There is widespread agreement that the successful development and use of nanotechnology depends on showing that nanotech materials are safe—for human health and for the environment. A new study will trace the movement of nanoparticles through the environment and determine their impact on health and natural systems. A particular focus is to find out what alterations fullerenes might undergo as a consequence of interactions with microbes in the environment. From Rice University, via AAAS EurekAlert “NSF-funded Rice study will trace path of nanomaterials“:

Researchers want to know if particles can be transported through food chain

Working to ensure the safe use of nanomaterials is the basis of a new Rice study funded by the National Science Foundation.

Led by Pedro Alvarez, the George R. Brown Professor and chair of the Civil and Environmental Engineering Department, and Vicki Colvin, the Pitzer-Schlumberger Professor of Chemistry and director of the Center for Biological and Environmental Nanotechnology, the study will trace tagged nanoparticles to increase understanding of how they move through the environment and what impact they may have on the health and function of natural systems.

With industrial-scale production of materials that use nanoparticles on the near horizon, Alvarez said now is the time to address concerns over their safety.

“Nanotechnology offers tremendous potential to enhance our quality of life, from improving the performance of commercial products, to enhanced diagnosis and treatment of disease, to refining water and cleaning up the environment,” he said.

Nanotechnology, said Alvarez, “is full of initially promising qualities, but you have to consider the potential for environmental damage. For example, look at DDT. Hans Mueller won the Nobel Prize in 1948 for using DDT to fight malaria, but now we know the environmental damage impact.”

He said the study will take a proactive approach to the potential dangers of nanoparticles, a subject that has found its way into the popular press in recent years. “When you have an increase in the production of nanomaterials, I can assure you some will enter the environment through waste or the manufacturing process. We’re focusing on fullerenes, and this grant is aimed at trying to understand their impact.”

…”There are many critical gaps in determining how dangerous nanomaterial is,” he said. “So our strategy is to inform safety by design, safe disposal, and safe manufacturing and handling.”

—Jim

Nanotech researchers continue to find novel nanostructures with promising applications. A web of single-crystalline titanium disilicide absorbs light efficiently and may be a useful catalyst to split water to furnish hydrogen for fuel. From Boston College, via AAAS EurekAlert “Scientists grow ‘nanonets’ able to snare added energy transfer“:

Using two abundant and relatively inexpensive elements, Boston College chemists have produced nanonets, a flexible webbing of nano-scale wires that multiplies surface area critical to improving the performance of the wires in electronics and energy applications.

Researchers grew wires from titanium and silicon into a two-dimensional network of branches that resemble flat, rectangular netting, Assistant Professor of Chemistry Professor Dunwei Wang and his team report in the international edition of the German Chemical Society journal Angewandte Chemie [citation].

By creating nanonets, the team conquered a longstanding engineering challenge in nanotechnology: creating a material that is extremely thin yet maintains its complexity, a structural design large or long enough to efficiently transfer an electrical charge.

“We wanted to create a nano structure unlike any other with a relatively large surface area,” said Wang. “The goal was to increase surface area and maintain the structural integrity of the material without sacrificing surface area and thereby improving performance.”

—Jim

In experiments in cell culture and in mice, adding the ability to target nanotech cancer therapy to the mitochondria within cancer cells renders the treatment more effective. One of the drugs made more effective may help to overcome the multiple drug resistance that develops in many tumors. From Nanowerk News “Targeting nanoparticles to specific locations inside cancer cells increases kills“:

The ability to target nanoparticles to specific types of cancer cells is one of the main reasons that nanoparticles have gained favor as a promising drug delivery vehicle. By increasing the amount of an anticancer agent that gets to tumor cells, as opposed to healthy cells, researchers hope to minimize the potential side effects of therapy while maximizing therapeutic response. Now, a team of investigators at Northeastern University has taken this approach one step farther by targeting the specific location inside a tumor cell, where the drug ceramide exerts its cell-killing activity.

Reporting its work in the journal Nano Letters (”Organelle-targeted nanocarriers: specific delivery of liposomal ceramide to mitochondria enhances its cytotoxicity in vitro and in vivo“), a team of investigators led by Volkmar Weissig, Ph.D., who has since moved to the Midwestern University College of Pharmacy in Glendale, AZ, developed a lipid-based nanoparticle and decorated its surface with a molecule known as triphenylphosphonium cation, which is known to be taken up specifically by mitochondria, the cell’s energy-producing organelles. The investigators then loaded this nanoparticle with ceramide, a drug that forms holes in the mitochondrial membrane, which in turn triggers cell death by a process known as apoptosis. Ceramide also has been shown to work in concert with other anticancer agents to overcome the multiple drug resistance that develops in many tumors.

…When administered to tumor-bearing mice, the investigators found that ceramide-loaded, targeted nanoparticles had a significant impact on reducing the tumor growth rate.

