Posts belonging to Category Carbon nanotubes

‘Spray-On’ Memory for Paper, Fabric, Plastic

USB flash drives are already common accessories in offices and college campuses. But thanks to the rise in printable electronics, digital storage devices like these may soon be everywhere – including on our groceries, pill bottles and even clothingDuke University researchers have brought us closer to a future of low-cost, flexible electronics by creating a new “spray-on digital memory device using only an aerosol jet printer and nanoparticle inks. The device, which is analogous to a 4-bit flash drive, is the first fully-printed digital memory that would be suitable for practical use in simple electronics such as environmental sensors or RFID tags. And because it is jet-printed at relatively low temperatures, it could be used to build programmable electronic devices on bendable materials like paper, plastic or fabric.


Duke University researchers have developed a new “spray-on” digital memory (upper left) that could be used to build programmable electronics on flexible materials like paper, plastic or fabric. They used LEDS to demonstrate a simple application.

We have all of the parameters that would allow this to be used for a practical application, and we’ve even done our own little demonstration using LEDs,” said Duke graduate student Matthew Catenacci, who describes the device in a paper published online in the Journal of Electronic Materials. At the core of the new device, which is about the size of a postage stamp, is a new copper-nanowire-based printable material that is capable of storing digital information.

Memory is kind of an abstract thing, but essentially it is a series of ones and zeros which you can use to encode information,” said Benjamin Wiley, an associate professor of chemistry at Duke and an author on the paper.


Artificial Embryo From Stem Cells

Scientists at the University of Cambridge have managed to create a structure resembling a mouse embryo in culture, using two types of stem cells – the body’s ‘master cells’ – and a 3D scaffold on which they can grow. Understanding the very early stages of embryo development is of interest because this knowledge may help explain why a significant number of human pregnancies fail at this time.

Once a mammalian egg has been fertilised by a sperm, it divides multiple times to generate a small, free-floating ball of stem cells. The particular stem cells that will eventually make the future body, the embryonic stem cells (ESCs) cluster together inside the embryo towards one end: this stage of development is known as the blastocyst. The other two types of stem cell in the blastocyst are the extra-embryonic trophoblast stem cells (TSCs), which will form the placenta, and primitive endoderm stem cells that will form the so-called yolk sac, ensuring that the foetus’s organs develop properly and providing essential nutrients.

Using a combination of genetically-modified mouse ESCs and TSCs, together with a 3D scaffold known as an extracellular matrix, Cambridge researchers were able to grow a structure capable of assembling itself and whose development and architecture very closely resembled the natural embryo.  There is a  remarkable degree of communication between the two types of stem cell: in a sense, the cells are telling each other where in the embryo to place themselves.

artificial embryo

We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership – these cells truly guide each other,”  says Professor Zernicka-Goetz. “Without this partnership, the correct development of shape and form and the timely activity of key biological mechanisms doesn’t take place properly.”

Comparing their artificial ‘embryo’ to a normally-developing embryo, the team was able to show that its development followed the same pattern of development. The stem cells organise themselves, with ESCs at one end and TSCs at the other.

The study has been published in the journal Science.


NanoCar Race

The NanoCar Race is an event in which molecular machines compete on a nano-sized racetrack. These “NanoCars” or molecule-cars can have real wheels, an actual chassis…and are propelled by the energy of electric pulses! Nothing is visible to the naked eye, however a unique microscope located in Toulouse (France) will make it possible to follow the race. A genuine scientific prowess and international human adventure, the race is a one-off event, and will be broadcast live on the web, as well as at the Quai des Savoirs, science center in Toulouse.


The NanoCar race takes place on a very small scale, that of molecules and atoms: the nano scale…as in nanometer! A nanometer is a billionth of a meter, or 0.000000001 meters or 10 -9 m. In short, it is 500,000 times thinner then a line drawn by a ball point pen; 30,000 times thinner than the width of a hair; 100 times smaller than a DNA molecule; 4 atoms of silicon lined up next to one another.

