Tag Archives: Northwestern University

Entanglement and biological systems

I think it was about five years ago thatI wrote a paper on something I called ‘cognitive entanglement’ (mentioned in my July 20,2012 posting) so the latest from Northwestern University (Chicago, Illinois, US) reignited my interest in entanglement. A December 5, 2017 news item on ScienceDaily describes the latest ‘entanglement’ research,

Nearly 75 years ago, Nobel Prize-winning physicist Erwin Schrödinger wondered if the mysterious world of quantum mechanics played a role in biology. A recent finding by Northwestern University’s Prem Kumar adds further evidence that the answer might be yes.

Kumar and his team have, for the first time, created quantum entanglement from a biological system. This finding could advance scientists’ fundamental understanding of biology and potentially open doors to exploit biological tools to enable new functions by harnessing quantum mechanics.

A December 5, 2017 Northwestern University news release (also on EurekAlert), which originated the news item, provides more detail,

“Can we apply quantum tools to learn about biology?” said Kumar, professor of electrical engineering and computer science in Northwestern’s McCormick School of Engineering and of physics and astronomy in the Weinberg College of Arts and Sciences. “People have asked this question for many, many years — dating back to the dawn of quantum mechanics. The reason we are interested in these new quantum states is because they allow applications that are otherwise impossible.”

Partially supported by the [US] Defense Advanced Research Projects Agency [DARPA], the research was published Dec. 5 [2017] in Nature Communications.

Quantum entanglement is one of quantum mechanics’ most mystifying phenomena. When two particles — such as atoms, photons, or electrons — are entangled, they experience an inexplicable link that is maintained even if the particles are on opposite sides of the universe. While entangled, the particles’ behavior is tied one another. If one particle is found spinning in one direction, for example, then the other particle instantaneously changes its spin in a corresponding manner dictated by the entanglement. Researchers, including Kumar, have been interested in harnessing quantum entanglement for several applications, including quantum communications. Because the particles can communicate without wires or cables, they could be used to send secure messages or help build an extremely fast “quantum Internet.”

“Researchers have been trying to entangle a larger and larger set of atoms or photons to develop substrates on which to design and build a quantum machine,” Kumar said. “My laboratory is asking if we can build these machines on a biological substrate.”

In the study, Kumar’s team used green fluorescent proteins, which are responsible for bioluminescence and commonly used in biomedical research. The team attempted to entangle the photons generated from the fluorescing molecules within the algae’s barrel-shaped protein structure by exposing them to spontaneous four-wave mixing, a process in which multiple wavelengths interact with one another to produce new wavelengths.

Through a series of these experiments, Kumar and his team successfully demonstrated a type of entanglement, called polarization entanglement, between photon pairs. The same feature used to make glasses for viewing 3D movies, polarization is the orientation of oscillations in light waves. A wave can oscillate vertically, horizontally, or at different angles. In Kumar’s entangled pairs, the photons’ polarizations are entangled, meaning that the oscillation directions of light waves are linked. Kumar also noticed that the barrel-shaped structure surrounding the fluorescing molecules protected the entanglement from being disrupted.

“When I measured the vertical polarization of one particle, we knew it would be the same in the other,” he said. “If we measured the horizontal polarization of one particle, we could predict the horizontal polarization in the other particle. We created an entangled state that correlated in all possibilities simultaneously.”

Now that they have demonstrated that it’s possible to create quantum entanglement from biological particles, next Kumar and his team plan to make a biological substrate of entangled particles, which could be used to build a quantum machine. Then, they will seek to understand if a biological substrate works more efficiently than a synthetic one.

Here’s an image accompanying the news release,

Featured in the cuvette on the left, green fluorescent proteins responsible for bioluninescence in jellyfish. Courtesy: Northwestern University

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

Generation of photonic entanglement in green fluorescent proteins by Siyuan Shi, Prem Kumar & Kim Fook Lee. Nature Communications 8, Article number: 1934 (2017) doi:10.1038/s41467-017-02027-9 Published online: 05 December 2017

This paper is open access.

Colliding organic nanoparticles caught on camera for the first time

There is high excitement about this development in a November 17, 2017 news item on Nanowerk,

A Northwestern University research team is the first to capture on video organic nanoparticles colliding and fusing together. This unprecedented view of “chemistry in motion” will aid Northwestern nanoscientists developing new drug delivery methods as well as demonstrate to researchers around the globe how an emerging imaging technique opens a new window on a very tiny world.

A November 17, 2017 Northwestern University news release (also on EurekAlert) by Megan Fellman, which originated the news item, further illuminates the matter,

This is a rare example of particles in motion. The dynamics are reminiscent of two bubbles coming together and merging into one: first they join and have a membrane between them, but then they fuse and become one larger bubble.

“I had an image in my mind, but the first time I saw these fusing nanoparticles in black and white was amazing,” said professor Nathan C. Gianneschi, who led the interdisciplinary study and works at the intersection of nanotechnology and biomedicine.

“To me, it’s literally a window opening up to this world you have always known was there, but now you’ve finally got an image of it. I liken it to the first time I saw Jupiter’s moons through a telescope. Nothing compares to actually seeing,” he said.

Gianneschi is the Jacob and Rosaline Cohn Professor in the department of chemistry in the Weinberg College of Arts and Sciences and in the departments of materials science and engineering and of biomedical engineering in the McCormick School of Engineering.

The study, which includes videos of different nanoparticle fusion events, was published today (Nov. 1 [2017]7) by the Journal of the American Chemical Society.

The research team used liquid-cell transmission electron microscopy to directly image how polymer-based nanoparticles, or micelles, that Gianneschi’s lab is developing for treating cancer and heart attacks change over time. The powerful new technique enabled the scientists to directly observe the particles’ transformation and characterize their dynamics.

“We can see on the molecular level how the polymeric matter rearranges when the particles fuse into one object,” said Lucas R. Parent, first author of the paper and a National Institutes of Health Postdoctoral Fellow in Gianneschi’s research group. “This is the first study of many to come in which researchers will use this method to look at all kinds of dynamic phenomena in organic materials systems on the nanoscale.”

In the Northwestern study, organic particles in water bounce off each other, and some collide and merge, undergoing a physical transformation. The researchers capture the action by shining an electron beam through the sample. The tiny particles — the largest are only approximately 200 nanometers in diameter — cast shadows that are captured directly by a camera below.

“We’ve observed classical fusion behavior on the nanoscale,” said Gianneschi, a member of Northwestern’s International Institute for Nanotechnology. “Capturing the fundamental growth and evolution processes of these particles in motion will help us immensely in our work with synthetic materials and their interactions with biological systems.”

The National Institutes of Health, the National Science Foundation, the Air Force Office of Scientific Research and the Army Research Office supported the research.

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

Directly Observing Micelle Fusion and Growth in Solution by Liquid-Cell Transmission Electron Microscopy by Lucas R. Parent, Evangelos Bakalis, Abelardo Ramírez-Hernández, Jacquelin K. Kammeyer, Chiwoo Park, Juan de Pablo, Francesco Zerbetto, Joseph P. Patterson, and Nathan C. Gianneschi. J. Am. Chem. Soc., Article ASAP DOI: 10.1021/jacs.7b09060 Publication Date (Web): November 17, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

Gold’s origin in the universe due to cosmic collision

An hypothesis for gold’s origins was first mentioned here in a May 26, 2016 posting,

The link between this research and my side project on gold nanoparticles is a bit tenuous but this work on the origins for gold and other precious metals being found in the stars is so fascinating and I’m determined to find a connection.

