Tag Archives: Northwestern University

E-tattoo without the nanotech

John Rogers and his team at the University of Illinois and a colleague’s (Yonggang Huang) team at Northwestern University have devised an ‘electronic tattoo’ (a soft, stick-on patch) made up from materials that anyone can purchase off-the-shelf. Rogers is known for his work with nanomaterials (my Aug. 10, 2012 posting titled ‘Surgery with fingertip control‘ mentioned a silicon nanomembrane that can be fitted onto the fingertips for possible use in surgical procedures) and with electronics (my Aug. 12, 2011 posting titled: ‘Electronic tattoos‘ mentioned his earlier attempts at developing e-tattoos).

This latest effort from Rogers and his multi-university team is mentioned in an April 4, 2014 article by Mark Wilson for Fast Company,

About a year ago, University of Illinois researcher John Rogers revealed a pretty amazing creation: a circuit that, rather than living on an inflexible board, could stick to and move with someone’s skin just like an ink stamp. But like any early research, it was mostly a proof-of-concept, and it would require relatively expensive, custom-printed electronics to work.

Today, Rogers, in conjunction with Northwestern University’s Yonggang Huang, has published details on version 2.0 in Science, revealing that this once-esoteric project has more immediate, mass market appeal.

… It means that you could create a wearable electronic that’s one-part special sticky circuit board, every other part whatever-the-hell-you-manufactured-in-China. This flexible circuit could accommodate a stock battery, an accelerometer, a Wi-Fi chip, and a Bluetooth circuitry, for instance, all living on your skin rather than inside your iPhone. And as an added bonus, it would be relatively cheap.

A University of Illinois April ?, 2014 news release describes Rogers, his multi-university team, and their current (pun intended) e-tattoo,

Engineers at the University of Illinois at Urbana-Champaign and Northwestern University have demonstrated thin, soft stick-on patches that stretch and move with the skin and incorporate commercial, off-the-shelf chip-based electronics for sophisticated wireless health monitoring.

The patches stick to the skin like a temporary tattoo and incorporate a unique microfluidic construction with wires folded like origami to allow the patch to bend and flex without being constrained by the rigid electronics components. The patches could be used for everyday health tracking – wirelessly sending updates to your cellphone or computer – and could revolutionize clinical monitoring such as EKG and EEG testing – no bulky wires, pads or tape needed.

“We designed this device to monitor human health 24/7, but without interfering with a person’s daily activity,” said Yonggang Huang, the Northwestern University professor who co-led the work with Illinois professor John A. Rogers. “It is as soft as human skin and can move with your body, but at the same time it has many different monitoring functions. What is very important about this device is it is wirelessly powered and can send high-quality data about the human body to a computer, in real time.”

The researchers did a side-by-side comparison with traditional EKG and EEG monitors and found the wireless patch performed equally to conventional sensors, while being significantly more comfortable for patients. Such a distinction is crucial for long-term monitoring, situations such as stress tests or sleep studies when the outcome depends on the patient’s ability to move and behave naturally, or for patients with fragile skin such as premature newborns.

Rogers’ group at Illinois previously demonstrated skin electronics made of very tiny, ultrathin, specially designed and printed components. While those also offer high-performance monitoring, the ability to incorporate readily available chip-based components provides many important, complementary capabilities in engineering design, at very low cost.

“Our original epidermal devices exploited specialized device geometries – super thin, structured in certain ways,” Rogers said. “But chip-scale devices, batteries, capacitors and other components must be re-formulated for these platforms. There’s a lot of value in complementing this specialized strategy with our new concepts in microfluidics and origami interconnects to enable compatibility with commercial off-the-shelf parts for accelerated development, reduced costs and expanded options in device types.”

The multi-university team turned to soft microfluidic designs to address the challenge of integrating relatively big, bulky chips with the soft, elastic base of the patch. The patch is constructed of a thin elastic envelope filled with fluid. The chip components are suspended on tiny raised support points, bonding them to the underlying patch but allowing the patch to stretch and move.

One of the biggest engineering feats of the patch is the design of the tiny, squiggly wires connecting the electronics components – radios, power inductors, sensors and more. The serpentine-shaped wires are folded like origami, so that no matter which way the patch bends, twists or stretches, the wires can unfold in any direction to accommodate the motion. Since the wires stretch, the chips don’t have to.

Skin-mounted devices could give those interested in fitness tracking a more complete and accurate picture of their activity level.

“When you measure motion on a wristwatch type device, your body is not very accurately or reliably coupled to the device,” said Rogers, a Swanlund Professor of Materials Science and Engineering at the U. of I. “Relative motion causes a lot of background noise. If you have these skin-mounted devices and an ability to locate them on multiple parts of the body, you can get a much deeper and richer set of information than would be possible with devices that are not well coupled with the skin. And that’s just the beginning of the rich range of accurate measurements relevant to physiological health that are possible when you are softly and intimately integrated onto the skin.”

The researchers hope that their sophisticated, integrated sensing systems could not only monitor health but also could help identify problems before the patient may be aware. For example, according to Rogers, data analysis could detect motions associated with Parkinson’s disease at its onset.

“The application of stretchable electronics to medicine has a lot of potential,” Huang said. “If we can continuously monitor our health with a comfortable, small device that attaches to our skin, it could be possible to catch health conditions before experiencing pain, discomfort and illness.”

Here’s a link to and a citation for the paper,

Soft Microfluidic Assemblies of Sensors, Circuits, and Radios for the Skin by Sheng Xu, Yihui Zhang, Lin Jia, Kyle E. Mathewson, Kyung-In Jang, Jeonghyun Kim, Haoran Fu, Xian Huang, Pranav Chava, Renhan Wang, Sanat Bhole, Lizhe Wang, Yoon Joo Na, Yue Guan, Matthew Flavin, Zheshen Han, Yonggang Huang, & John A. Rogers. Science 4 April 2014: Vol. 344 no. 6179 pp. 70-74 DOI: 10.1126/science.1250169

This paper is behind a paywall.

Richard Van Duyne solves mystery of Renoir’s red with surface-enhanced Raman spectroscopy (SERS) and Canadian scientists uncover forgeries

The only things these two items have in common is that they are concerned with visual art. and with solving mysteries The first item concerns research by Richard Van Duyne into the nature of the red paint used in one of Renoir’s paintings. A February 14, 2014 news item on Azonano describes some of the art conservation work that Van Duyne’s (nanoish) technology has made possible along with details about this most recent work,

Scientists are using powerful analytical and imaging tools to study artworks from all ages, delving deep below the surface to reveal the process and materials used by some of the world’s greatest artists.

