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USA-Austrian and Swiss Nanocars finish first in first Nanocar race

Posted by Jim Lewis on June 9th, 2017

If the current is high enough, the molecule starts to move and can be steered over the racetrack (University of Basel)

Our previous post announced a race around a 100 nm course of six NanoCars, each a unique concept created from only several dozen atoms and powered by electrical pulses. The race was run a few weeks later and two winners declared, due to two different tracks being used. From Swiss news “Swiss team wins shortest car race in the world“:

“Swiss Nano Dragster”, driven by scientists from Basel, has won the first international car race involving molecular machines. The race involved four nano cars zipping round a pure gold racetrack measuring 100 nanometres – or one ten-thousandth of a millimetre.

The two Swiss pilots, Rémy Pawlak and Tobias Meier from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel, had to reach the chequered flag – negotiating two curves en route – within 38 hours.

The winning drivers, who actually shared first place with a US-Austrian team, were not sitting behind a steering wheel but in front of a computer. They used this to propel their single-molecule vehicle with a small electric shock from a scanning tunnelling microscope.

During such a race, a tunnelling current flows between the tip of the microscope and the molecule, with the size of the current depending on the distance between molecule and tip. If the current is high enough, the molecule starts to move and can be steered over the racetrack, a bit like a hovercraft.

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First International NanoCar Race showcases molecular vehicles

Posted by Jim Lewis on April 12th, 2017

Entrants, not to scale. Top row (left to right): NanoMobile club (France); Nanocar Team: Rice(USA) & Graz (Austria) Universities; Nano-windmill Compagny, Dresden Technical University (Germany). Bottom row (left to right): MANA-NIMS, Nano-Vehicle (Japan); Ohio Bobcat nanowagon team, Ohio University (USA); Swiss-nano Dragster, University of Basel (CH) Credit: Nanocar Race

Twenty years ago Dr. Christian Joachim of CEMES-CNRS (France) shared the 1997 Foresight Feynman Prize in Nanotechnology for Experimental Work with two researchers then at IBM Research Zurich for work using scanning probe microscopes to manipulate molecules. Eight years later he won 2005 Foresight Feynman Prize in Nanotechnology for Theory for developing theoretical tools and establishing the principles for design of a wide variety of single molecule functional nanomachines. For the past few years he has been organizing the first ever international nanocar race which will provide an arena to test half a dozen very different designs for vehicles comprising only several dozen atoms each to race along a 100-nm course powered by electrical pulses from an STM tip. The races will be held April 28-29 in Toulouse, France. From a CNRS March 13 news release “The world’s first international race for molecule-cars, the Nanocar Race is on“:

Nanocars will compete for the first time ever during an international molecule-car race on April 28-29, 2017 in Toulouse (south-western France). The vehicles, which consist of a few hundred atoms, will be powered by minute electrical pulses during the 36 hours of the race, in which they must navigate a racecourse made of gold atoms, and measuring a maximum of a 100 nanometers in length. They will square off beneath the four tips of a unique microscope located at the CNRS’s Centre d’élaboration de matériaux et d’études structurales (CEMES) in Toulouse. The race, which was organized by the CNRS, is first and foremost a scientific and technological challenge, and will be broadcast live on the YouTube Nanocar Race channel. Beyond the competition, the overarching objective is to advance research in the observation and control of molecule-machines.

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Precisely removing individual atoms with microscope creates novel molecule

Posted by Jim Lewis on March 3rd, 2017

Left: Schematic of triangulene, with six fused benzene rings comprising 22 carbon atoms and 12 hydrogen atoms. Two hydrogen atoms have been removed from dihydrotriangulene (22 carbon atoms and 14 hydrogen atoms) leaving two unpaired electrons, designated by black dots. Scale bar: 5 Â = 0.5 nm. Right: AFM image of triangulene on Cu(111) surface. Credit: Pavliček et al. Nature Nanotechnology.

The application of scanning probe microscopy to building individual molecules on a surface took another step forward with the fabrication of a fragment of graphene that was too reactive to be synthesized using conventional chemistry. Over at Quartz Akshat Rathi describes how “IBM researchers have created an ‘impossible’ molecule that could power quantum computers“. Additional details from an IBM Research press release “IBM & Warwick Image Highly Reactive Triangular Molecule for the First Time“:

Published today in Nature Nanotechnology, IBM scientists are truly making the invisible visible.