The usefulness of targeting mitochondria in cancer cells, although promising in these experiments, may (or may not) ultimately be limited by an effect discovered by Nobel laureate Otto Warburg more than 80 years ago. He observed that most cancer cells differ from ordinary cells in that they produce energy by a process called glycolysis rather than by oxidation in mitochondria so they are less dependent than are ordinary cells on mitochondrial function.
—Jim

Characterization of graphene continues to reveal unusual properties that recommend it as a material for nanotech applications. Add to graphene’s record-breaking strength the discovery that graphene beams are unexpectedly stiff. From nanotechweb.org, written by Belle Dumé (requires free registration) “Graphene flakes stiffen up“:

Researchers have succeeded in making large sheets of graphene that measure up to 0.1 mm across and have found that the material is extraordinarily rigid, being able to support a thousand times its own weight. This means that the material could be incorporated into different technologies, such as micromechanical systems, and is ideal for use in electron microscopy.

Until recently, scientists thought that graphene — a one-atom thick material — was weak and flexible and would spontaneously roll or fold up into nanotube-like structures. Tim Booth and Peter Blake of Manchester University in the UK and colleagues have now shown that suspended graphene sheets can easily support their own weight and the weight of objects attached to them, without bending.

“Seeing the graphene sticking out without any support surprised us all,” Booth told nanotechweb.org, “even more so that it could support a thousand times its own weight in copper nanoparticles.”

From the abstract in Nano Letters:

In particular, we have found that long graphene beams supported by only one side do not scroll or fold, in striking contrast to the current perception of graphene as a supple thin fabric, but demonstrate sufficient stiffness to support extremely large loads, millions of times exceeding their own weight, in agreement with the presented theory.

—Jim

The newest addition to the toolkit for using DNA as a nanotech building block is the ability to program the circumference of nanotubes made from DNA. From nanotechweb.org, written by Belle Dumé (requires free registration) “DNA tubes control their size“:

Being able to synthesize nanostructures with controlled size is an important goal in nanotechnology. Now, researchers in the US have succeeded in exploiting modular single-stranded DNA building blocks to create molecular tubes with predefined circumferences. Such tubes could eventually be used as templates to make nanowires with controlled electronic properties for future nanoelectronic devices.

“We describe a simple modular approach to programming molecular-tube circumferences,” team member Peng Yin of Caltech told nanotechweb.org. “Single-step annealing results in the self-assembly of long tubes displaying monodisperse circumferences of 4, 5, 6, 7, 8, 10 or 20 DNA helices.”

…Compared with previous research in controlling DNA tube circumferences, Yin and colleagues’ new process is substantially simpler. The researchers begin by self-assembling DNA tubes composed of parallel DNA helices from distinct short strand species, each measuring 42 bases. By pairing up the modular complementary domains within the strands, they create DNA lattices made up of parallel helices connected by single-stranded links. This design scheme means that only tubes of a certain circumference form from a set of initial DNA strands.

…DNA with programmable geometrical and mechanical properties might be used as building blocks for sophisticated architectures and devices — like tracks for molecular motors and as templates for organizing functional groups, for example.

The results, obtained in Erik Winfree’s lab at Caltech, were reported in Science [abstract].

—Jim

KurzweilAI.net points us to this CNET News report that Ray Kurzweil’s concept of an impending “singularity,” in which machine intelligence surpasses human intelligence, has garnered support from Intel’s Chief Technology Officer Justin Rattner. From “Intel touts progress toward intelligent computers” by Stephen Shankland:

I hope Intel warned the Luddites and pessimists away at the door, because the chipmaker had a lot of bullish statements Thursday [August 21] about its belief that computers will become smarter than humans.

At the Intel Developer Forum here, Intel Chief Technology Officer Justin Rattner showed off a number of technologies in computing, robotics, and communication that he cited as evidence that Ray Kurzweil’s concept of “singularity,” when machine intelligence surpasses human intelligence, is impending. Demonstrations spotlighted the wireless transmission of electrical power, dextrous robots with new sensory abilities, a direct interface to the brain, programmable materials that can be used for shape-shifting devices such as resizable cell phones, and silicon photonics that enables chips to communicate with photons rather than electrons.

“We’re making steady progress toward Ray Kurzweil’s singularity,” Rattner said.

—Jim

Whether you are an American Express cardholder or not, you can vote for an innovative effort to inspire undergraduates to strive for fundamental advances in our ability to control the aging process. An Email this morning from David Gobel, Chief Executive Officer of the Methuselah Fund, said the project had 1200 nominations. I just checked and the number is now 1464. Keep the momentum building! From David Gobel:

Hi - We are at 1200 nominations to be in the running for the $1.5 million American Express Challenge Undergrads Fighting Age Related Disease researcher scholarships this morning

I believe we’ll need to have another 1,000 nominations over the next 4 days, and that this is absolutely doable. Now that we are solidly in the running, what can we do to dramatically improve our position? It’s totally important to note that of ALL the projects, ours is by far the most commented upon which counts heavily in the final selection.

From Aubrey de Grey

Calling All Who Support Extending Healthy Life….

