Tag Archives: nanotubes

Boron nitride nanotubes

Most of the talk about nanotubes is focused on carbon nanotubes but there are other kinds as a May 21, 2018 Rice University news release (also received via email and on EurekAlert and in a May 21, 2018 news item on ScienceDaily), notes,

Boron nitride nanotubes are primed to become effective building blocks for next-generation composite and polymer materials based on a new discovery at Rice University – and a previous one.

Scientists at known-for-nano Rice have found a way to enhance a unique class of nanotubes using a chemical process pioneered at the university. The Rice lab of chemist Angel Martí took advantage of the Billups-Birch reaction process to enhance boron nitride nanotubes.

The work is described in the American Chemical Society journal ACS Applied Nano Materials.

Boron nitride nanotubes, like their carbon cousins, are rolled sheets of hexagonal arrays. Unlike carbon nanotubes, they’re electrically insulating hybrids made of alternating boron and nitrogen atoms.

Insulating nanotubes that can be functionalized will be a valuable building block for nanoengineering projects, Martí said. “Carbon nanotubes have outstanding properties, but you can only get them in semiconducting or metallic conducting types,” he said. “Boron nitride nanotubes are complementary materials that can fill that gap.”

Until now, these nanotubes have steadfastly resisted functionalization, the “decorating” of structures with chemical additives that allows them to be customized for applications. The very properties that give boron nitride nanotubes strength and stability, especially at high temperatures, also make them hard to modify for their use in the production of advanced materials.

But the Billups-Birch reaction developed by Rice Professor Emeritus of Chemistry Edward Billups, which frees electrons to bind with other atoms, allowed Martí and lead author Carlos de los Reyes to give the electrically inert boron nitride nanotubes a negative charge.

That, in turn, opened them up to functionalization with other small molecules, including aliphatic carbon chains.

“Functionalizing the nanotubes modifies or tunes their properties,” Martí said. “When they’re pristine they are dispersible in water, but once we attach these alkyl chains, they are extremely hydrophobic (water-avoiding). Then, if you put them in very hydrophobic solvents like those with long-chain hydrocarbons, they are more dispersible than their pristine form.

“This allows us to tune the properties of the nanotubes and will make it easier to take the next step toward composites,” he said. “For that, the materials need to be compatible.”

After he discovered the phenomenon, de los Reyes spent months trying to reproduce it reliably. “There was a period where I had to do a reaction every day to achieve reproducibility,” he said. But that turned out to be an advantage, as the process only required about a day from start to finish. “That’s the advantage over other processes to functionalize carbon nanotubes. There are some that are very effective, but they may take a few days.”

The process begins with adding pure ammonia gas to the nanotubes and cooling it to -70 degrees Celsius (-94 degrees Fahrenheit). “When it combines with sodium, lithium or potassium — we use lithium — it creates a sea of electrons,” Martí said. “When the lithium dissolves in the ammonia, it expels the electrons.”

The freed electrons quickly bind with the nanotubes and provide hooks for other molecules. De los Reyes enhanced Billups-Birch when he found that adding the alkyl chains slowly, rather than all at once, improved their ability to bind.

The researchers also discovered the process is reversible. Unlike carbon nanotubes that burn away, boron nitride nanotubes can stand the heat. Placing functionalized boron nitride tubes into a furnace at 600 degrees Celsius (1,112 degrees Fahrenheit) stripped them of the added molecules and returned them to their nearly pristine state.

“We call it defunctionalization,” Martí said. “You can functionalize them for an application and then remove the chemical groups to regain the pristine material. That’s something else the material brings that is a little different.”

