Category Archives: water

Tanzanian research into nanotechnology-enabled water filters

Inexpensive 99.9999…% filtration of metals, bacteria, and viruses from water is an accomplishment worthy of a prize as the UK’s Royal Academy of Engineering noted by awarding its first ever International Innovation Prize of £25,000 ($38,348 [USD?]) to Askwar Hilonga, a Tanzanian academic and entrepreneur. A June 11, 2015 article by Sibusiso Tshabalala for Quartz.com describes the water situation in Tanzania and Hilonga’s accomplishment (Note: Links have been removed),

Despite Tanzania’s proximity to three major lakes almost half of it’s population cannot access potable water.

Groundwater is often the alternative, but the supply is not always clean. Mining waste (pdf, pg 410) and toxic drainage systems easily leak into fresh groundwater, leaving the water contaminated.

Enter Askwar Hilonga: a 38-year old chemical engineer PhD and entrepreneur. With 33 academic journal articles on nanotechnology to his name, Hilonga aims to solve Tanzania’s water contamination problems by using nanotechnology to customize water filters.

There are other filters available (according to Tshabalala’s article) but Hilonga’s has a unique characteristic in addition to being highly efficient and inexpensive,

Purifying water using nanotechnology is hardly a new thing. In 2010, researchers at the Yi Cui Lab at Stanford University developed a synthetic “nanoscanvenger” made out of two silver layers that enable nanoparticles to disinfect water from contaminating bacteria.

What makes Hilonga’s water filter different from the Stanford-developed “nanoscavenger”, or the popular LifeStraw developed by the Swiss-based health innovation company Vestergaard 10 years ago?

“It is customized. The filter can be tailored for specific individual, household and communal use,” says Hilonga.

A June 2, 2015 news item about the award on BBC (British Broadcasting Corporation) online describes how the filter works,

The sand-based water filter that cleans contaminated drinking water using nanotechnology has already been trademarked.

“I put water through sand to trap debris and bacteria,” Mr Hilonga told the BBC’s Newsday programme about the filter.

“But sand cannot remove contaminants like fluoride and other heavy metals so I put them through nano materials to remove chemical contaminants.”

Hilonga describes the filter in a little more detail in his May 30, 2014 video submitted for for the UK Royal Academy of Engineering’s prize (Africa Prize for Engineering Innovation)

Finalists for the prize (there were four) received a six month mentorship which included help to develop the technology further and with business plans. Hilonga has already enabled 23 entrepreneurs to develop nanofilter businesses, according to the Tshabalala article,

Through the Gongali Model Company, a university spin-off company which he co-founded, Hilonga has already enabled 23 entrepreneurs in Karatu to set up their businesses with the filters, and local schools to provide their learners with clean drinking water.

With this prize money, Hilonga will be able to lower the price of his filter ($130 [USD?) according to the BBC news item.

Congratulations to Dr. Hilonga and his team! For anyone curious about the Gongali Model Company, you can go here.

Water-fueled computer

A computer fueled by water? A fascinating concept as described in a June 9, 2015 news item on ScienceDaily,

Computers and water typically don’t mix, but in Manu Prakash’s lab, the two are one and the same. Prakash, an assistant professor of bioengineering at Stanford, and his students have built a synchronous computer that operates using the unique physics of moving water droplets.

A June 8, 2015 Stanford University news release by Bjorn Carey, which originated the news item, details the ideas (new applications) and research (open access to the tools for creating water droplet-fueled circuits) further,

The computer is nearly a decade in the making, incubated from an idea that struck Prakash when he was a graduate student. The work combines his expertise in manipulating droplet fluid dynamics with a fundamental element of computer science – an operating clock.

“In this work, we finally demonstrate a synchronous, universal droplet logic and control,” Prakash said.

Because of its universal nature, the droplet computer can theoretically perform any operation that a conventional electronic computer can crunch, although at significantly slower rates. Prakash and his colleagues, however, have a more ambitious application in mind.

“We already have digital computers to process information. Our goal is not to compete with electronic computers or to operate word processors on this,” Prakash said. “Our goal is to build a completely new class of computers that can precisely control and manipulate physical matter. Imagine if when you run a set of computations that not only information is processed but physical matter is algorithmically manipulated as well. We have just made this possible at the mesoscale.”

The ability to precisely control droplets using fluidic computation could have a number of applications in high-throughput biology and chemistry, and possibly new applications in scalable digital manufacturing.

The crucial clock

For nearly a decade since he was in graduate school, an idea has been nagging at Prakash: What if he could use little droplets as bits of information and utilize the precise movement of those drops to process both information and physical materials simultaneously. Eventually, Prakash decided to build a rotating magnetic field that could act as clock to synchronize all the droplets. The idea showed promise, and in the early stages of the project, Prakash recruited a graduate student, Georgios “Yorgos” Katsikis, who is the first author on the paper.

Computer clocks are responsible for nearly every modern convenience. Smartphones, DVRs, airplanes, the Internet – without a clock, none of these could operate without frequent and serious complications. Nearly every computer program requires several simultaneous operations, each conducted in a perfect step-by-step manner. A clock makes sure that these operations start and stop at the same times, thus ensuring that the information synchronizes.

The results are dire if a clock isn’t present. It’s like soldiers marching in formation: If one person falls dramatically out of time, it won’t be long before the whole group falls apart. The same is true if multiple simultaneous computer operations run without a clock to synchronize them, Prakash explained.

“The reason computers work so precisely is that every operation happens synchronously; it’s what made digital logic so powerful in the first place,” Prakash said.

A magnetic clock

Developing a clock for a fluid-based computer required some creative thinking. It needed to be easy to manipulate, and also able to influence multiple droplets at a time. The system needed to be scalable so that in the future, a large number of droplets could communicate amongst each other without skipping a beat. Prakash realized that a rotating magnetic field might do the trick.

Katsikis and Prakash built arrays of tiny iron bars on glass slides that look something like a Pac-Man maze. They laid a blank glass slide on top and sandwiched a layer of oil in between. Then they carefully injected into the mix individual water droplets that had been infused with tiny magnetic nanoparticles.

Next, they turned on the magnetic field. Every time the field flips, the polarity of the bars reverses, drawing the magnetized droplets in a new, predetermined direction, like slot cars on a track. Every rotation of the field counts as one clock cycle, like a second hand making a full circle on a clock face, and every drop marches exactly one step forward with each cycle.

