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New Microscopy Technique Could Reveal Mechanisms of Cancer

Typically when asked about the role of nanotechnology in treating cancer, people refer to nanoparticle-based drug delivery systems (DDS) that target cancer cells. While these DDS treatments certainly add a new weapon to the arsenal used in the killing of cancer cells, they are still, as George Whitesides has said, our cells. So, killing cancer cells with more targeted poisons remains somewhat problematic.

In some ways a more hopeful, albeit a less immediate, method of addressing cancer with nanotechnology, is the use of microscopy tools for both early detection and unraveling the mechanisms by which cancer develops in us.

It is in the latter case that Nongjian (N.J.) Tao and his fellow researchers at the Biodesign Institute at Arizona State University have developed a method for improving the spatial information to the microscopy technique known as electrochemical impedance spectroscopy (EIS).

The work that went into developing this technique was published in the journal Nature ChemistryIt seems the researchers have created a hybrid technique that combines EIS with a technique based on surface plasmon resonance (SPR).

The hybrid technique is being dubbed electrochemical impedance microscopy (EIM) and differs from traditional EIS in that it does not measure current but instead employs the plasmon resonance to show the changes in impedance optically.

This development means that it is now “possible to study individual cells, but also resolve subcellular structures and processes without labels, and with excellent detection sensitivity (~2 pS).”

What these characteristics of the new technique enable is made clear in the video below in which researchers at Arizona State University now have the tools they need to look at the chemical modifications of the proteins that wrap up DNA up to control gene expression.

“Lots of people have gene defects that could lead to cancer but few actually get cancer,” explains Dr. Stuart Lindsay, Director, Center for Single Molecule Biophysics, at the Biodesign Institute at ASU. “Cancer is not a disease based on gene defects per se, but rather based on the chemical factors that control gene expression and those are the factors that we want to probe.”

 

When a Two-Percent Solution Equals $22 million, Nanotechnology Matters

I have argued in the past that when it comes to nanotechnology and energy, it’s the mundane that’s interesting

Case in point, the UK-based airline EasyJet has just announced that they are embarking on a 12-month test of a new nanocoating that when applied to the exterior of their planes could reduce fuel consumption by as much as 2%.

 

When your annual fuel bill is £730m (nearly US$1.2 billion), then that 2% can mean a savings of £14m (approximately US$22.4 million). Suddenly a coating becomes interesting, doesn’t it?

Apparently the coating has been used on US military aircraft for some time but this will mark the first time the coating has been used on a commercial aircraft.

After coating an entire aircraft it only adds 4oz (113g) to the total weight of the plane, which, when compared to the 80kg (176 pounds) that regular paint adds to the weight of a plane, gives you an indication of how thin this nanocoating is.

The nanocoating basically fills in all the pits and crevices that exist within the paint on a microscopic scale, which ensures that no debris or dirt builds on the surface.

I don’t know who has developed the nanostructured coating but in the UK the company applying it the EasyJet aircraft is a company called TripleO. To get the coating to work, TripleO performs what they call a “polarizing wash” in which the surface of the aircraft is given a charge of positive polarity so when the polymer-based nanocoating is applied it will bond to the existing paint surface.

Initially, EasyJet is trying this out with eight planes, and if the cut in fuel costs are what they expecting then they will go ahead and coating the other rest of 200-plane fleet.

If this catches on with the entire commercial airline industry, then cuts in fuel consumption would be dramatic along with similar reductions in carbon emissions. You see, you don’t have to create a super efficient solar cell to make an impact in energy applications with nanotechnology.

For First Time Nanowires Create Programmable Logic

The typical refrain you hear when some introduces a new transistor design or material goes something like: “Let me know when you make a simple logic circuit.”

Okay, researchers at Harvard University, led by Charles Lieber, would like to let you know that they have used nanowires to create for the first time programmable logic “tiles”. The researchers dubbed the term “tiles” with the idea that each tile, which would have up to eight distinct logic gates, could be connected to other tiles to execute more complex logic functions.

An article here on the pages of Spectrum online has more on this breakthrough and the background research developments that led to it.

Just a personal note to this thorough article and the research, I have often gone back to an article penned by Professor Lieber back in 2007 for Scientific American entitled The Incredible Shrinking Circuit to inform my understanding of nanowire research, so I am always intrigued to see what he and his team are doing in this field.

While Lieber concedes that these nanowire-based logic tiles will not replace CMOS, since the transistors operate at comparatively slow speeds of only 10 to 100 megahertz, their high density and low power consumption could make them attractive for a “controller for some microelectromechanical device.”

Application possibilities are intriguing, but what is most appealing about this breakthrough to me is that it seems to be a major step in the process of leading us further down the road of the incredible shrinking circuit.

Risk and Opportunities of Nanotechnology

I have to confess to not always understanding the point of some forums or who the attended audience is supposed to be.

