Nanotechnology

Potential risks and benefits of nanotechnology: perceptions of risk in sunscreens

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The available evidence indicates that nanoparticle sunscreens are both effective and safe

The applications for engineered nanomaterials and nanotechnology are developing exponentially, along with the awareness in government, industry and public groups of nanosafety issues. There is also growing public concern caused by negative perceptions among some high profile groups that nano-enabled products are proliferating uncontrollably and being released without adequate testing of their safety.1

What are the potential risks?

In reality, a one-size-fits-all approach to evaluating the potential risks and benefits of nanotechnology for human health is not possible because it is both impractical and would be misguided. There are many types of engineered nanomaterials, and not all are alike or potential hazards. Many factors should be considered when evaluating the potential risks associated with an engineered nanomaterial: the likelihood of being exposed to nanoparticles (ranging in size from 1 to 100 nanometres, about one-thousandth of the width of a human hair) that may be shed by the nanomaterial; whether there are any hotspots of potential exposure to shed nanoparticles over the whole of the nanomaterial’s life cycle; identifying who or what may be exposed; the eventual fate of the shed nanoparticles; and whether there is a likelihood of adverse biological effects arising from these exposure scenarios.1

The intrinsic toxic properties of compounds contained in the nanoparticle are also important, as well as particle size, shape, surface charge and physico-chemical characteristics, as these greatly influence their uptake by cells and the potential for subsequent biological effects. In summary, nanoparticles are more likely to have higher toxicity than bulk material if they are insoluble, penetrate biological membranes, persist in the body, or (where exposure is by inhalation) are long and fibre-like.1 Ideally, nanomaterial development should incorporate a safety-by-design approach, as there is a marketing edge for nano-enabled products with a reduced potential impact on health and the environment.1

What are the potential benefits?

Numerous prospective benefits for health and the environment are offered by nanotechnology, with engineered nanomaterials being developed for renewable energy capture and battery storage, water purification, food packaging, environmental sensors and remediation, as well as greener engineering and manufacturing processes. Some examples of the latter include highly efficient, low energy lighting sources, and smart clothing including a layer of piezo-electric crystals in nanomaterials for powering the wearer’s electronic devices.

The field of nanomedicine has also rapidly progressed from specialised drug delivery applications deploying liposomes (while many are not strictly nanoparticle-sized by international standard definitions, they can be engineered at the nano-scale) to nanoshells and transdermal patches, as well as the development of biocompatible nanomaterial prosthetic implants, and the metal-containing functionalised nanoparticles used for both the imaging and treatment of various cancers. Nanotechnology is also being used to develop point-of-care internet-linked diagnostic devices (eg, “doctor-on-a-chip” diagnostic tools). Nanobionics has made advances in solving the problems of interfacing between medical devices or bionic prosthetics and the nervous system;2 for example, invasive cranial sensing electrodes made of traditional cytotoxic metals are being replaced by more biocompatible surface transistors that can also be coupled with a dosing device.

Some common nano-enabled products currently available contain silver nanoparticles for their antimicrobial effects,3 including clothing items that require less frequent washing. This was mainly because of the ease of incorporating nanosilver into the surface of such products, but the quality of these products has unfortunately been variable, with some rapidly leaching silver ions. Nanosilver should preferably be reserved for more important applications, such as medical dressings for treating resistant infections that impair wound healing.3

Risk perception and weighing up the risks and benefits

Public perception of the potential risks posed by nanotechnology is very different in certain regions. In Asia, where there is a very positive perception of nanotechnology, some products have been marketed as being nano-enabled to justify charging a premium price. This has resulted in at least four Asian economies adopting state-operated, user-financed product testing schemes to verify nano-related marketing claims, such as the original “nanoMark” certification system in Taiwan.4

In contrast, the negative perception of nanotechnology in some other regions may result in questionable marketing decisions; for example, reducing the levels of zinc oxide nanoparticles included as the active ingredient in sunscreens. This is despite their use in sunscreens having been extensively and repeatedly assessed for safety by regulatory authorities around the world, leading to their being widely accepted as safe to use in sunscreens and lip products.5

