A tutorial review available after free registration presents a theory-based exploration of the difficulty in moving from simple molecular switches to arrays of artificial molecular machines capable to doing substantial, useful external work.

A tutorial review addresses the distinction between the many simple artificial molecular devices that are currently available and truly effective artificial molecular machines that would mimic the ubiquitous molecular machines present in living systems.

RNA nanostructures chemically modified to be resistant to degradation retain 3D structure and biological activity.

Robert A. Freitas Jr. has made available his chapter on nanorobotics from the book The Future of Aging.

Hogg and Freitas provide a theoretical analysis of the power constraints when nanorobots rely entirely on ambient bloodstream oxygen and glucose and identify aspects of nanorobot design that significantly affect available power.

Futurisms – Critiquing the project to reengineer humanity: Happy Birthday, Nanotechnology?. Adam Keiper over at the New Atlantis reminds us it’s the 50th anniversary of Feynman’s Plenty of Room at the Bottom talk.

Futurists make lots of predictions, and usually by the time they can be tested they’ve been long forgotten. That’s great when we get them wrong (which is a lot more often than we’d like!) but I take pleasure in claiming I got one right. In this post I wrote: So what’s the next paradigm shift? [...]

Nanopolis writes "Imagine what would happen if you could introduce your break-through technology to thousands of viewers comprised of venture capitalists, banks, investors, brokerage firms, industrial and research players?

Find out by participating in the collaborative Nanopolis encyclopedias. The exclusive multimedia "Exploring Nanotechnology" encyclopedia CD-ROM will be launched within 30 days !

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Roland Piquepaille writes "Laser lights can be used for optical sensing applications, for example to identify unknown gases emitted by an engine. And as these unknown substances react differently to different wavelengths, researchers at the University of Wisconsin at Madison have developed unique wavelength-agile lasers. And I'm amazed by the beauty and the simplicity of their idea. They're using white lasers which produce all colors simultaneously — but with a twist. The white laser light goes through a 20-kilometers long optical fiber before reaching its target. And because different colors 'travel' at different speeds, this produces independent results for the different wavelengths. The researchers are using spectral resolutions smaller than a thousandth of a nanometer and they are able to get all the results within a millionth of a second. This method could be used to design cleaner engines or data storage applications in a few years. Read more for other details, pictures and references."

Just a reminder that the NSTI Nanotechnology Conference and Trade Show is coming up May 8-12, 2005 at the Anaheim Marriott & Convention Center in Anaheim, California. From the looks of the confirmed speaker list many people who have been mentioned on Nanodot or who have spoken at previous Foresight Insitute Conferences will be there.

Also worth noting is that the super early registration period for the Foresight Institute's 13th annual conference which will be in San Francisco October 22-27th, 2005 ends June 1st. The first two days are essentially what was previously known as the "Senior Associates" conference. The last four days are about busines, policy and R&D progress. This is explained in greater detail in the conference brochure here.

Roland Piquepaille writes "Today, anticancer drugs are delivered to patients in such a way that they can destroy both infected and healthy cells. But now, researchers at the Institute of Bioengineering and Nanotechnology (IBN), in Singapore, have designed 'smart' nanocarriers which deliver the drugs exactly where they are needed, reducing side effects and suppressing cancer growth. Their core-shell nanoparticles are both sensitive to temperature — which has been done before — and to acidic levels. When these nanocarriers encounter acidic environments such as tumor tissues, they break apart and release the molecules they contain. So far, this technology has only been tested on mice, but the researchers have filed an application patent in the U.S., so expect to see practical applications in a few years. Read more for other details and references. [Additional note for purists: these nanocarriers are "smaller than 200 nm," which doesn't guarantee they fit within the strict definition of nanotechnology. However, if the Advanced Materials journal thinks these are nanoparticles, who am I to argue?]"

Science Daily is documenting that Zhiyu Hu and associates, researchers at ORNL has developed a method for binding platinum nanoparticles to glass wool fibers that will enable a nano-catalytic reaction (aren't *all* catalytic reactions "nano-" by definition?) to allow self-combustion of methanol at temperatures ranging from room temperature to 600 deg. C.

