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Femtosecond imaging with near nanometer spatial resolution

Posted by Jim Lewis on August 31st, 2015

Three-dimensional rendering of surface features imaged by ptychographic coherent diffractive imaging. (Source: University of Colorado). The surface shown is a portion of Fig. 4a. Judging from the scale bar in the scanning electron micrograph of this surface shown in Fig. 1b, the inner diameter of the circle is about 10 µm (10,000 nm).

As we noted back in April, Richard Feynman in his classic 1959 talk challenged his fellow physicists to make the electron microscope 100 times better. A “new super powerful electron microscope that can pinpoint the position of single atoms” had been unveiled at a facility in the UK. While that SuperSTEM is one of only three in the world, a recently demonstrated technology based upon “tabletop extreme-ultraviolet ptychography” brings complementary nanometer-scale resolution to a much smaller (and presumably less expensive) instrument. A hat tip to John Faith for bringing this EETimes article by R Colin Johnson to our attention “EUV Breaks Through to Angstrom“:

The wavelength of visible light — 400-to-700 nanometers — makes it impossible with today’s tools to take photographs of nanoscale objects with any sort of reasonable resolution. The answer has been to use scanning electron microscopy (SEM) and atomic force microscopy (ATM), which yield reasonable images. These tools, however, produce nothing close to the angstrom-level (tenth of a nanometer) resolution of a new type of microscope that uses femtosecond pulses of extreme ultraviolet light (EUV) — the same wavelength light to be used for sub-10 nanometer semiconductor lithography.] …

The claim made here of angstrom-level resolution appears to be a substantial overstatement of the published result (see below). Nevertheless, the technique does appear to offer substantial advantages, and may approach this resolution in the near future.

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A tunable bandgap by doping a few atomic layers of black phosphorous

Posted by Jim Lewis on August 29th, 2015

Phosphorene (with in-situ deposition of potassium (K) atoms to induce doping) – The natural successor to Graphene? Credit: Institute for Basic Science

The process of finding novel arrangements of atoms with interesting and useful properties does not appear to be slowing. A hat tip to ScienceDaily for reprinting this news release from the Institute for Basic Science, Korea “Black Phosphorus (BP) Surges Ahead of Graphene“:

A Korean team of scientists tune BP’s band gap to form a superior conductor, allowing for the application to be mass produced for electronic and optoelectronics devices

The research team operating out of Pohang University of Science and Technology (POSTECH), affiliated with the Institute for Basic Science’s (IBS) Center for Artificial Low Dimensional Electronic Systems (CALDES), reported a tunable band gap in BP, effectively modifying the semiconducting material into a unique state of matter with anisotropic dispersion. This research outcome potentially allows for great flexibility in the design and optimization of electronic and optoelectronic devices like solar panels and telecommunication lasers.

To truly understand the significance of the team’s findings, it’s instrumental to understand the nature of two-dimensional (2-D) materials, and for that one must go back to 2010 when the world of 2-D materials was dominated by a simple thin sheet of carbon, a layered form of carbon atoms constructed to resemble honeycomb, called graphene. Graphene was globally heralded as a wonder-material thanks to the work of two British scientists who won the Nobel Prize for Physics for their research on it.

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Novel wireframe nanostructures from new DNA origami design process

Posted by Jim Lewis on August 18th, 2015

The versatility of the 3D wireframe design technique was demonstrated with the construction of the snub cube, an Archimedean solid with 60 edges, 24 vertices and 38 faces including 6 squares and 32 equilateral triangles. Credit: TED-43 GFDL ( or CC BY 3.0 (, via Wikimedia Commons

The scaffolded DNA origami technique has been extended to build complex, programmable wireframe structures exhibiting precise control of branching and curvature. A hat tip to KurzweilAI for reporting this Arizona State University Biodesign Institute news release “Rare form: novel structures built from DNA emerge“:

… Hao Yan, a researcher at Arizona State University’s Biodesign Institute, has worked for many years to refine [DNA origami]. His aim is to compose new sets of design rules, vastly expanding the range of nanoscale architectures generated by the method. In new research, a variety of innovative nanoforms are described, each displaying unprecedented design control. …

In the current study, complex nano-forms displaying arbitrary wireframe architectures have been created, using a new set of design rules. “Earlier design methods used strategies including parallel arrangement of DNA helices to approximate arbitrary shapes, but precise fine-tuning of DNA wireframe architectures that connect vertices in 3D space has required a new approach,” Yan says.

