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Paradigm Shift in Understanding of Biology Could Alter Electronics

The discovery that microbial nanowires inside the bacterium Geobacter sufurreducens can conduct electricity not only represents a paradigm shift in our fundamental understanding of biology but also could completely change how we manufacture and use electronics.

Researchers at the University of Massachusetts, led by microbiologist Derek Lovley with physicists Mark Tuominen and Nikhil Malvankar, have discovered that the Geobacter bacterium uses the nanowire-like protein filaments to transfer electrons into iron oxide (rust) contained within the soil where they live, and that this mechanism serves the same function as oxygen does for humans.

While the research, which was published in the August 7th advanced online edition of Nature Nanotechnologyrepresents the first time that metallic-like conduction of electrical charge has been observed in a protein filament, the researchers had conjectured as far back as 2005 that this was the case.

Because they didn’t have the mechanism to demonstrate this capability, their hypothesis was met with a fair amount of skepticism. It was believed that if such conduction occurred, it had to involve a mechanism that used a series of proteins known as cytochromes.

The researchers were able to continue their research in a fairly simple way by allowing the Geobacter to grow on electrodes, where the bacteria produce a electrically conductive biofilms. The researchers were able to use a series of genetically modified strains of the bacterium to narrow down the source of the metallic-like electrical conductivity inside the biofilm to a network of nanowires within the bacterium.

"This discovery not only puts forward an important new principle in biology but in materials science,” says Mark Tuominen in the U Mass press release. “We can now investigate a range of new conducting nanomaterials that are living, naturally occurring, nontoxic, easier to produce and less costly than man-made. They may even allow us to use electronics in water and moist environments. It opens exciting opportunities for biological and energy applications that were not possible before."

While Lovley (the microbiologist) has been working with the Geobacter bacterium now for nearly two decades in everything from bioremediation to the synthesis of biofuels (see video below), it was the addition of the physicists to the research that could make this a significant breakthrough in electronic materials research.


“As someone who studies materials, I see the nanowires in this biofilm as a new material, one that just happens to be made by nature, says Tuominen. “It’s exciting that it might bridge the gap between solid-state electronics and biological systems. It is biocompatible in a way we haven’t seen before."

While mobile phones that you can use while scuba diving may be a long way off, this would seem to be an inexpensive way to replace nanowires made from toxic and expensive materials in everything from biosensors to solid-state electronics that are used in connection with biological systems.

Flexible Displays Could Push Graphene into the Commercial Limelight

While graphene research has been growing seemingly exponentially since graphene's discovery seven years ago, it has had to cross some rather wide technological chasms to find its way into the electronic products of today.

It may be in the area of touch-screen displays for mobile devices, where the rising cost of indium tin oxide (ITO) is resulting in more expensive products, that graphene could find an early commercial adoption point.

Earlier this year, I covered research coming out of Eindhoven University in the Netherlands, which was using a combination of carbon nanotubes in a mix with plastic nanoparticles to create a material that could be sprayed onto a substrate for creating conductive flexible displays.

Now researchers out of James Tour’s lab at Rice University are using graphene to create a thin film for touch-screen displays

The research, which was originally published in the journal ACS Nano, used a single-layer sheet of graphene with a grid of metallic nanowires on a flexible substrate to create a highly conductive, see-through display that is unbreakable. Anyone who has suffered the heartbreak of watching the display on his or her Smartphone shatter after hitting the ground knows how important this breakthrough could be.

The key to success in the display was the combining of the graphene with the grid of nanowires.

"Other labs have looked at using pure graphene. It might work theoretically, but when you put it on a substrate, it doesn't have high enough conductivity at a high enough transparency. It has to be assisted in some way," says Tour in the article.

Tour’s post-doctoral researcher, Yu Zhu, further explains that the metal grid strengthens the graphene and in turn the graphene fills in the voids of the grid.

Perhaps most intriguing about the research is that it seems to lend itself to inexpensive manufacturing techniques. Tour indicates that roll-to-roll and ink-jet printing are both possible with this material.

"This material is ready to scale right now," he says.

DNA Origami Leaves a Trace on Silicon

Research has been increasing over the last couple of years in using DNA nanostructures for combining top-down and bottom-up approaches to help the semiconductor industry keep feature sizes of chips on their ever-downward trek.

The first I reported on this trend was when IBM two years ago this month announced the use of DNA origami structures as a sort of scaffold for attracting carbon nanotubes to them and thereby creating miniature circuit boards.

