miércoles, 16 de mayo de 2018

Plug-and-play diagnostic devices

Jose Gomez-Marquez, co-director of MIT’s Little Devices Lab, holds a sheet of paper diagnostic blocks, which can be easily printed and then combined in various ways to create customized diagnostic devices. Image: Melanie Gonick/MIT

Modular blocks could enable labs around the world to cheaply and easily build their own diagnostics.

Researchers at MIT’s Little Devices Lab have developed a set of modular blocks that can be put together in different ways to produce diagnostic devices. These “plug-and-play” devices, which require little expertise to assemble, can test blood glucose levels in diabetic patients or detect viral infection, among other functions.

Ampli blocks. Image by Melanie Gonick, MIT. 
Our long-term motivation is to enable small, low-resources laboratories to generate their own libraries of plug-and-play diagnostics to treat their local patient populations independently,” says Anna Young, co-director of MIT’s Little Devices Lab, lecturer at the Institute for Medical Engineering and Science, and one of the lead authors of the paper.

Using this system, called Ampli blocks, the MIT team is working on devices to detect cancer, as well as Zika virus and other infectious diseases. The blocks are inexpensive, costing about 6 cents for four blocks, and they do not require refrigeration or special handling, making them appealing for use in the developing world.

We see these construction kits as a way of lowering the barriers to making medical technology,” says Jose Gomez-Marquez, co-director of the Little Devices Lab and the senior author of the paper.

Elizabeth Phillips ’13, a graduate student at Purdue University, is also a lead author of the paper, which appears in the journal Advanced Healthcare Materials on May 16. Other authors include Kimberly Hamad-Schifferli, an associate professor of engineering at the University of Massachusetts at Boston and a visiting scientist in MIT’s Department of Mechanical Engineering; Nikolas Albarran, a senior engineer in the Little Devices Lab; Jonah Butler, an MIT junior; and Kaira Lujan, a former visiting student in the Little Devices Lab.

Advanced Healthcare Materials Paper (click to enlarge)
Customized diagnostics

Over the past decade, many researchers have been working on small, portable diagnostic devices based on chemical reactions that occur on paper strips. Many of these tests make use of lateral flow technology, which is the same approach used in home pregnancy tests.

Despite these efforts, such tests have not been widely deployed. One obstacle, says Gomez-Marquez, is that many of these devices are not designed with large-scale manufacturability in mind. Another is that companies may not be interested in mass-producing a diagnostic for a disease that doesn’t affect a large number of people.

The Little Devices Lab researchers realized that they could get these diagnostics into the hands of many more people if they created a kit of modular components that can be put together to generate exactly what the user needs. To that end, they have created about 40 different building blocks that lab workers around the world could easily assemble on their own, just as people began assembling their own radios and other electronic devices from commercially available electronic “breadboards” in the 1970s.

When the electronic breadboard came out, that meant people didn’t have to worry about building their own resistors or capacitors. They could worry about what they actually wanted to use electronics for, which is to make the entire circuit,” Gomez-Marquez says.


In this case, the components consist of a sheet of paper or glass fiber sandwiched between a plastic or metal block and a glass cover. The blocks, which are about half an inch on each edge, can snap together along any edge.
  • Some of the blocks contain channels for samples to flow straight through, 
  • some have turns, and 
  • some can receive a sample from a pipette or 
  • mix multiple reagents together.
The blocks can also perform different biochemical functions. Many contain antibodies that can detect a specific molecule in a blood or urine sample. Those antibodies are attached to nanoparticles that change color when the target molecule is present, indicating a positive result.

These blocks can be aligned in different ways, allowing the user to create diagnostics based on one reaction or a series of reactions. In one example, the researchers combined blocks that detect three different molecules to create a test for isonicotinic acid, which can reveal whether tuberculosis patients are taking their medication.

The blocks are color-coded by function, making it easier to assemble predesigned devices using instructions that the researchers plan to put online. They also hope that users will develop and contribute their own specifications to the online guide.

Better performance
The researchers also showed that in some ways, these blocks can outperform previous versions of paper diagnostic devices. For example, they found that they could run a sample back and forth over a test strip multiple times, enhancing the signal. This could make it easier to get reliable results from urine and saliva samples, which are usually more dilute than blood samples, but are easier to obtain from patients.

These are things that cannot be done with standard lateral flow tests, because those are not modular — you only get to run those once,” says Hamad-Schifferli.

The team is now working on tests for human papilloma virus, malaria, and Lyme disease, among others. They are also working on blocks that can synthesize useful compounds, including drugs, as well as blocks that incorporate electrical components such as LEDs.

The ultimate goal is to get the technology into the hands of small labs in both industrialized and developing countries, so they can create their own diagnostics. The MIT team has already sent them to labs in Chile and Nicaragua, where they have been used to develop devices to monitor patient adherence to TB treatment and to test for a genetic variant that makes malaria more difficult to treat.