Weighing the potential risks and benefits of using sunscreens with UV-filtering nanoparticles is an important issue for public health in Australia, which has the highest rate of skin cancer in the world as the result of excessive UV exposure. Some consumers are concerned about using these nano-sunscreens,6 despite their many advantages over conventional organic chemical UV filters, which can cause skin irritation and allergies, need to be re-applied more frequently, and are absorbed by the skin to a much greater extent (including some with potentially endocrine-disrupting activity). Zinc oxide nanoparticles are highly suitable for use in sunscreens as a physical broad spectrum UV filter because of their UV stability, non-irritating nature, hypo-allergenicity and visible transparency, while also having a greater UV-attenuating capacity than bulk material (particles larger than 100 nm in diameter) on a per weight basis.7

Concerns about nano-sunscreens began in 2008 with a report that nanoparticles in some could bleach the painted surfaces of coated steel.8This is a completely different exposure situation to the actual use of nano-sunscreen by people; here they are formulated to remain on the skin’s surface, which is constantly shedding its outer layer of dead cells (the stratum corneum). Many studies have shown that metal oxide nanoparticles do not readily penetrate the stratum corneum of human skin, including a hallmark Australian investigation by Gulson and co-workers of sunscreens containing only a less abundant stable isotope of zinc that allowed precise tracking of the fate of sunscreen zinc.9 The researchers found that there was little difference between nanoparticle and bulk zinc oxide sunscreens in the amount of zinc absorbed into the body after repeated skin application during beach trials. The amount absorbed was also extremely small when compared with the normal levels of zinc required as an essential mineral for human nutrition, and the rate of skin absorption was much lower than that of the more commonly used chemical UV filters.9 Animal studies generally find much higher skin absorption of zinc from dermal application of zinc oxide sunscreens than do human studies, including the meticulous studies in hairless mice conducted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) using both nanoparticle and bulk zinc oxide sunscreens that contained the less abundant stable zinc isotope.10These researchers reported that the zinc absorbed from sunscreen was distributed throughout several major organs, but it did not alter their total zinc concentrations, and that overall zinc homeostasis was maintained.10

The other metal oxide UV filter is titanium dioxide. Two distinct crystalline forms have been used: the photo-active anatase form and the much less photo-active rutile form,7 which is preferable for sunscreen formulations. While these insoluble nanoparticles may penetrate deeper into the stratum corneum than zinc oxide, they are also widely accepted as being safe to use in non-sprayable sunscreens.11

Investigation of their direct effects on human skin and immune cells have shown that sunscreen nanoparticles of zinc oxide and rutile titanium dioxide are as well tolerated as zinc ions and conventional organic chemical UV filters in human cell test systems.12 Synchrotron X-ray fluorescence imaging has also shown that human immune cells break down zinc oxide nanoparticles similar to those in nano-sunscreens, indicating that immune cells can handle such particles.13 Cytotoxicity occurred only at very high concentrations of zinc oxide nanoparticles, after cellular uptake and intracellular dissolution,14 and further modification of the nanoparticle surface can be used to reduce both uptake by cells and consequent cytotoxicity.15

The ongoing debate about the safety of nanoparticles in sunscreens raised concerns that they may potentially increase free radical levels in human skin during co-exposure to UV light.6 On the contrary, we have seen that zinc oxide and rutile titanium dioxide nanoparticles directly reduce the quantity of damaging free radicals in human immune cells in vitro when they are co-exposed to the more penetrating UV-A wavelengths of sunlight.16 We also identified zinc-containing nanoparticles that form immediately when dissolved zinc ions are added to cell culture media and pure serum, which suggests that they may even play a role in natural zinc transport.17

The known benefits therefore clearly outweigh the risks of using nano-sunscreens. The important message to be communicated to the Australian public is that the danger of excessive UV light itself with respect to skin damage and cancer is far greater than the perceived risk posed by nano-sunscreens, which is not supported by the scientific literature. It is crucial that people do not stop using the most effective broad spectrum sunscreens as part of their sun protection measures.

Quantum sensors for high-precision magnetometry of superconductors

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Scientists at the Swiss Nanoscience Institute and the Department of Physics at the University of Basel have developed a new method that has enabled them to image magnetic fields on the nanometer scale at temperatures close to absolute zero for the first time. They used spins in special diamonds as quantum sensors in a new kind of microscope to generate images of magnetic fields in superconductors with unrivalled precision. In this way the researchers were able to perform measurements that permit new insights in solid state physics, as they report in Nature Nanotechnology.

