Nanotechnology

By closely mimicking human walking, a molecule was designed that can move in a straight line on a flat surface, US scientists reported on Monday.

This so-called "nano-walker" will offer a new approach for storing large amounts of information on a tiny chip and demonstrate that concepts from the world we live in can be duplicated at the scale of atoms and molecules, scientists said.

The researchers at the University of California, Riverside, have published their work in next month's issue of Physical Review Letters.

The molecule, 9,10-dithioanthracene or "DTA," has two linkers that act as feet. Obtaining its energy from heat supplied to it, the molecule moves such that only one of the linkers is lifted from the surface; the remaining linker guides the motion of the molecule and keeps it on course.

"Keep cool to reduce friction" might be the advice given designers of nanoscale machinery by researchers who have just completed a study of factors influencing the formation of "water bridges" – capillary connections that can glue surfaces together, giving rise to friction forces.

When surfaces touch in a humid environment, moisture forms water bridges, or capillaries, between them. On familiar size scales, this process – known as nucleation – helps hold sand castles and wet concrete together, and is critical to the formation of clouds. But sometimes these structures can be less helpful, causing friction sufficient to slow or even stop nanoscale machinery – or in food processing, creating large clusters of sugar, salt, baby cereals or coffee.

By studying the frictional forces acting on an atomic force microscope (AFM) tip drawn across a glass surface, researchers at the Georgia Institute of Technology have demonstrated for the first time that the formation of these capillaries is thermally activated. Their study suggests that it may be possible to reduce the adhesion between surfaces by reducing temperatures and putting nanoscale surfaces into motion before the water bridges have time to form.

Nano-sized carbon tubes coated with strands of DNA can create tiny sensors with abilities to detect odors and tastes, according to researchers at the University of Pennsylvania and Monell Chemical Sciences Center. Their findings are published in the current issue of the journal Nano Letters, a publication of the American Chemical Society.

According to the researchers, arrays of these nanosensors could detect molecules on the order of one part per million, akin to finding a one-second play amid 278 hours of baseball footage or a single person in Times Square on New Years' Eve. In the report, the researchers tested the nanosensors on five different chemical odorants, including methanol and dinitrotoluene, or DNT, a common chemical that is also frequently a component of military-grade explosives. The nanosensors could sniff molecules out of the air or taste them in a liquid, suggesting applications ranging from domestic security to medical detectors.

The main objectives of the project are (i) to develop versatile, inexpensive, and easy-to-use diagnostic tools for health, environmental and other applications based on the measurement of molecular interactions (ligand-receptor interactions) by integrated micro- and nano-cantilever sensors and (ii) to test the developed diagnostic tools in two specific health care applications, namely (1) the detection of tumour markers in clinical diagnosis and (2) the high-sensitivity detection of proteins, providing a verification of the project's achievements and initiating a generation of innovative products with significant market potential. The proposed project capitalizes on the mechanical properties of micro- and nano-mechanical structures (cantilevers) to measure molecular (ligand-receptor) interactions.

Already being intensely studied as an agent for cleaning up toxic waste, a strain of bacteria has now surprised researchers with its ability to build conducting nanowires.

The long, very thin wires are unprecedented in biological systems, says the microbiologist who discovered the bacteria and the wires' conductivity. They completely change science's understanding of how microbes handle electrons, he said.

Derek Lovley and his colleagues at the University of Massachusetts (Amherst, Mass.) reported observing and measuring the conductivity of long wires, 3 to 5 nanometers in diameter, emanating from the Geobacter bacteria.

A standard technique for producing two-dimensional crystals just one atomic layer thick has been developed by physicists in the UK and Russia. The crystals, which are essentially gigantic 2D molecules, were created by Andre Geim and co-workers at Manchester University and the Institute for Microelectronics Technology in Chernogolovka. The structures were made by simply rubbing the freshly cleaved surface of a layered crystal onto another surface, like drawing chalk on a blackboard. This micromechanical "peeling" created flakes, some of which were -- unexpectedly -- just one layer thick. The crystals are stable and could be used to make transistors and sensors (Proc. Natl. Acad. Sci. 2005 102 10451).

A standard technique for producing two-dimensional crystals just one atomic layer thick has been developed by physicists in the UK and Russia. The crystals, which are essentially gigantic 2D molecules, were created by Andre Geim and co-workers at Manchester University and the Institute for Microelectronics Technology in Chernogolovka. The structures were made by simply rubbing the freshly cleaved surface of a layered crystal onto another surface, like drawing chalk on a blackboard. This micromechanical "peeling" created flakes, some of which were -- unexpectedly -- just one layer thick. The crystals are stable and could be used to make transistors and sensors (Proc. Natl. Acad. Sci. 2005 102 10451).

Scientists at The University of Manchester have discovered a new class of materials which have previously only existed in science fiction films and books.

A team of British and Russian scientists led by Professor Geim have discovered a whole family of previously unknown materials, which are one atom thick and exhibit properties which scientists had never thought possible.