Methuselah Foundation needs your help now - we are supporting a project named “Undergrads Fighting Age Related Disease” which has been submitted as part of the American Express Members Project initiative.

To advance this critical project please go to http://www.membersproject.com/project/view/BVVE2C

We need to get only 1,000 more votes in the next 4 days (by Sept 1, 2008) so please support your cause and vote now. Here are the instructions.

1. Go to: http://www.membersproject.com/project/view/BVVE2C
2. Log in either as an Amex Card Member or as a Guest Member on the top right side (any US resident can vote)
3. Complete the Registration Form, which will give you your login ID
4. Click the Nominate button at:
http://www.membersproject.com/project/view/BVVE2C and post a supportive comment

Cheers,
Aubrey de Grey
Chief Science Officer and Chairman
Methuselah Foundation

Don’t forget to add your own supportive comment. Although the project is not about nanotechnology, it is likely that nanotechnology will play a part in some of the approaches that will be researched. Plus the value of involving bright undergraduates in interdisciplinary efforts to tackle challenging and important problems is immense. For the many challenges that lie ahead, we need all the brilliant, creative researchers we can get.
—Jim

Government-sponsored discussions of the implications for society of advanced nanotechnology and other emerging technologies have taken place and are ongoing in both the US and Europe. A recent Nanowerk Spotlight written by Michael Berger gives an update of deliberations in Europe and compares and contrasts the US and European approaches. From “Europe and the U.S. take different approaches to Converging Technologies“:

The two differing approaches that the European Union and the U.S. take in tackling converging technologies is exemplary for the philosophical difference in how these two geographies approach the development of new technologies. Policies in the U.S., especially during the past eight years, have been, well, shaped is not the right word here, let’s say drifting, towards a purely market-driven approach to technology development: the government’s job was to provide sufficient basic R&D funding, keep a minimum of consumer safety levels, but otherwise not to get into the way of industrial activities. In addition, a major driver and funding agent for emerging technologies has been the military (for instance, over 30% of all federal investment dollars the U.S. spends on nanotechnology come from the U.S. Department of Defense — “Military nanotechnology - how worried should we be?”).

In contrast, the European approach places the emphasis on the agenda-setting process itself. Rather than letting the market call all the shots, the European approach favors a guided development where societal, safety and environmental aspects are incorporated into the decision-making process. It envisions that various European converging technologies research programs will be formulated, each addressing a different problem and each bringing together different technologies and technology-enabling sciences. The European concept of “CTEKS: Converging Technologies for the European Knowledge Society” (pdf download, 876 KB) adopts a demand-driven approach in which converging technologies respond to societal needs and demands. While the U.S.-pushed NBIC (nano, bio, info, cogno) approach focuses strongly on enhancement of the individual human being, the European approach urged to take the precautionary principle into account and made it “a priority to clarify the civil and societal benefits of this research to give them a new legitimacy and to put them firmly in a context of positive social dynamics.”

U.S. proposed agendas for convergence that include “Converging technologies for improving human performance” or “Converging technologies for battlefield domination” were rejected by the European expert group that helped define the European approach as troubling and potentially destabilizing.

The main task of the EU-funded project CONTECS was to develop ideas for a comprehensive and integrated European agenda with regard to converging technologies. The project delivered its final report — An analysis of critical issues and a suggestion for a future research agenda (pdf download, 2 MB) — in May of this year. This Nanowerk Spotlight summarizes the main points of this report and all quotes and most references are taken from it.

—Jim

The protein engineering pathway to advanced nanotech (see “Protein Bioengineering Overview”, paper 10 of the Productive Nanosystems Roadmap Working Group Proceedings—a 14.6 MB PDF) might benefit if proteins could be arrayed on a surface so that they could be quickly and easily scanned for function or interactions with other molecules. Protein ‘chips’ developed by UK scientists for rapid disease detection and drug discovery might be just what is needed. From the University of Manchester, via AAAS EurekAlert “Chips are down as Manchester makes protein scanning breakthrough“:

Scientists at The University of Manchester have developed a new and fast method for making biological ‘chips’ — technology that could lead to quick testing for serious diseases, fast detection of MRSA infections and rapid discovery of new drugs.

Researchers working at the Manchester Interdisciplinary Biocentre (MIB) and The School of Chemistry have unveiled a new technique for producing functional ‘protein chips’ in a paper in the Journal of the American Chemical Society [abstract]…

Protein chips — or ‘protein arrays’ as they are more commonly known — are objects such as slides that have proteins attached to them and allow important scientific data about the behaviour of proteins to be gathered.

Functional protein arrays could give scientists the ability to run tests on tens of thousands of different proteins simultaneously, observing how they interact with cells, other proteins, DNA and drugs.

As proteins can be placed and located precisely on a ‘chip’, it would be possible to scan large numbers of them at the same time but then isolate the data relating to individual proteins.

…Existing techniques for attaching proteins often results in them becoming fixed in random orientations, which can cause them to become damaged and inactive.