Such is the case for a webcast that ran live on Tuesday of this week (which has now been archived and you can access on the page I linked to here).

It has a distinguished panel, a noted moderator and a lively discussion for 50 minutes or so. But for what and for whom is this intended dare I ask?

It was put on by the University of Michigan Risk Research Center, which the moderator, Andrew Maynard, took the helm of late last year. And it has a clever title “Nanotechnology—Unplugged” that was somewhat unfortunate in that it left me wondering who thought that it was a good idea to plug it all into the Internet.

It’s not forming the basis of any regulatory framework, it’s not educating legislators or regulators as to the issues they face when tackling nanotechnology, it doesn’t present the kind of information that researchers, engineers and scientists might find beneficial to do their work and I think you could hardly call it a public engagement exercise—thank goodness for that.

So, the point of this webcast other than entertaining a handful of people eludes me. But alas, that’s not that important. Let’s take a look at the content.

We get a chemist who gives us the required definition of nanotech and its scale, we get a toxicologist who provides some science for looking at the risks of nanotechnology and a social scientist who is eager to have us take into account the instincts of the uninformed when approaching emerging technologies.

To me there were a few key exchanges. One that had my jaw drop and I already alluded to was when the social scientist said something to the effect: You don’t have to have an understanding of science to have instincts about a particular technology that are valuable in a few ways.

These ways amounted to market research for producers to avoid pitfalls and take advantage of unknown markets. Okay, but couldn’t I just ignore them and figure that out myself?

As the video below demonstrates, people’s instincts on science, especially when they are—shall we say—poorly informed, are really best avoided.

Then the toxicologist kind of made all the concern over nanotechnology, versus say just about any other toxic chemical that we use in our everyday lives, a little silly: There’s no connection yet between quantum mechanical properties of a material and toxicity.

Uh oh…somebody just spoiled the party. We were going to bring in Auntie Alice to ask about her instincts on the use of graphene versus molybdenite for gate materials, but it looks we might want to wait.

Nano-ink Research Gives New Life to Painted-on Solar Power Conversion

The perpetual balancing act between cost and efficiency that seems inherent in photovoltaics marches on.

We see this exhibited in among other things the “Photovoltaic Moore’s Law”, which is based on ever decreasing price points rather than the ever increasing number of transistors per unit of a chip—lowering price rather than heightening technology. But efficiencies still need to be improved for photovoltaics. So how do you improve the efficiency of a photovoltaic for turning sunlight into electricity when you’re overriding concern is to make the whole thing cheaper?

Recently, when it was argued that Multiexciton Generation, a process by which several charge carriers (electrons and holes) are generated from one photon, might not be as promising an avenue as had been hoped, the possibilities for thin film solar cells becoming more efficient took a fairly serious blow.

So, maybe the way to go is one that was presented to me in the comments to the blog entry cited at the top of this one: “When it comes to improving market penetration for solar power (which, after all, is what we are concerned with if we want to reduce fossil fuel use), you can't beat McDonalds for a business model. Make 'em cheap, make 'em fast, make 'em consistent, and have 'em ready when I'm hungry.”

Along these lines, researchers at the University of Texas have conducted research into using nanoparticle inks that would replace the standard solar cell manufacturing process. 

 

The research, which was originally published in the ACS journal The Journal of Physical Chemistry, could usher in that long-promised application of painting solar power onto a building.

However, at present spray-on nanoparticle inks for solar power are only 1% efficient. This will need to be improved, according to Brian Korgel, one of the researchers at the University of Texas.

“If we get to 10 percent, then there’s real potential for commercialization,” Korgel said. “If it works, I think you could see it being used in three to five years.”

It also appears that commercialization is at the forefront of the University of Texas’ plans as a partnership with Konarka Technologies was announced in January.

While three to five years may sound reasonable to a researcher who believes in their work, maybe the folks at Konarka can educate that researcher into the difficulties of getting a product to market no matter how promising the technology and the particularly difficult road for organic photovoltaics.

Nanosheets of Layered Materials Are Not Just for Graphite Anymore

In 2004, when researchers Andre Geim and Konstantin Novoselov devised a way to separate out a one-atom-thick sheet from graphite to create “graphene” they unleashed a tidal way of research into what this new wonder material could do when its charged-carrier mobility was used in various electronics applications.

But why just marvel at what graphite could do when separated out into a one-atom-thick sheet? Surely if you could do this with other materials, unexpected capabilities could be realized?

At least that’s what Professor Jonathan Coleman of Trinity College Dublin and Dr. Valeria Nicolosi  of Oxford University’s Department of Materials must have been thinking when they embarked on developing a technique that could separate a variety of materials into one-atom-thick sheets, and do it on an industrial scale.