An artist's impression of two neutron stars colliding. (Credit: Dana Berry / Skyworks Digital, Inc.) Courtesy: Kavli Foundation

An artist’s impression of two neutron stars colliding. (Credit: Dana Berry / Skyworks Digital, Inc.) Courtesy: Kavli Foundation

From a May 19, 2016 news item on phys.org,

The origin of many of the most precious elements on the periodic table, such as gold, silver and platinum, has perplexed scientists for more than six decades. Now a recent study has an answer, evocatively conveyed in the faint starlight from a distant dwarf galaxy.

In a roundtable discussion, published today [May 19, 2016?], The Kavli Foundation spoke to two of the researchers behind the discovery about why the source of these heavy elements, collectively called “r-process” elements, has been so hard to crack.

From the Spring 2016 Kavli Foundation webpage hosting the  “Galactic ‘Gold Mine’ Explains the Origin of Nature’s Heaviest Elements” Roundtable ,

Astronomers studying a galaxy called Reticulum II have just discovered that its stars contain whopping amounts of these metals—collectively known as “r-process” elements (See “What is the R-Process?”). Of the 10 dwarf galaxies that have been similarly studied so far, only Reticulum II bears such strong chemical signatures. The finding suggests some unusual event took place billions of years ago that created ample amounts of heavy elements and then strew them throughout the galaxy’s reservoir of gas and dust. This r-process-enriched material then went on to form Reticulum II’s standout stars.

Based on the new study, from a team of researchers at the Kavli Institute at the Massachusetts Institute of Technology, the unusual event in Reticulum II was likely the collision of two, ultra-dense objects called neutron stars. Scientists have hypothesized for decades that these collisions could serve as a primary source for r-process elements, yet the idea had lacked solid observational evidence. Now armed with this information, scientists can further hope to retrace the histories of galaxies based on the contents of their stars, in effect conducting “stellar archeology.”

Researchers have confirmed the hypothesis according to an Oct. 16, 2017 news item on phys.org,

Gold’s origin in the Universe has finally been confirmed, after a gravitational wave source was seen and heard for the first time ever by an international collaboration of researchers, with astronomers at the University of Warwick playing a leading role.

Members of Warwick’s Astronomy and Astrophysics Group, Professor Andrew Levan, Dr Joe Lyman, Dr Sam Oates and Dr Danny Steeghs, led observations which captured the light of two colliding neutron stars, shortly after being detected through gravitational waves – perhaps the most eagerly anticipated phenomenon in modern astronomy.

Marina Koren’s Oct. 16, 2017 article for The Atlantic presents a richly evocative view (Note: Links have been removed),

Some 130 million years ago, in another galaxy, two neutron stars spiraled closer and closer together until they smashed into each other in spectacular fashion. The violent collision produced gravitational waves, cosmic ripples powerful enough to stretch and squeeze the fabric of the universe. There was a brief flash of light a million trillion times as bright as the sun, and then a hot cloud of radioactive debris. The afterglow hung for several days, shifting from bright blue to dull red as the ejected material cooled in the emptiness of space.

Astronomers detected the aftermath of the merger on Earth on August 17. For the first time, they could see the source of universe-warping forces Albert Einstein predicted a century ago. Unlike with black-hole collisions, they had visible proof, and it looked like a bright jewel in the night sky.

But the merger of two neutron stars is more than fireworks. It’s a factory.

Using infrared telescopes, astronomers studied the spectra—the chemical composition of cosmic objects—of the collision and found that the plume ejected by the merger contained a host of newly formed heavy chemical elements, including gold, silver, platinum, and others. Scientists estimate the amount of cosmic bling totals about 10,000 Earth-masses of heavy elements.

I’m not sure exactly what this image signifies but it did accompany Koren’s article so presumably it’s a representation of colliding neutron stars,

NSF / LIGO / Sonoma State University /A. Simonnet. Downloaded from: https://www.theatlantic.com/science/archive/2017/10/the-making-of-cosmic-bling/543030/

An Oct. 16, 2017 University of Warwick press release (also on EurekAlert), which originated the news item on phys.org, provides more detail,

Huge amounts of gold, platinum, uranium and other heavy elements were created in the collision of these compact stellar remnants, and were pumped out into the universe – unlocking the mystery of how gold on wedding rings and jewellery is originally formed.

The collision produced as much gold as the mass of the Earth. [emphasis mine]

This discovery has also confirmed conclusively that short gamma-ray bursts are directly caused by the merging of two neutron stars.

The neutron stars were very dense – as heavy as our Sun yet only 10 kilometres across – and they collided with each other 130 million years ago, when dinosaurs roamed the Earth, in a relatively old galaxy that was no longer forming many stars.

They drew towards each other over millions of light years, and revolved around each other increasingly quickly as they got closer – eventually spinning around each other five hundred times per second.

Their merging sent ripples through the fabric of space and time – and these ripples are the elusive gravitational waves spotted by the astronomers.

The gravitational waves were detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (Adv-LIGO) on 17 August this year [2017], with a short duration gamma-ray burst detected by the Fermi satellite just two seconds later.

This led to a flurry of observations as night fell in Chile, with a first report of a new source from the Swope 1m telescope.

Longstanding collaborators Professor Levan and Professor Nial Tanvir (from the University of Leicester) used the facilities of the European Southern Observatory to pinpoint the source in infrared light.

Professor Levan’s team was the first one to get observations of this new source with the Hubble Space Telescope. It comes from a galaxy called NGC 4993, 130 million light years away.

Andrew Levan, Professor in the Astronomy & Astrophysics group at the University of Warwick, commented: “Once we saw the data, we realised we had caught a new kind of astrophysical object. This ushers in the era of multi-messenger astronomy, it is like being able to see and hear for the first time.”

Dr Joe Lyman, who was observing at the European Southern Observatory at the time was the first to alert the community that the source was unlike any seen before.

He commented: “The exquisite observations obtained in a few days showed we were observing a kilonova, an object whose light is powered by extreme nuclear reactions. This tells us that the heavy elements, like the gold or platinum in jewellery are the cinders, forged in the billion degree remnants of a merging neutron star.”

Dr Samantha Oates added: “This discovery has answered three questions that astronomers have been puzzling for decades: what happens when neutron stars merge? What causes the short duration gamma-ray bursts? Where are the heavy elements, like gold, made? In the space of about a week all three of these mysteries were solved.”

Dr Danny Steeghs said: “This is a new chapter in astrophysics. We hope that in the next few years we will detect many more events like this. Indeed, in Warwick we have just finished building a telescope designed to do just this job, and we expect it to pinpoint these sources in this new era of multi-messenger astronomy”.

Congratulations to all of the researchers involved in this work!

Many, many research teams were  involved. Here’s a sampling of their news releases which focus on their areas of research,

University of the Witwatersrand (South Africa)


Weizmann Institute of Science (Israel)


Carnegie Institution for Science (US)


Northwestern University (US)


National Radio Astronomy Observatory (US)


Max-Planck-Gesellschaft (Germany)


Penn State (Pennsylvania State University; US)


University of California – Davis


The American Association for the Advancement of Science’s (AAAS) magazine, Science, has published seven papers on this research. Here’s an Oct. 16, 2017 AAAS news release with an overview of the papers,


I’m sure there are more news releases out there and that there will be many more papers published in many journals, so if this interests, I encourage you to keep looking.