Current methods also require proteins to be purified first — and this means that creating large and powerful protein arrays would be hugely costly in terms of time, manpower and money.

Now researchers at The University of Manchester say they have found a reliable new way of attaching active proteins to a chip.

Biological chemists have engineered modified proteins with a special tag, which makes the protein attach to a surface in a highly specified way and ensures it remains functional.

The attachment occurs in a single step in just a few hours — unlike with existing techniques — and requires no prior chemical modification of the protein of interest or additional chemical steps.

—Jim

Two stories today in ScienceDaily point to different nanotech applications that could enable a solar solution to our energy problems—one including the use of self-repairing nanosystems. “Converting Sunlight To Cheaper Energy” describes the use of photoactive nanoscale systems to develop molecular electronics. Organic molecules and fullerenes will be used to make inexpensive photovoltaics and light emitting diodes:

Organic photovoltaics and organic LEDs are made up of thin films of semiconducting organic compounds that can absorb photons of solar energy. Typically an organic polymer, or a long, flexible chain of carbon-based material, is used as a substrate on which semiconducting materials are applied as a solution using a technique similar to inkjet printing.

…[South Dakota State University] scientists plan to use the variable band gap polymers to build multi-junction polymer solar cells or photovoltaics.

These devices use multiple layers of polymer/fullerene films that are tuned to absorb different spectral regions of solar energy.

Ideally, photons that are not absorbed by the first film layer pass through to be absorbed by the following layers.

The devices can harvest photons from ultraviolet to visible to infrared in order to efficiently convert the full spectrum of solar energy to electricity.

SDSU scientists also work with organic light-emitting diodes focusing on developing novel materials and devices for full color displays.

…The new technology will make it easy to insert lights into walls or ceilings. But instead of light bulbs, the lighting apparatus of the future may look more like a poster…

The second story describes how scientists are not only trying to exploit biology’s 3.7 billion year-old system for harvesting the sun’s energy, but planning to mimic it with artificial self-assembling and self-repairing nanodevices. From “Bacteria Power: Future For Clean Energy Lies In ‘Big Bang’ Of Evolution“:

Dramatic progress has been made over the last decade understanding the fundamental reaction of photosynthesis that evolved in cyanobacteria 3.7 billion years ago, which for the first time used water molecules as a source of electrons to transport energy derived from sunlight, while converting carbon dioxide into oxygen.

The light harvesting systems gave the bacteria their blue (”cyano”) colour, and paved the way for plants to evolve by “kidnapping” bacteria to provide their photosynthetic engines, and for animals by liberating oxygen for them to breathe, by splitting water molecules. For humans now there is the tantalising possibility of tweaking the photosynthetic reactions of cyanobacteria to produce fuels we want such as hydrogen, alcohols or even hydrocarbons, rather than carbohydrates.

Progress at the research level has been rapid, boosting prospects of harnessing photosynthesis not just for energy but also for manufacturing valuable compounds for the chemical and biotechnology industries. Such research is running on two tracks, one aimed at genetically engineering real plants and cyanobacteria to yield the products we want, and the other to mimic their processes in artificial photosynthetic systems built with human-made components. Both approaches hold great promise and will be pursued in parallel, as was discussed at a recent workshop focusing on the photosynthetic reaction centres of cyanobacteria, organised by the European Science Foundation (ESF).

…Among promising contenders discussed at the ESF conference was the idea of an artificial leaf that would simulate not just photosynthesis itself but also the ability of plants to regenerate themselves. This could be important, since the reactions of photosynthesis are destructive, dismantling the protein complexes where they take place, which therefore need regular reconstruction. Under a microscope, chloroplasts, the sub-cellular units where photosynthesis take place, resemble a permanent construction site, and even artificial systems would probably need some form of regenerative capability.

A future aim therefore is to build an artificial leaf-like system comprised of self-assembling nanodevices that are capable of regenerating themselves — just as in real plants or cyanobacteria. “Fundamental breakthroughs in these directions are expected on a time scale of 10 to 20 years and are recognized by the international science community as major milestones on the road to a renewable fuel,” said [Eva Mari Aro, the vice-chair of the ESF conference].

I found it particularly interesting that the researchers are thinking beyond simple nanodevices to harvest solar energy and considering self-repairing “leaf” systems in a 10-20 year time frame.
—Jim

Advanced nanotech would benefit from the ability to engineer atomically precise structures on nanoparticles. In a step in that direction, UK scientists have developed a combined computational and experimental method to determine how specific peptides self-assemble on the surface of a gold nanoparticle—in particular how closely spaced on the surface of the nanoparticle the peptides have to be to form chemical bonds. Via ScienceDaily, a news release from UK Biotechnology and Biological Sciences Research Council (includes images and molecular dynamics animations) “Scientists overcome nanotech hurdle“:

When you make a new material on a nanoscale how can you see what you have made? A team lead by a Biotechnology and Biological Sciences research Council (BBSRC) fellow has made a significant step toward overcoming this major challenge faced by nanotechnology scientists. With new research published today (13 August) in ChemBioChem [abstract], the team from the University of Liverpool, The School of Pharmacy (University of London) and the University of Leeds, show that they have developed a technique to examine tiny protein molecules called peptides on the surface of a gold nanoparticle. This is the first time scientists have been able to build a detailed picture of self-assembled peptides on a nanoparticle and it offers the promise of new ways to design and manufacture novel materials on the tiniest scale — one of the key aims of nanoscience.