A few weeks ago IBM released its annual five predictions for the next five years based on this theme. IBM scientists in Zurich are making a good argument to add a sixth prediction with their latest scientific achievement – imaging some of the tiniest objects known to science.

While not household names, molecules including pentacene, olympicene, hexabenzocoronene and cephalandole A are all microscopic molecules which are traditionally represented using 2D structural stick models – think back to your high school chemistry class.

But thanks to a microscopy technique published by the IBM scientists in 2009, physicists, biologists and chemists around the world can now image these molecules with remarkable clarity and precision, in some cases for the first time, decades after they were first theorized allowing them to study and manipulate with incredible precision.

David Fox, University of Warwick, explains “For chemists it is amazing to be able to see individual molecules in such high resolution, especially unusual or highly reactive ones. It is the best way to confirm their structure.”

In addition to imaging, the IBM team, which includes two European Research Council (ERC) grant winners, Leo Gross and Gerhard Meyer [who are also two of the three-member IBM Research-Zurich team who won the 2012 Foresight Institute Feynman Prize for Nanotechnology for Experiment], is also able to manipulate molecules to cause chemical reactions so molecules can be synthesized from adsorbed precursor molecules.

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From de novo protein design to molecular machine systems

Posted by Jim Lewis on January 30th, 2017

All the proteins in this image were designed with atomic accuracy, validated by X-ray crystal structures or NMR. Credit: Baker Lab, University of Washington

Regular readers will have noticed that the de novo design of proteins not found in nature has become an increasingly active area of nanotechnology research the past several years, including eight advances this past year that we have cited (here, here, here, here, here, here, here, here). To put this rapid acceleration of progress in perspective, David Baker’s group, source of 7 of the above 8 advances, recently published (Sept, 2016) a review “The coming of age of de novo protein design“:

Most protein design efforts to date have focused on reengineering existing proteins found in nature. By contrast, de novo protein design generates new structures from scratch, with sequences unrelated to naturally occurring proteins. Before 2011, the only successful de novo designed proteins were Top7 (2003), and an array of coiled coil peptides (helical bundles). In the past five years, the field of de novo protein design has exploded. The wealth of new structures, and advancements in methodology, should now now allow proteins to be precisely crafted and custom-made to solve specific modern-day problems.

The review is published in Nature (journal abstract) and the full text PDF is available courtesy of the Baker lab. The journal abstract:

There are 20200 possible amino-acid sequences for a 200-residue protein, of which the natural evolutionary process has sampled only an infinitesimal subset. De novo protein design explores the full sequence space, guided by the physical principles that underlie protein folding. Computational methodology has advanced to the point that a wide range of structures can be designed from scratch with atomic-level accuracy. Almost all protein engineering so far has involved the modification of naturally occurring proteins; it should now be possible to design new functional proteins from the ground up to tackle current challenges in biomedicine and nanotechnology.

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Two-component, 120-subunit icosahedral cage extends protein nanotechnology

Posted by Jim Lewis on January 28th, 2017

Ten designs spanning three distinct icosahedral architectures. Credit: Baker laboratory, Institute for Protein Design, University of Washington

Baker Lab researchers have extended their work that we cited last summer
assembling a large, stable, icosahedral protein molecular cage to a multi-component icosahedral protein complex. From a University of Washington Institute for Protein Design news release “Designed Protein Containers Push Bioengineering Boundaries“:

…Baker lab scientists and collaborators have taken this work to an exciting new level by engineering 120-subunit icosahedral nanocages that self-assemble from not one, but two distinct protein components. The new designed proteins are described in the latest issue of Science in a paper entitled “Accurate design of megadalton-scale multi-component icosahedral protein complexes” [abstract, full text PDF courtesy of Baker Lab].

In this paper, former Baker lab graduate student Jacob Bale, Ph.D. and collaborators describe the computational design and experimental characterization of ten two-component protein complexes that self-assemble into nanocages with atomic-level accuracy. These nanocages are the largest designed proteins to date with molecular weights of 1.8-2.8 megadaltons and diameters comparable to small viral capsids. The structures have been confirmed by X-ray crystallography (see figure). The advantage of a multi-component protein complex is the ability to control assembly by mixing individually prepared subunits. The authors show that in vitro mixing of the designed subunits occurs rapidly and enables controlled packaging of negatively charged GFP by introducing positive charges on the interior surfaces of the two components.