Two final pieces I’d like to draw your attention to: one answers basic questions and another focuses on how artists knew what to draw when neutron stars collide.

Keith A Spencer’s Oct. 18, 2017 piece on salon.com answers a lot of basic questions for those of us who don’t have a background in astronomy. Here are a couple of examples,

What is a neutron star?

Okay, you know how atoms have protons, neutrons, and electrons in them? And you know how protons are positively charged, and electrons are negatively charged, and neutrons are neutral?

Yeah, I remember that from watching Bill Nye as a kid.

Totally. Anyway, have you ever wondered why the negatively-charged electrons and the positively-charged protons don’t just merge into each other and form a neutral neutron? I mean, they’re sitting there in the atom’s nucleus pretty close to each other. Like, if you had two magnets that close, they’d stick together immediately.

I guess now that you mention it, yeah, it is weird.

Well, it’s because there’s another force deep in the atom that’s preventing them from merging.

It’s really really strong.

The only way to overcome this force is to have a huge amount of matter in a really hot, dense space — basically shove them into each other until they give up and stick together and become a neutron. This happens in very large stars that have been around for a while — the core collapses, and in the aftermath, the electrons in the star are so close to the protons, and under so much pressure, that they suddenly merge. There’s a big explosion and the outer material of the star is sloughed off.

Okay, so you’re saying under a lot of pressure and in certain conditions, some stars collapse and become big balls of neutrons?

Pretty much, yeah.

So why do the neutrons just stick around in a huge ball? Aren’t they neutral? What’s keeping them together? 

Gravity, mostly. But also the strong nuclear force, that aforementioned weird strong force. This isn’t something you’d encounter on a macroscopic scale — the strong force only really works at the type of distances typified by particles in atomic nuclei. And it’s different, fundamentally, than the electromagnetic force, which is what makes magnets attract and repel and what makes your hair stick up when you rub a balloon on it.

So these neutrons in a big ball are bound by gravity, but also sticking together by virtue of the strong nuclear force. 

So basically, the new ball of neutrons is really small, at least, compared to how heavy it is. That’s because the neutrons are all clumped together as if this neutron star is one giant atomic nucleus — which it kinda is. It’s like a giant atom made only of neutrons. If our sun were a neutron star, it would be less than 20 miles wide. It would also not be something you would ever want to get near.

Got it. That means two giant balls of neutrons that weighed like, more than our sun and were only ten-ish miles wide, suddenly smashed into each other, and in the aftermath created a black hole, and we are just now detecting it on Earth?

Exactly. Pretty weird, no?

Spencer does a good job of gradually taking you through increasingly complex explanations.

For those with artistic interests, Neel V. Patel tries to answer a question about how artists knew what draw when neutron stars collided in his Oct. 18, 2017 piece for Slate.com,

All of these things make this discovery easy to marvel at and somewhat impossible to picture. Luckily, artists have taken up the task of imagining it for us, which you’ve likely seen if you’ve already stumbled on coverage of the discovery. Two bright, furious spheres of light and gas spiraling quickly into one another, resulting in a massive swell of lit-up matter along with light and gravitational waves rippling off speedily in all directions, towards parts unknown. These illustrations aren’t just alluring interpretations of a rare phenomenon; they are, to some extent, the translation of raw data and numbers into a tangible visual that gives scientists and nonscientists alike some way of grasping what just happened. But are these visualizations realistic? Is this what it actually looked like? No one has any idea. Which is what makes the scientific illustrators’ work all the more fascinating.

“My goal is to represent what the scientists found,” says Aurore Simmonet, a scientific illustrator based at Sonoma State University in Rohnert Park, California. Even though she said she doesn’t have a rigorous science background (she certainly didn’t know what a kilonova was before being tasked to illustrate one), she also doesn’t believe that type of experience is an absolute necessity. More critical, she says, is for the artist to have an interest in the subject matter and in learning new things, as well as a capacity to speak directly to scientists about their work.

Illustrators like Simmonet usually start off work on an illustration by asking the scientist what’s the biggest takeaway a viewer should grasp when looking at a visual. Unfortunately, this latest discovery yielded a multitude of papers emphasizing different conclusions and highlights. With so many scientific angles, there’s a stark challenge in trying to cram every important thing into a single drawing.

Clearly, however, the illustrations needed to center around the kilonova. Simmonet loves colors, so she began by discussing with the researchers what kind of color scheme would work best. The smash of two neutron stars lends itself well to deep, vibrant hues. Simmonet and Robin Dienel at the Carnegie Institution for Science elected to use a wide array of colors and drew bright cracking to show pressure forming at the merging. Others, like Luis Calcada at the European Southern Observatory, limited the color scheme in favor of emphasizing the bright moment of collision and the signal waves created by the kilonova.

Animators have even more freedom to show the event, since they have much more than a single frame to play with. The Conceptual Image Lab at NASA’s [US National Aeronautics and Space Administration] Goddard Space Flight Center created a short video about the new findings, and lead animator Brian Monroe says the video he and his colleagues designed shows off the evolution of the entire process: the rising action, climax, and resolution of the kilonova event.

The illustrators try to adhere to what the likely physics of the event entailed, soliciting feedback from the scientists to make sure they’re getting it right. The swirling of gas, the direction of ejected matter upon impact, the reflection of light, the proportions of the objects—all of these things are deliberately framed such that they make scientific sense. …

Do take a look at Patel’s piece, if for no other reason than to see all of the images he has embedded there. You may recognize Aurore Simmonet’s name from the credit line in the second image I have embedded here.

Measurably fewer nanoparticles in São Paulo’s (Brazil) air after ethanol use

An Aug. 28, 2017 news item on Nanotechnology Now features news about nanoparticles and the environment in São Paulo, Brazil,

When ethanol prices at the pump rise for whatever reason, it becomes economically advantageous for drivers of dual-fuel vehicles to fill up with gasoline. However, the health of the entire population pays a high price: substitution of gasoline for ethanol leads to a 30% increase in the atmospheric concentration of ultrafine particulate matter, which consists of particles with a diameter of less than 50 nanometers (nm).

An Aug. 23, 2017 Fundação de Amparo à Pesquisa do Estado de São Paulo (The São Paulo Research Foundation [FAPESP]) press release, which originated the news item, explains further,

The phenomenon was detected in São Paulo City, Brazil, in a study supported by FAPESP and published in July 2017 in Nature Communications.

“These polluting nanoparticles are so tiny that they behave like gas molecules. When inhaled, they can penetrate the respiratory system’s defensive barriers and reach the pulmonary alveoli, so that potentially toxic substances enter the bloodstream and may increase the incidence of respiratory and cardiovascular problems,” said Paulo Artaxo, Full Professor at the University of São Paulo’s Physics Institute (IF-USP) and a co-author of the study.

Levels of ultrafine particulate matter in the atmosphere are neither monitored nor regulated by environmental agencies not only in Brazil but practically anywhere in the world, according to Artaxo. The São Paulo State Environmental Corporation (CETESB), for example, routinely monitors only solid particles with diameters of 10,000 nm (PM10) and 2,500 nm (PM2.5) – as well as other gaseous pollutants such as ozone (O3), carbon monoxide (CO) and nitrogen dioxide (NO2).

“Between 75% and 80% of the mass of the nanoparticles we measured in this study corresponds to organic compounds emitted by motor vehicles – carbon in different chemical forms. What these compounds are exactly and how they affect health are questions that require further research,” Artaxo said.