Northwestern University chemist Richard P. Van Duyne, in collaboration with conservation scientists at the Art Institute of Chicago, has been using a scientific method he discovered nearly four decades ago to investigate masterpieces by Pierre-Auguste Renoir, Winslow Homer and Mary Cassatt.

Van Duyne recently identified the chemical components of paint, now partially faded, used by Renoir in his oil painting “Madame Léon Clapisson.” Van Duyne discovered the artist used carmine lake, a brilliant but light-sensitive red pigment, on this colorful canvas. The scientific investigation is the cornerstone of a new exhibition at the Art Institute of Chicago.

The Art Institute of Chicago’s exhibition is called, Renoir’s True Colors: Science Solves a Mystery. being held from Feb. 12, 2014 – April 27, 2014. Here is an image of the Renoir painting in question and an image featuring the equipment being used,

Renoir-Madame-Leon-Clapisson.Art Institute of Chicago.

Renoir-Madame-Leon-Clapisson.Art Institute of Chicago.

Renoir and surface-enhanced Raman spectroscopy (SERS). Art Institute of Chicago

Renoir and surface-enhanced Raman spectroscopy (SERS). Art Institute of Chicago

The Feb. 13, 2014 Northwestern University news release (also on EurekAlert) by Megan Fellman, which originated the news item, gives a brief description of Van Duyne’s technique and its impact on conservation at the Art Institute of Chicago (Note: A link has been removed),

To see what the naked eye cannot see, Van Duyne used surface-enhanced Raman spectroscopy (SERS) to uncover details of Renoir’s paint. SERS, discovered by Van Duyne in 1977, is widely recognized as the most sensitive form of spectroscopy capable of identifying molecules.

Van Duyne and his colleagues’ detective work informed the production of a new digital visualization of the painting’s original colors by the Art Institute’s conservation department. The re-colorized reproduction and the original painting (presented in a case that offers 360-degree views) can be viewed side by side at the exhibition “Renoir’s True Colors: Science Solves a Mystery” through April 27 [2014] at the Art Institute.

I first wrote about Van Duyne’s technique in my wiki, The NanoTech Mysteries. From the Scientists get artful page (Note: A footnote was removed),

Richard Van Duyne, then a chemist at Northwestern University, developed the technique in 1977. Van Duyne’s technology, based on Raman spectroscopy which has been around since the 1920s, is called surface-enhanced Raman spectroscopy’ or SERS “[and] uses laser light and nanoparticles of precious metals to interact with molecules to show the chemical make-up of a particular dye.”

This next item is about forgery detection. A March 5, 2014 news release on EurekAlert describes the latest developments,

Gallery owners, private collectors, conservators, museums and art dealers face many problems in protecting and evaluating their collections such as determining origin, authenticity and discovery of forgery, as well as conservation issues. Today these problems are more accurately addressed through the application of modern, non-destructive, “hi-tech” techniques.

Dmitry Gavrilov, a PhD student in the Department of Physics at the University of Windsor (Windsor, Canada), along with Dr. Roman Gr. Maev, the Department of Physics Professor at the University of Windsor (Windsor, Canada) and Professor Dr. Darryl Almond of the University of Bath (Bath, UK) have been busy applying modern techniques to this age-old field. Infrared imaging, thermography, spectroscopy, UV fluorescence analysis, and acoustic microscopy are among the innovative approaches they are using to conduct pre-restoration analysis of works of art. Some fascinating results from their applications are published today in the Canadian Journal of Physics.

Since the early 1900s, using infrared imaging in various wave bands, scientists have been able to see what parts of artworks have been retouched or altered and sometimes even reveal the artist’s original sketches beneath layers of the paint. Thermography is a relatively new approach in art analysis that allows for deep subsurface investigation to find defects and past reparations. To a conservator these new methods are key in saving priceless works from further damage.

Gavrilov explains, “We applied new approaches in processing thermographic data, materials spectra data, and also the technique referred to as craquelure pattern analysis. The latter is based on advanced morphological processing of images of surface cracks. These cracks, caused by a number of factors such as structure of canvas, paints and binders used, can uncover important clues on the origins of a painting.”

“Air-coupled acoustic imaging and acoustic microscopy are other innovative approaches which have been developed and introduced into art analysis by our team under supervision of Dr. Roman Gr. Maev. The technique has proven to be extremely sensitive to small layer detachments and allows for the detection of early stages of degradation. It is based on the same principles as medical and industrial ultrasound, namely, the sending a sound wave to the sample and receiving it back. ”

Spectroscopy is a technique that has been useful in the fight against art fraud. It can determine chemical composition of pigments and binders, which is essential information in the hands of an art specialist in revealing fakes. As described in the paper, “…according to the FBI, the value of art fraud, forgery and theft is up to $6 billion per year, which makes it the third most lucrative crime in the world after drug trafficking and the illegal weapons trade.”

One might wonder how these modern applications can be safe for delicate works of art when even flash photography is banned in art galleries. The authors discuss this and other safety concerns, describing both historic and modern-day implications of flash bulbs and exhibit illumination and scientific methods. As the paper concludes, the authors suggest that we can expect that the number of “hi-tech” techniques will only increase. In the future, art experts will likely have a variety of tools to help them solve many of the mysteries hiding beneath the layers.

Here’s a link to and a citation for the paper,

A review of imaging methods in analysis of works of art: Thermographic imaging method in art analysis by D. Gavrilov, R.Gr. Maev, and D.P. Almond. Canadian Journal of Physics, 10.1139/cjp-2013-0128

This paper is open access.

‘Giving’ life to liquid crystals

A Feb. 18, 2014 news item on Azonano highlights a presentation about living liquid crystals that was given at the 58th annual Biophysical Society Meeting in San Francisco on Feb. 17, 2014,

Plop living, swimming bacteria into a novel water-based, nontoxic liquid crystal and a new physics takes over. The dynamic interaction of the bacteria with the liquid crystal creates a novel form of soft matter: living liquid crystal.

The new type of active material, which holds promise for improving the early detection of diseases, was developed by a research collaboration based at Ohio’s Kent State University and Illinois’ Argonne National Laboratory. The team will present their work at the 58th annual Biophysical Society Meeting, held in San Francisco, Feb.15-19 [2014].

ScienceDaily featured the story in a Feb. 17, 2014 news item,

As a biomechanical hybrid, living liquid crystal moves and reshapes itself in response to external stimuli. It also stores energy just as living organisms do to drive its internal motion. And it possesses highly desirable optical properties. In a living liquid crystal system, with the aid of a simple polarizing microscope, you can see with unusual clarity the wake-like trail stimulated by the rotation of bacterial flagella just 24-nanometers thick, about 1/4000th the thickness of an average human hair.

