University of Washington scientists have created a process for printing out molecules that can respond to their surroundings.

As a test, they created a bone-shaped plastic tab that turns purple under stretching, offering an easy way to record the force on an object.

“At the UW, this is a marriage that’s been waiting to happen – 3-D printing from the engineering side, and functional materials from the chemistry side,” said Andrew J. Boydston, a UW assistant professor of chemistry. He is corresponding author on a recent  open-access paper in the American Chemical Society’s Applied Materials and Interfaces journal.

To create the test material, they fed polycaprolactone into one print head of a 3D printer (similar the flexible filament used in conventional 3D printing). For the other print head, they used a plastic that is 99.5 percent identical, but designed to have occasional insertions of a molecule, spiropyran, that changes color when it is stretched.

The result was a printed piece of white plastic with barely visible stripes that turn purple under force. It acts as an inexpensive, mechanical sensor with no electronic parts. The whole device took about 15 minutes to print from materials that cost less than a dollar.

Low-cost instant customized sensors

Such a sensor might be used to record force or strain on a building or other structure. The researchers also want to create a version that records the speed of the force, or impact, which could allow for a football helmet that changes color when hit with sufficient force.

Different instructions can program the machine to print the plastics in any configuration — with the color-changing part in stripes in the middle, completely encased in the other plastic, or in any other desired shape. Varying how the plastic is made could yield molecules that respond in different ways. For example, a material could record load history.

The research was funded by the University of Washington.

Strokes, heart attacks, and traumatic brain injuries are separate diseases with certain shared pathologies that achieve a common end: cell death and human injury due to hypoxia, or lack of oxygen.

In these diseases, a lack of blood supply to affected tissues begins a signaling pathway that ultimately halts the production of energy-releasing ATP molecules — a death sentence for most cells.

By employing derivatives of humanin, a naturally occurring peptide encoded in the genome of cellular mitochondria, researchers at Ben Gurion University of the Negev are working to interrupt this process, buying precious time for tissues whose cellular mechanisms have called it quits.

“The present findings could provide a new lead compound for the development of drug therapies for necrosis-related diseases such as traumatic brain injury, stroke and myocardial infarction — conditions for which no effective drug-based treatments are currently available [that work by blocking necrosis],” said Abraham Parola, a professor of biophysical chemistry at Ben Gurion University of the Negev in Beer-Sheva, Israel.

Parola is presently a visiting professor of Biophysical Chemistry & Director of Natural Sciences at New York University Shanghai.

The humanin derivatives work by counteracting the decrease in ATP levels caused by necrosis. The researchers tested the effectiveness of the humanin analogues AGA(C8R)-HNG17 and AGA-HNG by treating neuronal cells with these peptides prior to exposure to a necrotic agent. The experiments were a success.

Parola’s previous work has dealt with membrane dynamics and the mechanism of action of anti-angiogenesis drugs, which cause starvation of malignant tumor growths by preventing the supply of nutrients and oxygen to the fast growing tissue, in addition to various other biophysical and molecular medicine and diagnostic topics.

“A recent paper published by our group suggested the involvement of cardiolipin [a phospholipid in inner mitochondrial membranes] in the necrotic process,” Parola said. “During this work we stumbled along humanin and were intrigued by its anti-apoptotic effect, and extended it to anti-necrotic effect.”

Parola and his colleagues also performed in vivo studies by treating mice that had had traumatic brain injuries with an HNG17 analogue, which successfully reduced cranial fluid buildup and lowered the mice’s neuronal severity scores, a metric in which a higher number corresponds with greater degrees of neurological motor impairment.

As the peptides Parola and his colleagues used are derivatives of naturally occurring humanin, an ideal treatment might involve a drug delivery system with the HNG17 as the lead compound, a process aided by the ability of the peptides to penetrate the cell membrane without the use of additional reagents.

Future work for Parola and his colleagues includes further exploration of ischemic activity in liver cirrhosis, as induced by acetaminophen activity, in addition to searching for a synergistic effect between humanin and other anti-necrotic agents, such as protease inhibitors, to increase its clinical potential.