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Cleanly placing atomically precise graphene nanoribbons

Posted by Jim Lewis on January 23rd, 2017

Researchers have made the first important step toward integrating atomically precise graphene nanoribbons (APGNRs) onto nonmetallic substrates. Credit: Radocea et al.

We have been following progress toward using graphene nanoribbons in nanotechnology for nearly a decade, most recently citing “Atomically precise boron doping of graphene nanoribbons“. Just published results from Joseph W. Lyding, winner of the 2014 Foresight Institute Feynman Prize, Experimental category, and his collaborators have demonstrated a major step toward integrating atomically precise graphene nanoribbons onto a semiconductor surface. A hat tip to first author Adrian Radocea for sending word of their accomplishment described in this Beckman Institute news release written by Maeve Reilly “Creating Atomic Scale Nanoribbons“:

Silicon crystals are the semiconductors most commonly used to make transistors, which are critical electronic components used to carry out logic operations in computing. However, as faster and more powerful processors are created, silicon has reached a performance limit: the faster it conducts electricity, the hotter it gets, leading to overheating.

Graphene, made of a single-atom-thick sheet of carbon, stays much cooler and can conduct much faster, but it must be [fabricated] into smaller pieces, called nanoribbons, in order to act as a semiconductor. Despite much progress in the fabrication and characterization of nanoribbons, cleanly transferring them onto surfaces used for chip manufacturing has been a significant challenge.

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Designing novel protein backbones through digital evolution

Posted by Jim Lewis on January 17th, 2017

Overview of the SEWING method. Each panel, from left to right: parental structures with extracted substructures; Graph schematic - colored nodes indicate substructures contained in final design model, superimposed structures show structural similarity indicated by adjacent edges; Design model before sequence optimization and loop design; Final design models. Credit: Jacobs et al.

Continuing yesterday’s discussion of two complementary approaches to balance designing protein structures with novel functions with designing protein structures with maximum stability, we focus on a method to create novel proteins by stitching together pieces of existing proteins, developed by Brian Kuhlman, one of two co-winners of the 2004 Feynman Prize, Theory category, and his collaborators. From the University of North Carolina Medical School newsroom “Scientists digitally mimic evolution to create new proteins“:

… researchers at the University of North Carolina School of Medicine have developed a method that creates novel proteins by stitching together pieces of already existing proteins.

The technique, called SEWING, is inspired by natural evolutionary mechanisms that also recombine portions of known proteins to produce new structures and functions. This approach can generate a diverse set of protein structures with many of the distinctive features that proteins require to carry out specific biological functions.

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Adding modular hydrogen-bond networks to protein design

Posted by Jim Lewis on January 15th, 2017

Molecular recognition in DNA is built upon a small set of hydrogen-bonding interactions in the core of the DNA double helix. Specificity in protein folding depends largely on buried packing of hydrophobic amino acid side chains complemented by irregular interactions of specific polar groups. A general method is described to design a wide range of protein oligomers that specifically interact via a network of hydrogen bonds. Credit: Baker Lab, University of Washington.

Advances last year in the bottom-up design and fabrication of increasingly complex atomically precise nanostrutures were so rapid we were not able to cover as many as we wanted. Before we dive into this year’s advances, we are catching up on some of the important advances we missed last year. Perhaps the most active area of molecular engineering research last year was the de novo protein design area, originally proposed by Foresight co-founder K. Eric Drexler as “a path to the fabrication of devices to complex atomic specifications”. Our most recent post in this area cites five earlier posts last year about protein design.

Continuing our coverage of important advances in protein design, the two co-winners of the 2004 Feynman Prize, Theory category (for developing the Rosetta software suite for biomolecular modeling and design) both reported important protein design advances in adjacent papers in Science last May. A perspective commentary “Inspired by nature” in the same issue by Ravit Netzer and Sarel J. Fleishman of the Weizmann Institute of Science points out that the great success over the past decade of de novo designing proteins that folded exactly as designed and were very stable has not produced all of the “important structural features seen in protein interfaces and enzyme active sites”. They note that computer algorithms like Rosetta used to design proteins optimize stability. “By contrast, evolution selects proteins for their ability to perform a vital molecular function, often at the expense of stability.” They discuss the complementary approaches to this issue taken by David Baker and his collaborators (today’s post) and by Brian Kuhlman and his collaborators (tomorrow’s post).

Writing in Geekwire, Alan Boyle reports “Scientists add twists to protein designs“:

Biochemists from the University of Washington have engineered complex protein molecules with additional chemical bonds that make it possible to mix and match them like the base pairs of DNA.

