It's the all-nano action edition of Friday Catch-Up! This week: titanium nanotubes and solar hydrogen; the Centers for Nanotechnology and Society and the Nanoethics group look at the social impact of nanotech; carbon nanotubes wrapped in DNA -- for a good reason; and a detailed look at the key next-generation nanotechnology, the nanofactory.
Hail, Titania: Everybody likes to talk about carbon nanotubes (including yours truly), but the action in non-carbon nanotubes is really heating up. Penn State scientist Craig Grimes and his group have found that nanotubes made from the element titanium can significantly boost the effectiveness of solar technologies. Adding titanium nanotube structures to low-efficiency dye solar cells boosted their efficiency enough to make them potentially competitive with traditional silicon photovoltaics, and using titanium nanotubes in a "water photolysis" system made it possible to crack hydrogen from water with 13.1% efficiency -- that's more than double the best results of just a year ago. The drawback? It works best under ultraviolet light. However, according to Dr. Grimes, "If we could successfully shift its bandgap into the visible spectrum we would have a commercially practical means of generating hydrogen by solar energy. It beats fighting wars over middle-eastern oil.”
Nanotechnology, Society and Ethics: On January 30, Arizona State University becomes the next university to open a Center for Nanotechnology and Society; the first CNS opened at UC Santa Barbara late last year. Both CNS groups are underwritten by the National Science Foundation, and seek to better understand the non-engineering dilemmas surrounding emerging nanotechnologies. They also form an important part of the growing International Nanotechnology and Society Network, which has representatives from 37 institutions in 11 countries.
While CNS and INSN represent a traditional academic approach to nanotech and society, The Nanoethics Group looks more like a small NGO. Nanoethics is a research group, not an advocacy group, with a strict focus on ethics:
In contrast to scientists and advocates who comment on matters of philosophy, we are professional ethicists with the right business and scientific background to share insights into the discipline we know best. [...] Finally, we want to open up the issues to the people who will be most affected by nanotechnology: the ordinary person. Not just for technologists or academia, we want to engage the broader public now - instead of waiting for their last-minute panic and surprise that usually derails progress - by making complex issues accessible and more easily understood.
The Nanoethics advisory board displays an intersection of NGOs, businesses and scholars, and includes such familiar names as Chris Phoenix and Mike Treder of the Center for Responsible Nanotechnology and bioethicist Dr. James Hughes, previously interviewed here on WorldChanging.
Carbon Nanotubes Getting Under Your Skin: One of the key ethical issues surrounding nanotech, of course, is safety. Enthusiasm for the myriad applications of carbon nanotubes, for example, has been tempered of late by reports of potentially serious biological risks under certain conditions combining nanotubes and cells. Fortunately, groups like the Woodrow Wilson International Center for Scholars' Project on Emerging Nanotechnologies and Rice University's Nano Risk and Benefit Database do an excellent job of compiling and assessing reports of health risks arising from nanomaterials.
It's this context, then, that triggers a bit of surprise at research done at the University of Illinois at Urbana-Champaign. A UIUC chemical and biomolecular engineering team led by Dr. Michael Strano has found that the properties that lead single wall carbon nanotubes to bind so closely to DNA allow a nanotube wrapped in DNA to be used as a supremely sensitive toxic material sensor potentially usable even within living cells.
When the sensor's DNA encounters ions of atoms like mercury and sodium, it changes shape; this, in turn, flexes the nanotube, which changes the way it fluoresces in infrared light. The researchers found that the DNA-nanotube sensors could detect very low concentrations of mercury in blood and tissues, signaling changes via infrared fluorescence (which can be detected through solid tissue). This is still years away from any possible application, but it's interesting to see the development of beneficial nanotube uses that take advantage of their biological behavior.
Inside a Nanofactory: The nanofactory -- a system to build physical goods from the bottom-up, atom-by-atom -- is a form of nanotechnology that remains just off in the future. We've covered the different categories of nanotech in the past, and the nanofactory is the one with the greatest disruptive potential. When nanofactories arrive, all of our lives, around the world, will be changed. But just how would one of these things work?