Treated buckyballs can remove potentially toxic metal particles from water and other liquids while recovering valuable particles for future use, according to scientists at Rice University.

The Rice lab of chemist Andrew Barron has discovered that carbon-60 fullerenes (aka buckyballs) that have gone through the chemical process known as hydroxylation aggregate into pearl-like strings as they bind to and separate metals from solutions.

Potential uses of the process include environmentally friendly removal of metals from acid mining drainage fluids, a waste product of the coal industry, and from fluids used for hydraulic fracturing (fraking) in oil and gas production.

The study led by Rice undergraduate Jessica Heimann appeared in the Royal Society of Chemistry journal Dalton Transactions.

Previous research in Barron’s lab had shown that hydroxylated fullerenes (known as fullerenols) combined with iron ions to form an insoluble polymer. Heimann and colleagues conducted a series of experiments to explore the relative binding ability of fullerenols to a range of metals.

“For more complex fluids [], the problem is to take out the ones you actually want,” Barron said. “Acid mining waste, for example, has large amounts of iron and aluminum and small amounts of nickel and zinc and copper, the ones you want. To be frank, iron and aluminum are not the worst metals to have in your water, because they’re in natural water, anyway.

“So our goal was to see if there is a preference between different types of metal, and we found one. Then the question was: Why?”

The answer was in the ions. An atom or molecule with more or fewer electrons than protons is an ion, with a positive or negative charge. All the metals the Rice lab tested were positive, with either 2-plus or 3-plus charges.

“Normally, the bigger the metal, the better it separates,” Barron said, but experiments proved otherwise. Two-plus metals with a smaller ionic radius bound better than larger ones. (Of those, zinc bound most tightly.) But for 3-plus ions, large worked better than small.

“That’s really weird,” Barron said. “The fact that there are diametrically opposite trends for metals with a 2-plus charge and metals with a 3-plus charge makes this interesting. The result is we should be able to preferentially separate out the metals we want.”

The experiments found that fullerenols combined with a dozen metals, turning them into solid cross-linked polymers. In order of effectiveness and starting with the best, the metals were zinc, cobalt, manganese, nickel, lanthanum, neodymium, cadmium, copper, silver, calcium, iron and aluminum.

The “pearl” reference isn’t far from literal, as one inspiration for the paper was the fact that metal ions are cross-linking agents for proteins that give certain marine mussels an amazing ability to adhere to wet rocks.

Heimann, a senior, started on the project before spending a semester at Rice’s sister institution in Germany, Jacobs University. “I initially worked with carbon nanotubes, oxidizing them to see how they would bind metals, and then I went abroad,” she said. By the time she came back, Barron was ready to try C-60. “Coming from Rice and its history with buckyballs, I thought that would be really cool,” Heimann said.

“I liked being able to see the end goal of making a filter that could be used to address contaminated water,” she said.

Barron said fullerenols act as chelate agents, which determine how ions and molecules bind with metal ions. Experiments with various metals showed the fullerenols bound with them in less than a minute, after which the combined solids could be filtered out.

Barron said the choices of aluminum, zinc and nickel for testing were due to their co-presence with iron in acid mining drainage water. Similarly, cadmium was tested for its association with fertilizer and sewage sludge and copper with mining discharge. Nickel, lanthanum and neodymium are used in batteries and drive motors in hybrid vehicles.

Barron said the research shows the versatility of the buckyball, discovered at Rice in 1985 by Nobel Prize winners Rick Smalley, Robert Curl and Harold Kroto. It also points the way forward. “The understanding we now have is allowing us to find alternatives to C-60s to design ways in which we can separate out metals more efficiently,” he said.

Co-authors of the paper are Rice graduate student Lauren Morrow and alumnus Robin Anderson. Barron is the Charles W. Duncan Jr.-Welch Professor of Chemistry and a professor of materials science and nanoengineering.