A camera records the interactions between individual droplets, allowing observation of computation as it occurs in real time. The presence or absence of a droplet represents the 1s and 0s of binary code, and the clock ensures that all the droplets move in perfect synchrony, and thus the system can run virtually forever without any errors.

“Following these rules, we’ve demonstrated that we can make all the universal logic gates used in electronics, simply by changing the layout of the bars on the chip,” said Katsikis. “The actual design space in our platform is incredibly rich. Give us any Boolean logic circuit in the world, and we can build it with these little magnetic droplets moving around.”

The current paper describes the fundamental operating regime of the system and demonstrates building blocks for synchronous logic gates, feedback and cascadability – hallmarks of scalable computation. A simple-state machine including 1-bit memory storage (known as “flip-flop”) is also demonstrated using the above basic building blocks.

A new way to manipulate matter

The current chips are about half the size of a postage stamp, and the droplets are smaller than poppy seeds, but Katsikis said that the physics of the system suggests it can be made even smaller. Combined with the fact that the magnetic field can control millions of droplets simultaneously, this makes the system exceptionally scalable.

“We can keep making it smaller and smaller so that it can do more operations per time, so that it can work with smaller droplet sizes and do more number of operations on a chip,” said graduate student and co-author Jim Cybulski. “That lends itself very well to a variety of applications.”

Prakash said the most immediate application might involve turning the computer into a high-throughput chemistry and biology laboratory. Instead of running reactions in bulk test tubes, each droplet can carry some chemicals and become its own test tube, and the droplet computer offers unprecedented control over these interactions.

From the perspective of basic science, part of why the work is so exciting, Prakash said, is that it opens up a new way of thinking of computation in the physical world. Although the physics of computation has been previously applied to understand the limits of computation, the physical aspects of bits of information has never been exploited as a new way to manipulate matter at the mesoscale (10 microns to 1 millimeter).

Because the system is extremely robust and the team has uncovered universal design rules, Prakash plans to make a design tool for these droplet circuits available to the public. Any group of people can now cobble together the basic logic blocks and make any complex droplet circuit they desire.

“We’re very interested in engaging anybody and everybody who wants to play, to enable everyone to design new circuits based on building blocks we describe in this paper or discover new blocks. Right now, anyone can put these circuits together to form a complex droplet processor with no external control – something that was a very difficult challenge previously,” Prakash said.

“If you look back at big advances in society, computation takes a special place. We are trying to bring the same kind of exponential scale up because of computation we saw in the digital world into the physical world.”

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

Synchronous universal droplet logic and control by Georgios Katsikis, James S. Cybulski, & Manu Prakash. Nature Physics (2015) doi:10.1038/nphys3341 Published online 08 June 2015

This paper is behind a paywall.

For anyone interested in creating a water-fueled circuit, you could try contacting Manu Prakash, Bioengineering: manup@stanford.edu

Tiny Science. Big Impacts. Cool Videos. Winners announced and new call for submissions.

The US National Nanotechnology Coordination Office (NNCO) on behalf of the National Nanotechnology Initiative (NNI) has announced the winners for its first, ‘Tiny Science. Big Impacts. Cool Videos.’ contest in a June 5, 2015 news item on Nanowerk,

The National Nanotechnology Coordination Office (NNCO) is pleased to announce the winners of the first Tiny Science. Big Impacts. Cool Videos. nanotechnology video contest for students. Abelardo Colon and Jennifer Gill from the University of Puerto Rico, Rio Piedras, Nanoscience and Nanotechnology Research Lab won the top honors for their video entitled Chlorination-less. The video explains a new method for disinfecting drinking water using a nanodiamond powder. This nanotechnology-enabled method can kill bacteria, is biocompatible, and is reusable, making it a good alternative to traditional chlorination. Congratulations Abelardo and Jennifer!

A June 5, 2015 NNCO news release on EurekAlert, which originated the news item, describes the judging process and plans for the video,

Videos submitted by students from universities across the United States and U.S. territories, were posted on NanoTube, the official National Nanotechnology Initiative (NNI) YouTube channel, for public voting. The winning video was chosen by representatives from the NNI member agencies from the top two videos identified by public voting. This video will be featured on Nano.gov for the next month. For more information on the Tiny Science. Big Impacts. Cool Videos. contest rules and judges, visit the student video contest page on Nano.gov.

Here is Chlorination-less,

From the Chlorination-less YouTube page,

Published on Apr 28, 2015

“Access to clean water is a major international issue that must not be ignored. Our research is finding a new method for the disinfection of drinking water. Even so, chlorination is the most common treatment for the disinfection of drinking water, but has a lot of disadvantages. Disinfectant by-products (DBP’s) produced by the chlorine disinfection process can cause health problems such as cancer to humans that drink water or inhale vapor. Also some bacteria are able to adapt to this chemical treatment. This is why we are proposing a physical treatment using Ultra Dispersed Diamond (UDD) for the disinfection of drinking water. The UDD is a nanodiamond powder, which has bactericidal properties and is biocompatible. After applying the UDD material to the contaminated water we have promising results. There was a reduction of fecal E. coli colonies as time passed and the density of the material increases. This process will be healthier, cheaper, and more environmentally friendly since it is reusable.”

University of Puerto Rico , Rio Piedras Campus

As for the next contest, that begins July 1, 2015 (from the Tiny Science. Big Impacts. Cool Videos. contest webpage), Note: Links have been removed,

Graduate students, will your research lead to nanotechnologies that impact our daily lives? Submit videos that demonstrate how your nanotechnology research will bring solutions to real-world problems. …

Email submissions information to NNCOvideos@gmail.com and include:

Name and affiliation:

Submissions will be accepted from teams and from individuals. A lead contact person must be designated for team submissions. The order in which names are listed in the submission is the order in which they will appear on the NNI public voting page, the NNI YouTube channel, and on Nano.gov.

Description (150 words or less): Explain your research, use plain language and avoid jargon. Concentrate on what problem your research will help to solve.

Title of uploaded video: It should be the same as the video file name you upload using Google Drive.

Releases for people appearing in the video: A release form is available here; print, collect signatures, scan, and email us electronic copies.

Laboratory website: Include link to the lab where you work, if available

Funding source: Include funding agency, program manager, and award/grant number, if possible

Upload videos using Google Drive to NNCOvideos@gmail.com:

Video Criteria

Video length should be between 2.5 and 3 minutes.

Maximum file size is 2 GB

File type must be H.264, MP4, FLV, or MOV

Use a camera that can shoot videos at least 1280 x 720 pixels in size.