You can also control and guide active movements of the bacteria by manipulating variables such as oxygen availability, temperature or surface alignment, thus introducing a new design concept for creating microfluidic biological sensors. Living liquid crystal provides a medium to amplify tiny reactions that occur at the micro- and nano-scales — where molecules and viruses interact — and to also easily optically detect and analyze these reactions. That suits living liquid crystal to making sensing devices that monitor biological processes such as cancer growth, or infection. Such microfluidic technology is of increasing importance to biomedical sensing as a means of detecting disease in its earliest stages when it is most treatable, and most cost-effectively managed.

Quotes from the lead researcher and presentation details can be found in the Feb. 17, 2013 news item on newswise.com,

“As far as we know, these things have never been done systematically as we did before in experimental physics,” explained Shuang Zhou, a Ph.D. candidate at Ohio’s Kent State University. He collaborated on the project with Oleg Lavrentovich of Kent State, Andrey Sokolov of Argonne National Laboratory, in Illinois, and Igor Aranson of Argonne National Laboratory and Northwestern University, in Evanston, Ill.

“There are many potential applications for this kind of new material, but some of the more immediate are new approaches to biomedical sensing design,” Zhou said. He likens the current investigation to the “first handful of gold scooped out of a just-opened treasure chest. There are many more things to be done.”

The presentation “Living Liquid Crystals” by Shuang Zhou, Andrey Sokolov, Oleg D. Lavrentovich and Igor S. Aranson will be at 1:45 p.m. on Monday, February 17, 2014 in Hall D in San Francisco’s Moscone Convention Center.
ABSTRACT: http://tinyurl.com/pmvbfbp

Here’s the presentation abstract (from the abstractsonline website),

Bio-mechanical hybrids are an emerging class of engineered composite soft materials with the ability to move and reconfigure their structure and properties in response to external stimuli. Similar to their biological counterparts, they can transduce energy stored in the environment to drive systematic movements. This functionality is critical for a variety of applications, from bioinspired micromachines and sensors to self-assembled microrobots. Here, by combining two seemingly incompatible concepts, living swimming bacteria and inanimate but orientationally ordered lyotropic liquid crystal, we conceive a fundamentally new class of matter – living liquid crystals (LLCs). LLCs can be actuated and controlled by the amount of oxygen available to bacteria, by concentration of ingredients or by the temperature. Our studies reveal a wealth of intriguing phenomena, caused primarily by the coupling between the activity-triggered flows and director reorientations. Among these are (a) coupling between the orientation and degree of order of LLC and the bacterial motion, (b) local nematic-isotropic phase transition caused by the bacteria-produced shear flows, (c) periodic stripe instabilities of the director in surface-anchored LLCs, (d) director pattern evolution into an array of disclinations with positive and negative topological charges as the surface anchoring is weakened or when the bacterial activity is enhanced; (e) direct optical visualization and quantitative characterization of microflows generated by the nanometers-thick bacterial flagella by the birefringent LLC medium. Our work suggests an unorthodox design concept of reconfigurable microfluidic chambers for control and manipulation of bacteria. Besides an obvious importance to active matter, our studies can result in valuable biosensing and biomedical applications.

The researchers associated with this work are,

Shuang Zhou, Andrey Sokolov, Oleg D. Lavrentovich, Igor S. Aranson

Their research has been published online by the Proceedings of the National Academy of Sciences (PNAS),

Living liquid crystals by Shuang Zhou, Andrey Sokolov, Oleg D. Lavrentovich, and Igor S. Aranson. PNAS approved December 12, 2013 (received for review November 22, 2013) doi: 10.1073/pnas.1321926111

This paper is behind a paywall but it can be accessed via the tabs seen directly after the publication history (approved … received …).  You will see Abstract, Authors, … and two symbols signifying the formats in which the paper is available.

New book ‘Wonder of Nanotechnology’ explores optical and electronic systems

Nature is nano.

Nature starts with the atom, the building block of all matter, and works hand-in-hand with her partner the photon, the piece of light that communicates energy from one atom to another.When nature binds atoms together or creates physical structures in the micro- and nano-range, the combinations interact differently with light, providing nature with a rich palette of colors to decorate the world around us,while also giving rise to the functional complexity of nature.The wings of a butterfly, the feather of a peacock, the sheen of a pearl—all of these are examples of nature’s photonic crystals: nanostructured arrangements of atoms that capture and recast the colors of the rainbow with iridescent beauty. These diverse combinations of microstructures and atoms in molecules, crystals, proteins, and cells on the nanoscale eventually give rise to ourselves, sentient beings, who, in turn, strive to explain the natural world that we see around us.. (from the Preface for the Wonder of Nanotechnology)

The Nov. 21, 2013 SPIE, the international society for optics and photonics news release touting the book is a little more restrained than the dramatic ‘Nature is nano’,,

BELLINGHAM, Washington, USA – Nanotechnology research has progressed into quantum-level systems where electrons, photonics, and even thermal properties can be engineered, enabling new structures and materials with which to create ever-shrinking, ever-faster electronics. The Wonder of Nanotechnology: Quantum Optoelectronic Devices and Applications, edited by Manijeh Razeghi and Nobel Laureates Leo Esaki and Klaus von Klitzing, focuses on the application of nanotechnology to modern semiconductor optoelectronic devices The book is published by SPIE, the international society of optics and photonics.

The volume is a compilation of research papers from the International Conference on Infrared Optoelectronics at Northwestern University’s Center for Quantum Devices in September 2012, developed into chapters representing state-of-the-art research in infrared materials and devices.

“Advances in material science at the nanometer scale are opening new doors in the area of optics and electronics. The ability to manipulate atoms and photons, and fabricate new material structures offers opportunities to realize new emitters, detectors, optics, ever-shrinking electronics, and integration of optics and electronics,” writes Nibir Dhar, program manager with Defense Advanced Research Project Agency (DARPA), in an essay in the book. “Imaging technology has the opportunity to leverage these developments to produce new products for military, industrial, medical, security, and other consumer applications.”