Engineering new materials through assembly of complex, but tiny, components is difficult for scientists. However, nature has become adept at engineering nanoscale building blocks, e.g. proteins and RNA. These are able to form dynamic and efficient nanomachines such as the cell’s protein assembly machine (the ribosome) and minute motors used for swimming by bacteria. The BBSRC-funded team, led by Dr Raphaël Lévy, has borrowed from nature, developing a way of constructing complex nanoscale building blocks through initiating self-assembly of peptides on the surface of a metal nanoparticle. Whilst this approach can provide a massive number and diversity of new materials relatively easily, the challenge is to be able to examine the structure of the material.

Using a chemistry-based approach and computer modelling, Dr Lévy has been able to measure the distance between the peptides where they sit assembled on the gold nanoparticle. The technique exploits the ability to distinguish between two types of connection or ‘cross-link’ — one that joins different parts of the same molecule (intramolecular), and another that joins together two separate molecules (intermolecular). As two peptides get closer together there is a transition between the two different types of connection. Computer simulations allow the scientists to measure the distance at which this transition occurs, and therefore to apply it as a sort of molecular ruler. Information obtained through this combination of chemistry and computer molecular dynamics shows that the interactions between peptides leads to a nanoparticle that is relatively organized, but not uniform. This is the first time it has been possible to measure distances between peptides on a nanoparticle and the first time computer simulations have been used to model a single layer of self-assembled peptides.

Dr Lévy said: “As nanotechnology scientists we face a challenge similar to the one faced by structural biologists half a century ago: determining the structure with atomic scale precision of a whole range of nanoscale materials. By using a combination of chemistry and computer simulation we have been able to demonstrate a method by which we can start to see what is going on at the nanoscale.

“If we can understand how peptides self-assemble at the surface of a nanoparticle, we can open up a route towards the design and synthesis of nanoparticles that have complex surfaces. These particles could find applications in the biomedical sciences, for example to deliver drugs to a particular target in the body, or to design sensitive diagnostic tests. In the longer term, these particles could also find applications in new generations of electronic components.”

Professor Nigel Brown, BBSRC Director of Science and Technology, said: “Bionanotechnology holds great promise for the future. We may be able to create stronger, lighter and more durable materials, or new medical applications. Basic science and techniques for working at the nanoscale are providing the understanding that will permit future such applications of bionanotechnology.”

—Jim

In a study with breast cancer in mice, a nanotech cancer therapy suppresses tumor growth with minimal side effects. Taking advantage of the fact that the blood vessels in tumor tissue are leakier than in normal tissue, carbon nanotubes of the right size and with the proper chemical coating deliver more tumor-killing drug to tumors, while sparing normal tissue. In future experiments, the researchers may add molecules that specifically target tumor cells to achieve even greater specificity. ScienceDaily features a story from Stanford University News, written by Louis Bergeron “Nanotubes deliver high-potency punch to cancer tumors in mice“:

The problem with using a shotgun to kill a housefly is that even if you get the pest, you’ll likely do a lot of damage to your home in the process. Hence the value of the more surgical flyswatter.

Cancer researchers have long faced a similar situation in chemotherapy: how to get the most medication into the cells of a tumor without “spillover” of the medication adversely affecting the healthy cells in a patient’s body.

Now researchers at Stanford University have addressed that problem using single-walled carbon nanotubes as delivery vehicles. The new method has enabled the researchers to get a higher proportion of a given dose of medication into the tumor cells than is possible with the “free” drug—that is, the one not bound to nanotubes—thus reducing the amount of medication that they need to inject into a subject to achieve the desired therapeutic effect.

“That means you will also have less drug reaching the normal tissue,” said Hongjie Dai, professor of chemistry and senior author of a paper, which will be published in the Aug. 15 issue of Cancer Research [abstract]. So not only is the medication more effective against the tumor, ounce for ounce, but it greatly reduces the side effects of the medication.

Graduate student Zhuang Liu is first author of the paper.

Dai and his colleagues worked with paclitaxel, a widely used cancer chemotherapy drug, which they employed against tumors cells of a type of breast cancer that were implanted under the skin of mice. They found that they were able to get up to 10 times as much medication into the tumor cells via the nanotubes as when the standard formulation of the drug, called Taxol®, was injected into the mice.

The tumor cells were allowed to proliferate for about two weeks prior to being treated. After 22 days of treatment, tumors in the mice treated with the paclitaxel-bearing nanotubes were on average less than half the size of those in mice treated with Taxol.