“Because of its extraordinary electronic properties graphene has been getting all the attention, including a recent Nobel Prize, as physicists hope that it might, one day, compete with silicon in electronics,” said Dr Nicolosi in an article  from Oxford’s media. “But in fact there are hundreds of other layered materials that could enable us to create powerful new technologies.”

The researchers published their findings in the 4 February edition of the journal Science. From the press reports, it seems the researchers developed a method to separate a variety of materials out into these two-dimensional nanosheets that uses something akin to the ultrasonic pulses used to clean jewelry.

When you can do this for a variety of materials and do it on an industrial scale, you would seemingly be opening up a potential treasure trove of application possibilities. And so it would seem from the quote of Professor Coleman: “'These novel materials have chemical and electronic properties which are well suited for applications in new electronic devices, super-strong composite materials and energy generation and storage. In particular, this research represents a major breakthrough towards the development of efficient thermoelectric materials.”

It’s not that scientists and researchers had not considered that nanosheets like this from a variety of different materials would possess uniquely attractive capabilities, but nobody was able to create them by a method that was fast, cheap and rendered a workable final material.

“Our new method offers low-costs, a very high yield and a very large throughput: within a couple of hours, and with just 1 mg of material, billions and billions of one-atom-thick graphene-like nanosheets can be made at the same time from a  wide variety of exotic layered materials,” said Dr Nicolosi.

Graphene or Molybdenite? Which Replaces Silicon in the Transistor of the Future?

Graphene is winning fans, awards and application possibilities seemingly daily. But the elephant in the room, if you will, when discussing graphene, is the problem of it lacking a band gap.

Huge strides have been made in overcoming that shortcoming, but let’s just say that not having a band gap in its nature is more than a small liability for graphene in electronic applications.

Into this mix, researchers at Ecole Polytechnique Federale de Lausanne’s (EPFL) Laboratory of Nanoscale Electronics and Structures (LANES) had their research published this week in the journal Nature Nanotechnology that offers the humble and abundant mineral molybdenite (MoS2) as an attractive alternative to silicon as a two-dimensional material (like graphene is) for replacing the three-dimensional silicon in transistors.

"It's a two-dimensional material, very thin and easy to use in nanotechnology. It has real potential in the fabrication of very small transistors, light-emitting diodes (LEDs) and solar cells," says EPFL Professor Andras Kis in an article that reports on the research.

The big advantage it has over graphene in the search for a replacement to silicon: it has a band gap. And when it comes to being better than silicon, the advantages are impressive.

"In a 0.65-nanometer-thick sheet of MoS2, the electrons can move around as easily as in a 2-nanometer-thick sheet of silicon," explains Kis. "But it's not currently possible to fabricate a sheet of silicon as thin as a monolayer sheet of MoS2."

The researchers also report that transistors made from molybdenite will use 100,000 times less energy in a standby state than traditional silicon transistors.

As explained in the Nature abstract, molybdenite does not have to stand in competition with graphene, but could complement graphene “in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.”

Two Good Gate Materials That Are Great Together

Okay, I couldn’t help myself. When I saw this story in which researchers at Georgia Tech had developed a top-gate organic field-effect transistor for plastic electronics that used a bilayer gate dielectric, I thought of those old Reese’s Peanut Butter Cup commercials: “Two great tastes that taste great together.”

“Rather than using a single dielectric material, as many have done in the past, we developed a bilayer gate dielectric,” said Bernard Kippelen, director of the Center for Organic Photonics and Electronics and professor in Georgia Tech’s School of Electrical and Computer Engineering.

The bilayer gate consists of a fluorinated polymer known as CYTOP and a high-k metal-oxide layer created by atomic layer deposition.

As noted in the Georgia Tech press release: “CYTOP is known to form few defects at the interface of the organic semiconductor, but it also has a very low dielectric constant, which requires an increase in drive voltage. The high-k metal-oxide uses low voltage, but doesn’t have good stability because of a high number of defects on the interface.”

So, in a sort of ‘let’s give it a shot’ spirit, the researchers wondered if they combined the two materials whether they would cancel out each other’s drawbacks. Answer: Yes.

“When we started to do the test experiments, the results were stunning. We were expecting good stability, but not to the point of having no degradation in mobility for more than a year,” said Kippelen.

“By having the bilayer gate insulator we have two different degradation mechanisms that happen at the same time, but the effects are such that they compensate for one another,” explains Kippelen.  “So if you use one it leads to a decrease of the current, if you use the other it leads to a shift of the threshold voltage and over time to an increase of the current. But if you combine them, their effects cancel out.”

The results have even surpassed the researchers’ expectations. “I had always questioned the concept of having air-stable field-effect transistors, because I thought you would always have to combine the transistors with some barrier coating to protect them from oxygen and moisture. We’ve proven ourselves wrong through this work,” said Kippelen.