The Robert A. Welch Foundation and the Welch Government Sêr Cymru Programme supported the research.

Researchers from South Korea have taken a new step toward more bendable devices by manufacturing a thin film that keeps its useful electric and magnetic properties even when highly curved.

Flexible electronics have been hard to manufacture because many materials with useful electronic properties tend to be rigid. Researchers have addressed this problem by taking tiny bits of materials like silicon and embedding them in flexible plastics.

A team of physicists and engineers from South Korea took the same approach with bismuth ferrite (BiFeO3) — one of the most promising materials whose electronic properties can be controlled by a magnetic field, and vice versa. Such materials are calledmultiferroics and attract interest for applications like energy-efficient, instant-on computing.

The researchers synthesized nanoparticles of bismuth ferrite and mixed them into a polymer solution. The solution was dried in a series of steps at increasing temperatures to produce a thin, flexible film.

When the researchers tested the electric and magnetic properties of the film they found that their new materials improved properties remained even as the film was curved into a cylindrical shape.

“Bulk bismuth ferrite has crucial problems for some applications, such as a high leakage current which hinders the strong electric properties,” said YoungPak Lee, a professor at Hanyang University in Seoul, South Korea. Mixing nanoparticles of bismuth ferrite into a polymer improved the current-leakage problem, he said, and also gave the film flexible, stretchable properties.

Flexible multiferrorics could enable new wearable devices such as health monitoring equipment or virtual reality attire, Lee said. The multiferroric materials could be used in high-density, energy-efficient memory, and switches in such devices, he said.

The research is described in a paper published in the journal Applied Physics Letters. The authors are affiliated with Hanyang University, Seoul National University, and Hankuk University of Foreign Studies.

By combining experimental data from X-ray crystallography,NMR spectroscopy, cryoelectron microscopy and lipidomics(the study of cellular lipid networks), researchers at theUniversity of Oxford have built a complete model of the outer envelope of an influenza A virion for the first time.

The simulation may help scientists better understand how the virus survives in the wild or find new ways to combat it.

The approach, known as a coarse-grained molecular dynamics simulation, has allowed them to generate trajectories at different temperatures and lipid compositions, revealing various characteristics about the membrane components.

How to simulate a virus

Their computer simulation begins by rendering the virus as a relatively large, 73-nanometer ball of loosely packed lipids. This ball then relaxes down into a smaller, 59-nanometer virion within 300 nanoseconds. The viral spike proteins are then embedded into the lipid envelope individually, before adding solvent to the system.

“In the current publication, this is just a single virion in a water droplet — but what could really get interesting is if we start putting in other molecules of interest, such as therapeutic agents,” said Tyler Reddy, a postdoctoral fellow at the University of Oxford.

Here’s what they learned from the simulation:

• The viral spike proteins protruding from the virion’s membrane spread out, rather than aggregating close together. This is key to the strength of the interactions between influenza A virions and host cells, which are determined by the number of spike proteins that can engage with receptors. “If the separation of the spike proteins is compatible with the ‘arms’ of Y-shaped, bivalent antibodies, this information might be exploited in therapeutic design, so that two antigens may be bound simultaneously for enhanced association,” Reddy said.
• Forssman glycolipid had a role in preventing protein aggregation and slowing down protein diffusion, so it would be important to include glycolipids in future virion simulations given their influence on the biophysical properties observed. The extended sugar head groups of glycolipids may mask antibody accessibility of the M2 proton channels in the flu envelope — the target of commonly prescribed anti-influenza drugs based on adamantanederivatives.

Understanding the membrane envelope’s structural dynamics also provides insight into the wide-ranging survival times of the virion in different environments, such as fresh-water rivers. Previous studies have indicated that the presence of influenza A in rivers has allowed waterfowl to be simultaneously exposed to source flu strains and residual anti-viral compounds excreted by local human populations, potentially giving rise to drug-resistant influenza strains. Reddy’s simulation currently monitors the virion’s stability on the microsecond scale, and it will be a challenge to assess stability over much longer time scales.