Save video file as the title listed on emailed submission information

Remember to avoid jargon while explaining your research

Collect signed releases (available here) from any recognizable individual appearing in your video

You are allowed to have others (e.g., film students) produce the video. If you put your own video together make sure everything is well lit. Fluorescent overhead lights aren’t the best, try to use natural or focused light if you can. Pay attention to sound quality; use a good microphone and listen for background noise. Watch for too much clutter in the background of your scenes, this can be distracting.

Timeline:

NNCO will begin accepting submissions for the Tiny Science. Big Impacts. Cool Videos. video contest on July 1, 2015.

The Tiny Science. Big Impacts. Cool Videos. video contest will close on November 12, 2015.

The deadline for submissions is 12:00 p.m. PST November 12, 2015.

Semifinalist judging for videos submitted before 12:00 p.m. PST on November 12, 2015 takes place from 12:00 p.m. November 19, 2015 to 12:00 p.m. November 30, 2015.

The winning video will be announced on December 15, 2015.

Good luck!

Computer modeling of engineered nanoparticles in surface water, the NanoDUFLOW model

A June 4, 2015 news item on phys.org features research that could be very helpful in understanding the impact that engineered nanoparticles (ENP) have on the water in our environment,

Researchers of Wageningen University (Netherlands) provide the world’s first spatiotemporally explicit model that simulates the behaviour and fate of engineered nanoparticles (ENPs) in surface waters. Wageningen researcher Bart Koelmans: “This is important in order to assure safe nanotechnology. We do need to have an assessment of the risks of ENPs to man and the environment.”

Nanotechnology is developing fast, with the fast growing emission of less than 100 nm engineered nanoparticles as a consequence. ENPs are hard to measure in the environment so that exposure assessments have to rely on modelling. Previous models could only predict average background concentrations on a continental or national scale.

A June 3, 2015 Wageningen University press release, which originated the news item, describes the computer model,

The new NanoDUFLOW model however, developed by Joris Quik, Jeroen de Klein and Bart Koelmans and recently described in Water Research magazine, is capable of simulating the concentrations of ENPs, and their homo- and heteroaggregates in space and time, for any hydrological flow regime of a river. Under the hood of NanoDUFLOW is an ‘engine’ that calculates all relevant interactions among 35 types of particles including the ENPs, and that decides upon aggregation, settling or prolonged flow in the river. The rate of these interactions depends on the flow conditions in the river, which are calculated in the hydrology module of NanoDUFLOW. This module can be set to match the channel structure of any catchment as defined by the user, allowing for a great flexibility.

Development of the model

Development of the model took a long and winding road. ENPs are emerging chemicals with unique properties, which implies that some new process descriptions needed to be developed. One of the main parameters in this new type of models is the attachment efficiency. The attachment efficiency is the chance that two particles stay together when they collide, a chance that depends on the nature of the colliding particles and the chemistry of the water. A smart calculation method needed to be developed that enabled the estimation of the attachment efficiency from laboratory experiments with ENPs and natural particles and waters collected in the field.

Using NanoDUFLOW for the risk assessment of nanomaterials

In order to assure safe nanotechnology, society calls for an assessment of the risks of ENPs to man and the environment. A risk assessment for ENPs requires an assessment of ENP exposure, and of the effects caused by ENPs, which then can be compared in a risk characterisation. Whereas previous screening-level models still may be first choice for lower tiers in the risk assessment, NanoDUFLOW is believed to be useful for higher tiers of the risk assessment, where site specific risks need to be addressed. Simulations with NanoDUFLOW showed the occurrence of clear ENP contamination ‘hot spots’ in the water column and in sediments. Furthermore, NanoDUFLOW was capable of simulating the speciation of ENPs over different size fractions. This speciation defines the ecotoxicologically relevant fractions of ENPs, for a variety of species traits. Also in this respect NanoDUFLOW will add to refining the risk assessment for ENPs.

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

Spatially explicit fate modelling of nanomaterials in natural waters by Joris T. K. Quika, Jeroen J.M. de Klein, & Albert A. Koelmans. Water Research Volume 80, 1 September 2015, Pages 200–208  doi:10.1016/j.watres.2015.05.025

This paper is behind a paywall.

A GEnIuS approach to oil spill remediation at 18th European Forum on Eco-innovation

In light of recent local events (an oil spill in Vancouver’s [Canada] English Bay, a popular local beach [more details in my April 16, 2015 post]), it seems appropriate to mention a environmentally friendly solution to mopping up oil spills (oil spill remediation). A May 21, 2015 news item on Azonano features a presentation on the topic at hand (Note: A link has been removed),

Directa Plus at 18th European Forum on Eco-innovation to present GEnIuS, the innovative project that leads to the creation of a graphene-based product able to remove hydrocarbons from polluted water and soil.

The Forum untitled “Boosting competitiveness and innovation” is being held by the European Commission on 20th and 21st of May in Barcelona. The main purpose of this event is presenting the last developments in the eco-innovation field: an important moment where emerging and cutting-edge innovators will get in contact with new promising solutions under political, financial and technological point of view.

Directa Plus research has driven to the creation of an ecologic, innovative and highly effective oil-adsorbent, characterized by unique performances in oil adsorbency, and at the same time absence of toxicity and flammability, and the possibility to recover oil.

The creation of this graphene-based oil-adsorbent product, commercialized as Grafysorber, has been promoted by GEnIuS project and already approved by the Italian Ministry of Enviroment to be used in occasion of oil spills clean-up activities.

Giulio Cesareo, Directa Plus President and CEO, commented:

“Grafysorber embodies the nano-carbon paradox -in fact, with a nano-carbon material we are able to cut down part of damages caused by hydrocarbons, derived from carbon itself.

“Moreover, our product, once exhausted after depuration of water, finishes positively its life cycle inside the asphalt and bitumen, introducing new properties as thermal conductivity and mechanical reinforcement. I believe that every company is obliged to work following a sustainable approach to guarantee a balanced use of resources and their reuse, where possible.”

I have mentioned a Romanian project employing Directa Plus’s solution, Grafysorber in a December 30, 2014 post. At the time, the product name was called Graphene Plus and Grafysorber was a constituent of the product.

You can find more information about Graphene Eco Innovative Sorbent (GENIUS) here and about Directa Plus here. The company is located in Italy.