Catherine Klapperich, associate dean for research and an associate professor of biomedical engineering at Boston University, says the MIT team’s work will help to make the diagnostic design process more inclusive.

By reducing the barriers to designing new point-of-care paperfluidics, the work invites nonexperts in and will certainly result in new ideas and collaborations in settings all around the world,” says Klapperich, who was not involved in the research. “The practical demonstrations of the system presented here are poised to be immediately useful, while the possibilities for others to build on the tool are large.

The researchers are now investigating large-scale manufacturing techniques, and they hope to launch a company to manufacture and distribute the kits around the world.

We are excited to open the platform to other researchers so they can use the blocks and generate their own reactions,” Young says.

The research was funded by a gift from Autodesk and the U.S. Public Health Service.


ORIGINAL: MIT News
By Anne Trafton | MIT News Office 
May 16, 2018

This Hard-to-Destroy Drone Goes From Rigid to Flexible When It Crashes

Image: EPFL Don't worry, the drone is fine!
Anyone who’s ever flown a drone of any sort will tell you that sooner or later, you’re going to crash it. The question is how exactly you will go about doing this, and how much of the drone will be functional after it’s happened. Most flying animals somewhat frustratingly don’t have this problem: Birds and insects run into things occasionally (or all the time, for small bugs), and just shrug it off and keep on going, thanks to their biological design, which includes both stiffness and flexibility. Now roboticists at the EPFL, in Lausanne, Switzerland, are relying on these same qualities to design a highly resilient quadrotor that’s impressively difficult to destroy.

There are three primary strategies for designing drones with impact resistance.
  1. The first is to just protect the propellers by surrounding them with the frame of the drone or with individual propeller guards. Most commercial drones have something like this. With this level of protection, you’re less likely to injure people, but since the prop protection is rigid, you’re more likely to injure the drone itself if (I mean, when) you crash it. The EPFL quadrotor uses a flexible frame that locks in place with magnets. When a collision occurs, the frame breaks away from the magnets, and once the energy is dissipated, elastic bands pull the frame back together and you’re good to go.
  2. The second level of impact protection is to design your drone in a way that it can absorb energy from the crash without breaking into pieces. One way of doing that is to decouple the frame of the drone by, say, using flexible, elastic couplers. This gives you a “squishy” drone, which is very effective at handling impacts, but it’s also squishy in-flight, which causes all kinds of structural and stability problems
  3. The most impressive level of impact protection that we’ve seen in drones is the brute force approach of just surrounding the entire thing with a flexible, rotating cage. Flyability has made a compelling business case for using drones with protective cages, and for some applications, it’s fantastic. You do, however, pay a penalty, since the cage can increase the overall size of the drone by upwards of 60 percent, meaning that it’s safer to run into things, but you’re also much more likely to run into things. The cage adds mass as well, leading to a drone that can’t lift as much or fly as far.

EPFL’s idea is a compromise of sorts: They’ve managed to create a drone with a frame that’s rigid right up until it smashes into something, at which point it turns flexible:

The inspiration for this design came from insect wings. To fly, insects need wings with high stiffness, but flexibility is critical for absorbing shock, and wasps do it with a special joint that allows the entire wing to “reversibly crumple” during a collision, as the EPFL researchers explain:

Wasp wings display dual stiffness, that is the ability to reversibly transition between rigid and soft states, which provides mechanical resilience without impairing flight performances. The wings of wasps contain a flexible resilin joint... This design allows the wing tip to slightly flex during flight (rigid state), but reversibly crumple… during collisions (soft state). If the dual-stiffness behavior is impaired... the rigid wings undergo severe tear during collision. Therefore, this design provides crash resilience by effectively preventing wing overload during collisions without compromising flight capabilities.
Image: EPFL The quadcopter has two main parts: the external frame and a central case. They are held together by magnetic joints, each with two magnets and a spring (inset).
The quadrotor that the researchers came up with uses a flexible frame that locks in place around the core of the quadrotor with magnets. When a collision occurs, the frame breaks away from the magnets, absorbing the energy of the collision. Once the energy is dissipated, elastic bands pull the frame back into its original configuration, and the magnets snap together again, and you’re good to go.

The uniqueness of the proposed design lies in the fact that the frame is rigid during flight, but softens during collisions. This allows combination of the advantages of both rigid and soft systems: stability and rapid response to user commands during flight, leading to flight performance equivalent to a drone equipped with a standard rigid frame, and crash resilience like a soft system. The experiments showed a satisfying survivability of the frame of the drone, that withstood roughly 50 collisions with no permanent damage.

The researchers, who are members of EPFL’s Laboratory of Intelligent Systems, suggest that an approach like this could be useful for all kinds of robots, not just drones. Most robots are rigid for various performance reasons (like precision), but the ability to be flexible when necessary without using intrinsically soft materials could could come in handy for grasping, locomotion, or simply as an added safety measure for human-robot interaction tasks.

