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Gelatin Nanospheres Serve as Building Blocks for Tissue Regenerative Gels

Nanowerk has a spotlight piece on a joint research project between Radboud University in the Netherlands and Sichuan University in China that has developed a method for producing oppositely charged gelatin nanospheres that enable a bottom-up approach for injectable gels that can aid in tissue repair.

The research, which was initially published in the Wiley journal Advanced Materials, improves on colloidal gels that have been developed in the past that were often cytotoxic because of their high charge density.

"We have used gelatin since both positively and negatively charged gelatin is commercially available without the need to chemically modify these biopolymers" says Huanan Wang, a PhD student in the Department of Biomaterials at Radboud University Nijmegen Medical Center, in the Nanowerk piece.

As the Nanowerk piece points out, one of the key features of this research was that they demonstrated that commercially available biopolymers, like gelatin, can be used in tissue regeneration without any additional chemical modification that could potentially negatively impact its biocompatibility.

Powering Our Electronic Devices with Nanogenerators Looks More Feasible

Professor Zhong Lin Wang, Director of the Center for Nanostructure Characterization at Georgia Tech, has managed to keep the otherwise obscure subject of the piezoelectric qualities of zinc oxide nanowires continuously in the press. I myself have alluded to his work twice on this blog (here and here).

The latest mainstream media outlet to pick up on his work is the UK-based publication the Telegraph, which gets quite excited about a presentation Dr. Wang made at the ongoing National Meeting and Exposition of the American Chemical Society.

You really have to hand it to Dr. Wang to have his presentation for an ACS meeting make it into a UK daily newspaper—chapeau. This time the trick was to bring in the prospect of an iPod that could be powered by our heartbeat. When you say “iPod” in relation to any technological development you’re sure to get mainstream media attention.

I would have happily chalked this story up to one more excellent job of getting nanomaterial research into the mainstream press, but because of recent work by Eric Pop and his colleagues at the University of Illinois’s Beckman Institute in reducing the energy consumed by electronic devices it seems a bit more intriguing now.

So low is the energy consumption of the electronics proposed by the University of Illinois research it is to the point where a mobile device may not need a battery but could possibly operate on the energy generated from piezoelectric-enabled nanogenerators contained within such devices like those proposed by Wang. (Just as a point of clarification on my previous post on the University of Illinois research, I misleadingly said that Pop’s research could mean mobile devices that run on their own thermal or mechanical energy. It would have been better to say: “mobile devices that could run on the thermal or mechanical energy they harvest.” I don’t want anyone to give up on the second law or believe that I was proposing a perpetual motion machine.) 

So,  according to Wang, five nanogenerators producing energy through the straining or flexing of nanowires brought on by the mechanical energy of your heartbeat or walking  could produce “about 1 micro ampere output current at 3 volts about the same voltage generated by two regular AA batteries.”

Research on Molecular Mechanosynthesis is Progressing Slowly

I have admired Philip Moriarty since I first saw a video of a nanotechnology debate at Nottingham University taped in 2005 in which Moriarty stood up and asked some pretty pointed questions to some of the panel members who were proposing molecular nanotechnology (MNT). (The nearly two-hour video I have included below).

The tenor of Moriarty’s questions and comments are exemplified by this comment: “To date there has not been a single mechanosynthesis experiment, in that the most basic step in terms of abstracting a hydrogen atom from a diamond surface has not been done. That has to be proved in order to demonstrate the viability of the machine approach. I’ve never been able to square that with the statement that there are no showstoppers—not one experiment has been done, correct?

I’m not sure he received an answer to that question. It’s likely he was told that Freitas and Merkle had run some computer model simulations. 

But my respect for Moriarty grew when he decided that since no one felt compelled to do these experiments, he would. And he didn’t moan about how he couldn’t get funding, he made a proposal for an experiment and got it funded. Then he set about beginning the long and arduous job of setting up experiments that weren’t done solely in the forgiving world of a computer model.

So I was intrigued to see what the update was on his research and we get it an interview with Sander Olson at the blog The Next Big Future.

The upshot is that things are not progressing well with diamonds but his work with silicon is a bit more hopeful.