Critical to achieving those results were the size and surface structure of the nanotubes, which governed how they interacted with the walls of the blood vessels through which they circulated after being injected. Though a leaky vessel—nautical or anatomical—is rarely a good thing, in this instance the relatively leaky walls of blood vessels in the tumor tissue provided the opening that the nanotubes needed to slip into the tumor cells.

“The results are actually highly dependent on the surface chemistry,” Dai said. “In other words, you don’t get this result just by attaching drugs to any nanotubes.”

The researchers used nanotubes that they had coated with polyethylene glycol (PEG), a common ingredient in cosmetics. The PEG they used was a form that has three little branches sprouting from a central trunk. Stuffing the trunks into the linked hexagonal rings that make up the nanotubes created a visual effect that Dai described as looking like rolled-up chicken wire with feathers sticking out all over. The homespun sounding appearance notwithstanding, the nanotubes proved to be highly effective delivery vehicles when the researchers attached the paclitaxel to the tips of the branches.

…Dai said that the technique holds potential for delivering a range of medications and that it may also be possible to develop ways to channel the nanotubes to their target even more precisely.

“Right now what we are doing is so-called ‘passive targeting,’ which is using the leaky vasculature of the tumor,” he said. “But a more active targeting would be attaching a peptide or antibody to the nanotube drug, one that will bind more specifically to the tumor, which should further enhance the treatment efficacy.”

Dai’s team is already at work developing more targeted approaches, and he is optimistic about the potential applications of nanotubes.

“We are definitely hoping to be able to push this to practical applications into the clinic. This is one step forward,” he said. “But it will still take time to truly prove the efficacy and the safety.”

—Jim

The production of syngas, a mixture of carbon monoxide, carbon dioxide, and hydrogen, from coal or other carbon source is an established industrial technology. A new nanotech catalyst now enables the efficient conversion of syngas to ethanol. From an Ames Laboratory news release (via ScienceDaily) “Turning Waste Material into Ethanol“

Say the word “biofuels” and most people think of grain ethanol and biodiesel. But there’s another, older technology called gasification that’s getting a new look from researchers at the U.S. Department of Energy’s Ames Laboratory and Iowa State University. By combining gasification with high-tech nanoscale porous catalysts, they hope to create ethanol from a wide range of biomass, including distiller’s grain left over from ethanol production, corn stover from the field, grass, wood pulp, animal waste, and garbage.

Gasification is a process that turns carbon-based feedstocks under high temperature and pressure in an oxygen-controlled atmosphere into synthesis gas, or syngas. Syngas is made up primarily of carbon monoxide and hydrogen (more than 85 percent by volume) and smaller quantities of carbon dioxide and methane.

It’s basically the same technique that was used to extract the gas from coal that fueled gas light fixtures prior to the advent of the electric light bulb. …

“There was some interest in converting syngas into ethanol during the first oil crisis back in the 70s,” said Ames Lab chemist and Chemical and Biological Science Program Director Victor Lin. “The problem was that catalysis technology at that time didn’t allow selectivity in the byproducts. They could produce ethanol, but you’d also get methane, aldehydes and a number of other undesirable products.”

…In studying the chemical reactions in syngas conversion, Lin found that the carbon monoxide molecules that yielded ethanol could be “activated” in the presence of a catalyst with a unique structural feature.

…Lin’s group looked at using a metal alloy as the catalyst. To increase the surface area, they used nano-scale catalyst particles dispersed widely within the structure of mesoporous nanospheres, tiny sponge-like balls with thousands of channels running through them. The total surface area of these dispersed catalyst nanoparticles is roughly 100 times greater than the surface area you’d get with the same quantity of catalyst material in larger, macro-scale particles.

—Jim

Silver nanoparticles continue to show promise for killing bacteria, especially in a hospital environment. Now a Swiss team has shown that a combination of silver and calcium phosphate nanoparticles provides an even more effective nanotech antiseptic. From Nanowerk News “New nanoparticle film up to 1000 times more effective at killing E. coli bacteria“:

Chemical Engineers in Switzerland have created a plastic film that’s up to 1000 times more effective at killing E. coli bacteria cells than conventional methods.

The team from the Swiss Federal Institute of Technology, Zurich have discovered that coating the film with a mix of silver and calcium phosphate nano-particles proves deadly to bacteria.

Wendelin Stark, a chemical engineer and leader of the project explained that it had been previously impossible to apply silver in a targeted and measured way. However, by using a film and applying the silver to the calcium phosphate, he believes the problem has been overcome: “Within 24 hours of the plastic film being applied to a surface, less than 1 bacterium out of 1 million bacteria will survive.”

Because bacteria rely on calcium for their metabolism, the 20-50 nanometer calcium phosphate particles are used by the micro-organisms as nutrition. When the bacteria consume the calcium phosphate, this releases thousands of small silver 1-2 nanometer particles. It’s these tiny silver particles that kill the bacteria and prevent germs from growing and spreading.