S. Mintchev, Member, IEEE, S. de Rivaz and D. Floreano, Senior Member, IEEE
Insect-Inspired Mechanical Resilience for Multicopters,” by S. Mintchev, S. de Rivas, and D. Floreano from EPFL was published in the 25 January 2017 issue of IEEE Robotics and Automation Letters.

[ EPFL ]

ORIGINAL: IEEE Spectrum
By Evan Ackerman
Posted 9 Mar 2017

lunes, 8 de enero de 2018

Hybrid solid-state system harvests more hydrogen from water

(From left) Junyoung Kim, Professor Guntae Kim, and Ohhun Gwona are part of the team who developed the Hybrid-SOEC, a more efficient new system for producing hydrogen(Credit:UNIST)
Clean and plentiful, hydrogen is a promising fuel source, but there are a few problems standing in the way of it becoming mainstream. South Korean scientists have now developed a new system for producing hydrogen from water, which that they say overcomes some of these issues and produces the gas more efficiently than other water electrolysis systems.

The new device was developed by a research team consisting of scientists from the 
and is based on an existing design called a solid oxide electrolyzer cell (SOEC).

These work like other electrolyzers in that an electrical current splits water into its constituent molecules – hydrogen and oxygen – which can then be harvested. The difference is that in this setup, both electrodes are solid-state, as is the electrolyte that carries the ions between them.

This has a few advantages over systems that use liquid electrolytes – namely, 
  • the liquids need to be topped up occasionally, and over time they tend to corrode other components. 
  • And since solid-state electrolyzers operate at higher temperatures, they don't need as much electrical energy to function because they can draw energy from that heat.
But SOECs still have room for improvement. There are two main designs that use different electrolytes: 
  • One allows only oxygen ions to pass through, and 
  • the other only hydrogen ions. 
In either case, that one-way street limits the amount of hydrogen that can be produced.


So the researchers developed a new Hybrid-SOEC, which uses a mixed-ion conductor to transport both negatively-charged oxygen ions and positively-charged hydrogen ions (protons) at the same time. The end result had all the benefits of a solid-state electrolyzer, with improved efficiency.

"By controlling the driving environment of the hydrogen ion conductive electrolyte, a 'mixed ion conductive electrolyte' in which two ions pass can be realized," says Junyoung Kim, first author of the study. "In Hybrid-SOEC where this electrolyte was first introduced, water electrolysis occurred at both electrodes, which results in significant increase in total hydrogen production."

Using the mixed-ion conductor and electrodes made of layered perovskite, the Hybrid-SOEC produced 1.9 liters (0.5 gal) of hydrogen per hour, running at a cell voltage of 1.5 V and a temperature of 700° C (1,292° F). The researchers say that's four times more efficient than existing water electrolysis systems, and after running the device continuously for 60 hours, there were no signs of that performance degrading.

The research was published in the journal Nano Energy.


Source: UNIST

ORIGINAL: New Atlas
December 28th, 2017

miércoles, 3 de enero de 2018

This Living Light is powered by a houseplant

1- The lamp works using photosynthesis. As organic compounds are released in the soil, bacteria generates electrons and protons. Those in turn are used as a battery to power the light.
Imagine a lamp that doesn’t need to be plugged in – and that you have to water once a week. Ermi van Oers is making it happen with this incredible plant-turned-lamp. The Living Light is an off-grid light that’s powered by a houseplant instead of an electrical socket.

2- The healthier your plant is, the more photosynthesis takes place and the more energy you generate, which is a pretty cool way to gauge how happy your plant lamp is.
3- Imagine a lamp that doesn't need to be plugged in and that you have to water once a week. Ermi van Oers is making it happen with this incredible plant-turned-lamp. The Living Light uses a houseplant to generate its energy in a totally self-sufficient, off-grid system that doesn't need an electric socket to power up.
As organic compounds are released into the soil from photosynthesis, bacteria generates electrons and protons. These particles are tapped as an energy source to power the light. The healthier the plant is, the more photosynthesis takes place – and the more energy the system generates. It’s a pretty cool way to gauge how happy your plant lamp is.
4- Living Light produces up to 0.1mW of energy, which isn't enough to light an entire room, but is plenty to act as your evening reading lamp.
5- Living Light produces up to 0.1mW of energy, which isn't enough to light an entire room, but is plenty to act as your evening reading lamp.
6- The plant and the light form a circle of energy that can go off-grid and requires no electric socket to work.
7- The project was featured at this year's Dutch Design Week.
8- Imagine a lamp that doesn't need to be plugged in and that you have to water once a week. Ermi van Oers is making it happen with this incredible plant-turned-lamp. The Living Light uses a houseplant to generate its energy in a totally self-sufficient, off-grid system that doesn't need an electric socket to power up.
The Living Light produces up to 0.1mW of energy, which isn’t enough to light an entire room, but it’s plenty to act as your evening reading lamp.
Van Oers and team aren’t done yet – they’re working on increasing the energy output, and they imagine that entire towns could be powered by forests one day.