A very powerful microscope is necessary to observe molecules and atoms: the scanning tunneling microscope (STM) makes this possible, and it is also responsible for propelling the NanoCars. The scanning tunneling microscope was invented in 1981 by Gerd Binnig and Heinrich Rohrer, and earned them the Nobel Prize in Physics in 1986. The tunnel effect is a phenomenon in quantum mechanics: using a tip and an electric current, the microscope will use this phenomenon to determine the electric conductance between the tip and the surface, in other words the amount of current that is passing through.

nanocar in movement Screening provides an electronic map of the surface and of each atom or molecule placed on it.At the CNRS‘s Centre d’élaboration de matériaux et d’études structurales (CEMES) in Toulouse, it is the one of a kind STM microscope that makes the race possible: the equivalent of four scanning tunneling microscopes, this device is the only one able to simultaneously and independently map four sections of the track in real time, thanks to its four tungsten tips.


Nanocoatings Reduce Dental Implant Bacterial Infection By 97%

According to the American Academy of Implant Dentistry (AAID), 15 million Americans have crown or bridge replacements and three million have dental implants – with this latter number rising by 500,000 a year. The AAID estimates that the value of the American and European market for dental implants will rise to $4.2 billion by 2022. Dental implants are a successful form of treatment for patients, yet according to a study published in 2005, five to ten per cent of all dental implants fail. The reasons for this failure are several-fold – mechanical problems, poor connection to the bones in which they are implanted, infection or rejection. When failure occurs the dental implant must be removed. The main cause for dental implant failure is peri-implantitis. This is the destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. This occurs when pathogenic microbes in the mouth and oral cavity develop into biofilms, which protects them and encourages growth. Peri-implantitis is caused when the biofilms develop on dental implants.

A research team comprising scientists from the School of Biological and Marine Sciences, Peninsula Schools of Medicine and Dentistry and the School of Engineering at the University of Plymouth, have joined forces to develop and evaluate the effectiveness of a new nanocoating for dental implants to reduce the risk of peri-implantitis.

dentistIn this cross-Faculty study we have identified the means to protect dental implants against the most common cause of their failure. The potential of our work for increased patient comfort and satisfaction, and reduced costs, is great and we look forward to translating our findings into clinical practice,”  commented Professor Christopher Tredwin, Head of Plymouth University Peninsula School of Dentistry.

In the study, the research team created a new approach using a combination of silver, titanium oxide and hydroxyapatite nanocoatings. The application of the combination to the surface of titanium alloy implants successfully inhibited bacterial growth and reduced the formation of bacterial biofilm on the surface of the implants by 97.5 per cent.

Not only did the combination result in the effective eradication of infection, it created a surface with anti-biofilm properties which supported successful integration into surrounding bone and accelerated bone healing.

The results of their work are published in the journal Nanotoxicology.


Clean Renewable Source Of Hydrogen Fuel For Electric Car

Rice University scientists have created an efficient, simple-to-manufacture oxygen-evolution catalyst that pairs well with semiconductors for solar water splitting, the conversion of solar energy to chemical energy in the form of hydrogen and oxygen.

anode RiceA photo shows an array of titanium dioxide nanorods with an even coating of an iron, manganese and phosphorus catalyst. The combination developed by scientists at Rice University and the University of Houston is a highly efficient photoanode for artificial photosynthesis. Click on the image for a larger version

The lab of Kenton Whitmire, a Rice professor of chemistry, teamed up with researchers at the University of Houston and discovered that growing a layer of an active catalyst directly on the surface of a light-absorbing nanorod array produced an artificial photosynthesis material that could split water at the full theoretical potential of the light-absorbing semiconductor with sunlight. An oxygen-evolution  catalyst splits water into hydrogen and oxygen. Finding a clean renewable source of hydrogen fuel is the focus of extensive research, but the technology has not yet been commercialized.

The Rice team came up with a way to combine three of the most abundant metalsiron, manganese and phosphorus — into a precursor that can be deposited directly onto any substrate without damaging it. To demonstrate the material, the lab placed the precursor into its custom chemical vapor deposition (CVD) furnace and used it to coat an array of light-absorbing, semiconducting titanium dioxide nanorods. The combined material, called a photoanode, showed excellent stability while reaching a current density of 10 milliamps per square centimeter, the researchers reported.

The results appear in two new studies. The first, on the creation of the films, appears in Chemistry: A European Journal. The second, which details the creation of photoanodes, appears in ACS Nano.