The editors of Wonder of Nanotechnology are:

  • Manijeh Razeghi, director of the Center for Quantum Devices at Northwestern University and one of the leading scientists in the field of semiconductor science and technology. Razeghi pioneered nanometer-scale architectures in semiconductor technology, and her research in quantum materials has culminated in various technologies such as type-II strained-layer superlattice infrared detectors, lasers, and terahertz technology. Her current interest is in nanoscale optoelectronic quantum devices.
  • Leo Esaki, who shared the 1973 Nobel Prize in Physics for his discovery of the phenomenon of electron tunneling while working at Tokyo Tsushin Kogyo (now known as Sony). He is known for his invention of the Esaki diode, which exploited that phenomenon. He also pioneered the development of the semiconductor superlattice while at IBM, and is president of the Yokohama College of Pharmacy in Japan.
  • Klaus von Klitzing, director of the Max Planck Institute for Solid State Research in Germany. Von Klitzing was awarded the 1985 Nobel Prize in Physics for his discovery of the integer quantum Hall effect. His current research focuses on the properties of low-dimensional electronic systems, typically in low temperatures and in high magnetic fields.

“The chapters in this book bear witness to how far we have come since the invention of manmade semiconductor superlattices in 1969,” Esaki writes in the book’s foreword. “I look back with wonder at all of the exciting developments of the last 44 years and can only imagine where the future will take this technology and what exciting discoveries await.”

The book’s editors also address the inspiration of nature in studying nanoscale structures, and how the human ability to control material composition on the nanometer scale is what allows us to achieve technological goals transcending the properties of naturally occurring materials.

“The wings of a butterfly, the feather of a peacock, the sheen of a pearl — all of these are examples of nature’s photonic crystals: nanostructured arrangements of atoms that capture and recast the colors of the rainbow with iridescent beauty,” von Klitzing writes in the book’s preface. “As our tools to manipulate matter reach ever smaller length scales, we, too, are able to join in the game of discovery in the nano-world — a game that nature has long since mastered.”

Notable chapters include:

  • “Advances in High-Power Quantum Cascade Lasers and Applications” by Arkadiy Lyakh, Richard Maulini, Alexei Tsekoun, and Boris Tadjikov (Pranalytica, Inc.), and CO2-laser inventor Kumar Patel (Pranalytica, Inc., and University of California Los Angeles)
  • “Type-II Superlattices: Status and Trends” by Elena Plis and Sanjay Krishna (Center for High-Technology Materials, University of New Mexico)
  • “Quantum Dots for Infrared Focal Plane Arrays Grown by MOCVD” by Manijeh Razeghi and Stanley Tsao (Center for Quantum Devices, Northwestern University)
  • “Quantum-Dot Biosensors using Fluorescence Resonance Energy Transfer (FRET)” by James Garland and Dinakar Ramadurai (Episensors, Inc., and Sivananthan Laboratories, Inc.) and Siva Sivananthan (Sivananthan Laboratories, Inc., and University of Illinois)
  • “Nanostructured Electrode Interfaces for Energy Applications” by Palash Gangopadhyay, Kaushik Balakrishnan, and Nasser Peyghambarian (College of Optical Sciences, University of Arizona)

You can go here to purchase the book.

Desktop nanofabrication is in the laboratory but not in the marketplace yet

Another Chad Mirkin, Northwestern University (Chicago, Illinois, US), research breakthrough has been announced (this man, with regard to research,  is as prolific as a bunny) in a July 19, 2013 news item on ScienceDaily,

A new low-cost, high-resolution tool is primed to revolutionize how nanotechnology is produced from the desktop, according to a new study by Northwestern University researchers.

Currently, most nanofabrication is done in multibillion-dollar centralized facilities called foundries. This is similar to printing documents in centralized printing shops. Consider, however, how the desktop printer revolutionized the transfer of information by allowing individuals to inexpensively print documents as needed. This paradigm shift is why there has been community-wide ambition in the field of nanoscience to create a desktop nanofabrication tool.

“With this breakthrough, we can construct very high-quality materials and devices, such as processing semiconductors over large areas, and we can do it with an instrument slightly larger than a printer,” said Chad A. Mirkin, senior author of the study.

The July 19, 2013 Northwestern University news release (on EurekAlert), which originated the news item, provides details,

The tool Mirkin’s team has created produces working devices and structures at the nanoscale level in a matter of hours, right at the point of use. It is the nanofabrication equivalent of a desktop printer.

Without requiring millions of dollars in instrumentation costs, the tool is poised to prototype a diverse range of functional structures, from gene chips to protein arrays to building patterns that control how stem cells differentiate to making electronic circuits.

“Instead of needing to have access to millions of dollars, in some cases billions of dollars of instrumentation, you can begin to build devices that normally require that type of instrumentation right at the point of use,” Mirkin said.

The paper details the advances Mirkin’s team has made in desktop nanofabrication based upon easily fabricated beam-pen lithography (BPL) pen arrays, structures that consist of an array of polymeric pyramids, each coated with an opaque layer with a 100 nanometer aperture at the tip. Using a digital micromirror device, the functional component of a projector, a single beam of light is broken up into thousands of individual beams, each channeled down the back of different pyramidal pens within the array and through the apertures at the tip of each pen.

The nanofabrication tool allows one to rapidly process substrates coated with photosensitive materials called resists and generate structures that span the macro-, micro- and nanoscales, all in one experiment.

Key advances made by Mirkin’s team include developing the hardware, writing the software to coordinate the direction of light onto the pen array and constructing a system to make all of the pieces of this instrument work together in synchrony. This approach allows each pen to write a unique pattern and for these patterns to be stitched together into functional devices.

“There is no need to create a mask or master plate every time you want to create a new structure,” Mirkin said. “You just assign the beams of light to go in different places and tell the pens what pattern you want generated.”

Because the materials used to make the desktop nanofabrication tool are easily accessible, commercialization may be as little as two years away, Mirkin said. In the meantime, his team is working on building more devices and prototypes.

In the paper, Mirkin explains how his lab produced a map of the world, with nanoscale resolution that is large enough to see with the naked eye, a feat never before achieved with a scanning probe instrument. Not only that, but closer inspection with a microscope reveals that this image is actually a mosaic of individual chemical formulae made up of nanoscale points. Making this pattern showcases the instrument’s capability of simultaneously writing centimeter-scale patterns with nanoscale resolution.

Here’s a link to and a citation for the published paper,

Desktop nanofabrication with massively multiplexed beam pen lithography by Xing Liao, Keith A. Brown, Abrin L. Schmucker, Guoliang Liu, Shu He, Wooyoung Shim, & Chad A. Mirkin. Nature Communications 4, Article number: 2103 doi:10.1038/ncomms3103 Published 19 July 2013

This paper is behind a paywall. As an alternative of sorts, you might like to check out this March 22, 2012 video of Mirkin’s presentation entitled, A Chemist’s Approach to Nanofabrication: Towards a “Desktop Fab” for the US Air Force Office of Scientific Research.