The researchers have provided this pretty illustration of boron nitride nanotube,

Caption: Rice University researchers have discovered a way to ‘decorate’ electrically insulating boron nitride nanotubes with functional groups, making them more suitable for use with polymers and composite materials. Credit: Martí Research Group/Rice University

Here’s a link to and a citation for the paper,

Chemical Decoration of Boron Nitride Nanotubes Using the Billups-Birch Reaction: Toward Enhanced Thermostable Reinforced Polymer and Ceramic Nanocomposites by Carlos A. de los Reyes, Kendahl L. Walz Mitra, Ashleigh D. Smith, Sadegh Yazdi, Axel Loredo, Frank J. Frankovsky, Emilie Ringe, Matteo Pasquali, and Angel A. Martí. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.8b00633 Publication Date (Web): May 16, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

The nanotube of a thousand faces (similar nanomaterials behaving differently)

Kudos to any one who recognizes the reference to the ‘man of a thousand faces’, Lon Chaney, a silent film horror star. As for the nanotubes, there’s this Sept. 14, 2016 news item on ScienceDaily,

Nanotubes can be used for many things: electrical circuits, batteries, innovative fabrics and more. Scientists have noted, however, that nanotubes, whose structures appear similar, can actually exhibit different properties, with important consequences in their applications. Carbon nanotubes and boron nitride nanotubes, for example, while nearly indistinguishable in their structure, can be different when it comes to friction. A study conducted by SISSA/CNR-IOM and Tel Aviv University created computer models of these crystals and studied their characteristics in detail and observed differences related to the material’s chirality. …

A Sept. 14, 2016 Scuola Internazionale Superiore di Studi Avanzati (SISSA) press release (PDF), which originated the news item, describes the research in more detail,

“We began with a series of experimental observations which showed that very similar nanotubes exhibit different frictional properties, with intensities ranging up to two orders of magnitude,” says Roberto Guerra, a researcher at CNR-IOM and the International School for Advanced Studies (SISSA) in Trieste, first author of the study. “This led us to hypothesize that the chirality of the materials may play a role in this phenomenon.” The study involving also Andrea Vanossi (CNR-IOM) and Erio Tosatti (SISSA), was conducted in collaboration with the University of Tel Aviv.

For materials, such as those used in the study, chirality is linked to the three-dimensional arrangement of the weft that form the nanotube. “If we wrap a sheet of lined paper around itself to form a tube, the angle that the lines form with the axis of the tube determines its chirality,” says Guerra. “In our work we reconstructed the behavior of double-walled nanototubes, which can be imagined as two tubes of slightly different diameters, one inside the other. We observed that the difference in chirality between the inner tube and the outer tube has a remarkable effect on the three-dimensional shape of the nanotubes.”

A polygonal tube

“If we continue with the paper metaphor, the difference in orientation between the lattice on the inner tube and the outer tube determine to what extent, and, in what way, planar regions (faces) along the tube will form,” says Guerra. To better understand what is meant by “faces,” imagine a cross section of the tube, which is polygonal rather than perfectly circular. “The smaller the difference in chirality, the clearer and more obvious the faces,” concludes Guerra. If, however, the difference in chirality becomes too large, the faces disappear and the nanotubes take on the classic cylindrical shape.

The faces appear spontaneously depending on the characteristics of the material. Double-walled carbon nanotubes tend to form with a greater difference in internal and external chirality compared to boron nitride. Therefore, the former usually maintains a cylindrical shape that allows for less friction. In further studies, Guerra and colleagues intend to work directly on measuring the level of friction between nanotubes.

Here’s a link to and a citation for the paper,

Multiwalled nanotube faceting unravelled by Itai Leven, Roberto Guerra, Andrea Vanossi, Erio Tosatti, & Oded Hod. Nature Nanotechnology (2016) doi:10.1038/nnano.2016.151 Published online 22 August 2016

This paper is behind a paywall.

Speeding up the process for converting carbon dioxide into hydrocarbon fuel

This is a personal thrill; it’s the first time in seven years that I’ve received a press release directly from an institution in Asia.

A March 10, 2015 MANA, the International Center for Materials Nanoarchitectonics at NIMS (National Institute for Materials Science) press release announces and describes hydrocarbon fuel research from Japan and China first published online in Nov. 2014 and later in print in January 2015,

A combination of semiconductor catalysts, optimum catalyst shape, gold-copper co-catalyst alloy nanoparticles and hydrous hydrazine reducing agent enables an increase of hydrocarbon generation from CO2 by a factor of ten.

