to overcoming both of these challenges. Combining techniques in nanotechnology and optics, they produced tiny (nanometric) diamond particles so small that they are capable of penetrating skin to deliver medicinal and cosmetic remedies. In addition, they created a safe, laser-based optical method that quantifies nanodiamond penetration into the various layers of the skin and determines their location and concentration within body tissue in a non-invasive manner—eliminating the need for a biopsy.
This innovation was just published by researchers from the University's Institute of Nanotechnology and Advanced Materials, in cooperation with the Kofkin Faculty of Engineering and Department of Chemistry, in the scientific journal ACS Nano.
A team from Queen Mary University of London, Imperial College London (U.K.), Northwestern University in Evanston (U.S.) and Bielefeld University (D) have produced a new breed of polymer nanomembranes with aligned supramolecular macrocycle molecules. These new nanomembranes demonstrate properties that promise to improve the efficiency of separation processes widely used across the chemical and pharmaceutical industries.
Conventional chemical and pharmaceutical industries use 45–55% of their total energy consumption during production in molecular separations. In order to make these processes more efficient, cost-effective, environmentally friendly and therefore sustainable, these processes need to be partially or wholly replaced by novel separation strategies that make use of innovative and ground-breaking membrane technologies.
A team of researchers from Tsinghua University, working with a colleague from Jilin University, has developed a new 3D nanoprinting technique that uses semiconducting quantum dots. In their paper published in the journal Science, the group describes their new technique and provides examples of resulting 3D objects. Jia-Ahn Pan and Dmitri Talapin with the University of Chicago provide a Perspective piece in the same journal issue regarding more versatile 3D printing devices and the work done by the team on this new effort.
The use of 3D printing to make three-dimensional objects has expanded greatly over the past decade, leading to new products and faster ways to create demonstration objects. But, as the researchers with this new effort note, 3D printers primarily use materials based on polymers, limiting the type of products that can be made. Manufacturers say they would buy 3D printers capable of printing products with optical or electronic properties. In this new effort, the researchers in China have taken a big step in that direction.
The new method involves using semiconductor quantum dots (nanocrystals made of cadmium selenide, covered with zinc sulfide and with caps made of 3-mercaptopropionic acid ligands) as additions to printing material. The dots are activated using a laser. Photons from the laser are absorbed by a nanocrystal, resulting in a change in chemistry that allows for bonding between the quantum dots—a process known as two-photon absorption. In their setup, absorption of the protons was only possible in places where the light intensity was at its highest. This allowed for creating bonds smaller than the wavelength of the light.
A team of researchers at Brave Analytics GmbH, working with a colleague from the Gottfried Schatz Research Center and another from the Institute of Physics, all in Austria, has developed a device that is capable of conducting real-time nanoparticle characterization. The group published their work in the journal Physical Review Applied.
Over the past several decades, product engineers have increasingly added nanoparticles to products to give them desired qualities—to thicken or color paints, for example. The types of nanoparticles used depend on many factors, such as their composition and shape, which are generally easily determined. The size of the nanoparticles is also important to ensure consistency, but figuring out how big they are has proven to be more challenging. One approach called dynamic light scattering has been found to work well, but only with tiny nanoparticles. In this new effort, the researchers created a device that can be used to determine the size of larger nanoparticles.
The new device is based on optofluidic force induction (OF2i). It consists of a clear cylinder and a laser beam. In use, the cylinder is filled with water into which sample nanoparticles have been added—in this case, tiny bits of polystyrene. The laser is fired in a way that allows the light to travel in a spiral through the water, forming a water vortex.
The laser light is used in two ways: to push the nanoparticles through the water and to track their motion. In such a setup, the amount of acceleration experienced by a given nanoparticle will depend on its size. The researchers suggest it is similar to a sailboat. Two boats of the same size experiencing the same force of wind will be pushed at different speeds if they have differently sized sails. And because the laser forms a vortex, the nanoparticles travel in a spiral, making collisions less likely.