“We are a long way from being able to perform molecular dynamics simulations that span the year time scale,” Reddy said. “Nonetheless, we now have a platform for looking at influenza A virion behavior in silico (in a computer simulation)  and perhaps certain compounds or solutions could be used to accelerate destabilization on an observable time scale.

“We’re making the coordinate data freely available in the hopes that other groups have interesting ideas for use with this model as well, and so that they can criticize and help improve the model.”

Hopefully, this information will go viral. …

Abstract for Nothing to sneeze at: a dynamic and integrative computational model of an influenza A virion

Tackling the ongoing challenge of influenza infectivity would benefit greatly from a molecular understanding of why the influenza A virion exhibits seasonal patterns of infectivity and has wide-ranging survival times in different environments. A computational approach to the study of the behaviour of the virion that focuses on the poorly-understood structural and dynamic role of the lipids is presented here. We have combined experimental data from X-ray crystallography, NMR spectroscopy, cryoelectron microscopy, and lipidomics to build a full-scale computational model of the influenza A virion. This represents the first set of microsecond-scale molecular dynamics simulations of an enveloped virion in explicit solvent that we are aware of. We report results for a set of simulations at different temperatures and with varying lipid compositions. The Forssman glycolipid, which is prevalent in the influenza A lipidome, influences several biophysical characteristics of the virion model, including diffusion and clustering of proteins and lipids. The distribution of peplomers on the virion surface is consistent with accessibility to bivalent antibodies. The distances of binding sites for host cell sialic acid-containing receptors have been analyzed in the virion model for a variety of planar host cell membrane attack orientations. The relatively rigid membrane of the influenza A virion model exhibits a number of biophysical properties consistent with experimental measurements, and may serve as a useful platform for in silico assessment of virion behaviour.

“Soft robotics” researchers have developed a flexible, microscopic hand-like gripper that could help doctors perform remotely guided surgical procedures, biopsies, and someday deliver therapeutic drugs to hard-to-reach places.

David H. Gracias at The Johns Hopkins University and colleagues note that many robotic tools require cords to provide power to generate their movements, adding to the bulk of robots and limiting the spaces they can access.

To address this constraint, scientists have turned to hydrogels. These soft materials can swell in response to changes in temperature, acidity or light, providing energy to carry out tasks without being tethered to a power source.

However, hydrogels are too floppy for some applications, so the group combined the hydrogels with a stiff biodegradable polymer, making the microhands strong enough to wrap around and remove cells. The team then sought a way to control where the grippers go once deployed in the body.

The researchers incorporated ferromagnetic nanoparticles in the materials so they could guide the microhands with a magnetic probe. That allows for microassembly or microengineering of soft or biological parts and gives surgeons the ability to remotely direct where biopsies are taken.

Also, Gracias says that the use of soft materials highlights the possibility of creating biodegradable, miniaturized surgical tools that can safely dissolve in the body.

The work was funded by the National Science Foundation and the National Institutes of Health.

http://www.kurzweilai.net/tiny-soft-robotic-hands-with-magnetic-nanoparticles-could-improve-cancer-diagnostics-drug-delivery

Scientists from UCLA’s California NanoSystems Institutehave developed a custom-designed Google Glass Android app that, when paired with a handheld device, enables the wearer to quickly analyze the health of a plant without damaging it or requiring expensive lab equipment and expertise.

The app analyzes the concentration of chlorophyll — the substance in plants responsible for converting sunlight into energy. Reduced chlorophyll production in plants can indicate degradation of water, soil, or air quality.

One current method for measuring chlorophyll concentration requires removing some of the plant’s leaves, dissolving them in a chemical solvent and then performing the chemical analysis. With the new system, leaves are examined and then left functional and intact.

The system, developed by at team led by Aydogan Ozcan, associate director of the UCLA California NanoSystems Institute, uses an image captured by the Google Glass camera to measure the chlorophyll’s light absorption in the green part of the optical spectrum.