So we soon get the question: Are you still a skeptic? (Just a personal note on the word skeptic, it is my sincerest hope that every scientist is an unashamed skeptic. But it seems in this context the word is presented as some kind of pejorative.) Thankfully, Moriarty without hesitations acknowledges that he indeed is a skeptic.

“I believe that the concept of molecular manufacturing - of creating macroscopic objects atom by atom for any material, is flawed,” Moriarty says in the interview. “I do not believe that this technique can be scaled-up to manufacture macrosized objects for arbitrary materials.”

Moriarty takes great pains to distinguish the recent body of thought on the subject from the original proposals of Drexler.

“In “Nanosystems” Drexler makes a careful and clever choice of the type of system required for mechanosynthesis/molecular manufacturing, taking into account the key surface science issues,” Moriatry argues. “I’ve never been able to see why it is then claimed that these schemes are extendable to all other materials (or practically all elements in the periodic table), for the reasons I discussed at considerable length in my debate with Chris Phoenix.”

Moriarty even weighs in on the Smalley/Drexler polemic that occurred on the pages of Chemical & Engineering News back in 2003.  “Richard Smalley, despite raising other important criticisms of the molecular manufacturing concept, misunderstood key aspects of mechanosynthesis and put forward flawed objections to the physical chemistry underlying Drexler’s proposals.”

A good portion of the remaining part of the interview revolves around Moriarty’s work and views on AFM and SPM research and makes the entire interview worthy for a thorough read. 

But back on the MNT front it would seem that the prospect put forward by Ray Kurzweil and others that “Around 2030, we should be able to flood our brains with nanobots…” seems more than a bit optimistic if Moriarty is hoping that by 2040 “that we are 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.”

Carbon Nanotubes in Advanced Composites Enable Detection of Aircraft Defects

I have made light of some efforts to use carbon nanotubes in the filler materials for carbon fiber composites. It always struck me as more a marketing ploy than an effort to produce a carbon composite that was significantly stronger than typical varieties.

But researchers at MIT may have devised an additional way to have it make sense to include carbon nanotubes in these composites by developing a simple, hand-held device capable of detecting internal damage to composites…just as long as the composite contains carbon nanotubes.

Brian L. Wardle, associate professor of aeronautics and astronautics at MIT, along with his colleagues have developed a solution that requires only a small current be applied to the material of the aircraft that quickly heats up the carbon nanotubes and allows the use of thermographic camera for detecting flaws without the cumbersome need for heating the entire surface of the aircraft.

"It's a very clever way to utilize the properties of carbon nanotubes to deliver that thermal energy, from the inside out," says Douglas Adams, associate professor of mechanical engineering at Purdue University, in an MIT press release.

The research, which was initially published in the March 22nd online edition of the UK’s Institute of Physics journal Nanotechnology, depends on carbon nanotubes being included in the material matrix in order for it to work.

This could be a way in which carbon nanotubes will become more widely used in these advanced composites. It allows for a much cheaper inspection method than is currently available, which alone could offset the extra costs of use CNTs in the fillers for these materials.

It certainly should benefit one of the main aims of Wardle’s work, which is “to improve the performance of advanced aerospace materials/structures through strategic use of carbon nanotubes (CNTs).” 

While the US Air Force and Navy are reportedly interested in the technology, it will be interesting to see if commercial aircraft become involved. It seems now CNTs are no longer only selling their strength in composites but their ability to cheapen inspection.

3D Nanostructure for Cathodes in Batteries Could Mean Cell Phones that Charge in Seconds

No sooner do I discuss University of Illinois researchers who have created 3D antennas for mobile phones using nanotechnology than another group of researchers at the University of Illinois (this time at Urbana-Champaign) have developed 3D material for batteries that combines the qualities of supercapacitors with those of batteries and could change the entire battery paradigm. 

Professor Paul Braun and his colleagues just published in the March 20th edition of the journal Nature Nanotechnology their results that showed ultra fast charge and discharge rates by “using cathodes made from a self-assembled three-dimensional bicontinuous nanoarchitecture consisting of an electrolytically active material sandwiched between rapid ion and electron transport pathways.”

