Tag Archives: nanotechnology

How to mass produce cell-sized robots

NanoRobots no bigger than a cell could be mass-produced using a new method developed by researchers at MIT. The microscopic devices, which the team calls “syncells” (short for synthetic cells), might eventually be used to monitor conditions inside an oil or gas pipeline, or to search out disease while floating through the bloodstream.

The key to making such tiny devices in large quantities lies in a method the team developed for controlling the natural fracturing process of atomically-thin, brittle materials, directing the fracture lines so that they produce miniscule pockets of a predictable size and shape. Embedded inside these pockets are electronic circuits and materials that can collect, record, and output data.  The system uses a two-dimensional form of carbon called graphene, which forms the outer structure of the tiny syncells. One layer of the material is laid down on a surface, then tiny dots of a polymer material, containing the electronics for the devices, are deposited by a sophisticated laboratory version of an inkjet printer. Then, a second layer of graphene is laid on top.

This photo shows circles on a graphene sheet where the sheet is draped over an array of round posts, creating stresses that will cause these discs to separate from the sheet. The gray bar across the sheet is liquid being used to lift the discs from the surface

People think of graphene, an ultrathin but extremely strong material, as being “floppy,” but it is actually brittle, Strano explains. But rather than considering that brittleness a problem, the team figured out that it could be used to their advantage. “We discovered that you can use the brittleness,” says Strano, who is the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “It’s counterintuitive. Before this work, if you told me you could fracture a material to control its shape at the nanoscale, I would have been incredulous.”

The novel process, called “autoperforation,” is described in a paper published today in the journal Nature Materials, by MIT Professor Michael Strano, postdoc Pingwei Liu, graduate student Albert Liu, and eight others at MIT.

Source: http://news.mit.edu/

Swarm Of NanoRobots Can Improve The Efficiency Of Any Machine

The research team of Prof. Massimiliano Esposito of the University of Luxembourg studied the thermodynamics of  nanomachines. All machines convert one form of energy into another form – for example a car engine turns the energy stored in fuel into motion energy. Those processes of energy conversion, described by the theory called thermodynamics, don’t only take place on the macro-level of big machines, but also at the micro-level of molecular machines that drive muscles or metabolic processes and even on the atomic level. The research team of Prof. Massimiliano Esposito of the University of Luxembourg studies the thermodynamics of nanomachines only consisting of a few atoms.

In a paper published in the prestigious scientific journal Physical Review X, they outline how these small machines behave in concert. Their insights could be used to improve the energy efficiency of all kinds of machines, big or small.

Recent progress in nanotechnology has enabled researchers to understand the world in ever-smaller scales and even allows for the design and manufacture of extremely small artificial machines.

There is evidence that these machines are far more efficient than large machines, such as cars. Yet in absolute terms, the output is low compared to the needs we have in daily life applications,” explains Tim Herpich, PhD student at Esposito’s research group and main author of the paper. “That is why we studied how the nanomachines interact with each other and looked at how ensembles of those small machines behave. We wanted to see if there are synergies when they act in concert.”

The researchers found that the nanomachines under certain conditions start to arrange in “swarms” and synchronise their movements. “We could show that the synchronisation of the machines triggers significant synergy effects, so that the overall energy output of the ensemble is far greater than the sum of the individual outputs,” said Prof. Esposito. While this is basic research, the principles outlined in the paper could potentially be used to improve the efficiency of any machine in the future, the researcher explains.

In order to simulate and study the energetic behaviour of swarms of nanomachines, the scientists created mathematical models that are based on existing literature and outcomes of experimental research.

Source: https://wwwen.uni.lu/

How To Make Concrete Leaner, Greener, Stronger And More Elastic

Rice University scientists have developed micron-sized calcium silicate spheres that could lead to stronger and greener concrete, the world’s most-used synthetic material. To Rice materials scientist Rouzbeh Shahsavari and graduate student Sung Hoon Hwang, the spheres represent building blocks that can be made at low cost and promise to mitigate the energy-intensive techniques now used to make cement, the most common binder in concrete.

