Tag Archives: asbestos

The latest in bulletproof vests: carbon nanotubes

Amendment II; An American Combat Apparel Company as it bills itself on Facebook, is offering new bulletproof body armour utilizing RynoHide, a carbon nanotube composite. From the April 26, 2012 news item on Nanowerk,

RynoHide™, the world’s first Carbon Nanotube compound for ballistic and shrapnel resistant products is now available to the personal protection equipment industry and the general public. On the cutting edge of scientific innovation, RynoHide is lighter than any other compound on the market, yet provide greater user protection from back-face deformation of projectiles. Designed to meet the needs of all military and law enforcement operations, RynoHide is also affordable for public consumers.

Here’s a 2 min. video where RynoHide’s bulletstopping capabilities are demonstrated,

Since carbon nanotubes have been compared to asbestos and there is research which indicates that they behave like asbestos fibres when inhaled (my Sept. 22, 2011 posting), I’d be a little nervous about the fibres which are spewed when the bullet hits the composite. It’s possible that these carbon nanotubes are encapsulated and are not released into the environment when a bullet or projectile hits the material but I have looked around on the Amendment II company website and was not able to find any information about safety and carbon nanotubes.

Perhaps in the excitement they forgot to include any details about the carbon nanotubes, how they are integrated into the composite, and the safety testing. The April 26, 2012 news item highlights one of the product’s big advantages,

Traditional armor is designed to stop projectiles moving thousands of feet per second from penetration and back-face deformation. Back-face deformation is the bulge that occurs in the back of the armor from a projectile hitting the front without passing completely though. Traditional armor is designed to minimize these threats by using 20 to 30 layers of a high tensile strength synthetic aramid, such as Kevlar.

The acceptable back-face deformation limit for body armor, as set by the National Institute of Justice, is 44mm, or nearly two inches. RynoHide helps body armor achieve a back-face deformation level in the low 30’s, without increasing the weight of the armor.

Less back-face deformation means less hurt on the body.

“That’s a huge advantage for the user of the armor if they get hit,” says R.G. Craig, President of Amendment II. “It could be the difference between a stay in the hospital or simply going home at the end of the day to your family.” Such protection is achieved without compromise in comfort and convenience.

The product was developed at the University of Utah’s Nano Institute in partnership with Amendment II.

Why asbestos and carbon nanotubes are so dangerous to cells

Sphere or spear? Apparently cells can’t tell that an asbestos fibre or long carbon nanotube are spears due to their rounded tips according to researchers at Brown University. From the Sept. 18, 2011 news item on Nanowerk,

Through molecular simulations and experiments, the team reports in Nature Nanotechnology that certain nanomaterials, such as carbon nanotubes, enter cells tip-first and almost always at a 90-degree angle. The orientation ends up fooling the cell; by taking in the rounded tip first, the cell mistakes the particle for a sphere, rather than a long cylinder. By the time the cell realizes the material is too long to be fully ingested, it’s too late.

Here’s a representation of what the scientists mean,

 

Something perpendicular this way comes Cells ingest things by engulfing them. When a long perpendicular fiber comes near, the cell senses only its tip, mistakes it for a sphere, and begins engulfing something too long to handle. Credit: Gao Lab/Brown University

Here’s what happens when a cell encounters a carbon nanotube, asbestos fibre, gold nanowires, and other materials that are long and perpendicular with rounded tips,

Like asbestos fibers, commercially available carbon nanotubes and gold nanowires have rounded tips that often range from 10 to 100 nanometers in diameter. Size is important here; the diameter fits well within the cell’s parameters for what it can handle. Brushing up against the nanotube, special proteins called receptors on the cell spring into action, clustering and bending the membrane wall to wrap the cell around the nanotube tip in a sequence that the authors call “tip recognition.” As this occurs, the nanotube is tipped to a 90-degree angle, which reduces the amount of energy needed for the cell to engulf the particle.

Once the engulfing — endocytosis — begins, there is no turning back. Within minutes, the cell senses it can’t fully engulf the nanostructure and essentially dials 911. “At this stage, it’s too late,” Gao [Huajian Gao] said. “It’s in trouble and calls for help, triggering an immune response that can cause repeated inflammation.”

I gather this is the starting point for mesothelioma. Here’s a description of the process (from the Brown University Sept. 18, 2011 news release,

“We thought the tube was going to lie on the cell membrane to obtain more binding sites. However, our simulations revealed the tube steadily rotating to a high-entry degree, with its tip being fully wrapped,” said Xinghua Shi, first author on the paper who earned his doctorate at Brown and is at the Chinese Academy of Sciences in Beijing. “It is counter-intuitive and is mainly due to the bending energy release as the membrane is wrapping the tube.”

Here’s a video from Brown illustrating the process,

Cells bite off more than they can chew from Brown PAUR on Vimeo.

The whole thing has me wondering about long vs. short carbon nanotubes. Does this mean that short carbon nanotubes can be ingested successfully? If so, at what point does short become too long to ingest? It doesn’t seem like my questions are going to be answered too soon since the team would like to go in this direction (from the Brown news release),

The team would like to study whether nanotubes without rounded tips — or less rigid nanomaterials such as nanoribbons — pose the same dilemma for cells.

“Interestingly, if the rounded tip of a carbon nanotube is cut off (meaning the tube is open and hollow), the tube lies on the cell membrane, instead of entering the cell at a high-degree-angle,” Shi said.