Simple DIY plant diagnostics

The device is simple to use. You insert the leaf into a slot in the illuminator, red and white LEDs emit light that enhances the leaf’s transmission image contrast, indoors or out, regardless of environmental lighting conditions.

Glass photographs the leaf in both colors and sends an enhanced JPEG image wirelessly to a remote server, which processes the data from the image and sends back a chlorophyll concentration reading (“SPAD index”) — all in less than 10 seconds. GPS and time data is also provided.

You can produce the main body of the handheld illuminator unit using 3D printing. It runs on three AAA batteries and with a small circuit board added, it can be assembled for less than $30.

The research, led by Aydogan Ozcan, associate director of the UCLA California NanoSystems Institute and Chancellor’s Professor of Electrical Engineering and Bioengineering at the UCLA Henry Samueli School of Engineering and Applied Science, was published online by the Royal Society of Chemistry journal Lab on a Chip.

“One pleasant surprise we found was that we used five leaf species to calibrate our system, and that this same calibration worked to accurately detect chlorophyll concentration in 15 different leaf species without having to recalibrate the app,” Ozcan said. “This will allow a scientist to get readings walking from plant to plant in a field of crops, or look at many different plants in a drought-plagued area and accumulate plant health data very quickly.”

The system could replace relatively costly and bulky laboratory instruments. Ozcan said that the convenience, speed and cost-effectiveness of the new system could aid scientists studying the effects of droughts and climate change in remote areas.

Ozcan’s lab specializes in computational imaging, sensing and diagnostic devices for various mobile-health and telemedicine applications. Its previous work includes quick analysis of food samples for allergens, water samples for heavy metals and bacteria and cell counts in blood samples. The research team has devised a way to use Google Glass to process diagnostic test results, and an app and attachment that converts a smartphone into a fluorescence microscope for imaging single viruses and individual DNA molecules.

Support for Ozcan’s lab is provided by the Presidential Early Career Award for Scientists and Engineers, the Army Research Office Life Sciences Division, the National Science Foundation, the Office of Naval Research, the Howard Hughes Medical Institute and the National Institutes of Health.

http://www.kurzweilai.net/google-glass-app-analyzes-plants-health-in-seconds

British researchers have cracked a code that governs infections by a major group of viruses including the common cold and polio, which could help prevent diseases.

Until now, scientists had not noticed the code, which had been hidden in plain sight in the sequence of the ribonucleic acid (RNA) that makes up this type of viral genome.

But a paper published in the Proceedings of the National Academy of Sciences (PNAS) Early Edition by a group from the University of Leeds and University of York unlocks its meaning and demonstrates that jamming the code can disrupt virus assembly, preventing disease.

Professor Peter Stockley, Professor of Biological Chemistry in the University of Leeds’ Faculty of Biological Sciences, who led the study, said: “If you think of this as molecular warfare, these are the encrypted signals that allow a virus to deploy itself effectively.

Single-stranded RNA viruses are the simplest type of virus and were probably one of the earliest to evolve. However, they are still among the most potent and damaging of infectious pathogens.

Rhinovirus (which causes the common cold) accounts for more infections every year than all other infectious agents put together (about 1 billion cases); emergent infections such as chikungunya and tick-borne encephalitis are from the same ancient family. Other single-stranded RNA viruses include the hepatitis C virus, HIV, and the winter vomiting bug norovirus.

“Now, for this whole class of viruses, we have found the ‘Enigma machine’—the coding system that was hiding these signals from us. We have shown that not only can we read these messages but we can jam them and stop the virus’ deployment.”

This breakthrough was the result of three stages of research:

• In 2012, researchers at the University of Leeds published the first observations at a single-molecule level of how the core of a single-stranded RNA virus packs itself into its outer shell — a remarkable process because the core must first be correctly folded to fit into the protective viral protein coat. The viruses solve this fiendish problem in milliseconds.
• University of York mathematicians Eric Dykeman and Professor Reidun Twarock, working with the Leeds group, then devised mathematical algorithms to crack the code governing the process and built computer-based models of the coding system.
• In this latest study, the two groups have unlocked the code. The group used single-molecule fluorescence spectroscopy to watch the codes being used by the satellite tobacco necrosis virus, a single stranded RNA plant virus.