Yan has long been fascinated with Nature’s seemingly boundless capacity for design innovation. The new study describes wireframe structures of high complexity and programmability, fabricated through the precise control of branching and curvature, using novel organizational principles for the designs. (Wireframes are skeletal three-dimensional models represented purely through lines and vertices.)

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Conference video: Artificial Biochemistry with DNA

Posted by Jim Lewis on August 13th, 2015

DNA as a Universal Substrate for Chemical Kinetics- embedded control circuit to direct molecular events. Credit: David Soloveichik

A select set of videos from the 2013 Foresight Technical Conference: Illuminating Atomic Precision, held January 11-13, 2013 in Palo Alto, have been made available on vimeo. Videos have been posted of those presentations for which the speakers have consented. Other presentations contained confidential information and will not be posted.

The fourth speaker at the Commercial Scale Devices – Part 2 session, the winner of the 2012 Feynman Prize for Theoretical work, David Soloveichik, presented his prize-winning work “Artificial Biochemistry with DNA” – video length 29:14. Dr. Soloveichik began his talk by asking if we could recapitulate the feats of biology, specifically computation with networks of molecular interactions, with de novo engineering. After the basic technology is developed, possible applications could include artificial control modules that could be inserted into cells to create “smart drugs”, or as control modules for completely artificial systems (“wet robots”). Dr. Soloveichik has made the slides from his talk available here.

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Another nanotechnology computer memory breakthrough from Feynman Prize winner

Posted by Jim Lewis on August 12th, 2015

A schematic shows the layered structure of tantalum oxide, multilayer graphene and platinum used for a new type of memory developed at Rice University. The memory device overcomes crosstalk problems that cause read errors in other devices. (Credit: Tour Group/Rice University)

One prominent area in which nanoscale science and technology is providing a rich pipeline feeding current and near-term improvements in technology is computer hardware, and in particular, solid-state computer memories. One year ago, we cited a breakthrough nanoporous silicon oxide technology for resistive random-access memory (RRAM) developed by the research group of James Tour, winner of the 2008 Foresight Institute Feynman Prize in the Experimental category. Now he appears to have topped this memory architecture with another memory breakthrough. A hat tip to KurzweilAI for reporting this Rice University news release “Tantalizing discovery may boost memory technology“:

Scientists at Rice University have created a solid-state memory technology that allows for high-density storage with a minimum incidence of computer errors.

The memories are based on tantalum oxide, a common insulator in electronics. Applying voltage to a 250-nanometer-thick sandwich of graphene, tantalum, nanoporous tantalum oxide and platinum creates addressable bits where the layers meet. Control voltages that shift oxygen ions and vacancies switch the bits between ones and zeroes.

The discovery by the Rice lab of chemist James Tour could allow for crossbar array memories that store up to 162 gigabits, much higher than other oxide-based memory systems under investigation by scientists. (Eight bits equal one byte; a 162-gigabit unit would store about 20 gigabytes of information.)

Details appear online in the American Chemical Society journal Nano Letters [abstract].

Like the Tour lab’s previous discovery of silicon oxide memories, the new devices require only two electrodes per circuit, making them simpler than present-day flash memories that use three. “But this is a new way to make ultradense, nonvolatile computer memory,” Tour said.

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Ribosome subunits tethered to make versatile artificial molecular machine

Posted by Jim Lewis on August 11th, 2015

An engineered ribosome with a permanent connection between its subunits (red) can operate side-by-side with a cell's own protein production machinery. Credit: Erik Carlson

Engineering Nature’s primordial molecular machine—the ribosome—promises a path to unnatural polymers that may expand the set of properties provided by proteins and biomimetic polymers to engineer artificial molecular machine systems. A hat tip to ScienceDaily for reprinting this University of Illinois at Chicago news release written by Sam Hostettler “Researchers design first artificial ribosome“:

Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins and enzymes within the cell.