Via Dezeen

ORIGINAL: Inhabitat

miércoles, 27 de diciembre de 2017

Scientists Develop A Battery That Can Run For More Than A Decade

Credit: Harvard University



Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new flow battery that stores energy in organic molecules dissolved in neutral pH water. This new chemistry allows for a
  • non-toxic,
  • non-corrosive battery
  • with an exceptionally long lifetime and
  • offers the potential to significantly decrease the costs of production.
The research, published in ACS Energy Letters, was led by Michael Aziz, the Gene and Tracy Sykes Professor of Materials and Energy Technologies and Roy Gordon, the Thomas Dudley Cabot Professor of Chemistry and Professor of Materials Science.

A Neutral pH Aqueous Organic–Organometallic Redox Flow Battery with Extremely High Capacity Retention
Eugene S. Beh†‡ , Diana De Porcellinis†#, Rebecca L. Gracia∥, Kay T. Xia∥, Roy G. Gordon*†‡, and Michael J. Aziz*
† John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
‡ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
# Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, 00133 Rome, Italy
∥ Harvard College, Cambridge, Massachusetts 02138, United States
ACS Energy Lett., 2017, 2 (3), pp 639–644
DOI: 10.1021/acsenergylett.7b00019
Publication Date (Web): February 7, 2017
Copyright © 2017 American Chemical Society
*E-mail: gordon@chemistry.harvard.edu., *E-mail: maziz@harvard.edu.

Abstract
Abstract Image
We demonstrate an aqueous organic and organometallic redox flow battery utilizing reactants composed of only earth-abundant elements and operating at neutral pH. The positive electrolyte contains bis((3-trimethylammonio)propyl)ferrocene dichloride, and the negative electrolyte contains bis(3-trimethylammonio)propyl viologen tetrachloride; these are separated by an anion-conducting membrane passing chloride ions. Bis(trimethylammoniopropyl) functionalization leads to ∼2 M solubility for both reactants, suppresses higher-order chemical decomposition pathways, and reduces reactant crossover rates through the membrane. Unprecedented cycling stability was achieved with capacity retention of 99.9943%/cycle and 99.90%/day at a 1.3 M reactant concentration, increasing to 99.9989%/cycle and 99.967%/day at 0.75–1.00 M; these represent the highest capacity retention rates reported to date versus time and versus cycle number. We discuss opportunities for future performance improvement, including chemical modification of a ferrocene center and reducing the membrane resistance without unacceptable increases in reactant crossover. This approach may provide the decadal lifetimes that enable organic–organometallic redox flow batteries to be cost-effective for grid-scale electricity storage, thereby enabling massive penetration of intermittent renewable electricity.
Flow batteries store energy in liquid solutions in external tanks—the bigger the tanks, the more energy they store. Flow batteries are a promising storage solution for renewable, intermittent energy like wind and solar but today’s flow batteries often suffer degraded energy storage capacity after many charge-discharge cycles, requiring periodic maintenance of the electrolyte to restore the capacity.

By modifying the structures of molecules used in the positive and negative electrolyte solutions, and making them water soluble, the Harvard team was able to engineer a battery that loses only one percent of its capacity per 1000 cycles.

Lithium ion batteries don’t even survive 1000 complete charge/discharge cycles,” said Aziz.

Because we were able to dissolve the electrolytes in neutral water, this is a long-lasting battery that you could put in your basement,” said Gordon. “If it spilled on the floor, it wouldn’t eat the concrete and since the medium is noncorrosive, you can use cheaper materials to build the components of the batteries, like the tanks and pumps.

This reduction of cost is important. The Department of Energy (DOE) has set a goal of building a battery that can store energy for less than $100 per kilowatt-hour, which would make stored wind and solar energy competitive to energy produced from traditional power plants.

If you can get anywhere near this cost target then you change the world,” said Aziz. “It becomes cost effective to put batteries in so many places. This research puts us one step closer to reaching that target.

This work on aqueous soluble organic electrolytes is of high significance in pointing the way towards future batteries with vastly improved cycle life and considerably lower cost,” said Imre Gyuk, Director of Energy Storage Research at the Office of Electricity of the DOE. “I expect that efficient, long duration flow batteries will become standard as part of the infrastructure of the electric grid.

The key to designing the battery was to first figure out why previous molecules were degrading so quickly in neutral solutions, said Eugene Beh, a postdoctoral fellow and first author of the paper. By first identifying how the molecule viologen in the negative electrolyte was decomposing, Beh was able to modify its molecular structure to make it more resilient.

Next, the team turned to ferrocene, a molecule well known for its electrochemical properties, for the positive electrolyte.

Ferrocene is great for storing charge but is completely insoluble in water,” said Beh. “It has been used in other batteries with organic solvents, which are flammable and expensive.