He added that a consensus is forming in the United States and Europe based on recent research indicating that these emissions are a potential health hazard and should be regulated. Several US states, such as California, have laws requiring a 20%-30% ethanol blend in gasoline, which also helps reduce emissions of ultrafine particulate matter.


The data analyzed in the study were collected during the period of January-May 2011, when ethanol prices fluctuated sharply compared with gasoline prices, owing to macroeconomic factors such as variations in the international price of sugar (Brazilian ethanol is made from sugarcane).

Collection was performed at the top of a ten-story building belonging to IF-USP in the western part of São Paulo City. According to Artaxo, the site was chosen because it is relatively distant from the main traffic thoroughfares so that the aerosols there are “older” in the sense that they have already interacted with other substances present in the atmosphere.

“Generally speaking, the pollution we inhale every day at home or at work isn’t what comes out of vehicular exhaust pipes but particles already processed in the atmosphere,” he explained. “For this reason, we chose a site that isn’t directly impacted by primary vehicle emissions.”

The study was conducted during Joel Ferreira de Brito’s postdoctoral research, which Artaxo supervised. The model used to analyze the data was developed by Brazilian economist Alberto Salvo, a professor at the National University of Singapore and first author of the article. Franz Geiger, a chemist at Northwestern University in the US, also collaborated.

“We adapted a sophisticated statistical model originally developed for economic analysis and used here for the first time to analyze the chemistry of atmospheric nanoparticles,” Artaxo said. “The main strength of this tool is that it can work with a large number of variables, such as the presence or absence of rainfall, wind direction, traffic intensity, and levels of ozone, carbon monoxide and other pollutants.”

Analyses were performed before, during and after a sharp fluctuation in ethanol prices leading consumers to switch motor fuels in São Paulo City. While no significant changes were detected in levels of inhalable fine particulate matter (PM2.5 and PM10), the study proved in a real, day-to-day situation that choosing ethanol reduces emissions of ultrafine particles. To date, this phenomenon had only been observed in the laboratory.

“These results reinforce the need for public policies to encourage the use of biofuels, as they clearly show that the public lose in health what they save at the pump when opting for gasoline,” Artaxo said.

In São Paulo, a city with 7 million motor vehicles and the largest urban fleet of flexible-fuel cars, it would be feasible to run all buses on biofuel. “We have the technology for this in Brazil – and at a competitive price,” he said.

The fact that the city’s bus fleet still depends on diesel, Artaxo warned, creates an even worse health hazard in the shape of emissions of black carbon, one of the main components of soot and a pollutant that contributes to global warming. Alongside electricity generation, the transportation sector is the largest emitter of pollutants produced by the burning of fossil fuels.

For Artaxo, incentives for electric, hybrid or biofuel vehicles are vital to reduce greenhouse gas emissions. “By incentivizing biofuels, we could solve several problems at once,” he said. “We could combat climate change, reduce harm to health and foster advances in automotive technology by offering a stimulus for auto makers to develop more economical and efficient cars fueled by ethanol.”

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

Reduced ultrafine particle levels in São Paulo’s atmosphere during shifts from gasoline to ethanol use by Alberto Salvo, Joel Brito, Paulo Artaxo, & Franz M. Geiger. Nature Communications 8, Article number: 77 (2017) doi:10.1038/s41467-017-00041-5 Published online: 18 July 2017

This paper is open access.

Sugar in your bones might be better for you than you think

These days sugar is often  viewed as leading to health problems but there is an instance where it may be useful—bone regeneration. From a June 19, 2017 news item on Nanowerk (Note: A link has been removed),

There hasn’t been a gold standard for how orthopaedic spine surgeons promote new bone growth in patients, but now Northwestern University scientists have designed a bioactive nanomaterial that is so good at stimulating bone regeneration it could become the method surgeons prefer.

While studied in an animal model of spinal fusion, the method for promoting new bone growth could translate readily to humans, the researchers say, where an aging but active population in the U.S. is increasingly receiving this surgery to treat pain due to disc degeneration, trauma and other back problems. Many other procedures could benefit from the nanomaterial, ranging from repair of bone trauma to treatment of bone cancer to bone growth for dental implants.

“Regenerative medicine can improve quality of life by offering less invasive and more successful approaches to promoting bone growth,” said Samuel I. Stupp, who developed the new nanomaterial. “Our method is very flexible and could be adapted for the regeneration of other tissues, including muscle, tendons and cartilage.”

Stupp is director of Northwestern’s Simpson Querrey Institute for BioNanotechnology and the Board of Trustees Professor of Materials Science and Engineering, Chemistry, Medicine and Biomedical Engineering.

For the interdisciplinary study, Stupp collaborated with Dr. Wellington K. Hsu, associate professor of orthopaedic surgery, and Erin L. K. Hsu, research assistant professor of orthopaedic surgery, both at Northwestern University Feinberg School of Medicine. The husband-and-wife team is working to improve clinically employed methods of bone regeneration.

Sugar molecules on the surface of the nanomaterial provide its regenerative power. The researchers studied in vivo the effect of the “sugar-coated” nanomaterial on the activity of a clinically used growth factor, called bone morphogenetic protein 2 (BMP-2). They found the amount of protein needed for a successful spinal fusion was reduced to an unprecedented level: 100 times less of BMP-2 was needed. This is very good news, because the growth factor is known to cause dangerous side effects when used in the amounts required to regenerate high-quality bone, and it is expensive as well.

A June 19, 2017 Northwestern University news release by Megan Fellman, which originated the news item, tells the rest of the story,

Stupp’s biodegradable nanomaterial functions as an artificial extracellular matrix, which mimics what cells in the body usually interact with in their surroundings. BMP-2 activates certain types of stem cells and signals them to become bone cells. The Northwestern matrix, which consists of tiny nanoscale filaments, binds the protein by molecular design in the way that natural sugars bind it in our bodies and then slowly releases it when needed, instead of in one early burst, which can contribute to side effects.

To create the nanostructures, the research team led by Stupp synthesized a specific type of sugar that closely resembles those used by nature to activate BMP-2 when cell signaling is necessary for bone growth. Rapidly moving flexible sugar molecules displayed on the surface of the nanostructures “grab” the protein in a specific spot that is precisely the same one used in biological systems when it is time to deploy the signal. This potentiates the bone-growing signals to a surprising level that surpasses even the naturally occurring sugar polymers in our bodies.

In nature, the sugar polymers are known as sulfated polysaccharides, which have super-complex structures impossible to synthesize at the present time with chemical techniques. Hundreds of proteins in biological systems are known to have specific domains to bind these sugar polymers in order to activate signals. Such proteins include those involved in the growth of blood vessels, cell recruitment and cell proliferation, all very important biologically in tissue regeneration. Therefore, the approach of the Stupp team could be extended to other regenerative targets.

Spinal fusion is a common surgical procedure that joins adjacent vertebra together using a bone graft and growth factors to promote new bone growth, which stabilizes the spine. The bone used in the graft can come from the patient’s pelvis — an invasive procedure — or from a bone bank.

“There is a real need for a clinically efficacious, safe and cost-effective way to form bone,” said Wellington Hsu, a spine surgeon. “The success of this nanomaterial makes me excited that every spine surgeon may one day subscribe to this method for bone graft. Right now, if you poll an audience of spine surgeons, you will get 15 to 20 different answers on what they use for bone graft. We need to standardize choice and improve patient outcomes.”