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A brief history of nanotechnology

Posted by Jim Lewis on January 3rd, 2017

Richard Feynman teaches a special lecture on March 13, 1964. United States government work.

Our two most recent posts (here and here) have been about efforts by the Advanced Manufacturing Office of the U.S. Department of Energy to promote atomically precise manufacturing—a specific vision for the future of nanotechnology—a vision upon which the Foresight Institute has been focused since our founding 30 years ago. The vision was far removed from then current laboratory technologies, but those current technologies were entering a period of very rapid progress. Progress in several areas led to very useful functional nanomaterials and nanodevices. Enthusiasm for near-term commercial applications became conflated with a long-term technology vision and combined to bring forth ambitious new funding in the US and elsewhere. The differing visions of what nanotechnology is and can become, and the resulting conflicts over funding and over the public image of nanotechnology, are part of the story of Foresight’s first 30 years “Thirty Years of Nanotechnology and Foresight“. An engaging perspective on the history of nanotechnology written by W. Patrick McCray, a professor in the history department at the University of California–Santa Barbara, was published by Slate earlier this year as part of its Futurography series: “Gods of Small Things“.

The field may seem new—but it dates back more than 50 years

… Since the 21st century began, few emerging technologies have been so heavily promoted, funded, and debated as nanotechnology. Defined (currently) by the U.S. government as “the understanding and control of matter at the nanoscale”—a nanometer is one-billionth a meter—nanotechnology as a field and research community has received billions of funding dollars, making it one of the nation’s largest technology investments since the space race.

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New Funding Opportunity from U.S. DOE

Posted by Jim Lewis on January 1st, 2017

U.S. Department of Energy Mission Innovation - a joint effort by more than 20 nations to double clean energy R&D by 2020.

David Forrest, Technology Manager, Advanced Manufacturing Office, U.S. Department of Energy, writes with news of a new funding opportunity at DOE:

Dear Friends and Colleagues who have shown some interest in Atomically Precise Manufacturing (APM),

I am pleased to forward this funding opportunity announcement (FOA) to you from the Advanced Manufacturing Office. The FOA includes a range of topics in advanced materials and processes, and explicitly includes a subtopic on Atomically Precise Manufacturing.

Note: scroll down to the line “DE-FOA-0001465 – Advanced Manufacturing Projects for Emerging Research Exploration (Last Updated: 12/21/2016 05:28 PM ET)” Download the PDF and scroll down to page 11/91 – “Subtopic 1.5 – Atomically Precise Manufacturing”

As some of you know, we have been soliciting SBIR projects in this space for several years now but this is the first AMO R&D Projects FOA in this space. And the application space has been expanded from the SBIR offerings—responsive concept papers and proposals will include atomically precise membranes and catalysts, sensors, molecular electronic computer circuits, and also tools and systems to perform APM through positional assembly (whether tip-based, or molecular machine-based–aka molecular additive manufacturing). Announcement is [here].

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DOE office focusing on atomically precise manufacturing

Posted by Jim Lewis on December 31st, 2016

David Forrest ScD, PE, FASM
Technology Manager, Advanced Manufacturing Office,
U.S. Department of Energy

Longtime Foresight member David Forrest has been involved with nanotechnology development since his student days at MIT with Foresight co-founders Eric Drexler and Christine Peterson, and since October 2012 he has been Technology Manager, Advanced Manufacturing Office, U.S. Department of Energy. At Foresight Institute’s Breakthrough Technologies for Energy workshop this past spring, Dr. Forrest spoke about “Progress in Atomically Precise Manufacturing at the Advanced Manufacturing Office”. The strategic goals of this effort include developing a suite of manufacturing technologies capable of building a broad range of macroscopic atomically precise products, and transitioning these to commercial practice to transform the U.S. manufacturing base to APM-centric production. The motivation from the standpoint of DOE is to reduce energy use. Current efforts began with a DOE workshop held August 5-6, 2015 in Berkeley, CA “Workshop on Integrated Nanosystems for Atomically Precise Manufacturing“. The six plenary presentations that can be downloaded from the workshop web page comprise arguably the best overview of progress toward APM since Foresight Institute and Battelle unveiled a Technology Roadmap for Productive Nanosystems in 2007. When complete, the workshop report is expected to be available from this page.