 Researchers in the group led by the Georg-H. Endress Professor Patrick Maletinsky have been conducting research into so-called nitrogen-vacancy centers (NV centers) in diamonds for several years in order to use them as high-precision sensors. The NV centers are natural defects in the diamond crystal lattice. The electrons contained in the NVs can be excited and manipulated with light, and react sensitively to electrical and magnetic fields they are exposed to. It is the spin of these electrons that changes depending on the environment and that can be recorded using various measurement methods.

Maletinsky and his team have managed to place single NV spins at the tips of atomic force microscopes to perform nanoscale imaging. So far, such analyses have always been conducted at room temperature. However, numerous fields of application require operation at temperatures close to . Superconducting materials, for example, only develop their special properties at very low temperatures around -200°C. They then conduct electric currents without loss and can develop exotic magnetic properties with the formation of so-called vortices.

At temperatures close to absolute zero for the first time

In their paper, the scientists successfully used their new microscope under cryogenic conditions at temperatures of about 4 Kelvin (~ -269 °C) for the first time. They were able to image magnetic stray fields of vortices in a high-temperature superconductor with a hitherto unrivalled precision.

The resulting spatial resolution of 10 nanometers is one to two magnitudes better than that obtained using alternative methods. This permits for the first time an unambiguous and quantitative analysis of important material parameters, such as the magnetic penetration depths of the superconducting probe – one of the fundamental characteristics of a superconductor.

“Our findings are of relevance not only for quantum sensor technology and superconductivity,” says Patrick Maletinsky, commenting on the paper, “on the long run they will also have an influence on and, with further improvements in sensitivity, they may even enable applications in biology.”

Nanotechnology in food industry.

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Center for Food Safety (CFS) today released a new searchable database of consumer food products that contain nanotechnology. Common food related products that contain nanotechnology include candies (M&M’s, Skittles), baby bottles, and plastic storage containers. Nanotechnology is a powerful but novel platform for taking apart and reconstructing nature at the atomic and molecular level with important human and environmental health ramifications. The database contains almost 300 food products and food contact products that use nano.

“Scientists agree that nanomaterials create novel risks that require new forms of toxicity testing. But very little testing and regulation of these new products exists, and consumers have almost no information,” said Jaydee Hanson, senior policy analyst at Center for Food Safety. “This easy to use database is a step to fill the information gap, to alert consumers of just how widespread this technology is and to improve transparency in our food supply.”

Because of their unique properties, nanomaterials pose new risks for human health and the environment. For example, nanomaterials have unprecedented mobility for a manufactured material. Nanomaterials can penetrate human skin and when ingested, reach sensitive places like bone marrow, lymph nodes, the heart, and the brain.

Despite these novel properties, nanomaterials are regulated the same way as larger materials of the same substance. Although they have not been properly evaluated, they are popping up in a wide variety of consumer goods.

The release of the database comes after a new study published by Friends of the Earth (FOE)- Australia that showed the presence of nanomaterials, specifically nano titanium dioxide and nano silica, in all 14 food products the group tested. None of these products were labeled as containing nano ingredients nor were they submitted for nano-specific regulation. Most of these products are being sold in the U.S.

This new database covers over 40 different types of nanomaterials and is the only database to focus exclusively on food and food contact products. Of particular concern is the prominence of nano ingredients in so many foods frequently consumed by children.

“The FDA is failing to prevent nano-laced foods from being sold. Our food safety agency should demand that these products be taken off the market, as companies are using food additives and food contact materials not approved at the nano scale,” said Hanson.

Bulk scale titanium dioxide is used as a food coloring agent, often to make foods look whiter or brighter, but the FDA has not set exposure limits yet for its use at the nano scale in the US. Moreover, the largest review of nano titanium dioxide studies show that many basic questions have not been answered. Candies like M&M’s, processed cheeses, and chewing gum have all been found to contain nano titanium dioxide.  Nano titanium dioxide is small enough to cross through the intestine and into organs where it can damage DNA and disrupt cell function.