“Solar-energy-driven conversion of CO2 into hydrocarbon fuels can simultaneously generate chemical fuels to meet energy demand and mitigate rising CO2 levels,” explain Jinhua Ye and her colleagues at the International Center for Materials Nanoarchitectonics in their latest report. Now the research team have identified the conditions and catalysts that will maximise the yield of hydrocarbons from CO2, generating ten times previously reported production rates.

Carbon dioxide can be converted into a hydrocarbon by means of ‘reduction reactions’ -a type of reaction that involves reducing the oxygen content of a molecule, increasing the hydrogen content or increasing the electrons. In photocatalytic reduction of CO2 light activates the catalyst for the reaction.

Ye and his team introduced four approaches that each contributed to an increased reaction rate. First, they combined two known semiconductor photocatalysts strontium titanate (STO) and titania [titanium dioxide] (TiO2) – which led to the separation of the charges generated by light and hence a more effective photocatalyst. Second, the high surface area of the nanotubes was made greater by holes in the tube surfaces, which enhances catalysis by increasing the contact between the gases and catalysts. Third, the tubes were decorated with gold-copper (Au3Cu) nanoparticle co-catalysts to further enhance the catalysis, and fourth, they used hydrous hydrazine (N2H4•H2O) as the source of hydrogen.

Although the high hydrogen content of hydrous hydrazine is widely recognised in the context of hydrogen storage there are no previous reports of its use for reduction reactions. The researchers demonstrated that the reducing properties of hydrous hydrazine were so great that oxidation of the co-catalytic nanoparticles – a problem when water or hydrogen are used – was avoided.

The researchers conclude their report, “This opens a feasible route to enhance the photocatalytic efficiency, which also aids the development of photocatalysts and co-catalysts.”


The researchers on this project are associated with the following institutions:

International Center for Materials Nanoarchitectonics (MANA), and the Environmental Remediation Materials Unit,  National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814, Japan

TU-NIMS Joint Research Center, School of Material Science and Engineering, Tianjin University 92 Weijin Road, Tianjin,  P.R. China

Here’s a link to and a citation for the paper,

Photocatalytic Reduction of Carbon Dioxide by Hydrous Hydrazine over Au–Cu Alloy Nanoparticles Supported on SrTiO3/TiO2 Coaxial Nanotube Arrays by Dr. Qing Kang, Dr. Tao Wang, Dr. Peng Li, Dr. Lequan Liu, Dr. Kun Chang, Mu Li, and Prof. Jinhua Ye. Angewandte Chemie International Edition Volume 54, Issue 3, pages 841–845, January 12, 2015 DOI: 10.1002/anie.201409183 Article first published online: 24 NOV 2014

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This research is behind a paywall.

Self-assembling, size-specific nanopores or nanotubes mimic nature

I guess you can call this biomimicry or biomimetics as it’s also known. From the  State University of New York at Buffalo  July 17, 2012 news releaseby Charlotte Hsu,

Inspired by nature, an international research team has created synthetic pores that mimic the activity of cellular ion channels, which play a vital role in human health by severely restricting the types of materials allowed to enter cells.

The pores the scientists built are permeable to potassium ions and water, but not to other ions such as sodium and lithium ions.

This kind of extreme selectivity, while prominent in nature, is unprecedented for a synthetic structure, said University at Buffalo chemistry professor Bing Gong, PhD, who led the study.

Here’s how they did it (from the news release),

To create the synthetic pores, the researchers developed a method to force donut-shaped molecules called rigid macrocycles to pile on top of one another. [emphasis mine] The scientists then stitched these stacks of molecules together using hydrogen bonding. The resulting structure was a nanotube with a pore less than a nanometer in diameter.

The July 17, 2012 media advisory by Tona Kunz from the Argonne National Laboratory (one of the partners in this research) describes why creating consistently sized nanopores/nanotubes has been so difficult and offers more information about the macrocycles,

Nanopores and their rolled up version, nanotubes, consist of atoms bonded to each other in a hexagonal pattern to create an array of nanometer-scale openings or channels. This structure creates a filter that can be sized to select which molecules and ions pass into drinking water or into a cell. The same filter technique can limit the release of chemical by-products from industrial processes.