Chad Mirkin’s periodic table of modified nucleic acid nanoparticles

Chad Mirkin has been pushing his idea for a new periodic table of ‘nanoparticles’ since at least Feb. 2013 (I wrote about this and some of Mirkin’s other work in my Feb. 19, 2013 posting) when he presented it at the 2013 American Association for the Advancement of Science (AAAS) annual meeting in Boston, Massachusetts. From a Feb. 17, 2013 news item on ScienceDaily,

Northwestern University’s Chad A. Mirkin, a leader in nanotechnology research and its application, has developed a completely new set of building blocks that is based on nanoparticles and DNA. Using these tools, scientists will be able to build — from the bottom up, just as nature does — new and useful structures.

Mirkin will discuss his research in a session titled “Nucleic Acid-Modified Nanostructures as Programmable Atom Equivalents: Forging a New Periodic Table” at the American Association for the Advancement of Science (AAAS) annual meeting in Boston.

“We have a new set of building blocks,” Mirkin said. “Instead of taking what nature gives you, we can control every property of the new material we make. [emphasis mine] We’ve always had this vision of building matter and controlling architecture from the bottom up, and now we’ve shown it can be done.”

Mirkin seems a trifle grandiose; I’m hoping he doesn’t have any grand creation projects that require seven days.

Getting back to the new periodic table, the Feb. 13, 2013 Northwestern University news release by Megan Fellman, which originated the news item,  provides a few more details,

Using nanoparticles and DNA, Mirkin has built more than 200 different crystal structures with 17 different particle arrangements. Some of the lattice types can be found in nature, but he also has built new structures that have no naturally occurring mineral counterpart.
….
Mirkin can make new materials and arrangements of particles by controlling the size, shape, type and location of nanoparticles within a given particle lattice. He has developed a set of design rules that allow him to control almost every property of a material.

New materials developed using his method could help improve the efficiency of optics, electronics and energy storage technologies. “These same nanoparticle building blocks have already found wide-spread commercial utility in biology and medicine as diagnostic probes for markers of disease,” Mirkin added.

With this present advance, Mirkin uses nanoparticles as “atoms” and DNA as “bonds.” He starts with a nanoparticle, which could be gold, silver, platinum or a quantum dot, for example. The core material is selected depending on what physical properties the final structure should have.

He then attaches hundreds of strands of DNA (oligonucleotides) to the particle. The oligonucleotide’s DNA sequence and length determine how bonds form between nanoparticles and guide the formation of specific crystal lattices.

“This constitutes a completely new class of building blocks in materials science that gives you a type of programmability that is extraordinarily versatile and powerful,” Mirkin said. “It provides nanotechnologists for the first time the ability to tailor properties of materials in a highly programmable way from the bottom up.”

Mirkin and his colleagues have since published a paper about this new periodic table in Angewandte Chemie (May 2013). And, earlier today (July 5, 2013) Philip Ball writing (A self-assembled periodic table) for the Royal Society of Chemistry provided a critique of the idea while supporting it in principle,

Mirkin and his colleagues perceive the pairing of [DNA] strands as somewhat analogous to the covalent pairing of electrons and call their DNA-tagged nanoparticles programmable atom equivalents (PAEs). These PAEs may bind to one another according to particular combinatorial rules and Mirkin proposes a kind of periodic table of PAEs that systematises their possible interactions and permutations.
Well, it’s not hard to start enumerating ways in which PAEs are unlike atoms. Most fundamentally, perhaps, the bonding propensity of a PAE need bear no real relation to the ‘atom’ (the nanoparticle) with which it is associated: a given nanoparticle might be paired with any other, and there’s nothing periodic about those tendencies.

I recommend reading Ball’s piece for the way he analyzes the weaknesses and for why he thinks the effort to organize PAEs conceptually is worthwhile.

For the curious, here’s a link to and a citation for the researchers’ published paper,

Nucleic Acid-Modified Nanostructures as Programmable Atom Equivalents: Forging a New “Table of Elements by Robert J. Macfarlane, Matthew N. O’Brien, Dr. Sarah Hurst Petrosko, and Prof. Chad A. Mirkin. Angewandte Chemie International Edition Volume 52, Issue 22, pages 5688–5698, May 27, 2013. Article first published online: 2 MAY 2013 DOI: 10.1002/anie.201209336

Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

One final comment, this is not the first ‘nanoparticle table of elements’.  Larry Bell mentioned one in his Dec. 7, 2010 NISENet (Nanoscale Informal Science Education Network) blog posting,

The focus of today’s sessions at NSF’s [US National Science Foundation] meeting of nanoscale science and engineering grantees focuses on putting the science to practical use. First up this morning is nanomanufacturing. Mark Tuonimen from the University of Massachusetts at Amherst gave a talk about the Nanoscale Manufacturing Network and one of his images caught my imagination. This image, which comes from the draft Nano2 vision document on the next decade of nanoscale research, illustrates and idea that is sometimes referred to as a periodic table of nanoparticles.

[downloaded from http://www.nisenet.org/blogs/observations_insights/periodic_table_nanoparticles]

[downloaded from http://www.nisenet.org/blogs/observations_insights/periodic_table_nanoparticles]

Bell goes on to describe one way in which a nanoparticle table of elements would have to differ from the traditional chemistry table.

DARPA (US Defense Advanced Research Projects Agency), nanoparticles, and your traumatized brain

According to the May 10, 2013 news item on Nanowerk,

DARPA, the U.S. Defense Advanced Research Projects Agency, has awarded $6 million to a team of researchers to develop nanotechnology therapies for the treatment of traumatic brain injury and associated infections.

Led by Professor Michael J. Sailor, Ph.D., from the University of California San Diego [UC San Diego], the award brings together a multi-disciplinary team of renowned experts in laboratory research, translational investigation and clinical medicine, including Erkki Ruoslahti, M.D., Ph.D. of Sanford-Burnham Medical Research Institute, Sangeeta N. Bhatia, M.D., Ph.D. of Massachusetts Institute of Technology and Clark C. Chen, M.D., Ph.D. of UC San Diego School of Medicine.

Ballistics injuries that penetrate the skull have amounted to 18 percent of battlefield wounds sustained by men and women who served in the campaigns in Iraq and Afghanistan, according to the most recent estimate from the Joint Theater Trauma Registry, a compilation of data collected during Operation Iraqi Freedom and Operation Enduring Freedom.

“A major contributor to the mortality associated with a penetrating brain injury is the elevated risk of intracranial infection,” said Chen, a neurosurgeon with UC San Diego Health System, noting that projectiles drive contaminated foreign materials into neural tissue.