Silica is an anti-caking agent used in powdered food products, but it, too, could cause health problems at the nano-scale. The European Commission’s Scientific Committee on Consumer Safety (SCCS) found evidence that nano silica can damage DNA and concluded that the data is inadequate and no conclusion of safety can be made. Several recent studies have shown that nano silica can cause liver toxicity.

Nanotechnology

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This Viewpoint explores nanotechnology for therapeutics, diagnostics, and imaging.

Nanotechnology involves systems on the order of one-thousandth the thickness of a human hair. Generally, a nanoparticle or nanosystem has an outer shell that protects an inner core of therapeutic molecule or diagnostic substance. Either the shell or core can be made up of polymers or metals (Figure). The small size and enormous surface area:volume ratio create uniquely advantageous abilities to enter cells, release drugs slowly over time, modulate small-molecule payload toxic effects, and, in some cases, amplify a signal that depends on surface contacts. Nanotechnology currently affects 3 distinct areas of medicine: therapeutics, diagnostics, and imaging. The potential in each of these areas is enormous.

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Nano ‘yarn’ next step in biomedical implants.

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Imagine a pacemaker or bionic ear that doesn’t require batteries but is powered by your very own cells.

That could be the future of biomedical implants once biofuel cells come to fruition, says an international team of scientists, who have taken the technology one step closer to reality.

The researchers have created a biofuel cell made from carbon nanotubes that generate energy from blood glucose.

The advance improves the power output and the lifetime of biofuel cells, they report in the journal Nature Communications.

Unlike batteries, which store chemical energy, conventional fuel cells convert a fuel such as hydrogen or methanol into electricity.

Biofuel cells, which have been in development since the 1960s, employ the same principle except they use biological enzymes to convert glucose into electricity inside the body.

However, there have been a number of serious technical hurdles that have impaired their performance, says study co-author Professor Gordon Wallace from the University of Wollongong.

One of the challenges is “immobilising” the enzyme that converts the fuel into electricity and making it stick to the electrodes of the fuel cell, rather than diffusing through the cell and into the fuel.

Another challenge is keeping the immobilised enzyme active for long periods of time.

“This is because the electrodes, like anything implanted in the body, tend to get fouled and performance drops off quite quickly with time,” says Wallace.

This has resulted in low power densities of only a few milliwatts per centimetre squared and a lifetime of only a few days, which is insufficient for practical use.

To tackle these problems Wallace and his colleagues turned to carbon nanotubes, which are microscopic cylinders made from long strings of interconnected carbon atoms.

They used a form of multi-walled carbon nanotube “yarn” to construct a microscopic structure for the biofuel cell.

“This provides an environment that gives stability to the enzymes and an environment that occludes the types of things that can poison the enzyme, therefore degrading its performance over time,” says Wallace.

The end result was a biofuel cell with an extended lifetime and a higher power density 2.2 milliwatts per square centimetre.

“In terms of the power density it’s a factor of two or three above what we were getting. That’s probably not staggering, but it is significant,” says Wallace.

“What is more significant is the length of time we can operate these biofuel cells for.”

Repair nerve damage

The researchers are aiming to develop the carbon nanotube yarn biofuel cells to power an implant that will help regenerate nerve damage.

“Our initial target is for peripheral nerve repair, whether that’s a finger or other limbs.”

The idea is to implant the conduit in the area where the nerves need to be regenerated, and the biofuel cells will produce a tiny electric current to stimulate nerve growth without requiring batteries or an external power source.

Wallace and his collaborators are also working on improving the power output and lifetime of biofuel cells even further.

“That then opens them up to powering all sorts of implants, not just this temporary power supply to repair a damaged area, but a power supply that will be able to service in an ongoing prosthetic, like the vagus nerve stimulators for epilepsy or for chronic pain management.”

The ultimate goal is to boost output and longevity to the point that biofuel cells can power a broad range of biomedical implants.

“If you can think of any type of device that is implantable that requires energy, this would be a great way to power it so you don’t have to go in and change the batteries all the time,” says Wallace.

30 Resources To Learn About Nanotechnology.

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It may deal with nanomaterials, but nanotechnology is bigger than ever nowadays.
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Thursday, April 03, 2014: The branch of science that deals with nanomaterials has become quite popular nowadays. With newer and more advanced technologies coming in, nanotechnology is being used with more fervour.