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Nobel Prize in Chemistry recognizes molecular machines

Posted by Jim Lewis on October 10th, 2016

Sir Fraser receiving the 2007 Foresight Feynman Prize for Experiment

Sir J. Fraser Stoddart, joint winner of the 2016 Nobel Prize in Chemistry, accepting the 2007 Foresight Institute Feynman Prize for Experiment.

The 2016 Nobel Prize in Chemistry was awarded to three scientists who “developed the world’s smallest machines”. From the Royal Swedish Academy of Sciences “Press Release: The Nobel Prize in Chemistry 2016“:

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry 2016 to
Jean-Pierre Sauvage, University of Strasbourg, France
Sir J. Fraser Stoddart, Northwestern University, Evanston, IL, USA, and
Bernard L. Feringa, University of Groningen, the Netherlands
“for the design and synthesis of molecular machines” …

A tiny lift, artificial muscles and minuscule motors. The Nobel Prize in Chemistry 2016 is awarded to Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa for their design and production of molecular machines. They have developed molecules with controllable movements, which can perform a task when energy is added.

The development of computing demonstrates how the miniaturisation of technology can lead to a revolution. The 2016 Nobel Laureates in Chemistry have miniaturised machines and taken chemistry to a new dimension.

The first step towards a molecular machine was taken by Jean-Pierre Sauvage in 1983, when he succeeded in linking two ring-shaped molecules together to form a chain, called a catenane. Normally, molecules are joined by strong covalent bonds in which the atoms share electrons, but in the chain they were instead linked by a freer mechanical bond. For a machine to be able to perform a task it must consist of parts that can move relative to each other. The two interlocked rings fulfilled exactly this requirement.

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Assembling a large, stable, icosahedral protein molecular cage

Posted by Jim Lewis on September 9th, 2016

The design model of the icosahedral nano-cage shows its large, empty volume. UW Institute for Protein Design

It feels like progress in the design and fabrication of atomically precise nanostructures and molecular machines is accelerating along several different paths. A couple days ago we cited advances in molecular machines fabricated using organic synthesis. Earlier this year we cited a number of advances along the protein design pathway to atomically precise manufacturing (here, here, here, here, here). A hat tip to Nanowerk for reprinting this recent advance from the University of Washington Health Sciences news room, written by Leila Gray, and describing work from the University of Washington Institute for Protein Design directed by David Baker, co-winner of the 2004 Feynman Prize, Theory categorySelf-assembling protein icosahedral shell designed“:

The same 20-sided solid that was morphed into geodesic domes in the past century may be the shape of things to come in synthetic biology.

For University of Washington Institute of Protein Design scientists working to invent molecular tools, vehicles, and devices for medicine and other fields, the icosahedron’s geometry is inspiring. Its bird cage-like symmetry and spacious interior suggest cargo-containing possibilities.

The protein designers took their cue from the many viruses that, en route to living cells, transport their genomes inside protective icosahedral protein shells. These delivery packages, termed viral capsids, are formed to be tough enough to withstand the trip, efficiently use storage room, and break apart to release their contents when conditions are right.

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Chemical fuel keeps molecular motor moving

Posted by Jim Lewis on September 4th, 2016

Earlier this year we cited further progress on molecular machines, in this case transporting cargo, from the group of Professor David A Leigh FRS FRSE MAE and winner of the 2007 Feynman Prize in Nanotechnology, Theoretical category. Further molecular machine progress was recently reported by Belle Dumé at “Chemically powered nanomotor goes autonomous“:

Researchers at the University of Manchester, UK have made the first autonomous chemically powered synthetic small-molecule motor. The new device, which is very much like the protein motors found in biological cells, might be used to design artificial molecular machines similar to those found in nature. Such machines could be important for applications such as synthetic muscles, nano- and micro-robots and advanced mechanical motors.

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Rational improvement of DNA nanodevice function

Posted by Jim Lewis on August 13th, 2016

Left panel shows tweezers in the open position, with the enzyme (green) on the upper arm and the co-factor (gold) on the lower arm. Supplying a complementary fuel strand causes the tweezers to close, producing the reaction of the enzyme-cofactor pair. (Right panel) while a set strand restores the tweezers to their open position. Image credit: Biodesign Institute, Arizona State University

We have frequently cited examples of the artificial molecular machines that can be built from DNA. An open question is whether these prototype molecular machines can be improved toward practical applications. For example, can simple machines for manipulating molecules be improved to the point of implementing atomically precise manufacturing? A recent publication provides an example of rational improvement of a simple DNA machine reported three years ago. Three years ago a news release from the Biodesign Institute of Arizona State University reported “Tiny tweezers allow precision control of enzymes“:

Tweezers are a handy instrument when it comes to removing a splinter or plucking an eyebrow.