One final bit about oil spills and remediation, the Deepwater Horizon/Gulf/BP oil spill has spawned, amongst many others, a paper from the University of Georgia (US) noting that we don’t know that much about the dispersants used to clean up, from a May 14, 2015 University of Georgia news release on EurekAlert,

New commentary in Nature Reviews Microbiology by Samantha Joye of the University of Georgia and her colleagues argues for further in-depth assessments of the impacts of dispersants on microorganisms to guide their use in response to future oil spills.

Chemical dispersants are widely used in emergency responses to oil spills in marine environments as a means of stimulating microbial degradation of oil. After the Deepwater Horizon spill in 2010, dispersants were applied to the sea surface and deep waters of the Gulf of Mexico, the latter of which was unprecedented. Dispersants were used as a first line of defense even though little is known about how they affect microbial communities or the biodegradation activities they are intended to spur.

The researchers document historical context for the use of dispersants, their approval by the Environmental Protection Agency and the uncertainty about whether they stimulate or in fact inhibit the microbial degradation of oil in marine ecosystems.

One challenge of testing the toxicity from the use of dispersants on the broader ecosystem is the complex microbial communities of the different habitats represented in a large marine environment, such as the Gulf of Mexico. Development of model microbial communities and type species that reflect the composition of surface water, deep water, deep-sea sediments, beach sediments and marsh sediments is needed to evaluate the toxicity effects of dispersants.

“The bottom line is that we do not truly understand the full range of impacts that dispersants have on microbial communities, and we must have this knowledge in hand before the next marine oil spill occurs to support the decision-making process by the response community,” Joye said.

I hope the Canadians who are overseeing our waterways are taking note.

Nanopollution of marine life

Concerns are being raised about nanosunscreens and nanotechnology-enabled marine paints and their effect on marine life, specifically, sea urchins. From a May 13, 2015 news item on Nanowerk (Note: A link has been removed),

Nanomaterials commonly used in sunscreens and boat-bottom paints are making sea urchin embryos more vulnerable to toxins, according to a study from the University of California, Davis [UC Davis]. The authors said this could pose a risk to coastal, marine and freshwater environments.

The study, published in the journal Environmental Science and Technology (“Copper Oxide and Zinc Oxide Nanomaterials Act as Inhibitors of Multidrug Resistance Transport in Sea Urchin Embryos: Their Role as Chemosensitizers”), is the first to show that the nanomaterials work as chemosensitizers. In cancer treatments, a chemosensitizer makes tumor cells more sensitive to the effects of chemotherapy.

Similarly, nanozinc and nanocopper made developing sea urchin embryos more sensitive to other chemicals, blocking transporters that would otherwise defend them by pumping toxins out of cells.

A May 12, 2015 UC Davis news release, which originated the news item, includes some cautions,

Nanozinc oxide is used as an additive in cosmetics such as sunscreens, toothpastes and beauty products. Nanocopper oxide is often used for electronics and technology, but also for antifouling paints, which prevent things like barnacles and mussels from attaching to boats.

“At low levels, both of these nanomaterials are nontoxic,” said co-author Gary Cherr, professor and interim director of the UC Davis Bodega Marine Laboratory, and an affiliate of the UC Davis Coastal Marine Sciences Institute. “However, for sea urchins in sensitive life stages, they disrupt the main defense mechanism that would otherwise protect them from environmental toxins.”

Science for safe design

Nanomaterials are tiny chemical substances measured in nanometers, which are about 100,000 times smaller than the diameter of a human hair. Nano-sized particles can enter the body through the skin, ingestion, or inhalation. They are being rapidly introduced across the fields of electronics, medicine and technology, where they are being used to make energy efficient batteries, clean up oil spills, and fight cancer, among many other uses. However, relatively little is known about nanomaterials with respect to the environment and health.

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

Copper Oxide and Zinc Oxide Nanomaterials Act as Inhibitors of Multidrug Resistance Transport in Sea Urchin Embryos: Their Role as Chemosensitizers by Bing Wu, Cristina Torres-Duarte, Bryan J. Cole, and Gary N. Cherr. Environ. Sci. Technol., 2015, 49 (9), pp 5760–5770 DOI: 10.1021/acs.est.5b00345 Publication Date (Web): April 7, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

While this research into nanoparticles as chemosensitizers is, according to UC Davis, the first of its kind, the concern over nanosunscreens and marine waters has been gaining traction over the last few years. For example, there’s  research featured in a June 10, 2013 article by Roberta Kwok for the University of Washington’s ‘Conservation This Week’ magazine,

Sunscreen offers protection from UV rays, reduces the risk of skin cancer, and even slows down signs of aging. Unfortunately, researchers have found that sunscreen also pollutes the ocean.

Although people have been using these products for decades, “the effect of sunscreens, as a source of introduced chemicals to the coastal marine system, has not yet been addressed,” a research team writes in PLOS ONE. Sunscreens contain chemicals not only for UV protection, but also for coloring, fragrance, and texture. And beaches are becoming ever-more-popular vacation spots; for example, nearly 10 million tourists visited Majorca Island in the Mediterranean Sea in 2010.

Here’s a link to the 2013 PLOS ONE paper,

Sunscreen Products as Emerging Pollutants to Coastal Waters by Antonio Tovar-Sánchez, David Sánchez-Quiles, Gotzon Basterretxea, Juan L. Benedé, Alberto Chisvert, Amparo Salvador, Ignacio Moreno-Garrido, and Julián Blasco. PLOS ONE DOI: 10.1371/journal.pone.0065451 Published: June 5, 2013

This is an open access journal.

Sealing graphene’s defects to make a better filtration device

Making a graphene filter that allows water to pass through while screening out salt and/or noxious materials has been more challenging than one might think. According to a May 7, 2015 news item on Nanowerk, graphene filters can be ‘leaky’,

For faster, longer-lasting water filters, some scientists are looking to graphene –thin, strong sheets of carbon — to serve as ultrathin membranes, filtering out contaminants to quickly purify high volumes of water.

Graphene’s unique properties make it a potentially ideal membrane for water filtration or desalination. But there’s been one main drawback to its wider use: Making membranes in one-atom-thick layers of graphene is a meticulous process that can tear the thin material — creating defects through which contaminants can leak.

Now engineers at MIT [Massachusetts Institute of Technology], Oak Ridge National Laboratory, and King Fahd University of Petroleum and Minerals (KFUPM) have devised a process to repair these leaks, filling cracks and plugging holes using a combination of chemical deposition and polymerization techniques. The team then used a process it developed previously to create tiny, uniform pores in the material, small enough to allow only water to pass through.