The researchers formed the spheres in a solution around nanoscale seeds of a common detergent-like surfactant. The spheres can be prompted to self-assemble into solids that are stronger, harder, more elastic and more durable than ubiquitous Portland cement.

Packed, micron-scale calcium silicate spheres developed at Rice University are a promising material that could lead to stronger and more environmentally friendly concrete

Cement doesn’t have the nicest structure,” said Shahsavari, an assistant professor of materials science and nanoengineering. “Cement particles are amorphous and disorganized, which makes it a bit vulnerable to cracks. But with this material, we know what our limits are and we can channel polymers or other materials in between the spheres to control the structure from bottom to top and predict more accurately how it could fracture.”

He said the spheres are suitable for bone-tissue engineering, insulation, ceramic and composite applications as well as cement.

Source: https://news.rice.edu/

Spray-On Electronic Nano-Antennas For Wearables

The promise of wearables, functional fabrics, the Internet of Things, and their “next-generation” technological cohort seems tantalizingly within reach. But researchers in the field will tell you a prime reason for their delayed “arrival” is the problem of seamlessly integrating connection technology — namely, antennas — with shape-shifting and flexible “things.”

But a breakthrough by researchers in Drexel’s College of Engineering, could now make installing an antenna as easy as applying some bug spray. In research recently published in Science Advances, the group reports on a method for spraying invisibly thin antennas, made from a type of two-dimensional, metallic material called MXene, that perform as well as those being used in mobile devices, wireless routers and portable transducers.

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Spray-applied MXene antennas could open the door for new applications in smart technology, wearables and IoT devices

This is a very exciting finding because there is a lot of potential for this type of technology,” said Kapil Dandekar, PhD, a professor of Electrical and Computer Engineering in the College of Engineering, who directs the Drexel Wireless Systems Lab, and was a co-author of the research. “The ability to spray an antenna on a flexible substrate or make it optically transparent means that we could have a lot of new places to set up networks — there are new applications and new ways of collecting data that we can’t even imagine at the moment.”

Source: https://drexel.edu/

New Solar Cells Could Harvest 85% of Visible Light

Scientists have developed a photoelectrode that can harvest 85 percent of visible light in a 30 nanometers-thin semiconductor layer between gold layers, converting light energy 11 times more efficiently than previous methods. In the pursuit of realizing a sustainable society, there is an ever-increasing demand to develop revolutionary solar cells or artificial photosynthesis systems that utilize visible light energy from the sun while using as few materials as possible. The research team, led by Professor Hiroaki Misawa of the Research Institute for Electronic Science at Hokkaido University (Japan), has been aiming to develop a photoelectrode that can harvest visible light across a wide spectral range by using gold nanoparticles loaded on a semiconductor. But merely applying a layer of gold nanoparticles did not lead to a sufficient amount of light absorption, because they took in light with only a narrow spectral range.

In the study published in Nature Nanotechnology, the research team sandwiched a semiconductor, a 30-nanometer titanium dioxide thin-film, between a 100-nanometer gold film and gold nanoparticles to enhance light absorption. When the system is irradiated by light from the gold nanoparticle side, the gold film worked as a mirror, trapping the light in a cavity between two gold layers and helping the nanoparticles absorb more light. To their surprise, more than 85 percent of all visible light was harvested by the photoelectrode, which was far more efficient than previous methods. Gold nanoparticles are known to exhibit a phenomenon called localized plasmon resonance which absorbs a certain wavelength of light.

“Our photoelectrode successfully created a new condition in which plasmon and visible light trapped in the titanium oxide layer strongly interact, allowing light with a broad range of wavelengths to be absorbed by gold nanoparticles,” says Hiroaki Misawa.

 Source: https://www.global.hokudai.ac.jp/

Portable Machine Harvests Water From Air

Driven by the scarcity of supply, climate change and ground watershed depletion, scientists present a design for a first of its kind portable harvester that mines freshwater from the atmosphere. For thousands of years, people in the Middle East and South America have extracted water from the air to help sustain their populations. Researchers and students from the University of Akron drew inspiration from those examples to develop a lightweight, battery-powered freshwater harvester that could someday take as much as 10 gallons (37,8 liters) per hour from the air, even in arid locations.