As an engineer, you would do well do gain at least some knowledge of nanotech. Here are some text and video tutorials that will help you learn.

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 nanotechnology, free ebooks, books on nanotechnology, learn nanotechnology,tutorials on nanotechnology, nanotechnology videos, YouTube, nanotech, technology news, news

1. Tutorials on Selected Topics in Nanotechnology (Playlist)

This is a set of seven video lectures that covers various topics in the nanotechnology arena. These include lectures on transport of thermal energy through conduction in nanomaterials etc.

2. Nanotechnology Lectures

These are another 18 videos that will help you understand the basics and various other more advanced concepts of nanotechnology.

3. Lecture on Nanotechnology Richard Freyaman

This is a lecture by the famous American physicist Richard Freyman. Freyman was an award winning physicist who won the Nobel Prize in Physics back in 1965.

4. There’s Plenty of Room At the Bottom’

This is a famous talk given by Freyman at the California Institute of Technology. As mentioned on the attached blog, “This is a transcript of the classic talk that Richard Feynman gave on December 29th 1959 at the annual meeting of the American Physical Society at the California Institute of Technology (Caltech). This was first published in the February 1960 issue of Caltech’s Engineering and Science, which owns the copyright.”

5. Plasmonic Metamaterials

With a wide range of functionalities, metamaterials have been an important part of nanoscience. This book explains this kind of material in detail.

6. The Opensource Handbook of Nanoscience and Nanotechnology

This is a wikibook that is explained like the website: This wikibook on nanoscience and nanotechnology gathers information about the various tools, methods and systems to provide students, researchers and everyone else an open-source handbook and overview guide to this vast interdisciplinary and expanding field – a book that can be adjusted as new things appear and improved by you!

7. Cutting Edge Nanotechnology

Book description: The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters.

Genome ‘navigation map’ revealed › News in Science (ABC Science)

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The clearest picture yet of how our genes are regulated to make the body work has been unveiled in a major international study.

The scientists, including Australians, have mapped how a network of switches, built into human DNA, controls where and when genes are turned on and off.

DNA

These “maps”, published today in two major studies in Nature, significantly increase our understanding of the human genome, which contains the genetic instructions needed to build and maintain all the many different cell types in the body.

The three-year-long project, called FANTOM5 (Functional Annotation of the Mammalian genome) and led by the RIKEN Centre for Life Science Technologies in Japan, involved more than 250 scientists across 20 countries and regions, including Australia.

Collaborator Australian Institute of Bioengineering and Nanotechnology Associate Professor Christine Wells says the work has allowed researchers to learn the rules of DNA information flow.

“We are starting to understand how cells find the right information in the precise instant that it is needed,” she says.

Dr Alistair Forrest, scientific co-ordinator of FANTOM5 from the RIKEN Centre, says humans are complex, multi-cellular organisms composed of at least 400 distinct cell types.

“This beautiful diversity of cell types allow us to see, think, hear, move and fight infection – yet all of this is encoded in the same genome.”

All of our cells contain the same instructions, but genes are turned on and off at different times in different cells.

This process is controlled by switches – called promoters and enhancers – found within the genome. It is the flicking of these switches that makes a muscle cell different to a liver or skin cell.

The FANTOM5 team studied the largest yet set of cell types and tissues from humans and mice so they could identify the location of these switches within the genome.

They also mapped where and when the switches are active in different cell types and how they interact with each other.

Professor David Hume, director of the Roslin Institute at Britain’s Edinburgh University and one of the lead researchers on the project, uses the analogy of an aeroplane: “We have made a leap in understanding the function of all of the parts. And we have gone well beyond that – to understanding how they are connected and control the structures that enable flight.”

‘Intricate’
Associate Professor Ernst Wolvetang, also at the Australian Institute of Bioengineering and Nanotechnology at the University of Queensland, says the work is a game changer in the field.

As part of the same project, Wolvetang and his team have been able to look at brain stem cells and see how “intricate and complex” the gene regulatory networks are already at that basic level of development.

“It is an amazing compendium of information,” he says.

“Nobody up to date has taken so many cell lines and worked out which genes are on and which genes are off – and in this case we now know the whole story.”