A May 8, 2015 MIT news release (also on EurkeAlert), which originated the news item, expands on the theme,

Combining these two techniques, the researchers were able to engineer a relatively large defect-free graphene membrane — about the size of a penny. The membrane’s size is significant: To be exploited as a filtration membrane, graphene would have to be manufactured at a scale of centimeters, or larger.

In experiments, the researchers pumped water through a graphene membrane treated with both defect-sealing and pore-producing processes, and found that water flowed through at rates comparable to current desalination membranes. The graphene was able to filter out most large-molecule contaminants, such as magnesium sulfate and dextran.

Rohit Karnik, an associate professor of mechanical engineering at MIT, says the group’s results, published in the journal Nano Letters, represent the first success in plugging graphene’s leaks.

“We’ve been able to seal defects, at least on the lab scale, to realize molecular filtration across a macroscopic area of graphene, which has not been possible before,” Karnik says. “If we have better process control, maybe in the future we don’t even need defect sealing. But I think it’s very unlikely that we’ll ever have perfect graphene — there will always be some need to control leakages. These two [techniques] are examples which enable filtration.”

Sean O’Hern, a former graduate research assistant at MIT, is the paper’s first author. Other contributors include MIT graduate student Doojoon Jang, former graduate student Suman Bose, and Professor Jing Kong.

A delicate transfer

“The current types of membranes that can produce freshwater from saltwater are fairly thick, on the order of 200 nanometers,” O’Hern says. “The benefit of a graphene membrane is, instead of being hundreds of nanometers thick, we’re on the order of three angstroms — 600 times thinner than existing membranes. This enables you to have a higher flow rate over the same area.”

O’Hern and Karnik have been investigating graphene’s potential as a filtration membrane for the past several years. In 2009, the group began fabricating membranes from graphene grown on copper — a metal that supports the growth of graphene across relatively large areas. However, copper is impermeable, requiring the group to transfer the graphene to a porous substrate following fabrication.

However, O’Hern noticed that this transfer process would create tears in graphene. What’s more, he observed intrinsic defects created during the growth process, resulting perhaps from impurities in the original material.

Plugging graphene’s leaks

To plug graphene’s leaks, the team came up with a technique to first tackle the smaller intrinsic defects, then the larger transfer-induced defects. For the intrinsic defects, the researchers used a process called “atomic layer deposition,” placing the graphene membrane in a vacuum chamber, then pulsing in a hafnium-containing chemical that does not normally interact with graphene. However, if the chemical comes in contact with a small opening in graphene, it will tend to stick to that opening, attracted by the area’s higher surface energy.

The team applied several rounds of atomic layer deposition, finding that the deposited hafnium oxide successfully filled in graphene’s nanometer-scale intrinsic defects. However, O’Hern realized that using the same process to fill in much larger holes and tears — on the order of hundreds of nanometers — would require too much time.

Instead, he and his colleagues came up with a second technique to fill in larger defects, using a process called “interfacial polymerization” that is often employed in membrane synthesis. After they filled in graphene’s intrinsic defects, the researchers submerged the membrane at the interface of two solutions: a water bath and an organic solvent that, like oil, does not mix with water.

In the two solutions, the researchers dissolved two different molecules that can react to form nylon. Once O’Hern placed the graphene membrane at the interface of the two solutions, he observed that nylon plugs formed only in tears and holes — regions where the two molecules could come in contact because of tears in the otherwise impermeable graphene — effectively sealing the remaining defects.

Using a technique they developed last year, the researchers then etched tiny, uniform holes in graphene — small enough to let water molecules through, but not larger contaminants. In experiments, the group tested the membrane with water containing several different molecules, including salt, and found that the membrane rejected up to 90 percent of larger molecules. However, it let salt through at a faster rate than water.

The preliminary tests suggest that graphene may be a viable alternative to existing filtration membranes, although Karnik says techniques to seal its defects and control its permeability will need further improvements.

“Water desalination and nanofiltration are big applications where, if things work out and this technology withstands the different demands of real-world tests, it would have a large impact,” Karnik says. “But one could also imagine applications for fine chemical- or biological-sample processing, where these membranes could be useful. And this is the first report of a centimeter-scale graphene membrane that does any kind of molecular filtration. That’s exciting.”

De-en Jiang, an assistant professor of chemistry at the University of California at Riverside, sees the defect-sealing technique as “a great advance toward making graphene filtration a reality.”

“The two-step technique is very smart: sealing the defects while preserving the desired pores for filtration,” says Jiang, who did not contribute to the research. “This would make the scale-up much easier. One can produce a large graphene membrane first, not worrying about the defects, which can be sealed later.”

I have featured graphene and water desalination work before  from these researchers at MIT in a Feb. 27, 2014 posting. Interestingly, there was no mention of problems with defects in the news release highlighting this previous work.

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

Nanofiltration across Defect-Sealed Nanoporous Monolayer Graphene by Sean C. O’Hern, Doojoon Jang, Suman Bose, Juan-Carlos Idrobo, Yi Song §, Tahar Laoui, Jing Kong, and Rohit Karnik. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.5b00456 Publication Date (Web): April 27, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Water is key component to making sub-10nm semiconducting wires

An April 6, 2015 news item on phys.org announces a new technique for making nanowires,

Water is the key component in a Rice University process to reliably create patterns of metallic and semiconducting wires less than 10 nanometers wide.

The technique by the Rice lab of chemist James Tour builds upon its discovery that the meniscus – the curvy surface of water at its edge – can be an effective mask to make nanowires.

The Rice team of Tour and graduate students Vera Abramova and Alexander Slesarev have now made nanowires between 6 and 16 nanometers wide from silicon, silicon dioxide, gold, chromium, tungsten, titanium, titanium dioxide and aluminum. They have also made crossbar structures of conducting nanowires from one or more of the materials.

An April 6, 2015 Rice University news release (also on EurekAlert), which originated the news item, explains why this could have an impact on the semiconductor industry and provides a few more details about the process,

The process is promising for the semiconductor industry as it seeks to make circuits ever smaller. State-of-the-art integrated circuit fabrication allows for signal wires that approach 10 nanometers, visible only with powerful microscopes. These are the paths that connect the billions of transistors in modern electronic devices.

“This could have huge ramifications for chip production since the wires are easily made to sub-10-nanometer sizes,” Tour said of the Rice process. “There’s no other way in the world to do this en masse on a surface.”