The polymer film only emits silver if bacteria are growing in the vicinity.

The research was published in Small (abstract).
—Jim

The Center for Nanotechnology in Society at Arizona State University is one of two centers funded by the National Science Foundation to study nanotechnology in society. One of their tools for studying the impact of nanotech upon society is the National Citizens’ Technology Forum (NCTF). They have recently published the results of their National Citizens’ Technology Forum: Public Deliberation about Nanotechnology for Human Enhancement. From their downloadable brochure:

In March 2008, eighty-six people across six nationwide panels participated in the National Citizens’ Technology Forum on “Human Enhancement Through Nanotechnology.” These citizens ranged from teens to seniors and had no previous expertise or experience in nanotechnology. They studied background material, met face-to-face, and participated in nine, two-hour Internet discussion forums with scientist experts. During their final meeting, each panel wrote a Citizen’s Report that outlines their optimism, concerns and recommendations regarding human enhancement technologies.

The reports address socio-economic, safety, environmental, health and governance issues, as well as regulatory challenges and human identity concerns. This project gives average citizens a voice in the early stages of nano-scale science and engineering research and development. It is noteworthy that every report implores policymakers, research scientists, and the private sector to recognize that real-time citizen input is essential to fully understanding the societal implications of emerging technologies.

The final reports from the six sites are available in their entirety here.
—Jim

To form practical nanotech circuits from arrays of nanowires, it is necessary to integrate different types of nanowires into multifunctional circuits. Two different types of nanowires (cadmium selenide for light sensors and germanium core/silicon shell for field-effect transistors) have been integrated on a chip to detect and amplify optical signals. From Lawrence Berkeley National Laboratory (credit PhysOrg.com) “A First in Integrated Nanowire Sensor Circuitry“:

Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the University of California at Berkeley have created the world’s first all-integrated sensor circuit based on nanowire arrays, combining light sensors and electronics made of different crystalline materials. Their method can be used to reproduce numerous such devices with high uniformity.

Nanostructures made with specific chemical, electronic, and other properties have a number of advantages over the same materials in bulk. For example, a nanowire is an ideal shape for a light detector; being virtually one-dimensional, practically “all surface,” a nanowire is not only highly sensitive to light energy, but its electronic response is greatly enhanced as well.

To be practical, however, the photosensors must be integrated with electronics on the same chip. And the materials that make an ideal photosensor are necessarily different from those that make a good transistor.

“Our integration of arrays of nanowires that perform separate functions and are made of heterogeneous substances — and doing this in a way that can be reproduced on a large scale in a controlled way — is a first,” says Ali Javey, who led the research team. Javey is a staff scientist in Berkeley Lab’s Materials Sciences Division (MSD) and an assistant professor in the Electrical Engineering and Computer Sciences Department at UC Berkeley. He and his colleagues report their work in the August 1 edition of Proceedings of the National Academy of Sciences [abstract].

…Results of the Javey group’s integrated nanowire circuit showed successful photoresponse in 80 percent of the circuits, with fairly small variations among them. Where circuits did fail, the causes were due to defects in fabrication of the circuit connections (10 percent), failure in photosensor printing (5 percent), or defective nanowires (5 percent). The relatively high yield of complex operational circuits proved the potential of the technology, with improvements readily achievable by optimizing nanowire synthesis and fabrication of the devices.

“In the future, we can foresee using a variety of different optical sensors to create nanoscale devices sensitive to multiple colors in high-resolution,” says Javey. “And that’s just the beginning. We contemplate printing nanowire sensor circuitry — photosensors, chemical sensors, biosensors — not on silicon but on paper or plastic tape. This could be used, easily and with instant results, where spills have occurred, or to test air quality, or to test for disease organisms — almost any use for a sensor that you can imagine.”

—Jim

Nanotech methods offer a variety of ways to alter the properties of nanostructures to optimize drug delivery. A process that allows the fabrication of different shapes of particles varying in size from about 100 nm to several micrometers demonstrates that long particles are internalized by cancer cells more efficiently than are round particles. From the University of North Carolina at Chapel Hill (credit PhysOrg.com) “UNC study: shape, not just size, impacts effectiveness of emerging nano-medicine therapies“:

In the budding field of nanotechnology, scientists already know that size does matter.

But now, researchers at the University of North Carolina at Chapel Hill have shown that shape matters even more — a finding that could lead to new and more effective methods for treating cancer and other diseases, from diabetes and multiple sclerosis to arthritis and obesity.

A team of researchers led by Joseph DeSimone, Ph.D., Chancellor’s Eminent Professor of Chemistry in UNC’s College of Arts and Sciences and William R. Kenan, Jr. Distinguished Professor of Chemical Engineering at North Carolina State University, and Stephanie Gratton, a graduate student in DeSimone’s lab, have demonstrated that nanoparticles designed with a specific shape, size and surface chemistry are taken up into cells and behave differently within cells depending on these attributes.