I was visiting China, which has a freshwater scarcity problem. There’s investment in wastewater treatment, but I thought that effort alone was inadequate,University of Akron professor Shing-Chung (Josh) Wong said.

Instead of relying on treated wastewater, Wong explained, it might be more prudent to develop a new type of water harvester that takes advantage of abundant water particles in the atmosphere. Freshwater makes up less than 3 percent of the earth’s water sources, and three quarters of that is locked up as ice in the north and south poles. Most water sustainability research is directed toward water supply, purification, wastewater treatment and desalination. Little attention has been paid to water harvesting from atmospheric particles.

Harvesting water from the air has a long history. Thousands of years ago, the Incas of the Andean region collected dew and channeled it into cisterns. More recently, some research groups have been developing massive mist and fog catchers in the Andean mountains and in Africa. Wong’s harvester is directed towards the most abundant atmospheric water sources and uses ground-breaking nanotechnology. If successful, it will produce an agile, lightweight, portable, freshwater harvester powered by a lithium-ion battery.

By experimenting with different combinations of polymers that were hydrophilic — which attracts water — and hydrophobic — which discharges water, the team concluded that a water harvesting system could indeed be fabricated using nanofiber technology. Unlike existing methods, Wong’s harvester could work in arid desert environments because of the membrane’s high surface-area-to-volume ratio. It also would have a minimal energy requirement. “We could confidently say that, with recent advances in lithium-ion batteries, we could eventually develop a smaller, backpack-sized device,” Wong said.

Source: https://www.uakron.edu/

2D Material Revolutionizes Solar Fuel Generation

Following the isolation of graphene in 2004, a race began to synthesize new two-dimensional materials. 2D materials are single-layer substances with a thickness of between one atom and a few nanometers (billionths of a meter). They have unique properties linked to their reduced dimensionality and play a key role in the development of nanotechnology and nanoengineering.

An international group of researchers including Brazilian scientists affiliated with the University of Campinas (UNICAMP) have succeeded in producing a new material with these characteristics.

The researchers extracted a 2D material they call hematene from ordinary iron ore like that mined in many parts of the world, including Brazil. The material is only three atoms thick and is thought to have enhanced photocatalytic properties.

International group of researchers including Brazilian scientists obtain new material from iron ore with application as a photocatalyst

The research was conducted at the Center for Computational Engineering and Sciences (CCES), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP, and during a research internship abroad that was also supported by FAPESP via a specific scholarship.

Douglas Soares Galvão, a researcher at CCES and one of the authors of the study, told Agência FAPESP about the discovery. “The material we synthesized can act as a photocatalyst to split water into hydrogen and oxygen, so that electricity can be generated from hydrogen, for example, as well as having several other potential applications,” he said.

The new material was exfoliated from hematite, one of the most common minerals on earth and the main source of iron, which is the cheapest metal, used in many products and above all to make steel.

Unlike carbon and its 2D form graphene, hematite is a non-van der Waals material, meaning it is held together by 3D bonding networks rather than by nonchemical and comparatively weaker atomic van der Waals interactions, which are noncovalent (they do not involve the sharing of one or more pairs of electrons by the atoms that participate in the bond).

Because it is a naturally occurring mineral, has highly oriented, large crystals and is a non-van der Waals material, the researchers believe that hematite is an excellent precursor for the exfoliation of novel 2D materials.

Most of the 2D materials synthesized to date were derived from samples of van der Waals solids. Non-van der Waals 2D materials with highly ordered atomic layers and large grains are still rare,” Galvão said.

Hematene was synthesized by the liquid-phase exfoliation of hematite ore in an organic solvent, N,N-dimethylformamide (DMF). Transmission electron microscopy confirmed the exfoliation and formation of hematene in single sheets with a thickness of only three iron and oxygen atoms (monolayer) and in randomly stacked sheets (bilayer).

The innovation is described in an article published in Nature Nanotechnology.

