Posts belonging to Category Materials

Quadriplegic Man Moves Again Just By Thinking

Bill Kochevar grabbed a mug of water, drew it to his lips and drank through the straw. His motions were slow and deliberate, but then Kochevar hadn’t moved his right arm or hand for eight years. And it took some practice to reach and grasp just by thinking about it. Kochevar, who was paralyzed below his shoulders in a bicycling accident, is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.

A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system activating his arm and hand, reconnect his brain to paralyzed muscles. Holding a makeshift handle pierced through a dry sponge, Kochevar scratched the side of his nose with the sponge. He scooped forkfuls of mashed potatoes from a bowl—perhaps his top goal—and savored each mouthful. Kochevar (56, of Cleveland) is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH).

brain implant2

For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar. “It’s better than I thought it would be.”


He’s really breaking ground for the spinal cord injury community,” commented Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”

A study of the work has been published in the The Lancet.


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.


How Brain Waves Can Control VR Video Games

Virtual reality is still so new that the best way for us to interact within it is not yet clear. One startup wants you to use your head, literally: it’s tracking brain waves and using the result to control VR video games.

Boston-based startup Neurable is focused on deciphering brain activity to determine a person’s intention, particularly in virtual and augmented reality. The company uses dry electrodes to record brain activity via electroencephalography (EEG); then software analyzes the signal and determines the action that should occur.


You don’t really have to do anything,” says cofounder and CEO Ramses Alcaide, who developed the technology as a graduate student at the University of Michigan. “It’s a subconscious response, which is really cool.”

Neurable, which raised $2 million in venture funding late last year, is still in the early stages: its demo hardware looks like a bunch of electrodes attached to straps that span a user’s head, worn along with an HTC Vive virtual-reality headset. Unlike the headset, Neurable’s contraption is wireless—it sends data to a computer via Bluetooth. The startup expects to offer software tools for game development later this year, and it isn’t planning to build its own hardware; rather, Neurable hopes companies will be making headsets with sensors to support its technology in the next several years.


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.


Glucose Monitoring Strip

A research group from the Center for Nanoparticle Research within the Institute for Basic Science (IBS) in South Korea has developed a convenient and accurate sweat-based glucose monitoring and maintenance device. The research group has furthered its previous study* (Nat. Nanotech. 11, 566, 2016) to enhance the efficiency of the sweat collection and sensing & therapy process. This sweat-based system allows rapid glucose measurement incorporating small and sensitive sensors and also comes in a disposable strip sensor to the convenience of users. This accurate glucose analysis allows to prescribe a multistep and precisely controlled dosage of drug.

sweat monitoring stripOptical camera image of the disposable sweat monitoring strip (left). The disposable sweat analysis strip on human skin with perspiration (middle).The disposable strip-type sensors connected to a zero insertion force AQ50 (ZIF) connector (right).

The previous study reported a wearable graphene-based patch that allows diabetes monitoring and feedback therapy by using human sweat. The device’s pH and temperature monitoring functions enable systematic corrections of sweat glucose measurements.

The conventional treatment protocol causes a huge stress to diabetics since it requires painful and repetitive blood-withdrawal and insulin shots. Patients become reluctant to take the periodic tests and treatments, aggravating the diabetes symptoms and suffer severe diabetic complications. A recent alternative approach, sweat-based monitoring offers a painless blood glucose monitoring method, enabling more convenient control of blood glucose levels. However, many challenges still exist for the practical application of the existing system: tedious blood collection procedure; error-prone, enzyme-based glucose sensing that may lead to overtreatment of drugs, etc.

To address such issues, the research group presented an easy-to-use and multistage module to ensure an accurate glucose monitoring and therapy. To speed up the sweat collection, the researchers redevised the system to work under a small amount of sweat. They used electrochemically active, porous metal electrodes (replacing the graphene materials of the previous study) to enhance the sensitivity of the system. Also the porous structure allows to form strong linkage among enzymes, resulting in increased reliability of the sensors under mechanical friction and deformation.


How To Build A 3D Printed House in One Day For $10,000

San Francisco-based Apis Cor reported on its blog that on a cold day last December it (and a number of its partners) built an entire 400 square foot house with its custom printer and it only cost $10,000. Oh, and it took just 24 hours to complete.


Others have claimed to build houses with 3D printers. But what makes Apis Cor’s house unique is that it wasn’t constructed from pre-printed panels that required assembly by construction workers. The “printer” used is a giant, mobile piece of crane-like equipment that layers on cement in one continuous process, building both the internal and external structure all at once instead of in multiple parts. It’s a one-story structure but it can be constructed in just about any shape and the company showed how it could be built in even the coldest of conditions in this YouTube video.

Contractors worrying about their jobs shouldn’t panic…yet. Once all the walls are put together, those workers are then needed to do everything else – like installing windows and the roof, plus painting, insulating and putting in appliances, according to this report in Quartz. A finished test house that the company built with a partner in Russia is “cozy and comfortable” and includes “a hall, a bathroom, a living room and a compact functional kitchen with the most modern appliances from Samsung company,” Apis Cor’s blog boasts.

3D printed house

As you can see with the advent of new technology,” the company says in its blog post. “Construction 3D printing is changing the view and approach to the construction of low-rise buildings and provides new opportunities to implement custom architectural solutions.

The possibilities of this advancement in 3D printing are many. Houses could be quickly constructed for refugee camps, people displaced by natural disaster or for those who do not have available housing, such as the homeless. Governments could build entire communities of affordable housing at just a fraction of what’s paid today.


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.


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.


Shape-shifting Molecular Robots

A research group at Tohoku University and Japan Advanced Institute of Science and Technology has developed a molecular robot consisting of biomolecules, such as DNA and protein. The molecular robot was developed by integrating molecular machines into an artificial cell membrane. It can start and stop its shape-changing function in response to a specific DNA signal.

This is the first time that a molecular robotic system has been able to recognize signals and control its shape-changing function. What this means is that molecular robots could, in the near future, function in a way similar to living organisms.

Using sophisticated biomolecules such as DNA and proteins, living organisms perform important functions. For example, white blood cells can chase bacteria by sensing chemical signals and migrating toward the target. In the field of chemistry and synthetic biology, elemental technologies for making various molecular machines, such as sensors, processors and actuators, are created using biomolecules. A molecular robot is an artificial molecular system that is built by integrating molecular machines. The researchers believe that realization of such a system could lead to a significant breakthrough – a bio-inspired robot designed on a molecular basis.

molecular robot

The molecular robot developed by the research group is extremely small – about one millionth of a meter – similar in size to human cells. It consists of a molecular actuator, composed of protein, and a molecular clutch, composed of DNA. The shape of the robot’s body (artificial cell membrane) can be changed by the actuator, while the transmission of the force generated by the actuator can be controlled by the molecular clutch. The research group demonstrated through experiments that the molecular robot could start and stop the shape-changing behavior in response to a specific DNA signal.

The findings were published in Science Robotics.