The May 9, 2013 UC San Diego news release by Susan Brown, which originated the news item, describes the reasons why DARPA wants to use nanoparticles in therapies for people suffering from traumatic brain injury,

Under normal conditions, the brain is protected from infection by a physiological system called the blood-brain barrier. “Unfortunately, those same natural defense mechanisms make it difficult to get antibiotics to the brain once an infection has taken hold,” said Chen, associate professor and vice-chair of research in the Division of Neurosurgery at UC San Diego School of Medicine.

DARPA hopes to meet these challenges with nanotechnology. The agency awarded this grant under its In Vivo Nanoplatforms for Therapeutics program to construct nanoparticles that can find and treat infections and other damage associated with traumatic brain injuries.

“Our approach is focused on porous nanoparticles that contain highly effective therapeutics on the inside and targeting molecules on the outside,” said Sailor, the UC San Diego materials chemist who leads the team. “When injected into the blood stream, we have found that these silicon-based particles can target certain tissues very effectively.”

Several types of nanoparticles have already been approved for clinical use in patients, but none for treatment of trauma or diseases in the brain. This is due in part to the inability of nanoparticle formulations to cross the blood-brain barrier and reach their intended targets.

“Poor penetration into tissues limits the application of nanoparticles to the treatment of many types of diseases,” said Ruoslahti, distinguished professor at Sanford-Burnham and partner in the research. “We are trying to overcome this limitation using targeting molecules that activate tissue-specific transport pathways to deliver nanoparticles.”

There is another major hurdle for treating brain injuries (from the news release),

Treating brain infections is becoming more difficult as drug-resistant strains of viruses and bacteria have emerged. Because drug-resistant strains mutate and evolve rapidly, researchers must constantly adjust their approach to treatment.

In an attempt to hit this moving target, the team is making their systems modular, so they can be reconfigured “on-the-fly” with the latest therapeutic advances.

Nanocomplexes that contain genetic material known as short interfering RNA, or siRNA, developed by Bhatia’s research group at MIT, will be key to this aspect of the team’s approach.

“The function of this type of RNA is that it specifically intereferes with processes in a diseased cell. The advantage of RNA therapies are that they can be quickly and easily modified when a new disease target emerges,” said Bhatia, a bioengineering professor at MIT and partner in the research.

But effective delivery of siRNA-based therapeutics in the body has proven to be a challenge because the negative charge and chemical structure of naked siRNA makes it very unstable in the body and it has difficulty crossing into diseased cells. To solve these problems, Bhatia has developed nanoparticles that form a protective coating around siRNA.

“The nanocomplexes we are developing shield the negative charge of RNA and protect it from nucleases that would normally destroy it. Adding Erkki’s tissue homing and cell-penetrating peptides allows the nanocomplex to transport deep into tissue and enter the diseased cells,” she said.

Bhatia has previously used the cell-penetrating nanocomplex to deliver siRNA to a tumor cell and shut down its protein production machinery. Although her group’s effort has focused on cancer, the team is now going after two other hard-to-treat cell types: drug-resistant bacteria and inflammatory cells in the brain.

“The work proposed by this multi-disciplinary team should provide new tools to mitigate the debilitating effects of penetrating brain injuries and offer our warfighters the best chance of meaningful recovery,” Chen said. [emphasis mine]

BTW, the term ‘warfighters’ is new to me; are we replacing the word ‘soldier’?

Returning to the matter at hand, I found DARPA’s In Vivo Nanoplatforms for Therapeutics program which is described this way on its home page,

Disease limits soldier readiness and creates healthcare costs and logistics burdens. Diagnosing and treating disease faster can help limit its impact. [emphasis mine] Current technologies and products for diagnosing disease are principally relegated to in vitro (in the lab) medical devices, which are often expensive, bulky and fragile.

DARPA’s In Vivo Nanoplatforms (IVN) program seeks to develop new classes of adaptable nanoparticles for persistent, distributed, unobtrusive physiologic and environmental sensing as well as the treatment of physiologic abnormalities, illness and infectious disease.

The IVN Diagnostics (IVN:Dx) program effort aims to develop a generalized in vivo platform that provides continuous physiological monitoring for the warfighter. [emphasis mine] Specifically, IVN:Dx will investigate technologies that may provide:

  • Implantable nanoplatforms using bio-compatible and nontoxic materials
  • In vivo sensing of small and large molecules of biological interest
  • Multiplexed detection of analytes at clinically relevant concentrations
  • External interrogation of the nanoplatform free from any implanted communications electronics
  • Complete system demonstration in a large animal

The IVN Therapeutics (IVN:Tx) program effort will seek unobtrusive nanoplatforms for rapidly treating disease in warfighters.

(I see DARPA is using both soldier and warfighter’.)

This team is not the only one wishing to deliver drug therapies in a targeted fashion to the brain. My Feb. 19, 2013 posting mentioned Chad Mirkin (Northwestern University) and his team’s efforts with spherical nucleic acids (SNAs), from the posting,

Potential applications include using SNAs to carry nucleic acid-based therapeutics to the brain for the treatment of glioblastoma, the most aggressive form of brain cancer, as well as other neurological disorders such as Alzheimer’s and Parkinson’s diseases. Mirkin is aggressively pursuing treatments for such diseases with Alexander H. Stegh, an assistant professor of neurology at Northwestern’s Feinberg School of Medicine. (originally excerpted from this the Feb. 15, 2013 news release on EurekAlert)

Coincidentally, Mirkin has just been named ‘Chemistry World Entrepreneur of the Year’ by the UK’s Royal Society of Chemistry, from the May 10, 2013 news item on Nanowerk,

Northwestern University scientist Chad A. Mirkin, a world-renowned leader in nanotechnology research and its application, has been named 2013 Chemistry World Entrepreneur of the Year by the Royal Society of Chemistry (RSC). The award recognizes an individual’s contribution to the commercialization of research.

The RSC is honoring Mirkin for his invention of spherical nucleic acids (SNAs), new globular forms of DNA and RNA. These structures form the basis for more than 300 products commercialized by licensees of the technology.

I’m never quite sure what to make of researchers who receive public funding then patent and license the results of that research.

Getting back to soldiers/warfighters, I’m glad to see this research being pursued. Years ago, a physician mentioned to me that soldiers in Iraq were surviving injuries that would have killed them in previous conflicts. The problem is that the same protective gear which insulates soldiers against many injuries makes them vulnerable to abusive head trauma (same principle as ‘shaken baby syndrome’). For example, imagine having a high velocity bullet hit your helmet. You’re protected from the bullet but the impact shakes your head so violently, your brain is injured.

Bend it, twist it, any way you want to—a foldable lithium-ion battery

Feb. 26, 2013 news item on ScienceDaily features an extraordinary lithium-ion battery,

Northwestern University’s Yonggang Huang and the University of Illinois’ John A. Rogers are the first to demonstrate a stretchable lithium-ion battery — a flexible device capable of powering their innovative stretchable electronics.