Wolvetang says the “map” will be a major resource for researchers and already researchers are investigating how to turn one cell type into another.

Researchers also hope the FANTOM5 work will be a reference atlas to figure out which genes are involved, and how, in a whole range of diseases.

In a linked study, a Roslin Institute team used information from the atlas to investigate the regulation of an important set of genes required to build muscle and bone.

Another study used the FANTOM5 atlas to look at the regulation of genes in cells of the blood, producing what scientists described as a roadmap of blood cells that will help them pinpoint where and how cancerous tumours start to grow.

“Now that we have these incredibly detailed pictures of each of these cell types, we can now work backwards to compare cancer cells to the cells they came from originally to better understand what may have triggered the cells to malfunction, so we will be better equipped to develop new and more effective therapies,” says Forrest.

 

Lack of nanotech regulations leaves developing world exposed.

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Nanotechnology is a promising field, but a lack of regulation means there is uncertainty over the safety of its implementation, particularly in developing countries. This week I received some unexpected insights on nanotechnology and its relationship with industry in different parts of the world. I have been visiting GIANT (Grenoble Innovation for Advanced New Technologies), an interdisciplinary alliance of research institutions in France devoted to promoting scientific development and building links between academics and industry.

Due to their scientific complexity and high research and development (R&D) costs, nanotechnologies have so far been generally available only to industrialised countries. But according to Caroline Gauthier, a senior professor of management and technology at Grenoble School of Management, part of the GIANT cluster, “large firms are today designing affordable solutions to address the so-called ‘bottom of the pyramid’”.

In other words, to thrive outside the saturated market of industrialised economies, nanotech multinationals are trying to reach the untapped pool of poor countries.

“Big companies are not only developing cheaper products, but they are [also] shaping brand new business models targeted at emerging economies. Though whether this will help developing nations or harm them is difficult to say at this stage,” says Gauthier.

Grenoble’s technology alliance is investing increasing energy andmoney in nanotech R&D, and in technology transfer, so I was surprised that one of its members acknowledged the field’s uncertainty.

“It’s a difficult balance between applying the precautionary principle and allowing for scientific potential,” explains Gauthier. “At the moment, we are not able to fully evaluate all the potential consequences that these new technologies may have, for example on the environment, but also on animals or the human population.” She says that some of the chemical components in nanotechnology may turn out to be difficult to control and may become dangerous to consumers and manufacturers.

At the moment, there is “no specific regulation” for nanotech, she adds.

According to Gauthier, informal international regulation of nanotechnology isn’t in the hands of public bodies or governments. Instead, it is large private companies that make the rules because they have the power to influence international markets.

Gauthier thinks that developing countries are more vulnerable than developed ones to the lack of statutory regulation on nanotechnology’s implementation.

“The leading R&D firms normally stick to ethical practices voluntarily adopted among competitors when they work in developed countries.” But they have more freedom not to apply these practices — or to test new ones — in developing countries, she says. This is because in developing countries there can be a lower awareness of the safest ways of deploying nanotechnology.

 “There is no choice any more,” she says. “Public institutions will have to cooperate with the private sector in order to set a code of conduct for nanotech implementation.”

A first: Stanford engineers build computer using carbon nanotube technology.

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A team of Stanford engineers has built a basic computer using carbon nanotubes, a semiconductor material that has the potential to launch a new generation of electronic devices that run faster, while using less energy, than those made from silicon chips.

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This unprecedented feat culminates years of efforts by scientists around the world to harness this promising material.

The achievement is reported today in an article on the cover of Nature magazine written by Max Shulaker and other doctoral students in electrical engineering. The research was led by Stanford professors Subhasish Mitra and H.S. Philip Wong.

“People have been talking about a new era of carbon nanotube electronics moving beyond silicon,” said Mitra, an electrical engineer and computer scientist, and the Chambers Faculty Scholar of Engineering. “But there have been few demonstrations of complete digital systems using this exciting technology. Here is the proof.”

Experts say the Stanford achievement will galvanize efforts to find successors to silicon chips, which could soon encounter physical limits that might prevent them from delivering smaller, faster, cheaper electronic devices.

“Carbon nanotubes (CNTs) have long been considered as a potential successor to the silicon transistor,” said Professor Jan Rabaey, a world expert on electronic circuits and systems at UC Berkeley.