CleanRooms magazine, a journal of process technologies, has a relatively technical article about nanofactories, written by Bruce Flickinger. It won't require an engineering degree to understand, but it's a step or two more complex than one might expect from a popular media article. The usual suspects show up -- Ralph Merkle, Chris Phoenix, Robert Freitas -- but this article gives one of the best depictions I've seen of the near-term plausibility of these devices. The article also discusses some of the issues around contamination control, as well as the potential application of similar technologies in the biomedical arena.
Freitas points to four overarching biocompatibility issues for nanorobotics:
1. Are the devices reliable in the sense of not malfunctioning once deployed and doing only what is intended with zero side effects?
2. Can the devices be removed safely and completely from the body once their mission is completed?
3. Will the body’s natural defenses accept the presence of a nanodevice without attacking it, and will a nanodevice possess active means to avoid eliciting such responses, or avoid succumbing to them if they are elicited?
4. Will the presence or operations of medical nanorobots inside the body interfere with natural biochemical, physiological, biomechanical or other processes?
I know that I regularly argue that we need to start thinking now about some technology or development that won't be around for another five, ten or twenty years, but it's absolutely the most important thing we can do regarding emerging nanotechnologies. The potential benefits of these materials and tools are enormous -- from easily meeting (and bettering) the Millennium Development Goals to fantastic leaps ahead in the efficiency of renewable power, just to mention two -- but so are the potential risks. When these technologies arise, there's every reason to think we'll be so dazzled and/or frightened by what they can do that many of us would be prone to making decisions based more on immediate reaction than on serious thought. And while we can't predict exactly how these technologies will turn out, we can come up with some pretty reasonable scenarios, letting us "wind tunnel" our ideas.
In short, I was us as a global society to be able to make the right choices when it comes to nanotechnology, because choosing wrong can have some pretty dramatic consequences.
Just a slight not, a Nanofactory is different from a Nanobot which is what Cleanrooms seems to be talking about.
Think of a Nanofactory as a extremely advanced Stereo-Lithography machine. A Nanobot would be analogous to RNA. The latter is the subject of a vigourous debate as to their feasiblity and even wether it violates the Laws of Thermodynamics or not.
Nanobots, in the Feynmann/Drexler sense, violate the laws the thermodynamics? That's news to me.
And I don't know if I really agree with the characterization of the nanofactory as being analogous to stereo-lith. The way it's described and portrayed it's more like playing lego atoms and molecules--a tiny factory filled with atom stacking machines.
But I agree that the distinction between a nanofactory and nanobot should be made.
I was trying to say it in more laymens terms and the only way it's really comparable to Stereo-lith is that it's on a desktop. I agree with the lego-block explanation, its much better explanation. I was just trying to draw a real world comparison.
As for the Thermodynamics debate its all Greek to me, my Physics prof just mentioned it briefly when I asked him and he thought that it may violate it, at least a "Hard" Nanobot(ei Strained bonds versus flexible bonds)
I think if we are to ever develop a working Nanobot it would have to be modeled off of the Nanobot in Nature and not our conception of them.
Here is a site that goes into some detail about the debate of Soft Nanobots versus Hard Nanobots.
"When the sensor's DNA encounters ions of atoms like mercury and sodium, it changes shape; this, in turn, flexes the nanotube, which changes the way it fluoresces in infrared light. The researchers found that the DNA-nanotube sensors could detect very low concentrations of mercury in blood and tissues, signaling changes via infrared fluorescence (which can be detected through solid tissue). This is still years away from any possible application, but it's interesting to see the development of beneficial nanotube uses that take advantage of their biological behavior."
I still remember the surprise I felt when learning from Guyton "Neuroscience: Anatomy and Physiology" that neurons transmitted signals via sodium ions. I had not previously thought of how the brain operated on a cell-by-cell level.
The question to be answered is this - are there any differences in the reactions various atoms, molecules, ions, etc, cause? Is there a discernable difference in the way a given nanotube will react to a sodium ion solution as opposed to a mercury ion solution? Eg, wavelength, polarization?
If so, it then becomes a sharp diagnostic tool. If not, it's a more blunt diagnostic tool, but still useful to a more limited degree.