But by functionalizing ferrocene molecules in the same way as with the viologen, the team was able to turn an insoluble molecule into a highly soluble one that could also be cycled stably.

Aqueous soluble ferrocenes represent a whole new class of molecules for flow batteries,” said Aziz.

The neutral pH should be especially helpful in lowering the cost of the ion-selective membrane that separates the two sides of the battery. Most flow batteries today use expensive polymers that can withstand the aggressive chemistry inside the battery. They can account for up to one third of the total cost of the device. With essentially salt water on both sides of the membrane, expensive polymers can be replaced by cheap hydrocarbons.

This research was coauthored by Diana De Porcellinis, Rebecca Gracia, and Kay Xia. It was supported by the Office of Electricity Delivery and Energy Reliability of the DOE and by the DOE’s Advanced Research Projects Agency-Energy.

With assistance from Harvard’s Office of Technology Development (OTD), the researchers are working with several companies to scale up the technology for industrial applications and to optimize the interactions between the membrane and the electrolyte. Harvard OTD has filed a portfolio of pending patents on innovations in flow battery technology.

ORIGINAL: Daily Accord
Credit: Harvard University
Feb 9, 2017 

domingo, 24 de diciembre de 2017

MIT Just Created Living Plants That Glow Like A Lamp, And Could Grow Glowing Trees To Replace Streetlights


Roads of the future could be lit by glowing trees instead of streetlamps, thanks to a breakthrough in creating bioluminescent plants. Experts injected specialized nanoparticles into the leaves of a watercress plant, which caused it to give off a dim light for nearly four hours. This could solve lots of problems.

The chemical involved, which produced enough light to read a book by, is the same as is used by fireflies to create their characteristic shine. To create their glowing plants, engineers from the Massachusetts Institute of Technology (MIT) turned to an enzyme called luciferase. Luciferase acts on a molecule called luciferin, causing it to emit light.
 
Roads of the future could be lit by glowing trees instead of streetlamps, thanks to a breakthrough in creating bioluminescent plants. Experts created a watercress plant which caused it to glow for nearly four hours and gave off enough light to illuminate this book
Another molecule called Co-enzyme A helps the process along by removing a reaction byproduct that can inhibit luciferase activity. The MIT team packaged each of these components into a different type of nanoparticle carrier.

The nanoparticles help them to get to the right part of the plant and also prevent them from building to concentrations that could be toxic to the plants. The result was a watercress plant that functioned like a desk lamp.

Researchers believe with further tweaking, the technology could also be used to provide lights bright enough to illuminate a workspace or even an entire street, as well as low-intensity indoor lighting

Michael Strano, professor of chemical engineering at MIT and the senior author of the study, said: 'The vision is to make a plant that will function as a desk lamp — a lamp that you don't have to plug in. The light is ultimately powered by the energy metabolism of the plant itself. Our work very seriously opens up the doorway to streetlamps that are nothing but treated trees, and to indirect lighting around homes.'

Luciferases make up a class of oxidative enzymes found in several species that enable them to 'bioluminesce', or emit light.
Fireflies are able to emit light via a chemical reaction.

In the chemical reaction luciferin is converted to oxyluciferin by the luciferase enzyme. Some of the energy released by this reaction is in the form of light. The reaction is highly efficient, meaning nearly all the energy put into the reaction is rapidly converted to light.

Lighting accounts for around 20 per cent of worldwide energy consumption, so replacing them with naturally bioluminescent plants would represent a significant cut to CO2 emissions. The researchers’ early efforts at the start of the project yielded plants that could glow for about 45 minutes, which they have since improved to 3.5 hours.

The light generated by one ten centimetre (four inch) watercress seedling is currently about one-thousandth of the amount needed to properly read by, but it was enough to illuminate the words on a page of John Milton's Paradise Lost.

The MIT team believes it can boost the light emitted, as well as the duration of light, by further optimising the concentration and release rates of the chemical components. For future versions of this technology, the team hopes to develop a way to paint or spray the nanoparticles onto plant leaves, which could make it possible to transform trees and other large plants into light sources. 

The researchers have also demonstrated that they can turn the light off by adding nanoparticles carrying a luciferase inhibitor. This could enable them to eventually create plants that shut off their light emission in response to environmental conditions such as sunlight, they say.

The full findings of the study were published in the American Chemical Society journal Nano Letters.

ORIGINAL: The Space Academy
December 18, 2017

viernes, 22 de diciembre de 2017

Electric eel inspires bio-friendly power source, what happens next may shock you

Could a device inspired by the electric eel offer a safer way to power medical implants?
Scientists are always on the lookout for safer, more natural ways to power devices that go into our bodies. After all, who really needs toxic battery elements and replacement surgery?

One organism that is pretty good at generating biocompatible power (for itself, at least) is the electric eel, and scientists have now used the high-voltage species as a blueprint for a promising new self-charging device that could one day power things like pacemakers, prosthetics and even augmented reality contact lenses.