NanoMachine Lifts 15 times Its Weight

Using advanced 3-D printing, Dartmouth College researchers have unlocked the key to transforming microscopic nanorings into smart materials that perform work at human-scaleNanomachines (nanocomputers) can already deliver medication and serve as computer memories at the tiny nanometer scale. By integrating a 3-D printing technique pioneered at Dartmouth’s Ke Functional Materials Group, researchers may unlock even greater potential for these mini-machines.

3D printing nanomachines

A 3-D printed gel structure lifts and lowers a U.S. dime when alternately exposed to water and DMSO solvent

Up until now, harnessing the mechanical work of nanomachines has been extremely difficult. We are slowly getting closer to the point that the tiny machines can operate on a scale that we can see, touch and feel.” said Chenfeng Ke, Assistant Professor for Chemistry at Dartmouth College and principle investigator for the research.

In an example provided by Ke, the first-generation smart material lifted a dime weighing 2.268g. The coin, 15 times the weight of the that lifted it, was raised 1.6 mm– the equivalent of a human lifting a car. “Creating nanomachine-based smart material is still extraordinarily complex and we are only just beginning, but this new technique could allow the design and fabrication of complex smart devices that are currently beyond our grasp,” said Ke.

The research was published on March 22 in the online edition of Angewandte Chemie, the journal of the German Chemical Society.


Cheap, Non-Toxic, Super Efficient Solar Cell

In the future, solar cells can become twice as efficient by employing a few smart little nano-tricks. Researchers are currently developing the environment-friendly solar cells of the future, which will capture twice as much energy as the cells of today. The trick is to combine two different types of solar cells in order to utilize a much greater portion of the sunlight.


These are going to be the world’s most efficient and environment-friendly solar cells. There are currently solar cells that are certainly just as efficient, but they are both expensive and toxic. Furthermore, the materials in our solar cells are readily available in large quantities on Earth. That is an important point,” says Professor Bengt Svensson of the Department of Physics at the University of Oslo (UiO) and Centre for Materials Science and Nanotechnology (SMN) in Norway.

Using nanotechnology, atoms and molecules can be combined into new materials with very special properties. The goal is to utilize even more of the spectrum of sunlight than is possible at present. Ninety-nine per cent of today’s solar cells are made from silicon, which is one of the most common elements on Earth. Unfortunately, silicon solar cells only utilize 20 per cent of the sunlight. The world record is 25 per cent, but these solar cells are laced with rare materials that are also toxic. The theoretical limit is 30 per cent. The explanation for this limit is that silicon cells primarily capture the light waves from the red spectrum of sunlight. That means that most of the light waves remain unutilized.

The new solar cells will be composed of two energy-capturing layers. The first layer will still be composed of silicon cells. “The red wavelengths of sunlight generate electricity in the silicon cells in a highly efficient manner. We’ve done a great deal of work with silicon, so there is only a little more to gain.” The new trick is to add another layer on top of the silicon cells. This layer is composed of copper oxide and is supposed to capture the light waves from the blue spectrum of sunlight.


Virtual Images that Blend In And Interact With The Real-World

Avegant, a Silicon Valley startup that sells a pair of headphones equipped with a VR-like portable screen, is breaking into augmented reality. The company today announced that it’s developed a new type of headset technology powered by a so-called light field display.


The research prototype, which Avegant eventually plans on turning into a consumer product, is based on the company’s previous work with its Glyph projector. That device was a visor of sorts that floats a virtual movie screen in front of your eyes, and developing it gave Avegant insight into how to build an AR headset of its own.

Like Microsoft’s HoloLens and the supposed prototype from secretive AR startup Magic Leap, Avegant’s new headset creates virtual images that blend in and interact with the real-world environment. In a demo, the company’s wired prototype proved to be superior in key ways to the developer version of the HoloLens. Avegant attributes this not to the power of its tethered PC, but to the device’s light field display — a technology Magic Leap also claims to have developed, yet has never been shown off to the public.

The demo I experienced featured a tour of a virtual Solar System, an immersion within an ocean environment, and a conversation with a virtual life-sized human being standing in the same room. To be fair, Avegant was using a tethered and bulky headset that wasn’t all that comfortable, while the HoloLens developer version is a refined wireless device. Yet with that said, Avegant’s prototype managed to expand the field of view, so you’re looking through a window more the size of a Moleskine notebook instead of a pack of playing cards. The images it produced also felt sharper, richer, and more realistic.