In the in vivo portion of the study, the nanomaterial was delivered to the spine using a collagen sponge. This is the way surgeons currently deliver BMP-2 clinically to promote bone growth.

The Northwestern research team plans to seek approval from the Food and Drug Administration to launch a clinical trial studying the nanomaterial for bone regeneration in humans.

“We surgeons are looking for optimal carriers for growth factors and cells,” Wellington Hsu said. “With its numerous binding sites, the long filaments of this new nanomaterial is more successful than existing carriers in releasing the growth factor when the body is ready. Timing is critical for success in bone regeneration.”

In the new nanomaterial, the sugars are displayed in a scaffold built from self-assembling molecules known as peptide amphiphiles, first developed by Stupp 15 years ago. These synthetic molecules have been essential in his work on regenerative medicine.

“We focused on bone regeneration to demonstrate the power of the sugar nanostructure to provide a big signaling boost,” Stupp said. “With small design changes, the method could be used with other growth factors for the regeneration of all kinds of tissues. One day we may be able to fully do away with the use of growth factors made by recombinant biotechnology and instead empower the natural ones in our bodies.”

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

Sulfated glycopeptide nanostructures for multipotent protein activation by Sungsoo S. Lee, Timmy Fyrner, Feng Chen, Zaida Álvarez, Eduard Sleep, Danielle S. Chun, Joseph A. Weiner, Ralph W. Cook, Ryan D. Freshman, Michael S. Schallmo, Karina M. Katchko, Andrew D. Schneider, Justin T. Smith, Chawon Yun, Gurmit Singh, Sohaib Z. Hashmi, Mark T. McClendon, Zhilin Yu, Stuart R. Stock, Wellington K. Hsu, Erin L. Hsu, & Samuel I. Stupp. Nature Nanotechnology 12, 821–829 (2017) doi:10.1038/nnano.2017.109 Published online 19 June 2017

This paper is behind a paywall.

‘Origami organs’ for tissue engineering

This is a different approach to tissue engineering and its the consequence of a serendipitous accident.  From an Aug. 7, 2017 Northwestern University news release (also on EurekAlert),

Northwestern Medicine scientists and engineers have invented a range of bioactive “tissue papers” made of materials derived from organs that are thin and flexible enough to even fold into an origami bird. The new biomaterials can potentially be used to support natural hormone production in young cancer patients and aid wound healing.

The tissue papers are made from structural proteins excreted by cells that give organs their form and structure. The proteins are combined with a polymer to make the material pliable.

In the study, individual types of tissue papers were made from ovarian, uterine, kidney, liver, muscle or heart proteins obtained by processing pig and cow organs. Each tissue paper had specific cellular properties of the organ from which it was made.

The article describing the tissue paper and its function will be published Aug. 7 in the journal Advanced Functional Materials.

“This new class of biomaterials has potential for tissue engineering and regenerative medicine as well as drug discovery and therapeutics,” corresponding author Ramille Shah said. “It’s versatile and surgically friendly.”

Shah is an assistant professor of surgery at the Feinberg School of Medicine and an assistant professor of materials science and engineering at McCormick School of Engineering. She also is a member of the Simpson Querrey Institute for BioNanotechnology.

For wound healing, Shah thinks the tissue paper could provide support and the cell signaling needed to help regenerate tissue to prevent scarring and accelerate healing.

The tissue papers are made from natural organs or tissues. The cells are removed, leaving the natural structural proteins – known as the extracellular matrix – that then are dried into a powder and processed into the tissue papers. Each type of paper contains residual biochemicals and protein architecture from its original organ that can stimulate cells to behave in a certain way.

In the lab of reproductive scientist Teresa Woodruff, the tissue paper made from a bovine ovary was used to grow ovarian follicles when they were cultured in vitro. The follicles (eggs and hormone-producing cells) grown on the tissue paper produced hormones necessary for proper function and maturation.

“This could provide another option to restore normal hormone function to young cancer patients who often lose their hormone function as a result of chemotherapy and radiation,” Woodruff, a study coauthor, said.

A strip of the ovarian paper with the follicles could be implanted under the arm to restore hormone production for cancer patients or even women in menopause.

Woodruff is the director of the Oncofertility Consortium and the Thomas J. Watkins Memorial Professor of Obstetrics and Gynecology at Feinberg.

In addition, the tissue paper made from various organs separately supported the growth of adult human stem cells. Scientists placed human bone marrow stem cells on the tissue paper, and all the stem cells attached and multiplied over four weeks.

“That’s a good sign that the paper supports human stem cell growth,” said first author Adam Jakus, who developed the tissue papers. “It’s an indicator that once we start using tissue paper in animal models it will be biocompatible.”

The tissue papers feel and behave much like standard office paper when they are dry, Jakus said. Jakus simply stacks them in a refrigerator or a freezer. He even playfully folded them into an origami bird.

“Even when wet, the tissue papers maintain their mechanical properties and can be rolled, folded, cut and sutured to tissue,” he said.

Jakus was a Hartwell postdoctoral fellow in Shah’s lab for the study and is now chief technology officer and cofounder of the startup company Dimension Inx, LLC, which was also cofounded by Shah. The company will develop, produce and sell 3-D printable materials primarily for medical applications. The Intellectual Property is owned by Northwestern University and will be licensed to Dimension Inx.

An Accidental Spill Sparked Invention

An accidental spill of 3-D printing ink in Shah’s lab by Jakus sparked the invention of the tissue paper. Jakus was attempting to make a 3-D printable ovary ink similar to the other 3-D printable materials he previously developed to repair and regenerate bone, muscle and nerve tissue. When he went to wipe up the spill, the ovary ink had already formed a dry sheet.

“When I tried to pick it up, it felt strong,” Jakus said. “I knew right then I could make large amounts of bioactive materials from other organs. The light bulb went on in my head. I could do this with other organs.”

“It is really amazing that meat and animal by-products like a kidney, liver, heart and uterus can be transformed into paper-like biomaterials that can potentially regenerate and restore function to tissues and organs,” Jakus said. “I’ll never look at a steak or pork tenderloin the same way again.”

For those who like their news in a video,

As someone who once made baklava, that does not look like filo pastry, where an individual sheet is quite thin and rips easily. Enough said.

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

“Tissue Papers” from Organ-Specific Decellularized Extracellular Matrices by Adam E. Jakus, Monica M. Laronda, Alexandra S. Rashedi, Christina M. Robinson, Chris Lee, Sumanas W. Jordan, Kyle E. Orwig, Teresa K. Woodruff, and Ramille N. Shah. Advnaced Functional Materials DOI: 10.1002/adfm.201700992 Version of Record online: 7 AUG 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Ora Sound, a Montréal-based startup, and its ‘graphene’ headphones

For all the excitement about graphene there aren’t that many products as Glenn Zorpette notes in a June 20, 2017 posting about Ora Sound and its headphones on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website; Note: Links have been removed),

Graphene has long been touted as a miracle material that would deliver everything from tiny, ultralow-power transistors to the vastly long and ultrastrong cable [PDF] needed for a space elevator. And yet, 13 years of graphene development, and R&D expenditures well in the tens of billions of dollars have so far yielded just a handful of niche products. The most notable by far is a line of tennis racquets in which relatively small amounts of graphene are used to stiffen parts of the frame.

Ora Sound, a Montreal-based [Québec, Canada] startup, hopes to change all that. On 20 June [2017], it unveiled a Kickstarter campaign for a new audiophile-grade headphone that uses cones, also known as membranes, made of a form of graphene. “To the best of our knowledge, we are the first company to find a significant, commercially viable application for graphene,” says Ora cofounder Ari Pinkas, noting that the cones in the headphones are 95 percent graphene.