Successes in making synthetic nanotubes from various materials have been reported previously, but their use has been limited because they degrade in water, the pore size of water-resistant carbon nanotubes is difficult to control, and, more critically, the inability to assemble them into appropriate filters.

An international team of researchers, with help of the Advanced Photon Source at Argonne National Laboratory, have succeeded in overcoming these hurdles by building self-assembling, size-specific nanopores. This new capability enables them to engineer nanotubes for specific functions and use pore size to selectively block specific molecules and ions.

Scientists used groupings of atoms called ridged macrocycles that share a planar hexahenylene ethynylene core that bears six amide side chains. Through a cellular self-assembly process, the macrocycles stack cofacially, or atom on top of atom. Each layer of the macrocycle is held together by bonding among hydrogen atoms in the amide side chains. This alignment creates a uniform pore size regardless of the length of the nanotube. A slight misalignment of even a few macrocycles can alter the pore size and greatly compromise the nanotube’s functionality.

Here’s an image of the macrocycles supplied by the Agronne National Labortory,

A snapshot of a helical stack of macryocycles generated in the computer simulation.

The size specificity is  important if  nanopores/nanotubes are going to be used in medical applications,

The pore sizes can be adjusted to filter molecules and ions according to their size by changing the macroycle size, akin to the way a space can be put into a wedding ring to make it fit tighter. The channels are permeable to water, which aids in the fast transmission of intercellular information. The synthetic nanopores mimic the activity of cellular ion channels used in the human body. The research lays the foundation for an array of exciting new technology, such as new ways to deliver directly into cells proteins or medicines to fight diseases.

The research group’s paper has appeared in Nature Communications as of July 17, 2012, from Hsu’s news release,

The study’s lead authors are Xibin Zhou of Beijing Normal University; Guande Liu of Shanghai Jiao Tong University; Kazuhiro Yamato, postdoctoral scientist at UB; and Yi Shen of Shanghai Jiao Tong University and the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Other institutions that contributed to the work include the University of Nebraska-Lincoln and Argonne National Laboratory. Frank Bright, a SUNY Distinguished Professor of chemistry at UB, assisted with spectroscopic studies.

Responsible science communication and magic bullets; lego and pasta analogies; sing about physics

Cancer’s ‘magic bullet],  a term which has been around for decades, is falling into disuse and deservedly. So it’s disturbing to see it used by someone in McGill University’s (Montreal, Canada) communications department for a recent breakthrough by their researchers.

The reason ‘magic bullet for cancer’ has been falling into is disuse because it does not function well as a metaphor with what we now know about biology. (The term itself dates from the 19th century and chemist, Paul Erlich.) It continues to exist because it’s an easy (and lazy) way to get attention and headlines. Unfortunately, hyperbolic writing of this type obscures the extraordinary and exciting work that researchers are accomplishing. From the news release on the McGill website (also available on Nanowerk here),

A team of McGill Chemistry Department researchers led by Dr. Hanadi Sleiman has achieved a major breakthrough in the development of nanotubes – tiny “magic bullets” that could one day deliver drugs to specific diseased cells.

The lead researcher seems less inclined to irresponsible hyperbole,

One of the possible future applications for this discovery is cancer treatment. However, Sleiman cautions, “we are still far from being able to treat diseases using this technology; this is only a step in that direction. Researchers need to learn how to take these DNA nanostructures, such as the nanotubes here, and bring them back to biology to solve problems in nanomedicine, from drug delivery, to tissue engineering to sensors,” she said.

You’ll notice that the researcher says these ‘DNA nanotubes’ have to be brought “back to biology.” This comment brought to mind a recent post on 2020 Science (Andrew Maynard’s blog) about noted chemist and nanoscientist’s, George Whitesides, concerns/doubts about the direction for cancer and nanotechnology research. From Andrew’s post,

Cancer treatment has been a poster-child for nanotechnology for almost as long as I’ve been involved with the field. As far back as in 1999, a brochure on nanotechnology published by the US government described future “synthetic anti-body-like nanoscale drugs or devices that might seek out and destroy malignant cells wherever they might be in the body.”