Current approaches to making such tiny wires take several paths. Lithography, the standard method for etching integrated circuits, is approaching the physical limits of its ability to shrink them further. Bulk synthesis of semiconducting and metallic nanowires is also possible, but the wires are difficult to position in integrated circuits.

Water’s tendency to adhere to surfaces went from an annoyance to an advantage when the Rice researchers found they could use it as a mask to make patterns. The water molecules gather wherever a raised pattern joins the target material and forms a curved meniscus created by the surface tension of water.

The meniscus-mask process involves adding and then removing materials in a sequence that ultimately leaves a meniscus covering the wire and climbing the sidewall of a sacrificial metal mask that, when etched away, leaves the nanowire standing alone.

Tour said the process should work with modern fabrication technology with no modifications to existing equipment and minimal changes in fabrication protocols. No new tools or materials are needed.

The researchers have provided an image,

These nanowires were created at Rice University through a process called meniscus-mask lithography. From left, they’re made of silicon, silicon dioxide, gold, chromium, tungsten, titanium, titanium dioxide and aluminum. The scale bar is 1 micron for all images. (Credit: Tour Group/Rice University)

These nanowires were created at Rice University through a process called meniscus-mask lithography. From left, they’re made of silicon, silicon dioxide, gold, chromium, tungsten, titanium, titanium dioxide and aluminum. The scale bar is 1 micron for all images. (Credit: Tour Group/Rice University)

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

Meniscus-Mask Lithography for Fabrication of Narrow Nanowires by Vera V. Abramova, Alexander S Slesarev, and James M. Tour. Nano Lett., Just Accepted Manuscript DOI: 10.1021/nl504716u Publication Date (Web): March 31, 2015
Copyright © 2015 American Chemical Society

The paper is freely available but you do need to register on the site for open access.

Filtration membranes with twice as much ability to remove unwanted materials from water

A March 26, 2015 news item on Nanowerk offers information about a new method for removing pollutants from water and some insight into the situation regarding bisphenol A (BPA) in Europe,

New types of membrane adsorbers remove unwanted particles from water and also, at the same time, dissolved substances such as the hormonally active bis-phenol A or toxic lead. To do this, researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB imbed selective adsorber particles in filtration membranes.

It was not until January 2015 that the European Food Safety Authority (EFSA) lowered the threshold value for bisphenol A in packaging. The hormonally active bulk chemical is among other things a basic material for polycarbonate from which, for example, CDs, plastic tableware or spectacles glasses are manufactured. Due to its chemical structure, bisphenol A is not completely degraded in the biological stages of treatment plants and is discharged into rivers and lakes by the purification facility.

Activated carbon or adsorber materials are already used to remove chemicals, anti-biotics [sic] or heavy metals from waste or process water. However, a disadvantage of these highly porous materials is the long contact time that the pollutants require to diffuse into the pores. So that as many of the harmful substances as possible are captured even in a shorter time, the treatment plants use larger quantities of adsorbers in correspondingly large treatment basins. However, activated carbon can only be regenerated with a high energy input, resulting for the most part in the need to dispose of large quantities of material contaminated with pollutants.

Also, membrane filtration with nanofiltration or reverse osmosis membranes, which can remove the contaminating substances, is not yet cost-effective for the removal of dissolved molecules from high-volume flows such as process or wastewater. Membranes filter the water through their pores when a pressure is built up on one side of the membrane, thus holding back larger molecules and solid particles. But the smaller the membrane pores are, the higher the pressure – and therefore the more energy – that is required to separate the substances from water.

A March 24, 2015 Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) press release, which originated the news item, goes on to describe their team’s new approach,

Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart have opted for a new approach that combines the advantages of both methods. When manufacturing the membranes they add small, polymeric adsorber particles. The resulting membrane adsorbers can – in addition to their filtration function – adsorptively bind substances dissolved in water. “We make use of the porous structure of the membrane located underneath the separation layer. The pores have a highly specific surface so that as many particles as possible can be imbedded, and they also provide optimum accessibility,” says Dr. Thomas Schiestel, Head of the “Inorganic Interfaces and Membranes” working group at the Fraunhofer IGB.

“Unlike conventional adsorbers, our membrane adsorbers transport the pollutants convectively. This means that, with the water flowing rapidly through the membrane pores, a contact time lasting only a few seconds is sufficient to adsorb pollutants on the particle surface,” says the scientist. Up to 40 percent of the weight of the membrane adsorbers is accounted for by the particles, so their binding capacity is correspondingly high. At the same time the membrane adsorbers can be operated at low pressures. As the membranes can be packed very tightly, very large volumes of water can be treated even with small devices.

Functional adsorber particles

The researchers manufacture the adsorber particles in a one-step, cost-efficient process. In this patented process monomeric components are polymerized with the help of a crosslinking agent to generate 50 to 500 nanometer polymer globules. “Depending on which substances are to be removed from the water, we select the most suitable one from a variety of monomers with differing functional groups,” Schiestel explains. The spectrum here ranges from pyridine, which tends to be hydrophobic, by way of cationic ammonium compounds and includes anionic phosphonates.

Selective removal of pollutants and metals

The researchers were able to show in various tests that the membrane adsorbers remove pollutants very selectively by means of the particles, which are customized for the particular contaminant in question. For example, membrane adsorbers with pyridine groups bind the hydrophobic bisphenol A especially well, whereas those with amino groups adsorb the negatively charged salt of the antibiotic penicillin G.

“The various adsorber particles can even be combined in one membrane. In this way we can remove several micropollutants simultaneously with just one membrane adsorber,” says Schiestel, pointing out a further advantage. Equipped with different functional groups, the membrane adsorbers can also remove toxic heavy metals such as lead or arsenic from the water. Phosphonate membrane adsorbers, for example, adsorb more than 5 grams of lead per square meter of membrane surface area – 40 percent more than a commercially available membrane adsorber.

Cost-effective and regenerable

So that the membrane adsorbers can be used several times, the adsorbed pollutants have to be detached once again from the particles in the membrane. “Membrane adsorbers for bisphenol A can be fully regenerated by a shift of the pH value,” Schiestel explains. The concentrated pollutants can then be disposed off cost-effectively or broken down using suitable oxidative processes.

The regenerability of the membrane adsorbers also makes possible a further application: reutilization of the separated molecules. This additionally makes the technology attractive for recovering valuable precious metals or rare earth metals.