It should be noted that participating in a Kickstarter campaign is an investment/gamble. I am not endorsing Ora Sound or its products. That said, this does look interesting (from the ORA: The World’s First Graphene Headphones Kickstarter campaign webpage),

ORA GQ Headphones uses nanotechnology to deliver the most groundbreaking audio listening experience. Scientists have long promised that one day Graphene will find its way into many facets of our lives including displays, electronic circuits and sensors. ORA’s Graphene technology makes it one of the first companies to have created a commercially viable application for this Nobel-prize winning material, a major scientific achievement.

The GQ Headphones come equipped with ORA’s patented GrapheneQ™ membranes, providing unparalleled fidelity. The headphones also offer all the features you would expect from a high-end audio product: wired/wireless operation, a gesture control track-pad, a digital MEMS microphone, breathable lambskin leather and an ear-shaped design optimized for sound quality and isolated comfort.

They have produced a slick video to promote their campaign,

At the time of publishing this post, the campaign will run for another eight days and has raised $650,949 CAD. This is more than $500,000 dollars over the company’s original goal of $135,000. I’m sure they’re ecstatic but this success can be a mixed blessing. They have many more people expecting a set of headphones than they anticipated and that can mean production issues.

Further, there appears to be only one member of the team with business experience and his (Ari Pinkas) experience includes marketing strategy for a few years and then founding an online marketplace for teachers. I would imagine Pinkas will be experiencing a very steep learning curve. Hopefully, Helge Seetzen, a member of the company’s advisory board will be able to offer assistance. According to Seetzen’s Wikipedia entry, he is a “… German technologist and businessman known for imaging & multimedia research and commercialization,” as well as, having a Canadian educational background and business experience. The rest of the team and advisory board appear to be academics.

The technology

A March 14, 2017 article by Andy Riga for the Montréal Gazette gives a general description of the technology,

A Montreal startup is counting on technology sparked by a casual conversation between two brothers pursuing PhDs at McGill University.

They were chatting about their disparate research areas — one, in engineering, was working on using graphene, a form of carbon, in batteries; the other, in music, was looking at the impact of electronics on the perception of audio quality.

At first glance, the invention that ensued sounds humdrum.

It’s a replacement for an item you use every day. It’s paper thin, you probably don’t realize it’s there and its design has not changed much in more than a century. Called a membrane or diaphragm, it’s the part of a loudspeaker that vibrates to create the sound from the headphones over your ears, the wireless speaker on your desk, the cellphone in your hand.

Membranes are normally made of paper, Mylar or aluminum.

Ora’s innovation uses graphene, a remarkable material whose discovery garnered two scientists the 2010 Nobel Prize in physics but which has yet to fulfill its promise.

“Because it’s so stiff, our membrane gets better sound quality,” said Robert-Eric Gaskell, who obtained his PhD in sound recording in 2015. “It can produce more sound with less distortion, and the sound that you hear is more true to the original sound intended by the artist.

“And because it’s so light, we get better efficiency — the lighter it is, the less energy it takes.”

In January, the company demonstrated its membrane in headphones at the Consumer Electronics Show, a big trade convention in Las Vegas.

Six cellphone manufacturers expressed interest in Ora’s technology, some of which are now trying prototypes, said Ari Pinkas, in charge of product marketing at Ora. “We’re talking about big cellphone manufacturers — big, recognizable names,” he said.

Technology companies are intrigued by the idea of using Ora’s technology to make smaller speakers so they can squeeze other things, such as bigger batteries, into the limited space in electronic devices, Pinkas said. Others might want to use Ora’s membrane to allow their devices to play music louder, he added.

Makers of regular speakers, hearing aids and virtual-reality headsets have also expressed interest, Pinkas said.

Ora is still working on headphones.

Riga’s article offers a good overview for people who are not familiar with graphene.

Zorpette’s June 20, 2017 posting (on Nanoclast) offers a few more technical details (Note: Links have been removed),

During an interview and demonstration in the IEEE Spectrum offices, Pinkas and Robert-Eric Gaskell, another of the company’s cofounders, explained graphene’s allure to audiophiles. “Graphene has the ideal properties for a membrane,” Gaskell says. “It’s incredibly stiff, very lightweight—a rare combination—and it’s well damped,” which means it tends to quell spurious vibrations. By those metrics, graphene soundly beats all the usual choices: mylar, paper, aluminum, or even beryllium, Gaskell adds.

The problem is making it in sheets large enough to fashion into cones. So-called “pristine” graphene exists as flakes, [emphasis mine] perhaps 10 micrometers across, and a single atom thick. To make larger, strong sheets of graphene, researchers attach oxygen atoms to the flakes, and then other elements to the oxygen atoms to cross-link the flakes and hold them together strongly in what materials scientists call a laminate structure. The intellectual property behind Ora’s advance came from figuring out how to make these structures suitably thick and in the proper shape to function as speaker cones, Gaskell says. In short, he explains, the breakthrough was, “being able to manufacture” in large numbers, “and in any geometery we want.”

Much of the R&D work that led to Ora’s process was done at nearby McGill University, by professor Thomas Szkopek of the Electrical and Computer Engineering department. Szkopek worked with Peter Gaskell, Robert-Eric’s younger brother. Ora is also making use of patents that arose from work done on graphene by the Nguyen Group at Northwestern University, in Evanston, Ill.

Robert-Eric Gaskell and Pinkas arrived at Spectrum with a preproduction model of their headphones, as well as some other headphones for the sake of comparison. The Ora prototype is clearly superior to the comparison models, but that’s not much of a surprise. …

… In the 20 minutes or so I had to audition Ora’s preproduction model, I listened to an assortment of classical and jazz standards and I came away impressed. The sound is precise, with fine details sharply rendered. To my surprise, I was reminded of planar-magnetic type headphones that are now surging in popularity in the upper reaches of the audiophile headphone market. Bass is smooth and tight. Overall, the unit holds up quite well against closed-back models in the $400 to $500 range I’ve listened to from Grado, Bowers & Wilkins, and Audeze.

Ora’s Kickstarter campaign page (Graphene vs GrapheneQ subsection) offers some information about their unique graphene composite,


Graphene is a new material, first isolated only 13 years ago. Formed from a single layer of carbon atoms, Graphene is a hexagonal crystal lattice in a perfect honeycomb structure. This fundamental geometry makes Graphene ridiculously strong and lightweight. In its pure form, Graphene is a single atomic layer of carbon. It can be very expensive and difficult to produce in sizes any bigger than small flakes. These challenges have prevented pristine Graphene from being integrated into consumer technologies.


At ORA, we’ve spent the last few years creating GrapheneQ, our own, proprietary Graphene-based nanocomposite formulation. We’ve specifically designed and optimized it for use in acoustic transducers. GrapheneQ is a composite material which is over 95% Graphene by weight. It is formed by depositing flakes of Graphene into thousands of layers that are bonded together with proprietary cross-linking agents. Rather than trying to form one, continuous layer of Graphene, GrapheneQ stacks flakes of Graphene together into a laminate material that preserves the benefits of Graphene while allowing the material to be formed into loudspeaker cones.

Scanning Electron Microscope (SEM) Comparison
Scanning Electron Microscope (SEM) Comparison

If you’re interested in more technical information on sound, acoustics, soundspeakers, and Ora’s graphene-based headphones, it’s all there on Ora’s Kickstarter campaign page.