The engineered ribosome may enable the production of new drugs and next-generation biomaterials and lead to a better understanding of how ribosomes function.

The artificial ribosome, called Ribo-T, was created in the laboratories of Alexander Mankin, director of the UIC College of Pharmacy’s Center for Biomolecular Sciences, and Northwestern’s Michael Jewett, assistant professor of chemical and biological engineering.

The human-made ribosome may be able to be manipulated in the laboratory to do things natural ribosomes cannot do.

When the cell makes a protein, mRNA (messenger RNA) is copied from DNA. The ribosomes’ two subunits, one large and one small, unite on mRNA to form the functional unit that assembles the protein in a process called translation. Once the protein molecule is complete, the ribosome subunits — both of which are themselves made up of RNA and protein — separate from each other.

In a new study in the journal Nature [abstract], the researchers describe the design and properties of Ribo-T, a ribosome with subunits that will not separate. Ribo-T may be able to be tuned to produce unique and functional polymers for exploring ribosome functions or producing designer therapeutics — and perhaps one day even non-biological polymers.

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Automated design of polyhedral meshes for DNA origami

Posted by Jim Lewis on August 7th, 2015

Björn Högberg and Erik Benson with models of their origami 3D meshes. Credit: Ulf Sirborn

Scaffolded DNA origami, one of the mainstays of structural DNA nanotechnology since its invention in 2006, continues to undergo improvement. A press release from Sweden’s Karolinska Institutet “3D ‘printouts’ at the nanoscale using self-assembling DNA structures“:

A novel way of making 3D nanostructures from DNA is described in a study published in the renowned journal Nature [abstract]. The study was led by researchers at Sweden’s Karolinska Institutet who collaborated with a group at Finland’s Aalto University. The new technique makes it possible to synthesize 3D DNA origami structures that are also able to tolerate the low salt concentrations inside the body, which opens the way for completely new biological applications of DNA nanotechnology. The design process is also highly automated, which enables the creation of synthetic DNA nanostructures of remarkable complexity.

The team behind the study likens the new approach to a 3D printer for nanoscale structures. The user draws the desired structure, in the form of a polygon object, in 3D software normally used for computer-aided design or animation. Graph-theoretic algorithms and optimization techniques are then used to calculate the DNA sequences needed to produce the structure.

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Arranging molecular chromophores on DNA brick nanobreadboards

Posted by Jim Lewis on August 6th, 2015

ON-OFF cycling of AND logic gate formed by arrangement of four single-molecule chromophores on a DNA brick nanobreadboard. Credit: Canon et al. ACS Photonics.

The idea of using a DNA framework as a “nanobreadboard” to prototype various nanoscale circuits and device arrays goes back at least to Paul Rothemund’s 2006 invention of scaffolded DNA origami technology. The idea played a central role in the development of the concept of modular molecular composite nanosystems formulated as part of the 2007 Foresight and Battelle Technology Roadmap for Productive Nanosystems. Earlier this year researchers at Boise State University in Idaho published an open access article in the journal ACS PhotonicsExcitonic AND Logic Gates on DNA Brick Nanobreadboards“. However, instead of scaffolded DNA origami, these researchers built their nanobreadboards using an alternate form of structural DNA nanotechnology (see “Arbitrarily complex 3D DNA nanostructures built from DNA bricks“) that has been extended to fabricate micrometer-scale structures that offer unique opportunities as molecular “breadboards”.