What this could mean, according to the excited science and technology press, are electric cars that could be charged in five minutes, a laptop in just a couple of minutes and a cell phone in seconds.

While thin film technology has allowed faster charging capabilities than seen in your typical li-ion batteries but it can’t store the energy well, meaning that a mobile device would run out of power in mere seconds.

What Braun and his team have done essentially is to take the thin film technology but built it up through self-assembly into a three-dimensional structure thereby increasing its surface area and its ability to store energy.

The actual structure apparently resembles a lattice of tightly packed spheres. Metal is used to fill in the spaces around the spheres and then it is all melted leaving a 3D scaffold that appears like a sponge. Then the structure is electropolished that increases the size of the pores.

The result is that lithium ions can move rapidly through the material with a high electrical conductivity.

According to Braun this could revolutionize the battery. "We like that it's very universal,” Braun is quoted as saying in a number of articles covering the report. “This is not linked to one very specific kind of battery, but rather it's a new paradigm in thinking about a battery in three dimensions for enhancing properties."

Nanoparticles Enable 3D Printing for Cell Phone Antennas

After nanotechnology manages to develop a solution for mobile devices so that they don’t need to be charged every day, I would like if nanotech could lead to a solution for the dropped call.

Mobile phones where the batteries run down in a few hours are really annoying but I think dropped calls from bad reception runs a close second in my annoyance scale.

I may not have to wait that long if research at the University of Illinois in making a 3D antenna for mobile phones can successfully make it commercially available cell phones.

The research, which was initially published in the Wiley journal Advanced Materials, employed an ink jet printing method that used silver nanoparticles and were sprayed on the inside or the ourside of a small hemispherical dome.

“To our knowledge, this is the first demonstration of 3D printed antennas on curvilinear surfaces,” Jennifer A. Lewis, the Hans Thurnauer Professor of Materials Science and Engineering and director of the Frederick Seitz Materials Research Laboratory at Illinois is quoted as saying in the University press release. “Omnidirectional printing of metallic nanoparticle inks offers an attractive alternative for meeting the demanding form factors of 3D electrically small antennas (ESAs).”

The functionality of antennas for mobile phones has not fared well in the overall miniaturization of the gadgets with characteristics such as gain, efficiency, bandwidth, and range all suffering.

According Jennifer T. Bernhard, a professor of electrical and computer engineering at Illinois, the 3D antennas that the research team has developed are an order of magnitude better in performance metrics than the typical monopole designs.

“There has been a long-standing problem of minimizing the ratio of energy stored to energy radiated—the Q—of an ESA,” Bernhard explains in the article. “By printing directly on the hemispherical substrate, we have a highly versatile single-mode antenna with a Q that very closely approaches the fundamental limit dictated by physics (known as the Chu limit).”

The researchers claim that this design can be quickly adapted to conform to different specifications, such as operating frequencies, device sizes or encapsulated designs. 

Phones that can last a month on a charge or don’t even need a battery because they can run own their own mechanical energy and no more dropped calls…mobile phones are beginning to sound a lot more attractive.

Nanomaterial Offers New Heat Management for Advanced Electronics

Researchers at GE Global Research under a DARPA contract have announced a new thermal material system for dissipating heat in advanced electronics that is far more effective than traditional copper.

According to the Dr. Tao Deng, the lead researcher on the project at GE, the new material is a phase-change material that was used in a prototype as a substrate for a chip.

With the all the work that is currently being done in the development of novel nanoscale materials for heat management of electronics (see, here and here) it seems that GE has set aside electronics for aviation as a market they are targeting with this technology.

In Dr. Teng’s blog discussing the technology a good deal of the description is devoted to how it performs in high gravity environments.

"In demonstrations, the prototype system has functioned effectively in a variety of electronics and application environments. We also subjected it to harsh conditions during testing and found it could successfully operate in extremely high gravity applications. More specifically, the prototype has operated in conditions that simulate more than 10 times the normal force of gravity! By comparison, this gravity force is more than four times greater than what someone would experience on the Mission Space ride at Disney."

I don’t recall any other new materials that were intended for heat management in computer chips spending so much time highlighting their functionality in high G’s without mentioning much in the way how much better their heat management is.