Earlier this year, researchers Hongbin Yu and Hao Yan at Arizona State University got all the trade press covering their research, which developed a way to ensure that DNA origami was placed where you wanted it to be on the silicon by using “nano islands” made from gold. The latest technique using DNA origami uses the molecules for the masking and etching of silicon. 

The research, which was originally published in the July 13, 2011 online issue of Journal of the American Chemical Society, exploits the ability of DNA to both promote and inhibit etching of SiO2 at the single-molecule level.

"Our approach to pattern transfer for bottom-up nanofabrication is based on the discovery that DNA promotes/inhibits the etching of SiO2 at the single-molecule level, resulting in negative/positive tone pattern transfers from DNA to the SiO2 substrate," Haitao Liu, an assistant professor in the Department of Chemistry at the University of Pittsburgh, explains in the Nanowerk article cited above.

"DNA nanostructures can be made with precise control over their sizes and shapes. Their use as lithography mask, however, has been limited due to their poor chemical stability. Our work provides a way to transfer the shape of the DNA nanostructure to silicon wafer, with sub-20 nm resolution."

In the research conducted thus far, the researchers were able to create 20-nm trenches, which could be used as nanofluidic channels, but the process is currently not optimized. However, the researchers believe that if a thinner layer of SiO2 film is used that a “patterned SiO2 layer could be used as a mask for etching of the underlying silicon substrate.”

"The formation of the trench indicates that the DNA origami locally increases the rate of oxide etching under these conditions" explains Liu in the Nanowerk Spotlight piece. "The full width at half-maximum of the trench (16.7 ± 2.8 nm) is comparable with the edge width of the DNA origami, indicating an overall faithful pattern transfer process. This result is consistent with our hypothesis that DNA can increase the etching rate of SiO2 by increasing the concentration of water. The small width of the trench shows that this effect is indeed spatially localized around the DNA." While the researchers move on to sub-10nm structures, it would seem that perfecting this process is some ways off.

As the Nanowerk story concludes, we get: “The major challenges in this undertaking are the issue of how to further increase the contrast of the transferred pattern and, crucially, to increase fidelity, consistency and accuracy of the process.” One might term all these increases as developing “manufacturability.” It seems like it’s kind of a long way off. We may be pinning a lot of hope on a process like this if we’re looking for it to step up and take up the challenge of getting feature sizes below that of photolithography and e-beam lithography.

Molecular Mechanosynthesis Not Far Away in the Dreams of a Journalist and Star Trek Fan

Molecular manufacturing is a seductive concept, especially for journalists when they first encounter the idea.

A recent example comes from a publication called International Business Times, and it reveals what is really the most attractive bit for these scribes: “Star Trek.”

The journalist, who files his report as a video, characterizes those who question the timeline and possibility for Star Trek-like replicators (I guess what he means is those who are skeptical of molecular mechanosynthesis) are “critics and naysayers.”

These critics are quickly swept aside in this brief report because, it explains, “Agents” at the Center for Responsible Technology “have stated that they believe molecular manufacturing will almost certainly be a reality by 2020.” I feel reassured, don’t you?

Of course, a tedious and unrewarding debate could ensue about what it means for molecular manufacturing to be a reality, but even one of the more optimistic of futurists, Ray Kurzweil, doesn’t believe nanobots will be swimming around in our brains until 2030.

I tend to follow more closely the timeline of Philip Moriarty, who said in a recent interview that in 2040 he hoped we will be “at the point where we could simply instruct a computer to build nanostructures, and let the computer handle all the details—no human operator involvement required.”

The critical word in the above is nanostructures, which is far cry from a cup of tea, Earl Grey, hot.

Viagra Patch Made Possible by Nanotechnology

Sildenafil citrate, known commonly by its brand name, Viagra, has extended the sex life of males since its introduction in 1998. The little blue pill comes with some unwanted side effects, however—and with a waiting period before it takes its full effect.

Seeing an opportunity to improve upon the popular prescription pill, researchers in Egypt have developed a nano-enabled transdermal patch that delivers the drug into the bloodstream far more quickly and reduces side effects that result from taking the drug orally in pill form. 

The researchers, led by Yosra S.R. Elnaggar of Alexandria University, have published their work in the International Journal of Nanotechnology. 

Others have attempted to develop a transdermal patch for delivering the sildenafil citrate into the body, butthe trick in this iteration is that the researchers have encapsulated the drug in a nanoemulsion-based system that can cross membranes.

According to a report in the publication In-Pharma Technologist:

"The researchers examined two types of nanocarrier—one forming an emulsion with the drug using a surfactant compound to allow the lipid molecules and drug to mix, and the other a self-emulsifying nanocarrier that has its own inbuilt sufactant."