While the applications for the transistor run the gamut of plastic electronics, including smart bandages, RFID tags, plastic solar cells, light emitters for smart cards, the transistors have only been demonstrated to date on glass substrates.

After seeing if they can get the transistors to work on plastic substrates, they will look into whether they can manufacture them with ink jet printing.

Nanotechnology and the State of the Union Address

Earlier this week in the President’s State of the Union Address, a 16-year-old girl by the name Amy Chyao accompanied the First Lady at her seat.

No doubt Ms. Chyao’s presence was a bit of stage craft to underscore the future of America’s ingenuity and innovation because Ms. Chyao, who is still a high school junior, managed to synthesize a nanoparticle that when exposed to infrared light even when it is inside the body can be triggered like a bomb to kill cancer cells. Ms. Chyao performed her research and synthesis in the lab of Kenneth J. Balkus, Jr., a chemistry professor at the University of Texas at Dallas.

This is a remarkable achievement and even more so from someone still so young, so we would have to agree with Prof. Balkus’ assessment that “At some point in her future, she’ll be a star.”

However, Chyao was given to us as a shining example of the US potential for innovation, and, as a result, its competitiveness. So beyond stage craft, what is the assessment of innovation for the US in a time of emerging technologies such as nanotechnology?

As President Obama attempts to rally the nation with “This is our Sputnik moment”, Andrew Maynard over on his 20/20 blog tries to work out what innovation means in our current context as compared to what it meant 50 years ago at the dawn of the space race.

The problems we now face as Maynard points “are increasingly complex technologies and a vastly more interconnected  world” that have forever changed “the dynamic between having a good idea and coming up with a sustainable solution.”

According to Maynard, technology innovation has to be re-examined so at least we have the tools, institutions and understanding of how to do it effectively and efficiently in this new context.

Maynard and Tim Harper of Cientifica published a paper last week on this topic through World Economic Forum entitled Building a Sustainable Future: Rethinking the Role of Technology Innovation in an Increasingly Interdependent, Complex and Resource-constrained World

I have touched on the themes of the paper previously here on this blog when the two authors were first arguing their idea at The Summit of the Global Agenda at the annual World Economic Forum Meeting in Dubai back in 2009.

The ideas struck me then, and have increased since, as being the kind of ideas that you stop and ask yourself: “Why didn’t I think of that?”

In other words, they’re the kind of ideas that will meet more than their fair share of resistance for the simple reason that many will believe that if they didn’t actually think of it themselves, they should have.

For me, the key issue Harper and Maynard address is that we all acknowledge that we have some major issues that we need to address (energy, food, water) and often technology is held out as some kind of savior in solving them. But we allow the technology that we need to be held up by the vagaries of the markets and the profits and interests of a handful of people. Maybe we should examine establishing a framework by which it is more likely that the technologies we need are developed rather than just those that might best turn a profit. 

While maintaining the status quo may temporarily lead us to greater competitiveness, it will hardly matter if we can’t find some way to ensure that the technologies we need get developed just as vigorously and swiftly as those that promise the biggest profit margins.

Electron Multiplication for Thin Film Solar Gets Some Skeptics

I have been very reluctant to get on the bandwagon that nanotechnology offered us any clear, never mind easy, solutions to getting solar power to be more efficient in generating electricity.

But I am always willing to consider the possibility that nanotechnology holds the key to making cheap and highly efficient solar power. One of the nano-related alternatives I discussed was the use of quantum dots for either electron multiplication or creating so-called “hot-carrier” cells.

As I had explained previously, “Electron multiplication involves making multiple electron-hole pairs for each incoming photon while with hot carrier cells the extra energy supplied by a photon that is usually lost as heat is exploited to make in higher-energy electrons which in turn leads to a higher voltage.”

The concept of electron multiplication has been a line of research vigorously pursued since 2004 when it was first proposed. In my blog on the subject, I highlighted research coming from the University of Minnesota and Texas that had investigated further the possibility of creating multiple charge carriers from one photon.

But Eran Rabani, a researcher at Tel Aviv University, was not so convinced by the research on electron multiplication.

"Our theory shows that current predictions to increase efficiencies won't work,” Rabani is quoted as saying in the linked article above. “The increase in efficiencies cannot be achieved yet through Multiexciton Generation, a process by which several charge carriers (electrons and holes) are generated from one photon."

Rabani has published two articles on his research, one is in the journal Chemical Physical Letters and the other in Nano Letters

While Rabani seems to be dismissing this line of research and the possibility that more than one electron pair can be generated from one photon, he believes that by eliminating this line of research it will open up other research directions that are more promising for solar technology.

However, it’s not clear that this has permanently closed the door on Multiexciton Generation as Rabani quote seems to indicate: “The increase in efficiencies cannot be achieved YET through Multiexciton Generation.”

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Nanoclast

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

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