In the Solar System demo, I was able to observe a satellite orbiting an Earth no larger than a bocce ball and identify the Big Red Spot on Jupiter. Avegant constructed its demo to show off how these objects could exist at different focal lengths in a fixed environment — in this case a converted conference room at the company’s Belmont, California office. So I was able to stand behind the Sun and squint until the star went out of focus in one corner of my vision and a virtual Saturn and its rings became crystal clear in the distance.


How To Recycle Carbon Dioxide

An international team of scientists led by Liang-shi Li at Indiana University (IU) has achieved a new milestone in the quest to recycle carbon dioxide in the Earth’s atmosphere into carbon-neutral fuels and others materials.


The chemists have engineered a molecule that uses light or electricity to convert the greenhouse gas carbon dioxide into carbon monoxide — a carbon-neutral fuel source — more efficiently than any other method of “carbon reduction.”

molecular leaf

If you can create an efficient enough molecule for this reaction, it will produce energy that is free and storable in the form of fuels,” said Li, associate professor in the IU Bloomington College of Arts and Sciences‘ Department of Chemistry. “This study is a major leap in that direction.”

Burning fuel — such as carbon monoxide — produces carbon dioxide and releases energy. Turning carbon dioxide back into fuel requires at least the same amount of energy. A major goal among scientists has been decreasing the excess energy needed.

This is exactly what Li’s molecule achieves: requiring the least amount of energy reported thus far to drive the formation of carbon monoxide. The molecule — a nanographene-rhenium complex connected via an organic compound known as bipyridine — triggers a highly efficient reaction that converts carbon dioxide to carbon monoxide. The ability to efficiently and exclusively create carbon monoxide is significant due to the molecule’s versatility.

Carbon monoxide is an important raw material in a lot of industrial processes,” Li said. “It’s also a way to store energy as a carbon-neutral fuel since you’re not putting any more carbon back into the atmosphere than you already removed. You’re simply re-releasing the solar power you used to make it.

The secret to the molecule’s efficiency is nanographene — a nanometer-scale piece of graphite, a common form of carbon (i.e. the black “lead” in pencils) — because the material’s dark color absorbs a large amount of sunlight.

Li said that bipyridine-metal complexes have long been studied to reduce carbon dioxide to carbon monoxide with sunlight. But these molecules can use only a tiny sliver of the light in sunlight, primarily in the ultraviolet range, which is invisible to the naked eye. In contrast, the molecule developed at IU takes advantage of the light-absorbing power of nanographene to create a reaction that uses sunlight in the wavelength up to 600 nanometers — a large portion of the visible light spectrum.

Essentially, Li said, the molecule acts as a two-part system: a nanographeneenergy collector” that absorbs energy from sunlight and an atomic rheniumengine” that produces carbon monoxide. The energy collector drives a flow of electrons to the rhenium atom, which repeatedly binds and converts the normally stable carbon dioxide to carbon monoxide.

The idea to link nanographene to the metal arose from Li’s earlier efforts to create a more efficient solar cell with the carbon-based material. “We asked ourselves: Could we cut out the middle man — solar cells — and use the light-absorbing quality of nanographene alone to drive the reaction?” he said.

Next, Li plans to make the molecule more powerful, including making it last longer and survive in a non-liquid form, since solid catalysts are easier to use in the real world.

The process is reported in the Journal of the American Chemical Society.


New Technique Identifies Cancer In Urine Or Blood

A team of researchers, led by Professor Yoon-Kyoung Cho of Life Science at UNIST  (South Korea) has recently developed a new technique that effectively identifies cancer-causing substances in the urine or blood.

In the study, Professor Yoon-Kyoung Cho of Life Science, a group leader at IBS Research Center for Soft and Living Matter (CSLM) presented an integrated centrifugal microfluidic platform (Exodisc), a device that isolates extracellular vesicles (EVs) from urine.  The research team expects that this may be potentially useful in clinical settings to test urinary EV-based biomarkers for cancer diagnostics.