The self-emulsifying approach proved successful. 

“In this paper, relevance of nanomedicine to improve SC characteristics and transdermal permeation was assessed,” the authors report in their paper. “Nanoemulsion elaborated could significantly enhance transdermal permeation of SC with higher initial permeation and prolonged release.”

Nanotechnology Plays Role in First Synthetic Organ Transplant

The world’s first synthetic organ transplant is taking on the role of scientific achievement by which all others are measured. Sort of like, ‘if we can land on the moon, why can’t we make a [fill in the blank] that works.’

It is a remarkable achievement and is in part made possible by a nanocomposite developed at University College London (UCL) that serves as a scaffold that allows the stem cells to build upon it.

The lead surgeon in the procedure heaped praise upon the synthetic organ’s nanotechnology underpinnings.

"Thanks to nanotechnology, this new branch of regenerative medicine, we are now able to produce a custom-made windpipe within two days or one week,” says Professor Paolo Macchiarini in a separate BBC article covering the procedure. 

We don’t know too much about the specifics of the nanomaterial used in the scaffolding, except that it’s being called a “novel nanocomposite polymer” and was developed by Professor Alexander Seifalian at UCL Division of Surgery & Interventional Science.

While the nanocomposite scaffold is a critical element to the artificial organ, perhaps no less important was the bioreactor used to grow the stem cells onto it, which was developed at Harvard Bioscience.

If you needed any evidence of how nanotechnology is not only interdisciplinary, but also international, you could just cite this case: UK-developed nanocomposite for the scaffolding material, US-based bioreactor in which the stem cells were grown onto the scaffolding and a Swedish-based medical institute to perform the transplant.

So I ask, which country or region is going to get rich from the breakthrough?

Political Posturing in Nanotech Settles along Party Lines

I hope I have made my position on the so-called nanotech race clear over the years.  While I have been skeptical that a regional focus to nanotechnology’s development will somehow pay off in the end for those regions that invest in it, I had not yet seen the debate around nanotech’s development start splitting across the lines of the US government’s party ideologies. That is until now.

I came across this article in last week’s CBS MarketWatch website in which the debate is not just about how the US is in danger of losing its leadership in nanotech (I am not so certain this is likely to occur, even if you go by the numbers), but about whether actual funding or tax breaks are the factor that lead to that leadership in the first place.

According to the MarketWatch article, Sen. Kay Hutchinson, the top Republican on the Senate Commerce Committee, said the U.S. led in nanotech over the last decade thanks to research-and-development tax cuts.

Can R&D tax cuts really be the factor that put the US in its strong position in nanotechnology’s development? I am a bit bewildered. Until this article I had never heard anyone mention tax cuts in the same breath as nanotech development.

I suppose the more than $14.5 billion the Federal government has spent in actual funding over the last decade was just a minor factor in that leadership. Instead the key factor seems to be, according to Sen. Hutchinson, that those tax cuts be made permanent.

I am not a Beltway expert by any means, but what is going on here? My understanding was that there was a vote to be taken by the US Senate to reauthorize the National Nanotechnology Initiative (NNI) that has managed to get its funding through annual appropriation bills since 2008.

Instead what we seem to be getting is some non-issue standing in the way of getting the reauthorization voted on. Was someone really threatening to take away R&D tax cuts so that they needed to be protected by some permanent law?

I have been observing the US’s nanotechnology initiative since it started and have witnessed a slew of other countries launch theirs since and I think all in all the US should feel satisfied not only with the results to date but they way the program has been managed as well.

It would be a pity if all the hard work...and hard cash...that have gone into creating a foundation for nanotechnology’s development in the US, and even for it becoming a leader in the field, would be squandered for some political ideology.

UK Nanotech in Turmoil

They say if you want to get the real story on just about anything, follow the money—or possibly, as in the case of the United Kingdom’s nanotechnology strategy, the lack thereof.

It started innocently enough, trying to figure out how much money governments around the world were spending on R&D for nanotech.

As it turns out, the UK, although one of the first countries to have a targeted nanotech program, sort of moved away from chasing other countries’ rising funding levels, leaving one noted UK nanotechnology researcher and occasional blogger wondering: Why has the UK given up on nanotechnology?

Richard Jones’ insights into the UK’s particular predicament are unique, and an important read for anyone interested in seeing how the emerging technology strategies of nations can slowly drift off course until they end up somewhere completely different from their intended destination.