Roman Tuma, Reader in Biophysics at the University of Leeds, said: “We have understood for decades that the RNA carries the genetic messages that create viral proteins, but we didn’t know that, hidden within the stream of letters we use to denote the genetic information, is a second code governing virus assembly. It is like finding a secret message within an ordinary news report and then being able to crack the whole coding system behind it.

“This paper goes further: it also demonstrates that we could design molecules to interfere with the code, making it uninterpretable and effectively stopping the virus in its tracks.”

The researchers say their next step will be to widen the study into animal viruses. They believe that their combination of single-molecule detection capabilities and their computational models offers a novel route for drug discovery.

The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the Engineering and Physical Sciences Research Council (EPSRC). Twarock’s Royal Society Leverhulme Trust Senior Research Fellowship and Dykeman’s Leverhulme Trust Early Career Fellowship also supported the work.

Rice University scientists have advanced their recent development of laser-induced graphene (LIG) by producing and testing stacked, three-dimensional supercapacitors — energy-storage devices that are important for portable, flexible electronics.

The Rice lab of chemist James Tour discovered last year that firing a laser at an inexpensive polymer burned off other elements and left a film of porous graphene, the much-studied atom-thick lattice of carbon.

The researchers viewed the porous, conductive material as a perfect electrode for supercapacitors or electronic circuits.

To prove it, members of the Tour group have since extended their work to make vertically aligned supercapacitors with laser-induced graphene on both sides of a polymer sheet. The sections are then stacked with solid electrolytes in between for a multilayer sandwich with multiple microsupercapacitors.

Combining energy and power density

The flexible stacks show excellent energy-storage capacity and power potential and can be scaled up for commercial applications. LIG can be made in air at ambient temperature, perhaps in industrial quantities through roll-to-roll processes, Tour said.

The research was reported in Applied Materials and Interfaces.

Capacitors use an electrostatic charge to store energy they can release quickly, to a camera’s flash, for example. Unlike chemical-based rechargeable batteries, capacitors charge fast and release all their energy at once when triggered.

But chemical batteries hold far more energy. Supercapacitors combine useful qualities of both — the fast charge/discharge of capacitors (power density) and high-energy capacity of batteries (energy density) — into one package.

Tour said that while thin-film lithium ion batteries are able to store more energy, LIG supercapacitors of the same size offer three times the performance in power (the speed at which energy flows). And the LIG devices can easily scale up for increased capacity.

“We’ve demonstrated that these are going to be excellent components of the flexible electronics that will soon be embedded in clothing and consumer goods,” he said.

Flexibility

LIG supercapacitors appear able to do all that with the added benefits of flexibility and scalability. The flexibility ensures they can easily conform to varied packages (they can be rolled within a cylinder, for instance) without giving up any of the device’s performance.

“What we’ve made are comparable to microsupercapacitors being commercialized now, but our ability to put devices into a 3D configuration allows us to pack a lot of them into a very small area,” Tour said.

“The other key is that we’re doing this very simply. Nothing about the process requires a clean room. It’s done on a commercial laser system, as found in routine machine shops, in the open air.”

Ripples, wrinkles and sub-10-nanometer pores in the surface and atomic-level imperfections give LIG its ability to store a lot of energy. But the graphene retains its ability to move electrons quickly and gives it the quick charge-and-release characteristics of a supercapacitor.

In testing, the researchers charged and discharged the devices for thousands of cycles with almost no loss of capacitance. The vertical supercapacitors also showed almost no change in electrical performance when flexed, even after 8,000 bending cycles.

The Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative (MURI) and the Office of Naval Research MURI supported the research.

http://www.kurzweilai.net/flexible-3d-graphene-supercapacitors-may-power-portables-and-wearables