Electric eels generate voltage through long stacks of thin cells that run end-on-end through their bodies. Called electrocytes, these cells create electricity by allowing sodium ions to rush into one end and potassium ions out the other, all at the same time. The voltage created by each cell is small, but together, the stacks within a single eel can generate as many as 600 V.

To recreate this effect, researchers from the University of Fribourg, the University of Michigan and the University of California San Diego turned to the difference in salinity between fresh and saltwater. They deposited hydrogel, ion-conducting blobs onto clear plastic sheets and separated them with ion-selective membranes.

Hundreds of blobs containing salt and freshwater were arranged in an alternating pattern. When the team had all these gel compartments make contact with one another, they were able to generate 100 V through what is known as reverse electrodialysis, where energy is generated through differing salt concentrations in the water.

While the eel triggers the simultaneous contact of its electrocytes using a neurotransmitter called acetylcholine as the command signal, the team achieved this by carefully working a special origami pattern – called a Miura-ori fold – into the plastic sheet. This meant that when pressure was applied to the sheet, it quickly snapped together and the cells shifted into exactly the right positions to create the electricity.

The device, which the team calls an artificial electric organ, isn't in the same ball park as an eel in terms of output, but the researchers do have some ideas around how to boost its efficiency. It points to the metabolic energy created by ion differences in the eel's stomach, or the mechanical muscle energy, as some of the possibilities, but does note that recreating these would be a major challenge.

"The electric organs in eels are incredibly sophisticated, they're far better at generating power than we are," Mayer said. "But the important thing for us was to replicate the basics of what's happening."

The research was published in the journal Nature. You can hear from Mayer in the video below.


 



Source: University of Fribourg, University of Michigan

ORIGINAL: NewAtlas
Nick Lavars
December 14th, 2017

jueves, 14 de diciembre de 2017

512-year-old Greenland shark may be the oldest living vertebrate on Earth

Images via Wikimedia and Julius Nelson
A recently identified 512-year-old Greenland shark may be the world’s oldest living vertebrate. Although scientists discovered the 18-foot fish in the North Atlantic months ago, its age was only recently revealed in a study published in the journal Science. Greenland sharks have the longest lifespan of any vertebrate animal, so it is perhaps unsurprising that the species would boast the oldest living individual vertebrate as well. Nonetheless, the fact that this creature may have been born as early as 1505 is remarkable. “It definitely tells us that this creature is extraordinary and it should be considered among the absolute oldest animals in the world,” said marine biologist Julius Nelson, whose research team studied the shark’s longevity.

Images via Wikimedia and Julius Nelson
To determine the shark’s age, scientists used a mathematical model that analyzes the lens and cornea of a shark’s eye and links size of the shark to its age. Greenland sharks grow at a rate of about 1 centimeter per year, which allowed scientists to estimate a particular shark’s age. The ability to measure the age of this mysterious shark is relatively new. “Fish biologists have tried to determine the age and longevity of Greenland sharks for decades, but without success,” said Steven Campana, a shark expert from the University of Iceland. “Given that this shark is the apex predator (king of the food chain) in Arctic waters, it is almost unbelievable that we didn’t know whether the shark lives for 20 years, or for 1,000 years.

Images via Wikimedia and Julius Nelson
The Greenland shark thrives in the frigid waters of the North Atlantic. Despite its considerable size, comparable to that of a great white shark, the Greenland shark is a scavenger and has never been observed hunting. Its diet primarily consists of fish, though remains of reindeer, polar bear, moose, and seals have been found in the species’ stomachs. To cope with life in deep water, the living tissues of a Greenland shark contains high levels of trimethylamine N-oxide, which makes the meat toxic. However, when the flesh is fermented, it can be consumed, as it is in Iceland as a dish known as Kæstur hákarl.

Images via Wikimedia and Julius Nelson

ORIGINAL: Inhabitat
by Greg Beach
2017/12/15

miércoles, 29 de noviembre de 2017

Semi-Synthetic Life Form Now Fully Armed and Operational

WILLIAM B. KIOSSES, PHD, THE SCRIPPS RESEARCH INSTITUTE

Could life have evolved differently? A germ with “unnatural” DNA letters suggests the answer is yes.

E. coli bacteria with an expanded genetic code could help manufacture new drugs.

Every living thing on Earth stores the instructions for life as DNA, using the four genetic bases A, G, C, and T.

All except one, that is.

In the San Diego laboratory of Floyd Romesberg—and at a startup he founded—grow bacteria with an expanded genetic code. They have two more letters, an “unnatural” pair he calls X and Y.

Romesberg, head of a laboratory at the Scripps Research Institute, first amended the genes of the bacterium E. Coli to harbor the new DNA components in 2014. Now, for the first time, the germs are using their expanded code to manufacture proteins with equally unusual components.

We wanted to prove the concept that every step of information storage and retrieval could be mediated by an unnatural base pair,” he says. “It’s not a curiosity anymore.