The Fraunhofer IGB is presenting the membrane adsorbers and other innovative technologies for water purification at the “Wasser Berlin International” Trade Fair and Congress from 24th to 27th March 2015 in Berlin. The IGB is in Hall 2.2, Stand 422.

While it’s too late to attend the presentation, here are two links and citations to papers concerning the work,

Removal of micropollutants from water by nanocomposite membrane adsorbers by Klaus Niedergall, Monika Bach, Thomas Hirth, Günter E.M. Tovar, and Thomas Schiestel. Separation and Purification Technology, Volume 131, 27 June 2014 DOI: 10.1016/j.seppur.2014.04.032

Nanostructured Composite Adsorber Membranes for the Reduction of Trace Substances in Water: The Example of Bisphenol A by Klaus Niedergall, Monika Bach, Thomas Schiestel, and Günter E.M. Tovar. Ind. Eng. Chem. Res., 2013, 52 (39), pp 14011–14018 DOI: 10.1021/ie303264r Publication Date (Web): May 16, 2013

Copyright © 2013 American Chemical Society

Both articles are behind a paywall.

Frogs: monitoring them, finding new species, and research about the golden ones in Panama

I have three frog-oriented items and while they’re not strictly speaking in my usual range of topics, given this blog’s name and the fact I haven’t posted a frog piece in quite a while, it seems this is a good moment to address that lack.

Monitoring frogs and amphibians at Trent University (Ontario, Canada)

From a March 23, 2015 Trent University news release,

With the decline of amphibian populations around the world, a team of researchers led by Trent University’s Dr. Dennis Murray will seek to establish environmental DNA (eDNA) monitoring of amphibian occupancy and aquatic ecosystem risk assessment with the help of a significant grant of over $596,000 from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Awarded to Professor Murray, a Canada research chair in integrative wildlife conservation, bioinformatics, and ecological modelling and professor at Trent University along with colleagues Dr. Craig Brunetti of the Biology department, and Dr. Chris Kyle of the Forensic Science program, and partners at Laurentian University, University of Toronto, McGill University, Ontario Ministry of Natural Resources and Forestry and Environment Canada, the grant will support the development of tools that will promote a cleaner aquatic environment.

The project will use amphibian DNA found in natural breeding habitats to determine the presence and abundance of amphibians as well as their pathogens. This new technology capitalizes on Trent University’s expertise and infrastructure in the areas of wildlife DNA and water quality.

“We’re honoured to have received the grant to help us drive the project forward,” said Prof. Murray. “Our plan is to place Canada, and Trent, in a leadership position with respect to aquatic wildlife monitoring and amphibian conservation.”

Amphibian populations are declining worldwide, yet in Canada, amphibian numbers are not monitored closely, meaning changes in their distribution or abundance may be unnoticeable. Amphibian monitoring in Canada is conducted by citizen scientists who record frog breeding calls when visiting bodies of water during the spring. However, the lack of formalized amphibian surveys leaves Canada in a vulnerable position regarding the status of its diverse amphibian community.

Prof. Murray believes that the protocols developed from this project could revolutionize how amphibian populations are monitored in Canada and in turn lead to new insights regarding the population trends for several amphibian species across the country.

Here’s more about NSERC and Trent University from the news release,

About NSERC

NSERC is a federal agency that helps make Canada a country of discoverers and innovators. The agency supports almost 30,000 post-secondary students and postdoctoral fellows in their advanced studies. NSERC promotes discovery by funding approximately 12,000 professors every year and fosters innovation by encouraging over 2,400 Canadian companies to participate and invest in post-secondary research projects.

The NSERC Strategic Project Grants aim to increase research and training in areas that could strongly influence Canada’s economy, society or environment in the next 10 years in four target areas: environmental science and technologies; information and communications technologies; manufacturing; and natural resources and energy.

About Trent University

One of Canada’s top universities, Trent University was founded on the ideal of interactive learning that’s personal, purposeful and transformative. Consistently recognized nationally for leadership in teaching, research and student satisfaction, Trent attracts excellent students from across the country and around the world. Here, undergraduate and graduate students connect and collaborate with faculty, staff and their peers through diverse communities that span residential colleges, classrooms, disciplines, hands-on research, co-curricular and community-based activities. Across all disciplines, Trent brings critical, integrative thinking to life every day. As the University celebrates its 50th anniversary in 2014/15, Trent’s unique approach to personal development through supportive, collaborative community engagement is in more demand than ever. Students lead the way by co-creating experiences rooted in dialogue, diverse perspectives and collaboration. In a learning environment that builds life-long passion for inclusion, leadership and social change, Trent’s students, alumni, faculty and staff are engaged global citizens who are catalysts in developing sustainable solutions to complex issues. Trent’s Peterborough campus boasts award-winning architecture in a breathtaking natural setting on the banks of the Otonabee River, just 90 minutes from downtown Toronto, while Trent University Durham delivers a distinct mix of programming in the GTA.

Trent University’s expertise in water quality could be traced to its proximity to Canada’s Experimental Lakes Area (ELA), a much beleaguered research environment due to federal political imperatives. You can read more about the area and the politics in this Wikipedia entry. BTW, I am delighted to learn that it still exists under the auspices of the International Institute for Sustainable Development (IISD),

Taking this post into nanotechnology territory while mentioning the ELA, Trent University published a Dec. 8, 2014 news release about research into silver nanoparticles,

For several years, Trent University’s Dr. Chris Metcalfe and Dr. Maggie Xenopoulos have dedicated countless hours to the study of aquatic contaminants and the threat they pose to our environment.

Now, through the efforts of the International Institute for Sustainable Development (IISD), their research is reaching a wider audience thanks to a new video (Note: A link has been removed).

The video is one of a five-part series being released by the IISD that looks into environmental issues in Canada. The video entitled “Distilling Science at the Experimental Lakes Area: Nanosilver” and featuring Professors Metcalfe and Xenopoulos profiles their research around nanomaterials at the Experimental Lakes Area.

Prof. Xenopolous’ involvement in the project falls in line with other environmental issues she has tackled. In the past, her research has examined how human activities – including climate change, eutrophication and land use – affect ecosystem structure and function in lakes and rivers. She has also taken an interest in how land use affects the material exported and processed in aquatic ecosystems.

Prof. Metcalfe’s ongoing research on the fate and distribution of pharmaceutical and personal care products in the environment has generated considerable attention both nationally and internationally.