So I was somewhat surprised to see the eminent chemist and nano-scientist George Whitesides questioning how much progress we’ve made in developing nanotechnology-based cancer treatments, in an article published in the Columbia Chronicle.

Whitesides comments are quite illuminating (from the article, Microscopic particles have huge possibilites [sic], by Ivana Susic,

George Whitesides, professor of chemistry and chemical biology at Harvard University, said that while the technology sounds impressive, he thinks the focus should be on using nanoparticles in imaging and diagnosing, not treatment.

The problem lies in being able to deliver the treatment to the right cells, and Whitesides said this has proven difficult.

“Cancer cells are abnormal cells, but they’re still us,” he said. [emphasis is mine]

The nanoparticles sent in to destroy the cancer cells may also destroy unaffected cells, because they can sometimes have cancer markers even if they’re healthy. Tumors have also been known to be “genetically flexible” and mutate around several different therapies, Whitesides explained. This keeps them from getting recognized by the therapeutic drugs.

The other problem with targeting cancer cells is the likelihood that only large tumors will be targeted, missing smaller clumps of developing tumors.

“We need something that finds isolated [cancer] clumps that’s somewhere else in the tissue … it’s not a tumor, it’s a whole bunch of tumors,” Whitesides said.

The upside to the treatment possibilities is that they buy the patient time, he said, which is very important to many cancer patients.

“It’s easy to say that one is going to have a particle that’s going to recognize the tumor once it gets there and will do something that triggers the death of the cell, it’s just that we don’t know how to do either one of these parts,” he said.

There is no simple solution. The more scientists learn about biology the more complicated it becomes, not less. [emphasis is mine] Whitesides said one effective way to deal with cancer is to reduce the risk of getting it by reducing the environmental factors that lead to cancer.

It’s a biology problem, not a particle problem,” he said. [emphasis is mine]

If you are interested , do read Andrew’s post and the comments that follow as well as the article that includes Whitesides’ comments and quotes from Andrew in his guise as Chief Science Advisor for the Project on Emerging Nanotechnologies.

All of this discussion follows on yesterday’s (Mar.17.10) post about how confusing inaccurate science reporting can be.

Moving onwards to two analogies, lego and pasta. Researchers at the University of Glasgow have ‘built’ inorganic (not carbon-based) molecular structures which could potentionally be used as more energy efficient and environmentally friendly catalysts for industrial purposes. From the news item on Nanowerk,

Researchers within the Department of Chemistry created hollow cube-based frameworks from polyoxometalates (POMs) – complex compounds made from metal and oxygen atoms – which stick together like LEGO bricks meaning a whole range of well-defined architectures can be developed with great ease.

The molecular sensing aspects of this new material are related to the potassium and lithium ions, which sit loosely in cavities in the framework. These can be displaced by other positively charged ions such as transition metals or small organic molecules while at the same time leaving the framework intact.

These characteristics highlight some of the many potential uses and applications of POM frameworks, but their principle application is their use as catalysts – a molecule used to start or speed-up a chemical reaction making it more efficient, cost-effective and environmentally friendly.

Moving from lego to pasta with a short stop at the movies, we have MIT researchers describing how they and their team have found a way to ‘imprint’ computer chips by using a new electron-beam lithography process to encourage copolymers to self-assemble on the chip. (Currently, manufacturers use light lasers in a photolithographic process which is becoming less effective as chips grow ever smaller and light waves become too large to use.) From the news item on Nanowerk,

The new technique uses “copolymers” made of two different types of polymer. Berggren [Karl] compares a copolymer molecule to the characters played by Robert De Niro and Charles Grodin in the movie Midnight Run, a bounty hunter and a white-collar criminal who are handcuffed together but can’t stand each other. Ross [Caroline] prefers a homelier analogy: “You can think of it like a piece of spaghetti joined to a piece of tagliatelle,” she says. “These two chains don’t like to mix. So given the choice, all the spaghetti ends would go here, and all the tagliatelle ends would go there, but they can’t, because they’re joined together.” In their attempts to segregate themselves, the different types of polymer chain arrange themselves into predictable patterns. By varying the length of the chains, the proportions of the two polymers, and the shape and location of the silicon hitching posts, Ross, Berggren, and their colleagues were able to produce a wide range of patterns useful in circuit design.