Not only are they ultra-thin, but depending on circumstances they can also be ultra-strong, highly-insulating or highly-conductive, offering a wide range of unique properties for space-age engineers and designers to choose from.

Professor Andre Geim said: "This discovery opens up practically infinite possibilities for applications which people have never even thought of yet. These materials are lightweight, strong and flexible, and there is a huge choice of them. This is not only about smart gadgets. Like polymers whose pervasiveness changed our everyday life forever, one-atom-thick materials could be used in a myriad of routine applications from clothing to computers."

The materials have been created by extracting individual atomic planes from conventional bulk crystals by using a technique called 'micromechanical cleavage'. Depending on a parent crystal, their one-atom-thick counterparts can be metals, semiconductors, insulators, magnets, etc. Previously, it was thought that such thin materials could not exist in principle, but the research team have, for the first time, demonstrated that they are not only possible but fairly easy to make.

UCLA chemists have created the first nano valve that can be opened and closed at will to trap and release molecules. The discovery, federally funded by the National Science Foundation, will be published July 19 in the Proceedings of the National Academy of Sciences.

"This paper demonstrates unequivocally that the machine works," said Jeffrey I. Zink, a UCLA professor of chemistry and biochemistry, a member of the California NanoSystems Institute at UCLA, and a member of the research team. "With the nano valve, we can trap and release molecules on demand. We are able to control molecules at the nano scale.

In this expanded interview transcript, inventor Ray Kurzweil discusses birth, death, and the potential offered by non-biological thinking processes.
By: Lucas Conley

Fast Company: First off, without death, CEOs will never give up their jobs. There won't be any succession plans.

Ray Kurzweil: I don't think we need to kill people off to provide opportunity for new leadership and creativity. The marketplace of ideas and technologies is going to expand -- it has been for years. Look at the computer industry. 60 years ago it was a handful of research projects, and now it's a trillion-dollar industry.

FC: But biotech? Who's to say how quickly it will advance?

Kurzweil: A lot of people say you can't really tell the future, and there are certain things that are hard to predict. What will Google's stock be three years from now? That's hard to predict. But if you ask me what it will cost to sequence a base pair of DNA in 2010 or the cost to move a megabyte of data wirelessly in 2015, those things turn out to be remarkably predictable.

Using high-intensity ultrasound, researchers at the University of Illinois at Urbana-Champaign have created hollow nanospheres and the first hollow nanocrystals. The nanospheres could be used in microelectronics, drug delivery and as catalysts for making environmentally friendly fuels.

"We use high-intensity ultrasound to generate nanoparticles of molybdenum disulfide or molybdenum oxide, which bind to the surface of tiny silica spheres that are much smaller than red blood cells," said Ken Suslick, the Marvin T. Schmidt Professor of Chemistry at Illinois and a researcher at the Beckman Institute for Advanced Science and Technology.

Scientists in the US and Israel have demonstrated an atomic force microscope that can take images of periodic processes with a time resolution of microseconds. This is an order of magnitude faster than is possible with conventional "rapid-scan" (M Anwar and I Rousso 2005 Appl. Phys. Lett 86 014101).

An atomic force microscope (AFM) works by measuring how the force between the sample and a tiny "tip" on a cantilever changes as the microscope is moved over the surface of the sample. This allows the AFM to record images with extremely high spatial resolutions. Previous attempts to increase the time resolution of AFMs have focused on scanning the tip over the sample as quickly as possible, but these techniques have had time resolutions of a few tens of milliseconds at best.

Higher temporal resolutions can be obtained by using the AFM in a "force-sensing" mode, which can detect movements from a single point on a sample. Moshiur Anwar of the Massachusetts Institute of Technology (MIT) and the University of California at San Francisco and Itay Rousso of MIT and the Weizmann Institute of Science have now developed a technique in which a series of individual force-sensing measurements are combined to construct images.

The new "step-scan" technique relies on breaking down a sample into individual pixels and then measuring the dynamics of each pixel separately with the AFM. The method, which only works for period processes, can resolve features 10 nanometres across with a time resolution of 5 microseconds.

In its tireless efforts to create smaller and more powerful structures for integrated circuits, Infineon Technologies AG has achieved a further breakthrough in its Munich laboratories: researchers here have constructed the world's smallest nanotube transistor, with a channel length of only 18 nm - the most advanced transistors currently in production are almost four times this size. To build their nanotransistor, the researchers grew carbon nanotubes, each one measuring only 0.7 to 1.1 nm in diameter, in a controlled process.

When it comes to the possibilities of nanotechnology, it can be hard to know what to expect: glittering visions of abundance and long, healthy life spans; fears of out-of-control world-destroying devices, pervasive surveillance tyrannies, and devastating nanotech wars; or maybe all of the above. The Foresight Institute's First Conference on Advanced Nanotechnology held last week across the Potomac River from Washington, D.C., offered hope, fear, and audacious scenarios for the future.