But until now it hasn’t been clear that CNTs could fulfill those expectations.

image_cnt_computer

“There is no question that this will get the attention of researchers in the semiconductor community and entice them to explore how this technology can lead to smaller, more energy-efficient processors in the next decade,” Rabaey said.

Mihail Roco, senior advisor for Nanotechnology at the National Science Foundation, called the Stanford work “an important, scientific breakthrough.”

It was roughly 15 years ago that carbon nanotubes were first fashioned into transistors, the on-off switches at the heart of digital electronic systems.

But a bedeviling array of imperfections in these carbon nanotubes has long frustrated efforts to build complex circuits using CNTs. Professor Giovanni De Micheli, director of the Institute of Electrical Engineering at École Polytechnique Fédérale de Lausanne in Switzerland, highlighted two key contributions the Stanford team has made to this worldwide effort.

“First, they put in place a process for fabricating CNT-based circuits,” De Micheli said. “Second, they built a simple but effective circuit that shows that computation is doable using CNTs.”

As Mitra said: “It’s not just about the CNT computer. It’s about a change in directions that shows you can build something real using nanotechnologies that move beyond silicon and its cousins.”

Why worry about a successor to silicon? Such concerns arise from the demands that designers place upon semiconductors and their fundamental workhorse unit, those on-off switches known as transistors

For decades, progress in electronics has meant shrinking the size of each transistor to pack more transistors on a chip. But as transistors become tinier they waste more power and generate more heat – all in a smaller and smaller space, as evidenced by the warmth emanating from the bottom of a laptop.

Many researchers believe that this power-wasting phenomenon could spell the end of Moore’s Law, named for Intel Corp. co-founder Gordon Moore, who predicted in 1965 that the density of transistors would double roughly every two years, leading to smaller, faster and, as it turned out, cheaper electronics.

But smaller, faster and cheaper has also meant smaller, faster and hotter.

“Energy dissipation of silicon-based systems has been a major concern,” said Anantha Chandrakasan, head of electrical engineering and computer science at MIT and a world leader in chip research. He called the Stanford work “a major benchmark” in moving CNTs toward practical use. CNTs are long chains of carbon atoms that are extremely efficient at conducting and controlling electricity. They are so thin – thousands of CNTs could fit side by side in a human hair – that it takes very little energy to switch them off, according to Wong, co-author of the paper and the Williard R. and Inez Kerr Bell Professor at Stanford.

“Think of it as stepping on a garden hose,” Wong said. “The thinner the hose, the easier it is to shut off the flow.” In theory, this combination of efficient conductivity and low-power switching make carbon nanotubes excellent candidates to serve as electronic transistors.

“CNTs could take us at least an order of magnitude in performance beyond where you can project silicon could take us,” Wong said. But inherent imperfections have stood in the way of putting this promising material to practical use.

First, CNTs do not necessarily grow in neat parallel lines, as chipmakers would like.

Over time, researchers have devised tricks to grow 99.5 percent of CNTs in straight lines. But with billions of nanotubes on a chip, even a tiny degree of misaligned tubes could cause errors, so that problem remained.

A second type of imperfection has also stymied CNT technology.

Depending on how the CNTs grow, a fraction of these carbon nanotubes can end up behaving like metallic wires that always conduct electricity, instead of acting like semiconductors that can be switched off.

Since mass production is the eventual goal, researchers had to find ways to deal with misaligned and/or metallic CNTs without having to hunt for them like needles in a haystack.

“We needed a way to design circuits without having to look for imperfections or even know where they were,” Mitra said. The Stanford paper describes a two-pronged approach that the authors call an “imperfection-immune design.”

To eliminate the wire-like or metallic nanotubes, the Stanford team switched off all the good CNTs. Then they pumped the semiconductor circuit full of electricity. All of that electricity concentrated in the metallic nanotubes, which grew so hot that they burned up and literally vaporized into tiny puffs of carbon dioxide. This sophisticated technique was able to eliminate virtually all of the metallic CNTs in the circuit at once.

Bypassing the misaligned nanotubes required even greater subtlety.

So the Stanford researchers created a powerful algorithm that maps out a circuit layout that is guaranteed to work no matter whether or where CNTs might be askew.