ETA (March 18,2010): Dexter Johnson at Nanoclast continues with his his posts (maybe these will form a series?) about more accuracy in reporting, specifically the news item I’ve just highlighted. Check it out here.

To finish on a completely different note (pun intended), I have a link (courtesy of Dave Bruggeman of the Pasco Phronesis blog by way of the Science Cheerleader blog) to a website eponymously (not sure that’s the right term) named physicssongs.org. Do enjoy such titles as: I got Physics; Snel’s Law – Macarena Style!; and much, much more.

Tomorrow: I’m not sure if I’ll have time to do much more than link to it and point to some commentary but the UK’s Nanotechnologies Strategy has just been been released today.

More titanium dioxide news; the 5th anniversary of the Royal Society’s Report on Nanotechnology; Copyright in Canada

While titanium dioxide particles in sunscreens are considered safe (see my blog posting here), there is a new study which suggests concerns. A study was done in Japan on pregnant mice who were injected with titanium dioxide nanoparticles. The results suggest that the particles affected brain development in the foetuses. (The media release is located at Nanowerk News here.) My questions since I haven’t looked at the study are this:  Where was the injection site? What was the concentration of  titanium dioxide nanoparticles in the solution? Where several concentrations used or only one? (After all, a lot of medicines are poison if taken in the wrong dosage or misapplied [taken internally instead of externally].)

Still on the titanium dioxide trail, there’s a study by researchers in Switzerland which suggests that nanowires and nanotubes made of titanium dixoide are toxic. There’s an article by Miichael Berger here on Nanowerks. From Berger’s article,

One of the complications of nanotoxicology is that the toxicity of a specific nanomaterial cannot be predicted from the toxicity of the same material in a different form.

“TiO2 nanoparticles are widely used as UV blockers in sunscreens” says Arnaud Magrez [researcher]. “Their cytotoxicity has been tested before and they were found to be rather non-toxic. Our new study shows that TiO2 based nanofilaments, however, can be quite toxic. The geometry of nanoparticles appears to play a crucial role in cytotoxicity. Furthermore, the toxicity can be enhanced by the presence of defects on the nanofilament surface, resulting from chemical treatment.”

Both of these studies highlight why more research needs to be done. A comment which is made in an entirely different context by Dr. Andrew Maynard in his essay commemorating the anniversary of the Royal Society/Royal Academy of Engineering 2004 report on nanotechnologies. Maynard’s essay is the foreword to a report, 5 years on – a beacon or just a landmark? Reflections on the 2004  Royal Society/Royal Academy of Engineering report into nanotechnologies – what was its impact and what is its legacy? published by the Responsible Nano Forum. Maynard’s essay can be read here on his 2020 Science blog and the report can be found here. From Maynard’s essay,

At the time, concerns were mounting over possible new risks associated with creating materials and devices at the nanoscale, and how these would affect the technology’s development.  The previous year, Michael Crichton’s book Prey had sent the nanotech community into a tizzy over a speculative public backlash against the emerging science and technology.  And researchers were beginning to reveal hints that novel nanoscale materials could also affect humans and the environment in unconventional ways—getting to places and causing harm on a scale that belied their small size.

Do read it if you have the time. Maynard’s perspective is both historical and contemporary.

And now for something which concerns me when writing this blog, copyright. Since this blog isn’t profitmaking and I give attribution and encourage people to visit the sites and blogs I quote from, I’ve considered what I do ‘fair use’. If you’ve been following the copyright discussion, you know ‘fair use’ is being debated fiercely as is intellectual property law which includes copyright, patents, and trademarks.