To make single-molecule optical devices for computing and other applications, which exploit the interactions between light and matter at much smaller length scales than the free-space wavelength of light, these molecular chromophores must be precisely arranged to enhance non-radiative dipole-dipole coupling between neighboring chromophores. subnanometer resolution. This coupling facilitates an energy transfer process (FRET – Förster Resonance Energy Transfer) that occurs over a distance that is typically 5 nm or less. Molecular orientation also plays a role. Previous studies of multi-chromophore excitonic circuits have positioned the chromophores using single DNA duplexes or multiarm DNA junctions, or DNA origami. With DNA origami, however, it is only practical to conjugate chromophores to selected staple strands; the long scaffold strand can only play a role in the overall structure since conjugation to the scaffold strand is impractical. This restricted role of the scaffold strand limits the feasibility of using DNA origami for the rapid prototyping of excitonic circuits that is essential to achieve complex functionality.

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Facilitating structural DNA nanotechnology with non-aqueous solvents

Posted by Jim Lewis on August 2nd, 2015

Georgia Tech postdoctoral researcher Isaac Gállego prepares a sample DNA nanostructure for imaging in an atomic force microscope. (Credit: Rob Felt)

Not only does structural DNA nanotechnology work in non-aqueous solvents, but in some ways it may work best in non-aqueous solvents. A hat tip to for reprinting this Georgia Tech news release “Who needs water to assemble DNA? Non-aqueous solvent supports DNA nanotechnology“:

Scientists around the world are using the programmability of DNA to assemble complex nanometer-scale structures. Until now, however, production of these artificial structures has been limited to water-based environments, because DNA naturally functions inside the watery environment of living cells.

Researchers at the Georgia Institute of Technology have now shown that they can assemble DNA nanostructures in a solvent containing no water. They also discovered that adding a small amount of water to their solvent increases the assembly rate and provides a new means for controlling the process. The solvent may also facilitate the production of more complex structures by reducing the problem of DNA becoming trapped in unintended structures.

The research could open up new applications for DNA nanotechnology, and help apply DNA technology to the fabrication of nanoscale semiconductor and plasmonic structures. Sponsored by the National Science Foundation and NASA, the research will be published as the cover story in Volume 54, Issue 23 of the journal Angewandte Chemie International Edition [abstract].

“DNA nanotechnology structures are getting more and more complex, and this solvent could help researchers that are working in this growing field,” said Nicholas Hud, a professor in Georgia Tech’s School of Chemistry and Biochemistry. “With this work, we have shown that DNA nanostructures can be assembled in a water-free solvent, and that we can mix water with the same solvent to speed up the assembly. We can also take the structures that were assembled in this solvent mixed with water –remove the water by applying vacuum – and have the DNA structures remain intact in the water-free solvent.”

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Foresight co-sponsors Berkeley Bench to Market event

Posted by Jim Lewis on July 30th, 2015

Progress in biotechnology has played an important role in progress in nanotechnology since Eric Drexler proposed in 1981 protein design as a pathway to develop general capabilities for molecular manipulation and, eventually, molecular manufacturing. The second Feynman Prize in nanotechnology was awarded in 1995 for pioneering work in building atomically precise 3-D objects from DNA. The use of large scaffolds buit with DNA origami and other biomimetic polymers played a central role in the 2007 Technology Roadmap for Productive Nanosystems. Since the beginning of this blog, progress in structural DNA nanotechnology and protein design have been frequent topics for posts.

Biotechnology and nanotechnology are increasingly playing synergistic roles in opening new opportunities for near-term medical advances, as we try to indicate here with posts on Future Medicine and Nanomedicine. A crucial factor in obtaining the benefits of these research advances is how quickly and efficiently discoveries can move from the laboratory bench to the market. Whether the technology is biotechnology, nanotechnology, or the interface of the two, the basic issues of founding and funding a startup are probably not all that different. And what better place to explore those issues than Foresight’s location in the heart of Silicon Valley! Accordingly Foresight was happy to co-sponsor an event last month hosted by the Berkeley Postdoc Entrepreneur Program “Bench to Market: Idea Evaluation and Commercialization for Product-market Fit“.