No longer needing to be connected by a cord to an electrical outlet, the stretchable electronic devices now could be used anywhere, including inside the human body. The implantable electronics could monitor anything from brain waves to heart activity, succeeding where flat, rigid batteries would fail.

Huang and Rogers have demonstrated a battery that continues to work — powering a commercial light-emitting diode (LED) — even when stretched, folded, twisted and mounted on a human elbow. The battery can work for eight to nine hours before it needs recharging, which can be done wirelessly.

The researchers at Northwestern have produced a video where they demonstrate the battery’s ‘stretchability’,

The Northwestern University Feb. 26, 2013 news release by Megan Fellman, which originated the news item, offers this detail,

“We start with a lot of battery components side by side in a very small space, and we connect them with tightly packed, long wavy lines,” said Huang, a corresponding author of the paper. “These wires provide the flexibility. When we stretch the battery, the wavy interconnecting lines unfurl, much like yarn unspooling. And we can stretch the device a great deal and still have a working battery.”

The power and voltage of the stretchable battery are similar to a conventional lithium-ion battery of the same size, but the flexible battery can stretch up to 300 percent of its original size and still function.

Huang and Rogers have been working together for the last six years on stretchable electronics, and designing a cordless power supply has been a major challenge. Now they have solved the problem with their clever “space filling technique,” which delivers a small, high-powered battery.

For their stretchable electronic circuits, the two developed “pop-up” technology that allows circuits to bend, stretch and twist. They created an array of tiny circuit elements connected by metal wire “pop-up bridges.” When the array is stretched, the wires — not the rigid circuits — pop up.

This approach works for circuits but not for a stretchable battery. A lot of space is needed in between components for the “pop-up” interconnect to work. Circuits can be spaced out enough in an array, but battery components must be packed tightly to produce a powerful but small battery. There is not enough space between battery components for the “pop-up” technology to work.

Huang’s design solution is to use metal wire interconnects that are long, wavy lines, filling the small space between battery components. (The power travels through the interconnects.)

The unique mechanism is a “spring within a spring”: The line connecting the components is a large “S” shape and within that “S” are many smaller “S’s.” When the battery is stretched, the large “S” first stretches out and disappears, leaving a line of small squiggles. The stretching continues, with the small squiggles disappearing as the interconnect between electrodes becomes taut.

“We call this ordered unraveling,” Huang said. “And this is how we can produce a battery that stretches up to 300 percent of its original size.”

The stretching process is reversible, and the battery can be recharged wirelessly. The battery’s design allows for the integration of stretchable, inductive coils to enable charging through an external source but without the need for a physical connection.

Huang, Rogers and their teams found the battery capable of 20 cycles of recharging with little loss in capacity. The system they report in the paper consists of a square array of 100 electrode disks, electrically connected in parallel.

I’d like to see this battery actually powering a device even though the stretching is quite alluring in its way. For those who are interested here’s a citation and a link to the research paper,

Stretchable batteries with self-similar serpentine interconnects and integrated wireless recharging systems by Sheng Xu, Yihui Zhang, Jiung Cho, Juhwan Lee, Xian Huang, Lin Jia, Jonathan A. Fan, Yewang Su, Jessica Su, Huigang Zhang, Huanyu Cheng, Bingwei Lu,           Cunjiang Yu, Chi Chuang, Tae-il Kim, Taeseup Song, Kazuyo Shigeta, Sen Kang, Canan Dagdeviren, Ivan Petrov  et al.   Nature Communications 4, Article number: 1543 doi: 10.1038/ncomms2553  Published 26 February 2013

The article is behind a paywall.

Chad Mirkin, spherical nucleic acids, and a new ‘periodic table’

There was a big splash in July 2012 with the announcement that Chad Mirkin’s team at Northwestern University (Chicago, Illinois) had devised a skin cream that penetrated the skin barrier to deliver medication (my July 4, 2012 posting),

A team led by a physician-scientist and a chemist — from the fields of dermatology and nanotechnology — is the first to demonstrate the use of commercial moisturizers to deliver gene regulation technology that has great potential for life-saving therapies for skin cancers.

The topical delivery of gene regulation technology to cells deep in the skin is extremely difficult because of the formidable defenses skin provides for the body. The Northwestern approach takes advantage of drugs consisting of novel spherical arrangements of nucleic acids. These structures, each about 1,000 times smaller than the diameter of a human hair, have the unique ability to recruit and bind to natural proteins that allow them to traverse the skin and enter cells.

Mirkin has just finished presenting (Feb. 15, 2013 and Feb. 17, 2013) more information about spherical nucleic acids and their implications at the AAAS  (American Association for the Advancement of Science) 2013 meeting in Boston, Massachusetts. From the Feb. 15, 2013 news release on EurekAlert,

Northwestern University’s Chad A. Mirkin, a world-renowned leader in nanotechnology research and its application, has invented and developed a powerful material that could revolutionize biomedicine: spherical nucleic acids (SNAs).

Potential applications include using SNAs to carry nucleic acid-based therapeutics to the brain for the treatment of glioblastoma, the most aggressive form of brain cancer, as well as other neurological disorders such as Alzheimer’s and Parkinson’s diseases. Mirkin is aggressively pursuing treatments for such diseases with Alexander H. Stegh, an assistant professor of neurology at Northwestern’s Feinberg School of Medicine.

“These structures are really quite spectacular and incredibly functional,” Mirkin said. “People don’t typically think about DNA in spherical form, but this novel arrangement of nucleic acids imparts interesting chemical and physical properties that are very different from conventional nucleic acids.”

Spherical nucleic acids consist of densely packed, highly oriented nucleic acids arranged on the surface of a nanoparticle, typically gold or silver.  [emphasis mine] The tiny non-toxic balls, each roughly 15 nanometers in diameter, can do things the familiar but more cumbersome double helix can’t do:

  • SNAs can naturally enter cells and effect gene knockdown, making SNAs a superior tool for treating genetic diseases using gene regulation technology.
  • SNAs can easily cross formidable barriers in the human body, including the blood-brain barrier and the layers that make up skin.
  • SNAs don’t elicit an immune response, and they resist degradation, resulting in longer lifetimes in the body.

“The field of medicine needs new constructs and strategies for treating disease,” Mirkin said. “Many of the ways we treat disease are based on old methods and materials. Nanotechnology offers the ability to rapidly create new structures with properties that are very different from conventional forms of matter.”