The story is complicated, with different bureaucratic boards leading the initiative and then being dissolved, but at the core of it the problem is one of simple economics. Nanotechnology is an enabling technology, and while the UK has a thriving pharmaceutical industry, its chemical industry is moribund, and it never really had much of an electronics industry. This leaves nanotechnology without much to enable.

From a certain perspective, you would have to agree with those officials who oversaw the slow bleeding of funds from nanotechnology research in the country. What is the point, after all?

Well, one could reasonably argue, as some have in the comments section of Jones’ piece, that nanotech may have been an opportunity to jump-start the manufacturing industry in the UK. Yes, maybe, but when the money guys are making money hand over fist from derivatives and other convoluted financial instruments, it’s hard to convince them of the importance of creating a manufacturing base.

It is all a cautionary tale indeed. But of particular interest to me was that no sooner had Richard Jones hearkened back to the foundational nanotechnology strategy document for the UK published in 2002, and known as the Taylor report, than I read that a new report had been published that “outlines recommendations for future success of UK nanotechnology.” Ironic? You bet.

You know, they might have spared themselves the latest effort if they had simply read and followed the recommendations of the Taylor report written nealy10 years ago. Of course, in the absence of a manufacturing base it would appear the “nanotechnology industry” in the UK consists of writing up strategy reports and then ensuring that no one bothers to read them so they can be written over and over again

Commercial Interests for Nanoparticles in Li-Ion Batteries for Electrical Vehicles Heats Up

In the commercial world of batteries for electrical vehicles (EVs), lithium-iron-phosphate batteries are the popular approach among lithium-battery technologies because of their safety and durability.

This has already led to some disputes, developing in the last couple of years, over charge/discharge rates and intellectual property rights within the field.

As if the commercial situation were not tense enough, it now appears there is a new player in the lithium-iron-phosphate battery universe. The new start up is called Wuhe, and it is located outside of Beijing.

Wuhe was founded by Yu-Guo Guo, a professor at the Institute of Chemistry at the Chinese Academy of Sciences (CAS), and is based on work he has published in journals such as Energy and Environmental Science

According to published reports, Wuhe’s technology reduces the production costs of working with nanoscale lithium-iron-phosphate materials to the point where it could cut battery-cell manufacturing costs by 10 percent.

The reduction in production costs seems to come from the material's being easier to work with than the fine nanoscale powders of lithium-iron phosphate produced by companies such as A123 Systems. Instead Wuhe seems to use lithium-iron-phosphate nanoparticles embedded in larger particles of porous carbon, based on some of the other research published by Guo.

Guo claims that the production method costs only 10 to 20 percent more than bulk lithium-iron phosphate but produces twice as much power as the bulk material while making available twice as much energy in the lithium-iron phosphate, which results in an approximately doubled energy storage capacity. 

It does seem odd that in the reporting of this, there is no mention of how Wuhe’s nanoparticles are easier to work with than the milled nanopowder, resulting in a 10 percent reduction in production costs. But I guess that will be something of which they will have to convince their buyers. 

Carbon Nanotubes Get Functionalized Without Losing Key Characteristics

Carbon nanotubes (CNTs) possess characteristics that have tantalized researchers for decades with their extraordinary electrical conductivity.

But in many applications it hardly seemed to matter because CNTs have remained insoluble, making them impossible to disperse in a liquid for coating applications. Instead of dispersing in the liquid the CNTs would just lump together.

Researchers have known for some time that functionalizing CNTs in such a way that they don’t lump together is the way forward, but the problem has been once you functionalize CNTs for that purpose they lose their conductive and luminescent capabilities that made them so attractive in the first place.

But research out of the University of Maryland may have made a breakthrough in this area.

The researchers have found a way through wet chemistry, in a process known as Billups-Birch reductive alkylcarboxylation, to introduce a defect into CNTs that keeps them from lumping together but doesn’t prevent them from retaining their conductivity along certain parts of the CNT.

The research, which was just published in the journal Nature Communications and led by Assistant Professor Yu Huang Wang of the Department of Chemistry and Biochemistry, is targeted for battery applications and luminescent biosensors. For those interested a seven-page PDF file on the Nature research can be downloaded here

"This is important for the future use of these materials in batteries and solar cells where efficient charge collection and transport are sought," Wang explains. "These CNTs also could be used as highly sensitive biochemical sensors because of their sharp optical absorption and long-lived fluorescence in the near infrared regions where tissues are nearly optically transparent."

Interestingly the research claims to be the first wet chemistry process for producing “clustered functional groups at a controlled, constant propagation rate” with carbon nanotubes.



IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

Dexter Johnson
Madrid, Spain
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
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