Betterhmans is reporting on progress of scientists at USC in combining several nanoscale technologies (transferrin based transport vehicles with small interfering RNA segments (siRNAs)) to effectively combat cancer, in this case Ewing's sarcoma, a type of cancer which impacts children. Interfering RNAs are small RNA strands which preferentially bind to complementary messenger RNA (mRNA). This activates cellular processes, presumably evolved to defend against double stranded RNA viruses, that destroy the double stranded RNA effectively reducing or eliminating the activity of the protein normally produced by the specific mRNA targeted by the siRNA.

The article with links to background information is here. There is significant potential for using this type of therapy to combat other types of cancer where the overexpression of a specific gene or protein is the primary cause of the disease.

While this is not diamondoid molecular nanotechnology it it can legitimately be considered molecular nanotechnology because it is nanoscale, it is based on precision activity at the nanoscale level and takes advantage of molecular processes and machinery normally found in cells.

Sandia is reporting that porphyrin nanotubes coated with gold on the inside and platinum on the outside may be able to use sunlight to split water and produce hydrogen. The tubes are actual nanoscale devices having diameters from 50-70nm and tube walls 20nm thick. Scientists indicated that the tubes may be able to use the ultraviolet part of the solar spectrum as well as the visible which would likely make them more efficient than solar cells unable to do this.

This fits well with recent articles discussing energy production as one key application of nanotechnology.

Check out the new journal Small from Wiley Interscience, publisher of the book Nanosystems. Sample article from the first issue: "Powering a Supramolecular Machine with a Photoactive Molecular Triad" and from issue 3: "DNA Nanodevices". Most articles are on nanostructures which are not atomically precise, such as from issue 5: "Halloysite Nanotubes as Biomimetic Nanoreactors". (OK, maybe that last title is a bit jargony…) A problem: many articles have no free abstract.

In some rather stunning work, Joseph AuBuchon, a graduate student in Sungho Jin's group at UCSD, has demonstrated how to make *bent* nanotubes. PhysOrg has a report here. (Check out the pictures!) They also claim to be able to make T and Y shapes out of nanotubes.

This could be a potential start towards methods that might be used to construct subcomponents for a real molecular assembler. That would allow one to bypass the chicken and egg problem we now face.

Roland Piquepaille writes "Researchers at the University of Toronto (U of T) have designed an infrared-sensitive material made of nanocrystals so small they were able to tune them to catch the Sun's invisible rays. In "Nanotechnologists' new plastic can see in the dark," you'll discover that it's the first time that a light-sensitive material works in the invisible light spectrum. This opens the way to a broad range of applications, from clothing to digital cameras that work in the dark. But the real breakthrough is that it will permit to catch five more times energy from the Sun, up to 30 percent from the 6 percent achieved today by the best plastic solar cells. Hats off to these researchers… This overview contains more details, comments and references."

Erik Winfree's group at CALTECH, led by Paul Rothemund, is reporting in PLOS that they have successfully implemented DNA based cellular automata. It is uses two-dimensional self-assembly of DNA tiles to produce Sierpinski triangles. Technology Research News has a summary article and Slashdot may have additional discussion.

Roland Piquepaille writes " Physicists from several U.S. labs have clocked the transition of vanadium dioxide nanoparticles from a transparent to a reflective, mirror-like state, at less than 100 femtoseconds (a tenth of a trillionth of a second). According to this Vanderbilt University report, this effect has a size limit: "it does not occur in particles that are smaller than about 20 atoms across (10 nanometers)." This opens the door — if I can say so — to windows that are transparent at low temperatures and block out sunlight when the temperature rises. But other applications are possible, such as nanosensors which could measure the temperature at different locations within human cells, or "ultrafast" optical switches which could be used in communications and optical computing. Read this overview for more details, references and a surprising nanoscale image of Don Quixote and Sancho Panza."

Scientists at LBL and LLNL are reporting that using a clever method of attaching quantum dots to the protein used by the SV40 virus to target it to the cell nucleus they can get quantum dots inside the nucleus. If this were combined with Sangamo Biosciences method of using its engineered zinc fingers to target specific chromosome locations one could use quantum dots to provide information about *where* those chromosomes are within the nucleus as well as perhaps whether or not the genes are active.

This could potentially be much faster than current chemical methods for determining cellular gene activity. Or how living cells respond to different signals in succession (something which is more difficult to do with chemical methods).