“We now can go after a whole new set of diseases,” Mirkin said. “Thanks to the Human Genome Project and all of the genomics research over the last two decades, we have an enormous number of known targets. And we can use the same tool for each, the spherical nucleic acid. We simply change the sequence to match the target gene. That’s the power of gene regulation technology.”

###

A member of President Obama’s Council of Advisors on Science and Technology, Mirkin is known for invention and development of biological and chemical diagnostic systems based upon nanomaterials. He is the inventor and chief developer of Dip-Pen Nanolithography, a groundbreaking nanoscale fabrication and analytical tool, and is the founder of four Chicago-based companies: AuraSense, AuraSense Therapeutics, Nanosphere and NanoInk.

Mirkin, in addition to his work with spherical nucleic acids, has been busy with other nanoparticles and possible dreams of a new ‘periodic table of elements’, from the Feb. 17, 2013 news release on EurekAlert,

Forging a new periodic table using nanostructures

Northwestern University’s Chad A. Mirkin, …, has developed a completely new set of building blocks that is based on nanoparticles and DNA. Using these tools, scientists will be able to build — from the bottom up, just as nature does — new and useful structures.

“We have a new set of building blocks,” Mirkin said. “Instead of taking what nature gives you, we can control every property of the new material we make. We’ve always had this vision of building matter and controlling architecture from the bottom up, and now we’ve shown it can be done.”

Using nanoparticles and DNA, Mirkin has built more than 200 different crystal structures with 17 different particle arrangements. Some of the lattice types can be found in nature, but he also has built new structures that have no naturally occurring mineral counterpart.

Mirkin can make new materials and arrangements of particles by controlling the size, shape, type and location of nanoparticles within a given particle lattice. He has developed a set of design rules that allow him to control almost every property of a material.

New materials developed using his method could help improve the efficiency of optics, electronics and energy storage technologies. “These same nanoparticle building blocks have already found wide-spread commercial utility in biology and medicine as diagnostic probes for markers of disease,” Mirkin added.

With this present advance, Mirkin uses nanoparticles as “atoms” and DNA as “bonds.” He starts with a nanoparticle, which could be gold, silver, platinum or a quantum dot, for example. The core material is selected depending on what physical properties the final structure should have.

He then attaches hundreds of strands of DNA (oligonucleotides) to the particle. The oligonucleotide’s DNA sequence and length determine how bonds form between nanoparticles and guide the formation of specific crystal lattices.

“This constitutes a completely new class of building blocks in materials science that gives you a type of programmability that is extraordinarily versatile and powerful,” Mirkin said. “It provides nanotechnologists for the first time the ability to tailor properties of materials in a highly programmable way from the bottom up.”

If I read these two news releases rightly, the process (nanoparticles as atoms and DNA as bonds), Mirkin uses to create new structures is the same process he has used to create spherical nucleic acids. Given Mirkin’s entrepreneurial inclinations, I am curious as to how many and what kind of patents might be ‘protecting’ this work.

Love, hate, and the whole damn thing affect batteries, semiconductors, and electronic memory

A Jan. 24, 2013 news item on ScienceDaily features love triumphing over hate where tetracationic rings are concerned,

Northwestern University graduate student Jonathan Barnes had a hunch for creating an exotic new chemical compound, and his idea that the force of love is stronger than hate proved correct. He and his colleagues are the first to permanently interlock two identical tetracationic rings that normally are repelled by each other. Many experts had said it couldn’t be done.

On the surface, the rings hate each other because each carries four positive charges (making them tetracationic). But Barnes discovered by introducing radicals (unpaired electrons) onto the scene, the researchers could create a love-hate relationship in which love triumphs.

The Jan. 24, 2013 Northwestern University news release by Megan Fellman, which originated the news item, probes into the nature of the problem and its solution (Note: A link has been removed),

Unpaired electrons want to pair up and be stable, and it turns out the attraction of one ring’s single electrons to the other ring’s single electrons is stronger than the repelling forces.

The process links the rings not by a chemical bond but by a mechanical bond, which, once in place, cannot easily be torn asunder.

The study detailing this new class of stable organic radicals will be published Jan. 25 [2013] by the journal Science.

“It’s not that people have tried and failed to put these two rings together — they just didn’t think it was possible,” said Sir Fraser Stoddart, a senior author of the paper. “Now this molecule has been made. I cannot overemphasize Jonathan’s achievement — it is really outside the box. Now we are excited to see where this new chemistry leads us.”

The rings repel each other like the positive poles of two magnets. Barnes saw an opportunity where he thought he could tweak the chemistry by using radicals to overcome the hate between the two rings.

“We made these rings communicate and love each other under certain conditions, and once they were mechanically interlocked, the bond could not be broken,” Barnes said.

Barnes’ first strategy — adding electrons to temporarily reduce the charge and bring the two rings together — worked the first time he tried it. He, Stoddart and their colleagues started with a full ring and a half ring that they then closed up around the first ring (using some simple chemistry), creating the mechanical bond.

When the compound is oxidized and electrons lost, the strong positive forces come roaring back — “It’s hate on all the time,” Barnes said — but then it is too late for the rings to be parted. “That’s the beauty of this system,” he added.

Most organic radicals possess short lifetimes, but this unusual radical compound is stable in air and water. The compound tucks the electrons away inside the structure so they can’t react with anything in the environment. The tight mechanical bond endures despite the unfavorable electrostatic interactions.

The two interlocked rings house an immense amount of charge in a mere cubic nanometer of space. The compound, a homo[2]catenane, can adopt one of six oxidation states and can accept up to eight electrons in total.

“Anything that accepts this many electrons has possibilities for batteries,” Barnes said.

“Applications beckon,” Stoddart agreed. “Now we need to spend more time with materials scientists and people who make devices to see how this amazing compound can be used.”

For anyone interested in the details of the work, here’s a citation and link to the paper published in Science,

A Radically Configurable Six-State Compound by Jonathan C. Barnes, Albert C. Fahrenbach, Dennis Cao, Scott M. Dyar, Marco Frasconi, Marc A. Giesener, Diego Benítez, Ekaterina Tkatchouk, Oleksandr Chernyashevskyy, Weon Ho Shin, Hao Li, Srinivasan Sampath, Charlotte L. Stern, Amy A. Sarjeant, Karel J. Hartlieb, Zhichang Liu, Raanan Carmieli, Youssry Y. Botros, Jang Wook Choi, Alexandra M. Z. Slawin, John B. Ketterson, Michael R. Wasielewski, William A. Goddard III, J. Fraser Stoddart. Science 25 January 2013: Vol. 339 no. 6118 pp. 429-433 DOI: 10.1126/science.1228429

This is paper is behind a paywall.