The Québec nanotechnology scene in context and graphite flakes for graphene

There are two Canadian provinces that are heavily invested in nanotechnology research and commercialization efforts. The province of Québec has poured money into their nanotechnology efforts, while the province of Alberta has also invested heavily in nanotechnology, it has also managed to snare additional federal funds to host Canada’s National Institute of Nanotechnology (NINT). (This appears to be a current NINT website or you can try this one on the National Research Council website). I’d rank Ontario as being a third centre with the other provinces being considerably less invested. As for the North, I’ve not come across any nanotechnology research from that region. Finally, as I stumble more material about nanotechnology in Québec than I do for any other province, that’s the reason I rate Québec as the most successful in its efforts.

Regarding graphene, Canada seems to have an advantage. We have great graphite flakes for making graphene. With mines in at least two provinces, Ontario and Québec, we have a ready source of supply. In my first posting (July 25, 2011) about graphite mines here, I had this,

Who knew large flakes could be this exciting? From the July 25, 2011 news item on Nanowerk,

Northern Graphite Corporation has announced that graphene has been successfully made on a test basis using large flake graphite from the Company’s Bissett Creek project in Northern Ontario. Northern’s standard 95%C, large flake graphite was evaluated as a source material for making graphene by an eminent professor in the field at the Chinese Academy of Sciences who is doing research making graphene sheets larger than 30cm2 in size using the graphene oxide methodology. The tests indicated that graphene made from Northern’s jumbo flake is superior to Chinese powder and large flake graphite in terms of size, higher electrical conductivity, lower resistance and greater transparency.

Approximately 70% of production from the Bissett Creek property will be large flake (+80 mesh) and almost all of this will in fact be +48 mesh jumbo flake which is expected to attract premium pricing and be a better source material for the potential manufacture of graphene. The very high percentage of large flakes makes Bissett Creek unique compared to most graphite deposits worldwide which produce a blend of large, medium and small flakes, as well as a large percentage of low value -150 mesh flake and amorphous powder which are not suitable for graphene, Li ion batteries or other high end, high growth applications.

Since then I’ve stumbled across more information about Québec’s mines than Ontario’s  as can be seen:

There are some other mentions of graphite mines in other postings but they are tangential to what’s being featured:

  • (my Oct. 26, 2015 posting about St. Jean Carbon and its superconducting graphene and
  • my Feb. 20, 2015 posting about Nanoxplore and graphene production in Québec; and
  • this Feb. 23, 2015 posting about Grafoid and its sister company, Focus Graphite which gets its graphite flakes from a deposit in the northeastern part of Québec).


After reviewing these posts, I’ve begun to wonder where Ora’s graphite flakes come from? In any event, I wish the folks at Ora and their Kickstarter funders the best of luck.

Regrowing bone

The ability to grow bone or bone-like material could change life substantially for people with certain kinds of injuries. Scientists at Northwestern University and the University of Chicago have been able to regrow bone in a skull (according to a March 8, 2017 Northwestern University news release (also on EurekAlert),

A team of researchers repaired a hole in a mouse’s skull by regrowing “quality bone,” a breakthrough that could drastically improve the care of people who suffer severe trauma to the skull or face.

The work by a joint team of Northwestern Engineering and University of Chicago researchers was a resounding success, showing that a potent combination of technologies was able to regenerate the skull bone with supporting blood vessels in just the discrete area needed without developing scar tissue — and more rapidly than with previous methods.

“The results are very exciting,” said Guillermo Ameer, professor of biomedical engineering at Northwestern’s McCormick School of Engineering, and professor of surgery at Feinberg School of Medicine.

Supported by the China Scholarship Council, National Institute of Dental and Craniofacial Research, Chicago Community Trust, and National Center for Advancing Translational Sciences, the research was published last week in the journal PLOS One. Russell Reid, associate professor of surgery at the University of Chicago Medical Center, is the article’s corresponding author. Reid, his long-time collaborator Dr. Tong-Chuan He, and colleagues in Hyde Park brought the surgical and biological knowledge and skills. Zari P. Dumanian, affiliated with the medical center’s surgery department, was the paper’s first author.

“This project was a true collaborative team effort in which our Regenerative Engineering Laboratory provided the biomaterials expertise,” Ameer said.

Injuries or defects in the skull or facial bones are very challenging to treat, often requiring the surgeon to graft bone from the patient’s pelvis, ribs, or elsewhere, a painful procedure in itself. Difficulties increase if the injury area is large or if the graft needs to be contoured to the angle of the jaw or the cranial curve.

But if all goes well with this new approach, it may make painful bone grafting obsolete.

In the experiment, the researchers harvested skull cells from the mouse and engineered them to produce a potent protein to promote bone growth. They then used Ameer’s hydrogel, which acted like a temporary scaffolding, to deliver and contain these cells to the affected area. It was the combination of all three technologies that proved so successful, Ameer said.

Using calvaria or skull cells from the subject meant the body didn’t reject those cells.

The protein, BMP9, has been shown to promote bone cell growth more rapidly than other types of BMPs. Importantly, BMP9 also appeared to improve the creation of blood vessels in the area. Being able to safely deliver skull cells that are capable of rapidly regrowing bone in the affected site, in vivo as opposed to using them to grow bone in the laboratory, which would take a very long time, promises a therapy that might be more “surgeon friendly, if you will, and not too complicated to scale up for the patients,” Ameer said.

The scaffolding developed in Ameer’s laboratory, which is a material based on citric acid and called PPCN-g, is a liquid that when warmed to body temperature becomes a gel-like elastic material. “When applied, the liquid, which contains cells capable of producing bone, will conform to the shape of the bone defect to make a perfect fit,” Ameer said. “It then stays in place as a gel, localizing the cells to the site for the duration of the repair.” As the bone regrows, the PPCN-g is reabsorbed by the body.

“What we found is that these cells make natural-looking bone in the presence of the PPCN-g,” Ameer said. “The new bone is very similar to normal bone in that location.”

In fact, the three-part method was successful on a number of fronts: The regenerated bone was better quality, the bone growth was contained to the area defined by the scaffolding, the area healed much more quickly, and the new and old bone were continuous with no scar tissue.

The potential, if the procedure can be adapted to treat people that suffered trauma from car accidents or aggressive cancers that have affected the skull or face, would be huge, and give surgeons a much-sought-after option.

“The reconstruction procedure is a lot easier when you can harvest a few cells, make them produce the BMP9 protein, mix them in the PPCN-g solution, and apply it to the bone defect site to jump-start the new bone growth process where you want it.” Ameer said.

Ameer cautioned that the technology is years away to being used in humans, but added, “We did show proof of concept that we can heal large defects in the skull that would normally not heal on their own using a protein, cells and a new material that come together in a completely new way. Our team is very excited about these findings and the future of reconstructive surgery.”

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

Repair of critical sized cranial defects with BMP9-transduced calvarial cells delivered in a thermoresponsive scaffold by Zari P. Dumanian, Viktor Tollemar, Jixing Ye, Minpeng Lu, Yunxiao Zhu, Junyi Liao, Guillermo A. Ameer, Tong-Chuan He, Russell R. Reid. PLOS http://dx.doi.org/10.1371/journal.pone.0172327 Published: March 1, 2017

This is an open access paper.