“This ‘imperfections-immune design’ (technique) makes this discovery truly exemplary,” said Sankar Basu, a program director at the National Science Foundation.

The Stanford team used this imperfection-immune design to assemble a basic computer with 178 transistors, a limit imposed by the fact that they used the university’s chip-making facilities rather than an industrial fabrication process.

Their CNT computer performed tasks such as counting and number sorting. It runs a basic operating system that allows it to swap between these processes. In a demonstration of its potential, the researchers also showed that the CNT computer could run MIPS, a commercial instruction set developed in the early 1980s by then Stanford engineering professor and now university President John Hennessy.

Though it could take years to mature, the Stanford approach points toward the possibility of industrial-scale production of carbon nanotube semiconductors, according to Naresh Shanbhag, a professor at the University of Illinois at Urbana-Champaign and director of SONIC, a consortium of next-generation chip design research.

“The Wong/Mitra paper demonstrates the promise of CNTs in designing complex computing systems,” Shanbhag said, adding that this “will motivate researchers elsewhere” toward greater efforts in chip design beyond silicon.

“These are initial necessary steps in taking carbon nanotubes from the chemistry lab to a real environment,” said Supratik Guha, director of physical sciences for IBM’s Thomas J. Watson Research Center and a world leader in CNT research.

Journal reference: Nature

 

Nanotechnology May Lead To The End Of Laundry Forever.

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A few months ago, I reported on the futuristic possibility of robots learning how to do laundry. Alas, technology marches on, and it may well be that laundry robots are already obsolete. Several different companies using nanotechnology are working on products that may well spell the end of the need to do laundry – forever.

 

Take, for example, Schoeller textile’s Nanosphere technology. This is a finishing technology utilizing polymer nanospheres which take their cues from the way leaves let water run right off of them. Schoeller has partnered with several different companies to use their finishing technology on their clothing. Perhaps one of the most notable companies they’ve partnered with is iRepel, which makes chef shirts and aprons, and whose products are featured on ThinkGeek.

Check out a video of the iRepel chef shirt in action below:

Another interesting bit of research was recently published describing cotton shirts that are treated with Titanium Oxide particles. When exposed to light in the visible spectrum, the fabric turns out to be self-cleaning. Robert Gonzales has a nice writeup of the technology in io9.

Simply put, Long and Wu’s fabric is more versatile. For decades, TiO2 was only known to exhibit photocatalytic properties in the presence of ultraviolet light. But recently, it was shown that spiking TiO2 with nitrogen ions gives it photocatalytic capabilities in UV light and visible light. By coating their fabric with nano particles made from this new N-TiO2, the researchers have created a fabric that self-cleans in the presence of a very broad spectrum of light. What’s more, they found that further dispersing additional silver iodide nanoparticles in the fabric accelerated the N-TiO2‘s stain-fighting properties.

Neat as that particular fabric sounds, however, I think I might hold off on buying a shirt made from it until we’re sure that Titanium Oxide doesn’t cause brain damage. If it’s safe, however, that’s a pretty amazing thing – just lay your shirts out in the sun and they clean themselves.

Perhaps one of the most amazing upcoming nanotech coatings, however, is Ross Nanotechnology’s Neverwet. Neverwet is a superhydrophobic coating that can be used on a variety of surfaces, including use as a spray coating for clothing, the way you might use a typical waterproofing spray. Check out this video from LancasterOnline showing the coating applied to a pair of shoes – chocolate syrup literally runs right off of them.

With more and more companies using nanotechnology create clothing and other materials that are resistant to water and staining, it may not be too long before we never have to do the laundry again – because our clothes are always clean. Imagine the time, money, energy and money that would save.  Especially imagine the benefits for people living in developing countries where all the laundry is done by hand. Not only does the lack of laundry mean cleaner water, it means that people can be spared hours of tedious, backbreaking labor.

This is one of those things that seems kind of neat at first – hey look, no stains! But when you think about it, the ramifications for day to day life are pretty extraordinary. I’m excited to see where this technology goes.

Also, I look forward to never having to do laundry again. I’m also glad that robots won’t be doing the laundry, either. That’s just one less reason for them to want to rise up and overthrow their human masters.

Source: http://wakeup-world.com