Art conservation and nanotechnology; the science of social networks; carbon nanotubes and possible mesothelioma; Eric Drexler has a few words

It looks like nanotechnology innovations in the field of art conservation may help preserve priceless works for longer and with less damage. The problem as articulated in Michael Berger’s article on Nanowerk is,

“Nowadays, one of the most important problems faced during the cleaning of works of art is the removal of organic materials, mainly acrylic polymers, applied in the past as consolidants or protective coatings,” explains Piero Baglioni, a professor of Physical Chemistry at the University of Florence. “Unfortunately, their application induces a drastic alteration of the interfacial properties of the artwork and leads to increased degradation. These organic materials must therefore be removed.”

Baglioni and his colleagues at the University of Florence have developed “… a micro-emulsion cleaning agent that is designed to dissolve only the organic molecules on the surface of a painting …”

This is a little off Azonano’s usual beat (and mine too) but Rensselaer Polytechnic Institute’s Army Research Laboratory is launching an interdisciplinary research center for the study of social and cognitive networks.  From the news item,

“Rensselaer offers a unique research environment to lead this important new network science center,” said Rensselaer President Shirley Ann Jackson. “We have assembled an outstanding team of researchers, and built powerful new research platforms. The team will work with one of the largest academic supercomputing centers in the world – the Rensselaer Computational Center for Nanotechnology Innovations – and the leading visualization and simulation capabilities within our new Experimental Media and Performing Arts Center. The Center for Social and Cognitive Networks will bring together our world-class scientists in the areas of computer science, cognitive science, physics, Web science, and mathematics in an unprecedented collaboration to investigate all aspects of the ever-changing and global social climate of today.”

The center will study the fundamentals of social and cognitive networks and their roles in today’s society and organizations, including the U.S. Army. The goal will be to gain a deeper understanding of these networks and build a firm scientific basis in the field of network science. The work will include research on large social networks, with a focus on networks with mobile agents. An example of a mobile agent is someone who is interacting (e.g., communicating, observing, helping, distracting, interrupting, etc.) with others while moving around the environment.

My suspicion is that the real goal for the work is to exploit the data for military advantage, if possible. Any other benefits would be incidental. Of course, a fair chunk of the technology we enjoy today (for example, tv and the internet) was investigated by the military first.

I’ve mentioned carbon nanotubes and possible toxicology before. Specifically, some carbon nanotubes resemble asbestos fibers and pilot studies have suggested they may behave the same way when ingested by one means or another  into the body. There is a new confirmation of this hypothesis with a study where mice inhaled carbon nanotubes. From the news item on Nanowerk,

Using mice in an animal model study, the researchers set out to determine what happens when multi-walled carbon nanotubes are inhaled. Specifically, researchers wanted to determine whether the nanotubes would be able to reach the pleura, which is the tissue that lines the outside of the lungs and is affected by exposure to certain types of asbestos fibers which cause the cancer mesothelioma. The researchers used inhalation exposure and found that inhaled nanotubes do reach the pleura and cause health effects.

This was one exposure and the mice recovered after three months. More studies will be needed to determine the effects of repeated exposure. This study (Inhaled Carbon Nanotubes Reach the Sub-Pleural Tissue in Mice by Dr. James Bonner, Dr. Jessica Ryman-Rasmussen, Dr. Arnold Brody, et. al.) can be found in the Oct. 25, 2009 issue of Nature Nanotechnology.

On Friday (Oct. 23, 2009) I mentioned an essay by Chris Toumey on the forthcoming 50th anniversary of Richard Feynman’s seminal talk, There’s plenty of room at the bottom. Today I found a response to the essay by Eric Drexler.  From Drexler’s essay on Nanowerk,

Unfortunately, yesterday’s backward-looking guest article in Nanowerk reinforces the widespread but quite mistaken idea that my views are essentially the opposite of what I’ve stated above, and that those perverse ideas are also those of the Foresight Institute. I cannot speak for that organization, or vice versa, because I left it years ago. Contrary to what the article may suggest, I have no affiliation with the organization whatsoever. Regarding terminology, it is of course entirely appropriate to use the term “nanotechnology” to describe nanoscale technologies. The idea that there is a conflict between progress in the field and future applications of that progress is puzzling. This idea appears to stem from a strange episode that came to a head during the political push for the bill that established and funded the U.S. National Nanotechnology Initiative, an episode in which some leading science spokesmen quite properly rejected a collection of popular fantasies, but quite improperly attributed those fantasies to me. Reading claims by confused enthusiasts and the press that “Drexler says this” or “Drexler says that” is no substitute for reading my journal articles, or the technical analysis in my book, Nanosystems, and in my MIT dissertation). The failure of these leaders to do their homework has had substantial and lingering toxic effects.

(My own focus was on the ‘origin’ story for nanotechnology and not on Drexler’s theories.) If I understand the situation rightly, much of the controversy has its roots in Drexler’s popular book, Engines of Creation. It was written over 20 years ago and struck a note which reverberates to this day. The irony is that there are writers who’d trade places with Drexler in a nano second. Imagine having that kind of impact on society and culture (in the US primarily). The downside as Drexler has discovered is that the idea or story has taken on its own life. For a similar example, take Mary Shelley’s book where Frankenstein is not the monster’s name, it’s the scientist’s name. However, the character took its own life and name.