The speaker Dr. David Kirn, Co-Founder, President & CEO; Co-Chairman of 4D Molecular Therapeutics and his co-panelists shared the lessons learned in their biotech and nanotech ventures with the aspiring entrepreneurs in attendance. Commercial success for their efforts collectively and individually could lead not only to near-term clinical advances, but also to further improvements in the molecular toolkits needed for advanced nanotechnology leading to atomically precise manufacturing.
—James Lewis, PhD

Foresight 1999 Distinguished Student wins Galactic Grant Competition

Posted by Jim Lewis on July 28th, 2015

Galactic Grant Competition award announcement July 7 2015. Dr. Goel of Nanobiosym is third from the left. Credit: Center for the Advancement of Science in Space (CASIS)

The 1999 Foresight Institute Distinguished StudentAnita Goel, at that time an MD/PhD candidate at the Harvard/MIT Division of Health Sciences and Technology and also a PhD candidate at Harvard’s Physics Department—went on to found Nanobiosym to integrate physics, nanotechnology, and biomedicine. Two years ago Nanobiosym’s Gene-RADAR® sensing technology won the first competition of the Nokia Sensing XCHALLENGE “Nanobiosym Health Radar brings point-of-diagnosis technology directly to consumers“:

Nanobiosym Health RADAR, a Boston-based research incubator institute led by Dr. Anita Goel, was awarded the $525,000 Grand Prize in the first competition of the Nokia Sensing XCHALLENGE for their Gene-RADAR® sensing technology that will transform the way health care is delivered by enabling personalized diagnostic testing.

The Gene-RADAR platform analyzes a drop of blood, saliva or other body fluid placed on a nanochip and inserted into a mobile device, which then detects the presence or absence of a disease’s pathogen in less than an hour, with the same accuracy available only in a diagnostic lab. The technology was developed to be easy-to-use and does not require overhead infrastructure, such as electricity or running water, which can lead to widespread adoption by developing countries.

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Rejuvenation Biotechnology Conference 2015

Posted by Jim Lewis on July 10th, 2015

August 19 – 21 · Hyatt Regency San Francisco Airport in Burlingame CA

To Foresight friends,

We’re pleased to announce that the SENS Research Foundation is once again hosting its Rejuvenation Biotechnology Conference here in Silicon Valley. The Rejuvenation Biotechnology Conference is designed to bring together a global community to transform the treatment of age-related disease, and they would like all of us to be there.

Last year’s conference was truly one of the most informative and engaging longevity research events ever held.

The Rejuvenation Biotechnology Conference provides ways to:

  • Increase your knowledge about the key components of the new Rejuvenation Biotechnology Industry – the science, the regulatory issues, the financial and economic challenges
  • Discover new opportunities in research in Gene Therapy, Stem Cells, and Tissue Engineering
  • Learn the latest advances in Cancer, Alzheimer’s Disease, and Cardiovascular Research
  • Develop new collaborations with industry-leading researchers

This is a ground-breaking meeting featuring over 50 amazing speakers including Judith Campisi (Buck Institute for Aging Research), Russ Altman (Stanford Medical School), Anthony Atala (Wake Forest Institute for Regenerative Medicine), Mahendra Rao (New York Stem Cell Foundation), Jeanne Loring (Scripps Research Institute), Chas Bountra (University of Oxford) plus speakers from leading Biotech Companies Sanofi, Kite Pharma, BlueBird Bio, Sangamo BioScience, and Capricor Therapeutics.

To round out the event, there’s a keynote by Frances Colon, Deputy Science and Technology Adviser to the Secretary of State, and even-returning again this year—comedian Hal Sparks.

We wouldn’t miss it, so please join us August 19 – 21 at the Hyatt Regency San Francisco Airport in Burlingame CA. Register before July 15 to take advantage of early bird pricing at

Hope to see you there!

Conference video: Conformational and compositional dynamics of a molecular machine

Posted by Jim Lewis on July 8th, 2015

Credit: Joseph Puglisi

A select set of videos from the 2013 Foresight Technical Conference: Illuminating Atomic Precision, held January 11-13, 2013 in Palo Alto, have been made available on vimeo. Videos have been posted of those presentations for which the speakers have consented. Other presentations contained confidential information and will not be posted.

The 3rd speaker at the Commercial Scale Devices session was Joseph Puglisi. His talk was titled “Deciphering the Molecular Choreography of Translation” biography and abstracts, video – video length 34:08.