After a rather disastrous attempt to introduce new copyright legislation (last fall I think), the Canadian government has launched a public consultation process. (I too was surprised to find out about it.) The roundtable meeting in Vancouver took place about 10 days ago. There will be roundtable meetings  elsewhere and two town hall meetings (where the public will be invited). If you’re a member of the public who’s lucky enough to live in either Toronto or Montreal, you can have your say in real time. The rest of us can participate online here at the Copyright Counsultations website. You do have to register to participate. The Vancouver roundtable meeting has been transcribed and is available online here and the trasncript for the Calgary roundtable is here.

HIV testing, nano gold, and Uganda; not so obsolete?; new nanotube manufacturing technique from McGill University

There’s a portable blood-testing machine, designed by US-based PointCare, which can give a print-out detailing a patient’s immune status in 10 minutes. The machine was designed for use in third-world or developing world clinics such as the one in Uganda which is described in this BBC story.

One of the problems doctors and medical staff had with equipment for testing HIV patients’ immune system was that the chemicals used as reagents in the testing process were too easily perishable in the high heat common in a lot of countries. PointCare soved the problem this way (from the BBC article):

Dr Hansen [from PointCare] invented a test that uses chemical reagent that can be freeze-dried and stored in temperatures of over 40C.

CD4 screening tests use antibodies – molecular tags that recognise and latch onto a chemical marker on the surface of the cell. By attaching to the cells, they act as flags distinguishing CD4 cells from other white blood cells.

But these antibodies need to be “labelled”, so they can be detected by a machine.

Traditionally, antibodies are labelled using fluorescent markers, but these fluorescent chemicals perish if they are not kept refrigerated. So they’re useless for a medical team operating from a temporary clinic in the heat of an African summer.

Dr Hansen developed a new label. “We use colloidal gold,” explains Dr Krauledat [community physician]. “It’s true nanotechnology – extremely tiny gold particles attached to the anti-CD4 antibody.”

Do go and read the full story because there’s more to it than I’ve included. Meanwhile I had another look at those lithography stories (SFU’s new maskwriting facilities and RAPID) that I was posting about last week. While the new RAPID technique may make the use of ultra-violet light obsolete, they still haven’t approached the nanoscale. The measurement mentioned is “… 2500 times smaller than a human hair” [more here]. The measurement usually mentioned when discussing the nanoscale  is between 1/100,000 ro 1/60,000 (nobody seems to agree on the exact measurement, you can check here) of the width of a human hair equals 1 nanometre.  Weirdly, the Simon Fraser University (SFU) release notes that the new facilities will be able to create structures “… under 20 nanometres about 10,000 times smaller than the diameter of a human hair” [more here]. If I’m doing the math correctly, wouldn’t that be between 1/50,0000 and 1/30,000 of the human hair? I know it’s a little fussy but once a technical writer, always a technical writer and that kind of detail can make a big difference.

Researchers led by Dr. Hanadi Sleiman and Dr. Gonzalo Cosa at McGill University (Montreal, Canada) have developed a new way to manufacture nanotubes using DNA, in short they are DNA nanotubes. The longer story is here and the shorter story is here.

Healthy carbon nanotubes? or mesothelioma

It seems there are two studies that have been published about multiwalled, long carbon nanotubes having effects similar to asbestos on mice according to the International Council on Nanotechology’s backgrounder here. Short of looking up the articles in Nature Nanotechnology or the Journal of Toxicological Sciences, the briefing gives a pretty good description of the experimental methods used in each of the studies and some of the issues associated with each. For example, were there any possible contaminants and did they have any impact on the results? That’s the research process isn’t it? Testing an hyothesis, examining the results, and testing again as we add to the body of knowledge.

The study reported in Natural Nanotechnology is getting a lot of attention from different sectors, including the investment sector. According to the blog, 24/7 Wall St., the exchange-traded fund, PowerShares Lux Nanotech, experienced a dip shortly after the study was released.

It’s such early days yet, that’s it hard to know how to interpret any of this but it bears thinking about anyway, especially as I get ready to produce my nanotechnology wiki. (more about the wiki tomorrow)