Extracellular vesicles (EVs) are cell-derived nanovesicles (40-1000 nm in size), present in almost all types of body fluids, which play a vital role in intercellular communication and are involved in the transport of biological signals for regulating diverse cellular functions. Despite the increasing clinical importance of EVs as potential biomarkers in the diagnosis and prognosis of various diseases, current methods of EV isolation and analysis suffer from complicated procedures with long processing times. For instance, even ultracentrifugation (UC), the most commonly used method for EV isolation, requires time-consuming steps involving centrifugation and acquisition of large sample volumes, and the results suffer from low yield and purity.

To overcome these limitations, Professor Cho presented a new lab-on-a-disc platform for rapid, size-selective, and efficient isolation and analysis of nanoscale EVs from raw biological samples, such as cell-culture supernatant (CCS) or cancer-patient urine.


The Exodisc is compoased of two independent filteration units (20nm and 600nm in size) within a disk-shaped chip to enable the processing of two different samples simulateously,” says Hyun-Kyung Woo (Combined M.S./Ph.D. student of Natural Science), the first author of the study. “Upon spinning the disc, the urine sample is transferred through two integrated nanofilters, allowing for the enrichment of unirary EVs within the size range of 20 to 600 nm.”
Using Exodisc, it is possible to isolate EVs from raw samples within 30 minutes,” says Professor Cho. “The process of passing the filter through centrifugal force is automatically carried out, effectively recovering the enriched EVs.”

On-disc ELISA using urinary EVs isolated from bladder cancer patients showed high levels of CD9 and CD81 expression, suggesting that this method may be potentially useful in clinical settings to test urinary EV-based biomarkers for cancer diagnostics,” explains Vijaya Sunkara of Life Sciences, the co-first author.
The results of the study has been published in the February issue of ACS Nano journal.


Efficient, Fast, Large-scale 3-D Manufacturing

Washington State University (WSU) researchers have developed a unique, 3-D manufacturing method that for the first time rapidly creates and precisely controls a material’s architecture from the nanoscale to centimeters – with results that closely mimic the intricate architecture of natural materials like wood and bone.

3D manufacturing Hex-Scaffold-web-

This is a groundbreaking advance in the 3-D architecturing of materials at nano- to macroscales with applications in batteries, lightweight ultrastrong materials, catalytic converters, supercapacitors and biological scaffolds,” said Rahul Panat, associate professor in the School of Mechanical and Materials Engineering, who led the research. “This technique can fill a lot of critical gaps for the realization of these technologies.”

The WSU research team used a 3-D printing method to create foglike microdroplets that contain nanoparticles of silver and to deposit them at specific locations. As the liquid in the fog evaporated, the nanoparticles remained, creating delicate structures. The tiny structures, which look similar to Tinkertoy constructions, are porous, have an extremely large surface area and are very strong.

The researchers would like to use such nanoscale and porous metal structures for a number of industrial applications; for instance, the team is developing finely detailed, porous anodes and cathodes for batteries rather than the solid structures that are now used. This advance could transform the industry by significantly increasing battery speed and capacity and allowing the use of new and higher energy materials.

They report on their work in the journal  Science Advances  and have filed for a patent.


Frozen Organs Get Life Via Nanotechnology

Scientists are developing a new method to safely bring frozen organs back to life using nanotechnology, an advance that may make donated organs for transplants available to virtually everyone who needs them.

A research team, led by the University of Minnesota, has discovered a groundbreaking process to successfully rewarm large-scale animal heart valves and blood vessels preserved at very low temperatures. The discovery is a major step forward in saving millions of human lives by increasing the availability of organs and tissues for transplantation through the establishment of tissue and organ banks.


This is the first time that anyone has been able to scale up to a larger biological system and demonstrate successful, fast, and uniform warming hundreds of degrees Celsius per minute of preserved tissue without damaging the tissue,” said University of Minnesota mechanical engineering and biomedical engineering professor John Bischof, the senior author of the study.

The researchers manufactured silica-coated nanoparticles that contained iron oxide. When they applied a magnetic field to frozen tissues suffused with the nanoparticles, the nanoparticles generated heat rapidly and uniformly.

Currently, more than 60 percent of the hearts and lungs donated for transplantation must be discarded each year because these tissues cannot be kept on ice for longer than four hours. According to recent estimates, if only half of unused organs were successfully transplanted, transplant waiting lists could be eliminated within two years.

The research was published  in Science Translational Medicine, a peer-reviewed research journal published by the American Association for the Advancement of Sciences (AAAS). The University of Minnesota holds two patents related to this discovery.