In new [2013] research, Hao Yan and his colleagues at Arizona State University’s Biodesign Institute describe a pair of tweezers shrunk down to an astonishingly tiny scale. When the jaws of these tools are in the open position, the distance between the two arms is about 16 nanometers—over 30,000 times smaller than a single grain of sand.

The group demonstrated that the nanotweezers, fabricated by means of the base-pairing properties of DNA, could be used to keep biological molecules spatially separated or to bring them together as chemical reactants, depending on the open or closed state of the tweezers.

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Atomically precise location of dopants a step toward quantum computers

Posted by Jim Lewis on August 4th, 2016

An STM image showing the atomic level detail of the electron wave function of a sub-surface phosphorus dopant. Through highly precise matching with theoretical calculations the exact lattice site position and depth of the dopant can be determined. Credit: University of Melbourne

A couple months ago we cited the demonstration of a quantum simulator with dopant atoms placed in silicon with atomic precision. The same Australian and New Jersey teams have since further advanced the prospects for tomorrow’s silicon-based quantum computers. A hat tip to Nanowerk for reprinting this University of Melbourne news release “World-first pinpointing of atoms at work for quantum computers“:

Scientists can now identify the exact location of a single atom in a silicon crystal, a discovery that is key to greater accuracy in the operation of tomorrow’s silicon-based quantum computers.

It’s now possible to track and see individual phosphorus atoms in a silicon crystal allowing confirmation of quantum computing capability but which also has use in nano detection devices.

Quantum computing has the potential for enormous processing power in the future. Your current laptop has transistors that use a binary code, an on or off state (bits). But tomorrow’s quantum computer will use quantum bits ‘qubits’, which have multiple states.

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Watching individual chemical bonds during a reaction

Posted by Jim Lewis on August 2nd, 2016

Identification of reactants, transient intermediates, and products in a bimolecular enediyne coupling and cyclization cascade on a silver surface by non-contact atomic force microscopy. The corresponding chemical structures are depicted below the nc-AFM images. Image credit: A. Riss, adapted from DOI: 10.1038/nchem.2506

One path to advanced nanotechnologies begins with using scanning probe microscopes (SPM) to make atomically precise surface modifications—see, for example p. xii of Productive Nanosystems: A Technology Roadmap. The more precisely the SPM tip can image and manipulate atoms on a surface, the more rationally this path can be planned and implemented. Some of the most impressive progress along this path has come from using noncontact-atomic force microscopy (NC-AFM), such as measuring individual chemical bonds using a carbon monoxide-functionalized tip. Now researchers have succeeded in seeing changes in bond configurations as an organic reaction is catalyzed on a surface. A hat tip to Nanowerk for reprinting this press release from the Max Planck Institute for the Structure and Dynamics of Matter “Viewing a catalytic reaction in action“:

To be able to follow and directly visualize how the structure of molecules changes when they undergo complex chemical transformations has been a long-standing goal of chemistry. While reaction intermediates are particularly difficult to identify and characterize due to their short lifetimes, knowledge of the structure of these species can give valuable insights into reaction mechanisms and therefore impact fields beyond the chemical industry, such as materials science, nanotechnology, biology and medicine. Now an international team of researchers led by Felix R. Fischer, Michael F. Crommie (University of California at Berkeley and Lawrence Berkeley National Laboratory), and Angel Rubio (Max Planck Institute for the Structure and Dynamics of Matter at CFEL in Hamburg and University of the Basque Country in San Sebastián) has imaged and resolved the bond configuration of reactants, intermediates and final products of a complex and technologically relevant organic surface reaction at the single-molecule level. The findings are published in the journal Nature Chemistry [abstract].

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Peptoid nanosheets assemble by different design rule

Posted by Jim Lewis on July 31st, 2016

Snakes on a plane: This atomic-resolution simulation of a peptoid nanosheet reveals a snake-like structure never seen before. The nanosheet’s layers include a water-repelling core (yellow), peptoid backbones (white), and charged sidechains (magenta and cyan). The right corner of the nanosheet’s top layer has been “removed” to show how the backbone’s alternating rotational states give the backbones a snake-like appearance (red and blue ribbons). Surrounding water molecules are red and white. Image courtesy of Ranjan V. Mannige, Molecular Foundry, Berkeley.