The bacterium is termed a “semi-synthetic” organism, since while it harbors an expanded alphabet, the rest of the cell hasn’t been changed. Even so, Peter Carr, a biological engineer at MIT’s Lincoln Laboratory, says it suggests that scientists are only beginning to learn how far life can be redesigned, a concept known as synthetic biology.

We don’t know what the ultimate limits are on our ability to engineer living systems, and this paper helps show we’re not limited to four bases,” he says. “I think it’s pretty impressive.

Humankind has been disappointed in the quest to find life on Mars or Jupiter. Yet the alien germs growing in San Diego already hint that our Earth biology isn’t the only one possible. “It suggests that if life did evolve elsewhere, it might have done so using very different molecules or different forces,” says Romesberg. “Life as we know it is may not be the only solution, and may not be the best one.”

Romesberg’s efforts to lay a genetic cuckoo’s egg inside bacteria started 15 years ago. After creating a candidate pair of new genetic letters, the first step was to add them to a bacterium’s genome and show it could use them to store information. That is, could the organism abide by the unnatural DNA and also copy it faithfully as it divided?

The answer, his lab showed in 2014, was yes. But early versions of the bacteria were none too healthy. They died or got rid of the extra letters in their DNA, which are stored in a mini-chromosome called a plasmid. In Romesberg’s words, his creations “lacked the fortitude of real life.”

By this year, the team had devised a more stable bacterium. But it wasn’t enough to endow the germ with a partly alien code—it needed to use that code to make a partly alien protein. That’s what Romesberg’s team, reporting today in the journal Nature, says it has done.

Using the extra letters, they instructed bacteria to manufacture a glowing green protein that has in it a single unnatural amino acid. “We stored information, and now we retrieved it. The next thing is to use it. We are going to do things no one else can,” says Romesberg.

The practical payoff of an organism with a bigger genetic alphabet is that it has a bigger vocabulary—it can assemble proteins with components not normally found in nature. That could solve some tricky problems in medicinal chemistry, which is the art of shaping molecules so they do exactly what’s wanted in the body, and nothing that isn’t.

Pursuing such aims is a startup Romesberg founded, named Synthorx. It has raised $16 million so far and hopes to turn the science into new drugs. One project aims to make a new version of interleukin-2, an anticancer drug with some nasty side effects. Maybe the semi-synthetic germs could fix that by swapping in some unusual components at key points. “This company needs to get out of the lab and into the clinic,” says its newly installed CEO, Laura Shawver.

Carr says an expanded genetic code could have implications beyond providing a shortcut for programming new properties into proteins. He also thinks the new letters might be used to hide information in ways other biologists couldn’t easily see. That could be useful in concealing intellectual property or, perhaps, to disguise a bioweapon.

Synthorx Inc 2015


Credit: William B. Kiosses, PhD, The Scripps Research Institute


November 29, 2017
William B. Kiosses, PhD, The Scripps Research Institute

viernes, 10 de noviembre de 2017

The Fungus That Turns Ants Into Zombies Is More Diabolical Than We Realized

A dead spiny ant with fungal spores erupting out of its head. (Image: David Hughes/Penn State University)

Carpenter ants of the Brazilian rain forest have it rough. When one of these insects gets infected by a certain fungus, it turns into a so-called “zombie ant” and is no longer in control of its actions. Manipulated by the parasite, an infected ant will leave the cozy confines of its arboreal home and head to the forest floor—an area more suitable for fungal growth. After parking itself on the underside of a leaf, the zombified ant anchors itself into place by chomping down onto the foliage. This marks the victim’s final act. From here, the fungus continues to grow and fester inside the ant’s body, eventually piercing through the ant’s head and releasing its fungal spores. This entire process, from start to finish, can take upwards of ten agonizing days.“We found that a high percentage of the cells in a host were fungal cells,” said Hughes. “In essence, these manipulated animals were a fungus in ants’ clothing.

We’ve known about zombie ants for quite some time, but scientists have struggled to understand how the parasitic fungus, O. unilateralis (pronounced yu-ni-lat-er-al-iss), performs its puppeteering duties. This fungus is often referred to as a “brain parasite,” but new research published this week in Proceedings of the National Academy of Sciences shows that the brains of these zombie ants are left intact by the parasite, and that O. unilateralis is able to control the actions of its host by infiltrating and surrounding muscle fibers throughout the ant’s body. In effect, it’s converting an infected ant into an externalized version of itself. Zombie ants thus become part insect, part fungus. Awful, right?