Their findings appear in this week’s online early edition of the journal PNAS, the Proceedings of the National Academy of Sciences [abstract].

…Using PRINT® (Particle Replication in Non-wetting Templates) technology — a technique invented in DeSimone’s lab that allows scientists to design and produce “custom-made” nanoparticles — the UNC researchers made particles with specific shapes, sizes and surface charges. DeSimone said the aim is to optimize particle attributes for specific therapeutic objectives.

“This would mean that we could deliver lower dosages of drugs to specific cells and tissues in the body and actually be more effective in treating the cancer,” said DeSimone, who is also a member of UNC’s Lineberger Comprehensive Cancer Center and the co-principal investigator for the Carolina Center for Cancer Nanotechnology Excellence.

…the scientists discovered that long, rod-shaped particles (diameter, 150 nanometers; height, 450 nanometers) were internalized by cells approximately four times faster than lower aspect ratio particles (diameter, 200 nanometers; height, 200 nanometers), and traveled significantly further into the cells as well.

More information about the PRINT® process can be found on the web site of the DeSimone research group.
—Jim

Nanotech has fashioned from graphene a one atom-thick membrane impermeable even to helium gas. From “World’s Thinnest Balloon Developed: Just One Atom Thick“:

Researchers in New York are reporting development of the world’s thinnest balloon, made of a single layer of graphite just one atom thick. This so-called graphene sealed microchamber is impermeable to even the tiniest airborne molecules, including helium.

It has a range of applications in sensors, filters, and imaging of materials at the atomic level.

Paul L. McEuen and colleagues note that membranes are fundamental components of a wide variety of physical, chemical and biological systems, found in everything from cellular compartments to mechanical pressure sensing. Graphene, a single layer of graphite, is the upper limit: A chemically stable and electrically conducting membrane just one atom thick. The researchers wanted to answer whether such an atomic membrane would be impermeable to gas molecules and easily incorporated into other devices.

Their data showed that graphene membranes were impermeable to even the smallest gas molecules. These results show that single atomic sheets can be integrated with microfabricated structures to create a new class of atomic scale membrane-based devices.

The research was published in Nano Letters (abstract)
—Jim

Nanotech has taken a major step along the road to molecular electronics with the demonstration that one molecule of benzene can form a highly conductive junction between two platinum electrodes. From an article on nanotechweb.org, written by Belle Dumé (requires free registration) “Ballistic breakthrough could lead to molecular logic gates“:

The first highly-conductive connection between a single organic molecule and a metal electrode has been made by an international team of physicists. This achievement could lead to the development of ‘molecular electronics’ devices with the potential to be smaller and faster than conventional transistors and logic gates.

The majority of electronic devices are made from just a handful of semiconductor materials — the most common being silicon. However, some organic molecules such as DNA appear to have electronic properties similar to traditional semiconductors and some researchers believe that some types of molecules could be used to make electronic devices.

A potential benefit of such devices is that molecules are extremely small compared to semiconductor structures, which could help manufacturers pack more and more circuits onto a chip.

However, it has proven very difficult to connect single molecules to a metal electrode such that electrons are conducted easily between the two. These junctions are essential for making real-world devices like transistors and logic gates.

…Now, Jan van Ruitenbeek of the University of Leiden in the Netherlands along with colleagues in Australia, Germany and Spain may have solved this problem by making the first highly conductive molecular junctions. This involved binding benzene molecules directly to platinum metal electrodes, and the team found that the conductance of these devices reaches the maximum value possible for a single electron channel.

…”What makes this work stand out is that [the scientists] have presented a new way to attach organic molecules to metal electrodes, by forming a direct metal-carbon bond, and have proven conclusively that their devices have a strong metal-molecule link,” commented Latha Venkataraman of Columbia University in an American Physical Society Viewpoint article on the research. “This enables them to overcome a major barrier in molecular based devices,” she said.

The research was published in Physical Review Letters (abstract).
—Jim

The SmallTimes web site reports the introduction of H.R. 6661, which establishes a prize competition for five key areas of nanotech. From “Nanotechnology prize competition bill to drive U.S. innovation“:

Congressman Dan Lipinski (D-IL) , Vice Chairman of the House Science and Technology Committee, and Congressman (R-MO) Todd Akin, have introduced H.R. 6661, the Nanotechnology Innovation and Prize Competition Act, which establishes an X-Prize competition for nanotechnology.

H.R. 6661 would stimulate public-private partnership and focus investment towards key goals. The bill identifies five key categories — green nanotechnology, alternative energy, human health, nanoelectronics, and commercialization of consumer products — and establishes a board comprised of government and private sector experts to select criteria for prize competitions.

…The bill also authorizes the government to contract with an outside organization, such as the X-PRIZE Foundation, to administer the competition. This organization, and the board, also will recruit private contributions to fund the prize awards. In this way, H.R. 6661 enables the government to leverage a relatively small amount of resources to stimulate a much greater level of investment in nanotech research.

—Jim