Prof. Puglisi began with the observation that one of the triumphs of the application of chemistry and physics to biology has been the field of structural biology, his department at Stanford. Three of the last six Nobel Prizes in Chemistry have been given for determining, using primarily X-ray diffraction methods, the three-dimensional position of atoms in key molecules that drive biological function. The example that he focused upon is the ribosome—the macromolecular machine that synthesizes proteins from the genetic code. He noted, however, that one of the problems not addressed in these studies is that the pictures are static snapshots. X-ray crystallography gives you a static view of the positions of atoms. There is no motion embedded in that structure. Prof. Puglisi’s goal over the last 10-15 years has been trying to bring these structures to life—a molecular choreography to bring a time axis to structural biology to understand underlying mechanism.

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Linking together small DNAs to build more diverse DNA nanostructures

Posted by Jim Lewis on July 2nd, 2015

DNA ligase is used to link varying amounts of repeated structural units A and B and unique addressable unit X together into a long DNA segment, which can then be amplified by DNA polymerase to make many copies. Credit: Sleiman's research group and McGill University.

A few months ago we cited a cheaper, easier way developed by researchers at McGill University to build long DNA scaffolds. A further substantial improvement, in which long DNA segments of up to 1000 base pairs are produced less expensively than the short 100-base strands they previously used is described at “A new technique to build complex custom-designed DNA scaffolds“:

McGill University researchers have devised a new technique to produce long, custom-designed DNA strands to build nanoscale structures to deliver drugs to targets within the body or take electronic miniaturization to a new level.

Researchers have been assembling and experimenting with DNA structures or “DNA origami” for years, as KurzweilAI has reported. But as these applications continue to develop, they require increasingly large and complex strands of DNA. It can take hundreds of these short strands to assemble nanotubes for applications such as smart drug-delivery systems.

That poses a problem: automated systems used for making synthetic DNA can’t produce strands containing more than about 100 bases (the chemicals that link up to form the DNA strands). …

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Toward advanced nanotechnology: Working solid state molecular shuttle

Posted by Jim Lewis on July 1st, 2015

Credit: Loeb Research Group, University of Windsor

Two years ago we cited the demonstration by a group at the University of Windsor of a solid state molecular machine comprising a molecular wheel made from a rotaxane molecule held in place in a self-assembled metal organic framework. This work was widely recognized as a step toward solid state molecular machinery. A recent article at written by Heather Zeiger explains the most recent step forward along that path, the creation of a molecular shuttle in which the ring around the axle of the rotaxane molecule shuttles back and forth between two positions. “Toward solid-state molecular circuitry: Molecular shuttle within a metal-organic framework“:

…Kelong Zhu, Christopher A. O’Keefe, V. Nicholas Vukotic, Robert W. Schurko and Stephen J. Loeb from the Department of Chemistry and Biochemistry at the University of Windsor have designed and characterized a molecular shuttle that functions both in solution and when placed within a rigid chemical structure called a metal-organic framework. Their work appears in Nature Chemistry [abstract].

This research makes use of the rotaxane architecture, a MIM [mechanically interlocked molecule] comprised of a ring-shaped molecule and two recognition sites. Rotaxanes have two components: A molecule is threaded through a macrocyclic ring, like a wheel with an axle. The macrocycle moves linearly along the axle between two recognition sites. Zhu, et al. used a 24-crown-8 macrocycle and benzimidazole recognition sites on the axle. …

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Wafer-scale atomically precise thin layers for nanotechnology

Posted by Jim Lewis on June 30th, 2015

A molybdenum disulphide device array on a transparent silica wafer. Credit: Kibum Kang, Cornell University

The path of progress in nanotechnology stretches from approximate control of the structure of matter—a precision of 1 to 100 nm in at least one dimension in which unique phenomena enable novel applications—to atomic precision in three dimensions. We at Foresight have been primarily interested in mechanical properties of systems of atomically precise machines. Progress along this path leads toward productive nanosystems and inexpensive high throughput atomically precise manufacturing. Current computer and other important technologies, however, rely upon electronic and optoelectronic properties. For these applications, progress toward atomically precise thin films, especially thin films of semiconductors, looks very promising. A hat tip to ScienceDaily for reprinting this Cornell University news article written by Anne Ju “Chemists cook up three atom-thick electronic sheets“:

Making thin films out of semiconducting materials is analogous to how ice grows on a windowpane: When the conditions are just right, the semiconductor grows in flat crystals that slowly fuse together, eventually forming a continuous film.