To make this discovery, the scientist who first uncovered the zombie ant fungus, David Hughes from Penn State, launched a multidisciplinary effort that involved an international team of entomologists, geneticists, computer scientists, and microbiologists. The point of the study was to look at the cellular interactions between O. unilateralis and the carpenter ant host Camponotus castaneus during a critical stage of the parasite’s life cycle—that phase when the ant anchors itself onto the bottom of leaf with its powerful mandibles.
Ants infected with late stage O. unilateralis infection. (Image: David Hughes/PLOS ONE)

The fungus is known to secrete tissue-specific metabolites and cause changes in host gene expression as well as atrophy in the mandible muscles of its ant host,” said lead author Maridel Fredericksen, a doctoral candidate at the University of Basel Zoological Institute, Switzerland, in a statement. “The altered host behavior is an extended phenotype of the microbial parasite’s genes being expressed through the body of its host. But it’s unknown how the fungus coordinates these effects to manipulate the host’s behavior.

By referring to the parasite’s “extended phenotype,” Fredericksen is referring to the way that O. unilateralis is able to hijack an external entity, in this case the carpenter ant, and make it a literal extension of its physical self.

For the study, the researchers infected carpenter ants with either O. unilateralis or a less threatening, non-zombifying fungal pathogen known as Beauveria bassiana, which served as the control. By comparing the two different fungi, the researchers were able to discern the specific physiological effects of O. unilateralis on the ants.

Using electron microscopes, the researchers created 3D visualizations to determine location, abundance, and activity of the fungi inside the bodies of the ants. Slices of tissue were taken at a resolution of 50 nanometers, which were captured using a machine that could repeat the slicing and imaging process at a rate of 2,000 times over a 24-hour period. To parse this hideous amount of data, the researchers turned to artificial intelligence, whereby a machine-learning algorithm was taught to differentiate between fungal and ant cells. This allowed the researchers to determine how much of the insect was still ant, and how much of it was converted into the externalized fungus.
3D reconstruction of an ant mandible adductor muscle (red) surrounded by a network of fungal cells (yellow). (Image: Hughes Laboratory/Penn State)


The results were truly disturbing. Cells of O. unilateralis had proliferated throughout the entire ant’s body, from the head and thorax right down to the abdomen and legs. What’s more, these fungal cells were all interconnected, creating a kind of Borg-like, collective biological network that controlled the ants’ behavior.

We found that a high percentage of the cells in a host were fungal cells,” said Hughes in a statement. “In essence, these manipulated animals were a fungus in ants’ clothing.

But most surprising of all, the fungus hadn’t infiltrated the carpenter ants’ brains.

Normally in animals, behavior is controlled by the brain sending signals to the muscles, but our results suggest that the parasite is controlling host behavior peripherally,” explained Hughes. “Almost like a puppeteer pulls the strings to make a marionette move, the fungus controls the ant’s muscles to manipulate the host’s legs and mandibles.

As to how the fungus is able to navigate the ant towards the leaf, however, is still largely unknown. And in fact, that the fungus leaves the brain alone may provide a clue. Previous work showed that the fungus may be chemically altering the ants’ brains, leading Hughes’ team to speculate that the fungus needs to the ant to survive long enough to perform its final leaf-biting behavior. It’s also possible, however, that the fungus needs to leverage some of that existing ant brain power (and attendant sensorial capabilities) to “steer” the ant around the forest floor. Future research will be required to turn these theories into something more substantial.

This is an excellent example of how interdisciplinary research can drive our knowledge forward,” Charissa de Bekker, an entomologist at the University of Central Florida not affiliated with the new study, told Gizmodo. “The researchers used cutting-edge techniques to finally confirm something that we thought to be true but weren’t sure about: that the fungus O. unilateralis does not invade or damage the brain.

de Bekker says this work confirms that something much more intricate is going on, and that the fungus might be controlling the ant by secreting compounds that can work as neuromodulators. Data gleaned from the fungal genome points to this conclusion as well.

This means the fungus might produce a wealth of bioactive compounds that could be of interest in terms of novel drug discovery,” said de Bekker. “I am, thus, very excited about this work!

An authority on the zombie ant fungus herself, de Bekker also released new research this week. Her new study, published in PLOS One and co-authored with David Hughes and others, looked into the molecular clock of the Ophiocordyceps kimflemingiae fungus (a recently named species of the O. unilateralis complex) to see if the daily rhythms, and thus biological clocks, are an important aspect of the parasite-host interactions studied by biologists.

In addition to confirming that the fungus indeed has a molecular clock, we found that this results in the daily oscillation of certain genes,” de Bekker told Gizmodo. “While some of them are active during the day-time, others are active during the night-time. Interestingly, we found that the fungus especially activates genes encoding for secreted proteins during the night-time. These are the compounds that possibly interact with the host’s brain! The fungus, therefore, does not just release bioactive compounds to manipulate behavior, but there seems to be a precise timing to it as well.

There’s clearly still lots to learn about this insidious parasite and how it hijacks its insectoid hosts, but as these recent studies attest, we’re getting steadier closer to the answer—one that’s clearly disturbing in nature.

[Proceedings of the National Academy of Sciences, PLOS One
ORIGINAL: Gizmodo
By George Dvorsky