This preoccupation along with the DARPA contract leads me to suspect that we will likely see this in aerospace before we see in laptops. 

 

Report on Potential Risks of Nanotechnology in Electronics Needs a Second Draft

I have encountered both hopeless ideologues and blinded cheerleaders on either side of the nanotechnology and toxicity debate, and in my experience it is the environmentalists who are just unreachable.

Like Pavlovian Dogs, they see the term “nanotechnology” and bark back “What about the environment?”. They don’t really discern between microscopy tools and nanoparticles, never mind delineate among the vast amount of different nanoparticles. They just know that nanotechnology is untested and being foisted upon them as unsuspecting consumers by some evil industry.

At least with the nanotech cheerleaders you can temper their enthusiasm if you explain the situation a little bit. After all greed has as its close relative fear, but ideology’s closest kin is ignorance. There is a little you can do to overcome that, certainly the force of argument doesn’t help.

In both observing this debate and covering the issue, I have not come across any organization that has presented more faulty thinking on the subject than the Silicon Valley Toxics Coalition (SVTC).

So egregious is their thinking in these matters that I am torn between believing that it must be a deliberate misrepresentation of the issues or they just don’t know or understand them. The latest insult to our collective intelligence is their white paper entitled “Nanotechnology in Electronics: The Risk to Human Health”.

Let’s take a look at it. It starts out with a definition of nanotechnology in the first sentence that is not too bad as these definitions go. But in the next sentence manages to confuse the concept of molecular nanotechnology with the nanomaterials variety that they are no doubt railing against. This is just an introduction to the confused thinking we find further.

For instance, in the second page we are provided a glossary. At the top of the list, I guess because the list is alphabetical, are “brominated flame retardants” (BFRs). Okay, but why? What does this have to with nanotechnology or nanoparticles? In fact, if anything, it demonstrates why we should hardly be concerned about nanoparticles in electronics when 2.5 million tons of BFRs are used annually in polymers.

After presenting BFRs and explaining they have been shown to be detrimental to both human and environmental health, we are given “engineered nanoparrticles” next in the glossary. A somewhat facile definition is provided “ENPs are so small they cannot be seen with a regular light microscope” but no detrimental effects are attributed to them, except, of course, that it is listed right under BFRs. Guilt by association? I am beginning to lean towards deliberate misrepresentation.

On the same page, we get the question “How Small is Small?” (Poorly informed pieces such as these spend a lot of time providing definitions, no doubt because of the author’s need for them). And for the first time, we get the term that is supposed to connote the Evil Empire: The Nanotechnology Industry. I challenge anyone, including misguided environmentalists, to tell me what the nanotechnology industry is, or is supposed to be.

Of course, having a monolithic nanotechnology industry planning to do us harm for profit is a lot more satisfying and can produce amusing banners that say stuff like this: “Nano, it’s not green, it’s totalitarian”. Sigh.

Next in the SVTC report we get the questions of why nanoparticles are important and why they would be used in electronics. The answers are more or less accurate, but it’s not clear why the use of nano lithium iron oxide in rechargeable batteries is presented so ominously when it is explained that they may replace conventional batteries in laptops and cell phones.

Are conventional batteries, filled as they are with all sorts of toxic materials, any less of a threat? Or maybe the SVTC wants to eliminate laptops and cell phones all together? I ask this because when I recently suggested that nanotech research might eliminate the need for batteries in cell phones, I was met with the Pavlovian response: What about the environment?

Just as a note to the SVTC the next time you put one of these together you should know that a majority of today’s Li-ion batteries already use nanofibers.

Finally, by the fifth page we get an answer to the question: How is nanotechnology used in electronics? And who is their source for an answer to this question: The Project on Emerging Technology (PET). Now I almost feel sorry for the SVTC, bad data in bad data out.

Since the PET list offers little explanation of their, shall we say, less than rigorous nanotech product list, the SVTC doesn’t present any specific examples of how nanotechnology is used in electronics either. We are just told that it is found in nearly every form of consumer electronics. You can claim that, but can you show it?