Source: http://agencia.fapesp.br/

 

Orthodontic Surgery Without Incision

Researchers at the Technion-Israel Institute of Technology have developed a nanotechnology that replaces the surgical scalpel with an “enzymatic blade.” In an article published recently in ACS Nano, the researchers describe the application of this technology in a surgical procedure in the oral cavity. The application spares the pain associated with orthodontic surgeries and significantly reduces tissue recovery time.

The study was led by Dr. Assaf Zinger, within the framework of his doctoral research, mentored by Assistant Professor Avi Schroeder, the director of the Laboratory of Targeted Drug Delivery and Personalized Medicine at the Wolfson Faculty of Chemical Engineering. The novel technology is based on rational use of enzymesbiological molecules the body uses to repair itself, as well as on use of nanoparticles for achieving a targeted therapeutic profile.

In the United States alone, approximately five million people undergo orthodontic treatment each year. To speed up treatment, which typically lasts about two years, many undergo invasive surgery, in which collagen fibers that connect the tooth to the underlying bone tissue are cut.

The technology developed at the Technion softens the collagen fibers via the targeted release of collagenase – an enzyme that specifically breaks down collagen. Using techniques developed in Schroeder’s lab, the collagenase is packaged into liposomesnanometric vesicles. As long as the collagenase particles are packaged in the liposome, they are inactive. But with this special nanotechnology, an ointment is applied on the target site, so that the enzyme begins to gradually leak from the liposome and soften the collagen fibers. The researchers performed a series of tests to determine the collagenase concentration optimal for the procedure and to accelerate tissue repair thereafter.

Source: http://t3news.trdf.co.il/

How To Charge In Seconds 3D Batteries

The world is a big place, but it’s gotten smaller with the advent of technologies that put people from across the globe in the palm of one’s hand. And as the world has shrunk, it has also demanded that things happen ever faster – including the time it takes to charge an electronic device.

A cross-campus collaboration led by Ulrich Wiesner, Professor of Engineering in the Department of Materials Science at Cornell University, addresses this demand with a novel energy storage device architecture that has the potential for lightning-quick charges.

The group’s idea: Instead of having the batteries’ anode and cathode on either side of a nonconducting separator, intertwine the components in a self-assembling, 3D gyroidal structure, with thousands of nanoscale pores filled with the components necessary for energy storage and delivery.

A rendering of the 3D battery architecture (top; not to scale) with interpenetrating anode (grey, with minus sign), separator (green), and cathode (blue, plus sign), each about 20 nanometers in size. Below are their respective molecular structures

This is truly a revolutionary battery architecture,” said Wiesner, whose group’s paper, “Block Copolymer Derived 3-D Interpenetrating Multifunctional Gyroidal Nanohybrid for Electrical Energy Storage,” was published in Energy and Environmental Science, a publication of the Royal Society of Chemistry.

This three-dimensional architecture basically eliminates all losses from dead volume in your device,” Wiesner said. “More importantly, shrinking the dimensions of these interpenetrated domains down to the nanoscale, as we did, gives you orders of magnitude higher power density. In other words, you can access the energy in much shorter times than what’s usually done with conventional battery architectures.”

How fast is that? Wiesner said that, due to the dimensions of the battery’s elements being shrunk down to the nanoscale, “by the time you put your cable into the socket, in seconds, perhaps even faster, the battery would be charged.”

The architecture for this concept is based on block copolymer self-assembly, which the Wiesner group has employed for years in other devices, including a gyroidal solar cell and a gyroidal superconductor. Joerg Werner, Ph.D. ’15, lead author on this work, had experimented with self-assembling filtration membranes, and wondered if the same principles could be applied to carbon materials for energy storage.

Source: http://news.cornell.edu/

Bio-material Stronger Than Steel

At DESY‘s X-ray light source PETRA III, a team led by Swedish researchers has produced the strongest bio-material that has ever been made. The artifical, but bio-degradable cellulose fibres are stronger than steel and even than dragline spider silk, which is usually considered the strongest bio-based material. The team headed by Daniel Söderberg from the KTH Royal Institute of Technology in Stockholm reports the work in the journal ACS Nano of the American Chemical Society. The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products.

 

The resulting fibre seen with a scanning electron microscope (SEM)

Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

Source: http://www.desy.de/