The inside scoop on beetle exoskeletons

In the past I’ve covered work on the Namib beetle and its bumps which allow it to access condensation from the air in one of the hottest places on earth and work on jewel beetles and how their structural colo(u)r is derived. Now, there’s research into a beetle’s body armor from the University of Nebraska-Lincoln according to a Feb. 22, 2017 news item on ScienceDaily,

Beetles wear a body armor that should weigh them down — think medieval knights and turtles. In fact, those hard shells protecting delicate wings are surprisingly light, allowing even flight.

Better understanding the structure and properties of beetle exoskeletons could help scientists engineer lighter, stronger materials. Such materials could, for example, reduce gas-guzzling drag in vehicles and airplanes and reduce the weight of armor, lightening the load for the 21st-century knight.

But revealing exoskeleton architecture at the nanoscale has proven difficult. Nebraska’s Ruiguo Yang, assistant professor of mechanical and materials engineering, and his colleagues found a way to analyze the fibrous nanostructure. …

A Feb. 22, 2017 University of Nebraska-Lincoln news release by Gillian Klucas (also on EurekAlert), which originated the news item, describes skeletons and the work in more detail,

The lightweight exoskeleton is composed of chitin fibers just around 20 nanometers in diameter (a human hair measures approximately 75,000 nanometers in diameter) and packed and piled into layers that twist in a spiral, like a spiral staircase. The small diameter and helical twisting, known as Bouligand, make the structure difficult to analyze.

Yang and his team developed a method of slicing down the spiral to reveal a surface of cross-sections of fibers at different orientations. From that viewpoint, the researchers were able to analyze the fibers’ mechanical properties with the aid of an atomic force microscope. This type of microscope applies a tiny force to a test sample, deforms the sample and monitors the sample’s response. Combining the experimental procedure and theoretical analysis, the researchers were able to reveal the nanoscale architecture of the exoskeleton and the material properties of the nanofibers.

Yang holds a piece of the atomic force microscope used to measure the beetle's surface. A small wire can barely be seen in the middle of the piece. Unseen is a two-nano-size probe attached to the wire, which does the actual measuring.

Craig Chandler | University Communication

Yang holds a piece of the atomic force microscope used to measure the beetle’s surface. A small wire can barely be seen in the middle of the piece. Unseen is a two-nano-size probe attached to the wire, which does the actual measuring.

They made their discoveries in the common figeater beetle, Cotinis mutabilis, a metallic green native of the western United States. But the technique can be used on other beetles and hard-shelled creatures and might also extend to artificial materials with fibrous structures, Yang said.

Comparing beetles with differing demands on their exoskeletons, such as defending against predators or environmental damage, could lead to evolutionary insights as well as a better understanding of the relationship between structural features and their properties.

Yang’s co-authors are Alireza Zaheri and Horacio Espinosa of Northwestern University; Wei Gao of the University of Texas at San Antonio; and Cheryl Hayashi of the University of California, Riverside.

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

Exoskeletons: AFM Identification of Beetle Exocuticle: Bouligand Structure and Nanofiber Anisotropic Elastic Properties by Ruiguo Yang, Alireza Zaheri,Wei Gao, Charely Hayashi, Horacio D. Espinosa. Adv. Funct. Mater. vol. 27 (6) 2017 DOI: 10.1002/adfm.201770031 First published: 8 February 2017

This paper is behind a paywall.

A DNA switch for new electronic applications

I little dreamed when reading “The Double Helix : A Personal Account of the Discovery of the Structure of DNA” by James Watson that DNA (deoxyribonucleic acid) would one day become just another material for scientists to manipulate. A Feb. 20, 2017 news item on ScienceDaily describes the use of DNA as a material in electronics applications,

DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices.

Much like flipping your light switch at home — only on a scale 1,000 times smaller than a human hair — an ASU [Arizona State University]-led team has now developed the first controllable DNA switch to regulate the flow of electricity within a single, atomic-sized molecule. The new study, led by ASU Biodesign Institute researcher Nongjian Tao, was published in the advanced online journal Nature Communications.

DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices. Courtesy: ASU

A Feb. 20, 2017 ASU news release (also on EurekAlert), which originated the news item, provides more detail,

“It has been established that charge transport is possible in DNA, but for a useful device, one wants to be able to turn the charge transport on and off. We achieved this goal by chemically modifying DNA,” said Tao, who directs the Biodesign Center for Bioelectronics and Biosensors and is a professor in the Fulton Schools of Engineering. “Not only that, but we can also adapt the modified DNA as a probe to measure reactions at the single-molecule level. This provides a unique way for studying important reactions implicated in disease, or photosynthesis reactions for novel renewable energy applications.”

Engineers often think of electricity like water, and the research team’s new DNA switch acts to control the flow of electrons on and off, just like water coming out of a faucet.

Previously, Tao’s research group had made several discoveries to understand and manipulate DNA to more finely tune the flow of electricity through it. They found they could make DNA behave in different ways — and could cajole electrons to flow like waves according to quantum mechanics, or “hop” like rabbits in the way electricity in a copper wire works —creating an exciting new avenue for DNA-based, nano-electronic applications.

Tao assembled a multidisciplinary team for the project, including ASU postdoctoral student Limin Xiang and Li Yueqi performing bench experiments, Julio Palma working on the theoretical framework, with further help and oversight from collaborators Vladimiro Mujica (ASU) and Mark Ratner (Northwestern University).

To accomplish their engineering feat, Tao’s group, modified just one of DNA’s iconic double helix chemical letters, abbreviated as A, C, T or G, with another chemical group, called anthraquinone (Aq). Anthraquinone is a three-ringed carbon structure that can be inserted in between DNA base pairs but contains what chemists call a redox group (short for reduction, or gaining electrons or oxidation, losing electrons).

These chemical groups are also the foundation for how our bodies’ convert chemical energy through switches that send all of the electrical pulses in our brains, our hearts and communicate signals within every cell that may be implicated in the most prevalent diseases.

The modified Aq-DNA helix could now help it perform the switch, slipping comfortably in between the rungs that make up the ladder of the DNA helix, and bestowing it with a new found ability to reversibly gain or lose electrons.

Through their studies, when they sandwiched the DNA between a pair of electrodes, they careful [sic] controlled their electrical field and measured the ability of the modified DNA to conduct electricity. This was performed using a staple of nano-electronics, a scanning tunneling microscope, which acts like the tip of an electrode to complete a connection, being repeatedly pulled in and out of contact with the DNA molecules in the solution like a finger touching a water droplet.

“We found the electron transport mechanism in the present anthraquinone-DNA system favors electron “hopping” via anthraquinone and stacked DNA bases,” said Tao. In addition, they found they could reversibly control the conductance states to make the DNA switch on (high-conductance) or switch-off (low conductance). When anthraquinone has gained the most electrons (its most-reduced state), it is far more conductive, and the team finely mapped out a 3-D picture to account for how anthraquinone controlled the electrical state of the DNA.

For their next project, they hope to extend their studies to get one step closer toward making DNA nano-devices a reality.

“We are particularly excited that the engineered DNA provides a nice tool to examine redox reaction kinetics, and thermodynamics the single molecule level,” said Tao.

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

I last featured Tao’s work with DNA in an April 20, 2015 posting.

Gate-controlled conductance switching in DNA by Limin Xiang, Julio L. Palma, Yueqi Li, Vladimiro Mujica, Mark A. Ratner, & Nongjian Tao.  Nature Communications 8, Article number: 14471 (2017)  doi:10.1038/ncomms14471 Published online: 20 February 2017

This paper is open access.