This process of film deposition is common for traditional semiconductors like silicon or gallium arsenide – the basis of modern electronics – but Cornell scientists are pushing the limits for how thin they can go. They have demonstrated a way to create a new kind of semiconductor thin film that retains its electrical properties even when it is just atoms thick.

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DNA nanomachines more stable than expected in human serum and blood

Posted by Jim Lewis on June 29th, 2015

Credit: Boise State University and Sara Goltry et al.

Over the past several years we have cited substantial progress in making ever more complex molecular machinery using structural DNA nanotechnology. Much of this work is focused on eventual medical applications, so it becomes important to ask how fragile such machinery would be in human serum and blood. A year ago we cited work work showing that a Lipid coat protects DNA nanorobot from immune attack, and six months ago that Swarms of DNA nanorobots execute complex tasks in living animals. More recently researchers at Boise State University have demonstrated that some DNA nanomachines are surprisingly stable in human serum and blood. From a Boise State news article “Nanobots! – DNA Nanomachines Operating In Blood” (scroll down):

Everyone knows DNA is rapidly degraded by enzymes in serum; except it isn’t–at least not always. While most studies of DNA in serum use fetal bovine serum, which exhibits a high enzyme activity and does degrade DNA rapidly, few studies have looked at DNA nanostructures in human serum. With the aim of creating new tools for biomedical diagnostic applications in humans (sorry bovines!), Sara Goltry, a PhD student in Materials Science & Engineering at Boise State, and co-workers measured the lifetimes of DNA devices in human serum and blood. The results of their four-year study, published recently in Nanoscale [abstract], show that some DNA nanostructures survive in human serum for about two days while others last only about an hour. Interestingly, the device lifetime can be programmed by changing the shape of the molecule. Beyond lifetime studies, Goltry also demonstrated that a circular DNA nanomachine operates in human serum and blood just fine. The nanomachine can be made to open and close with DNA fuels, similar to the DNA tweezers first published by Yurke et al. in 2000. Demonstrating operation in serum and blood supports the goal of building programmable molecular machines as a means to engineer new DNA-based tools for biotechnology.

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Self-assembly of silicon metamaterial for nanoscale reflectors

Posted by Stephanie C on June 25th, 2015

A scanning electron micrograph shows a tilted view of a metamaterial mirror made of silicon cylinders patterned on a silicon wafer. Credit: ACS Photonic

Recently highlighted in a C&EN article titled Simple Process Creates Near-Perfect Mirrors Out of a Metamaterial, researchers out of Vanderbilt University developed a method to self-assemble silicon nanostructures to achieve highly (Bragg-like) reflective mirrors which capitalize on nanoscale properties not present in bulk structures. The self-assembly method is far simpler than previous, conventional electron beam lithography approaches.

…Metamaterials are engineered to have properties, typically derived from nanoscale patterning, that do not occur in the bulk material. They made their reflector by patterning a silicon wafer’s surface with an array of silicon cylinders a few hundred nanometers in diameter. Each of the cylinders acted like a tiny resonator for particular light frequencies—analogous to the way certain sound frequencies will make a tuning fork hum. By adjusting the size of the cylinders, Valentine could control how well they reflected light of a given frequency. This mirror reflected more than 99% of light at the peak wavelength.