Just to add insult to injury they present “molecular” electronics. Really? Again, this is just poorly informed. Why add molecular electronics to your list of boogey men unless you had no idea of how it really fit into the universe of nanotechnology and electronics. I am leaning back towards not knowing or understanding.

Look, I am in favor of the most rigorous research into determining the risks of nanoparticles in electronics and a host of other applications and products. But if I may take the exhortation at the end of this report and turn it around it somewhat: Be an informed environmentalist. 

Nanotech Research into Improving Cladding of Nuclear Fuel Rods

Last July, Dr. Hongbing Lu, a nanomaterials expert and researcher at the University of Texas at Dallas, received nearly $900,000 from the US Department of Energy (DoE) to begin to look at how it may be possible to improve the materials used for cladding nuclear fuel rods

At the time of the announcement, it seemed the main benefit to come from the research would be a reduction in fuel burn rate and increasing efficiency of nuclear power plants. But now with the unfolding nuclear disaster in Japan one can’t help but wonder if improving the cladding materials of the nuclear rods might have helped avoid leakage when the rods were temporarily exposed.

Lu was planning to first investigate how cracks propagate in the materials and then ultimately to start looking at various materials that could avoid this kind of cracking.

“We’re working on a very general simulation methodology that can be applied to that kind of environment,” Lu said. “It’s more than just crack growth. We need to understand how the material behaves under extreme pressure, temperature, corrosion and irradiation. With the methodology we’re using, we’re taking all of those factors into consideration and incorporating material behaviors into some mathematical models to describe them under very complicated conditions.”

At the time of the article announcing the DoE research grant, Lu expected that the materials research they were conducting would not only be beneficial for the materials cladding the nuclear fuel rods but also for other parts of a nuclear power plant.

Nanotechnology Could Make Batteries in Mobile Devices Obsolete

Beyond making mobile phones and other mobile devices flexible enough to wrap around your wrist, I have been a strong proponent of efforts to improve the battery life of these mobile gadgets

There have been a number of announcements recently reporting on work that improves the li-ion batteries used in mobile phones, or efforts to reduce the amount of energy used by these devices through the use of steep-slope transistors and thereby lengthen the battery life.

It is in this latter area of  seeking to lower power consumption in these devices that  we have our latest breakthrough to extend the battery life of mobile phone from hours to weeks.

Researchers from the University of Illinois’s Beckman Institute for Advanced Science and Technology, led by electrical and computer engineering professor Eric Pop, have reported in Science that they have used carbon nanotubes to control bits and lower power switching in phase change materials (PCM).

Just as a bit of background on PCM, one of the major commercial initiatives with the material in memory applications was the joint venture between Intel and STMicroelectronics with their Swiss-based Numonyx, which Micron Technologies acquired last year. PCM compares quite favorably with NOR-type flash, memory NAND-type flash memory, and RAM or EEpROM. Cost is still high compared to DRAM and read speed is not as good as DRAM, but unlike it DRAM it is non-volatile. You can read more about PCM memory here.

But what the researchers recognized was that one of the drawbacks with PCM memory was that high programming currents have made it difficult to realize low power operation. The researchers overcame this drawback by replacing metal wires with carbon nanotubes.

In a press release prepared by the University of Illinois, graduate student Feng Xiong, the first author of the paper, explains, “The energy consumption is essentially scaled with the volume of the memory bit,” says Xiong. “By using nanoscale contacts, we are able to achieve much smaller power consumption.”

The way the system works is that bits are created by putting a small amount of PCM in the a nanoscale gap located in the middle of a carbon nanotube and then by applying just small currents to the nanotube they can switch the tube on and off.

According to the abstract in Science, the researchers were able to achieve “programming currents as low as 0.5 μA (SET) and 5 μA (RESET), two orders of magnitude lower than state-of-the-art devices.”

What this may translate to for your mobile phone is that a smart phone will consume so little energy that it may not even need a battery but could run on its own thermal or mechanical energy. (Battery manufacturers are not going to like that part).

“I think anyone who is dealing with a lot of chargers and plugging things in every night can relate to wanting a cell phone or laptop whose batteries can last for weeks or months,” Pop is quoted as saying in the University of Illinois press release.

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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.

 
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Dexter Johnson
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