The earliest proposal to “open a path to the fabrication of devices to complex atomic specifications” envisioned designing proteins to fold in predetermined ways. Over the years we have cited here numerous advances along this path, most recently here, here, here, here, and here. There has also been interest in polymers that are chemical cousins of proteins, for example, the peptoids, in which the side chains are appended to the nitrogen atom in the peptide bond joining the monomers, rather than to the alpha carbon atom, as is the case with proteins. Four years ago we cited a report of initial successes in the rational design of peptoids, speculated that it might be opening a path to advanced nanotechnology, but noted that their successful computer modeling had so far only produced structures composed of nine subunits. Now we can cite further work by a subset of that group reporting a peptoid nanosheet, two molecules thick but extending laterally for micrometers, based on a structural element not seen in the natural world. A hat tip to Nanowerk for reprinting this news release from the U.S. Dept.of Energy Office of Science “Understanding and Predicting Self-Assembly“:

To mimic complex natural proteins’ capabilities as sensors, catalysts, and more using synthetic materials that can withstand industrial conditions, scientists must first know how to finesse the building blocks they’ll use. Molecular Foundry staff worked with scientists to discover a new design rule that controls the way in which polymer building blocks adjoin to form the backbones that run the length of tiny biomimetic sheets.

Understanding the rules that govern how the nanosheets self-assemble could be used to piece together complex sheet structures and others, such as nanotubes and crystalline solids, that could be customized into incredibly sensitive chemical detectors or long-lasting catalysts, to name a few possibilities.

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Engineered protein assembles molecules into atomically precise lattice

Posted by Jim Lewis on July 30th, 2016

A buckyball, a sphere-like molecule composed of 60 carbon atoms shaped like a soccer ball. (Image credit: St Stev via / CC BY-NC-ND)

An important step as nanotechnology develops toward the ultimate goal of general purpose, high-throughput, atomically precise manufacturing is the use of molecules specifically designed to organize other molecules into precise orientations in space. Simple first steps would be to organize repeating lattices of one component to make novel functional materials; more complex further steps would be to precisely organize the multiple components of molecular machine systems. An early step in this process was reported this spring using a specially engineered protein. A hat tip to Nanowerk for reprinting this Dartmouth College news release “Researchers Create Artificial Protein to Control Assembly of Buckyballs“:

A Dartmouth College scientist and his collaborators have created an artificial protein that organizes new materials at the nanoscale.

“This is a proof-of-principle study demonstrating that proteins can be used as effective vehicles for organizing nano-materials by design,” says senior author Gevorg Grigoryan, an assistant professor of computer science at Dartmouth. “If we learn to do this more generally – the programmable self-assembly of precisely organized molecular building blocks — this will lead to a range of new materials towards a host of applications, from medicine to energy.”

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Another powerful nanoengine remembered

Posted by Jim Lewis on July 11th, 2016

A nanocrystal ram is sandwiched between two MWNT lever arms. On one nanotube a metal particle serves as an atom reservoir that can source or sink atoms to or from the nanocrystal ram. The nanotube conveys the thermally excited atoms between the atom reservoir and ram. Credit: Regan et al. 2005 Nano Letters DOI: 10.1021/nl0510659

Last month we posted a report of a powerful new type of nanoengine, able to deliver a force of ~5 nN (nanonewtons). The authors noted that “The resulting nanoscale forces are several orders of magnitude larger than any produced previously.” A couple weeks later Foresight Senior Fellow—Standards David R. Forrest wrote to challenge that comparison:

Just a quick note on

Cambridge claimed: “The forces exerted by these tiny devices are several orders of magnitude larger than those for any other previously produced device”

I don’t think that is true.

Zettl’s actuator force was 2.6 nN, vs. 5 nN for this “device.” See Reference 8

Given the similar sizes, and noting that the gold nanoparticles ALSO require the surrounding polymer mass as part of the actuation system, I think Zettl’s device has the edge regarding smallest total mass although it’s hard to beat Cambridge’s I/O (light). Also I would note that Zettl’s actuator was positioned on a fixed CNT surface, which allowed the force to be applied at a known location; not true for the particles in suspension. To get useful work out of the device there would need to be attached substrates/levers/something. (More mass, then.)

They probably don’t know about Zettl’s work.

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