Although the work showed that metamaterial mirrors could be effective, the method for making them was far from practical: The researchers painstakingly created the arrays using electron-beam lithography, which is difficult to scale up. So Valentine and his team adopted a simpler method to make bigger, near-perfect reflectors.
They started with off-the-shelf polystyrene beads 820 nm across and dropped them into a film of water. Driven by electrostatic forces, the beads self-assembled into a monolayer on the water’s surface with a repeated hexagonal pattern. Valentine’s group then drained the water, lowering the bead layer onto a submerged silicon wafer, and used a plasma etching process to shrink the beads to 560 nm. Finally, they used the bead layer as a lithographic mask to pattern the underlying silicon. The resulting 2-cm2 arrays were covered in silicon cylinders, each 335 nm tall and 480 nm across the top.

The arrays reflect 99.7% of incident infrared light at 1,530 nm. Valentine is now working on making larger area reflectors by patterning with silicon nanospheres.

“This is a phenomenal result, especially for something made by self-assembly,” says Michael B. Sinclair, who develops metamaterials at Sandia National Laboratories. Bragg reflectors are an established technology that will be difficult to compete with anytime soon, he says, but the work is “an impressive step forward for making large-area metamaterials.”

-Posted by Stephanie C

Google Tech Talk video by Feynman Prize Winner

Posted by Jim Lewis on June 24th, 2015

Christian Schafmeister Google Tech Talk June 10, 2015.

Christian Schafmeister, winner of the 2005 Foresight Institute Feynman Prize for Experimental work and participant in last year’s Foresight Institute Workshop on Directed/Programmable Matter for Energy, began programming at age 12 on a Radio Shack TRS-80, followed that interest into a career in chemistry, and is currently a chemistry professor at Temple University. Earlier this month he gave a Google Tech Talk that is available on You Tube “Clasp: Common Lisp using LLVM and C++ for Molecular Metaprogramming – Towards a Matter Compiler” (57:37).

Prof. Schafmeister’s goal is to build molecules as easily as he can write software; specifically he wants to build molecules that can do things, like go into the body and fix things. Inspired by Richard Feynman’s 1959 talk in which Feynman proposed building machines on a molecular scale that were atomically precise, where you know where every atom is in space, he went into biophysics, where he made proteins and solved crystal structures of proteins, and from there into chemistry.

We understand a great deal about proteins, the molecular machines that make us work. Explaining how proteins are made of chains of amino acids that fold into precise 3D shapes that do specific things, like catalyze chemical reactions, or like antibodies, which bind to specific structures to start the immune system attacking pathogens, or like channels that let specific molecules, and nothing else, pass through cellular membranes, Prof. Schafmeister asserted that we could solve most of humanity’s problems if we could build similar machines. He actually began this process as a graduate student, building one of the first unnatural proteins, called DHP1. He designed the protein on paper, designed a gene to make it, got bacteria to make it, and determined the crystal structure, showing it to be a four-helix bundle, a very common structural motif in proteins.

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US OSTP seeking suggestions for Nanotechnology Grand Challenges

Posted by Jim Lewis on June 23rd, 2015

The US White House Office of Science and Technology Policy (OSTP) is seeking suggestions for Nanotechnology Grand Challenges. As explained in the Federal Register for June 17, 2015 “Nanotechnology-Inspired Grand Challenges for the Next Decade“:

A Notice by the Science and Technology Policy Office on 06/17/2015

The purpose of this Request for Information (RFI) is to seek suggestions for Nanotechnology-Inspired Grand Challenges for the Next Decade: Ambitious but achievable goals that harness nanoscience, nanotechnology, and innovation to solve important national or global problems and have the potential to capture the public’s imagination. This RFI is intended to gather information from external stakeholders about potential grand challenges that will help guide the science and technology priorities of Federal agencies, catalyze new research activities, foster the commercialization of nanotechnologies, and inspire different sectors to invest in achieving the goals. Input is sought from nanotechnology stakeholders including researchers in academia and industry, non-governmental organizations, scientific and professional societies, and all other interested members of the public. …

Responses must be received by July 16, 2015 to be considered. …

The announcement continues with background information, instructions on how to submit a response, just what information is requested, questions to be addressed in proposals, and lastly examples of potential nanotechnology-inspired grand challenges for the next decade. All of the six examples given are worthy, but we find #4 the most interesting:

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