Together, their research into nanomaterials is getting some attention. Nanomaterials are submicroscopic particles whose physical and chemical properties make them useful for a variety of everyday applications. They can be found in certain pieces of clothing, home appliances, paint, and kitchenware. Initial laboratory research conducted at Trent University showed that nanosilver could strongly affect aquatic organisms at the bottom of the food chain, such as bacteria, algae and zooplankton.

To further examine these effects in a real ecosystem, a team of researchers from Trent University, Fisheries and Oceans Canada and Environment Canada has been conducting studies at undisclosed lakes in northwestern Ontario. The Lake Ecosystem Nanosilver (LENS) project has been monitoring changes in the lakes’ ecosystem that occur after the addition of nanosilver.

“In our particular case, we will be able to study and understand the effects of only nanosilver because that is the only variable that is going to change,” says Prof. Xenopoulos. “It’s really the only place in the world where we can do that.”

The knowledge gained from the study will help policy-makers make decisions about whether nanomaterials can be a threat to aquatic ecosystems and whether regulatory action is required to control their release into the environment.

You can find the 13 mins. video here: https://www.youtube.com/watch?v=_nJai_B4YH0#action=share

Shapeshifting frogs, a new species in Ecuador

Caption: This image shows skin texture variation in one individual frog (Pristimantis mutabilis) from Reserva Las Gralarias. Note how skin texture shifts from highly tubercular to almost smooth; also note the relative size of the tubercles on the eyelid, lower lip, dorsum and limbs. Credit: Zoological Journal of the Linnean Society

Caption: This image shows skin texture variation in one individual frog (Pristimantis mutabilis) from Reserva Las Gralarias. Note how skin texture shifts from highly tubercular to almost smooth; also note the relative size of the tubercles on the eyelid, lower lip, dorsum and limbs.
Credit: Zoological Journal of the Linnean Society

Here’s more about the shapeshifting and how the scientists figured out what the frogs were doing (from a March 23, 2015 Case Western Research University news release on EurekAlert; Note: A link has been removed),

A frog in Ecuador’s western Andean cloud forest changes skin texture in minutes, appearing to mimic the texture it sits on.

Originally discovered by a Case Western Reserve University PhD student and her husband, a projects manager at Cleveland Metroparks’ Natural Resources Division, the amphibian is believed to be the first known to have this shape-shifting capability.

But the new species, called Pristimantis mutabilis, or mutable rainfrog, has company. Colleagues working with the couple recently found that a known relative of the frog shares the same texture-changing quality–but it was never reported before.

The frogs are found at Reserva Las Gralarias, a nature reserve originally created to protect endangered birds in the Parish of Mindo, in north-central Ecuador.

The researchers, Katherine and Tim Krynak, and colleagues from Universidad Indoamérica and Tropical Herping (Ecuador) co-authored a manuscript describing the new animal and skin texture plasticity in the Zoological Journal of the Linnean Society this week. They believe their findings have broad implications for how species are and have been identified. The process may now require photographs and longer observations in the field to ensure the one species is not mistakenly perceived as two because at least two species of rain frogs can change their appearance.

Katherine Krynak believes the ability to change skin texture to reflect its surroundings may enable P. mutabilis to help camouflage itself from birds and other predators.

The Krynaks originally spotted the small, spiny frog, nearly the width of a marble, sitting on a moss-covered leaf about a yard off the ground on a misty July night in 2009. The Krynaks had never seen this animal before, though Tim had surveyed animals on annual trips to Las Gralarias since 2001, and Katherine since 2005.

They captured the little frog and tucked it into a cup with a lid before resuming their nightly search for wildlife. They nicknamed it “punk rocker” because of the thorn-like spines covering its body.

The next day, Katherine Krynak pulled the frog from the cup and set it on a smooth white sheet of plastic for Tim to photograph. It wasn’t “punk “–it was smooth-skinned. They assumed that, much to her dismay, she must have picked up the wrong frog.

“I then put the frog back in the cup and added some moss,” she said. “The spines came back… we simply couldn’t believe our eyes, our frog changed skin texture!

“I put the frog back on the smooth white background. Its skin became smooth.”

“The spines and coloration help them blend into mossy habitats, making it hard for us to see them,” she said. “But whether the texture really helps them elude predators still needs to be tested.”

During the next three years, a team of fellow biologists studied the frogs. They found the animals shift skin texture in a little more than three minutes.

Juan M. Guayasamin, from Universidad Tecnológica Indoamérica, Ecuador, the manuscript’s first author, performed morphological and genetic analyses showing that P. mutabilis was a unique and undescribed species. Carl R. Hutter, from the University of Kansas, studied the frog’s calls, finding three songs the species uses, which differentiate them from relatives. The fifth author of the paper, Jamie Culebras, assisted with fieldwork and was able to locate a second population of the species. Culebras is a member of Tropical Herping, an organization committed to discovering, and studying reptiles and amphibians.

Guayasamin and Hutter discovered that Prismantis sobetes, a relative with similar markings but about twice the size of P. mutabilis, has the same trait when they placed a spiny specimen on a sheet and watched its skin turn smooth. P. sobetes is the only relative that has been tested so far.

Because the appearance of animals has long been one of the keys to identifying them as a certain species, the researchers believe their find challenges the system, particularly for species identified by one or just a few preserved specimens. With those, there was and is no way to know if the appearance is changeable.

The Krynaks, who helped form Las Gralarias Foundation to support the conservation efforts of the reserve, plan to return to continue surveying for mutable rain frogs and to work with fellow researchers to further document their behaviors, lifecycle and texture shifting, and estimate their population, all in effort to improve our knowledge and subsequent ability to conserve this paradigm shifting species.

Further, they hope to discern whether more relatives have the ability to shift skin texture and if that trait comes from a common ancestor. If P. mutabilis and P. sobetes are the only species within this branch of Pristimantis frogs to have this capability, they hope to learn whether they retained it from an ancestor while relatives did not, or whether the trait evolved independently in each species.

Golden frog of Panama and its skin microbiome

Caption: Researchers studied microbial communities on the skin of Panamanian golden frogs to learn more about amphibian disease resistance. Panamanian golden frogs live only in captivity. Continued studies may help restore them back to the wild. Credit: B. Gratwicke/Smithsonian Conservation Biology Institute

Caption: Researchers studied microbial communities on the skin of Panamanian golden frogs to learn more about amphibian disease resistance. Panamanian golden frogs live only in captivity. Continued studies may help restore them back to the wild.
Credit: B. Gratwicke/Smithsonian Conservation Biology Institute

Among many of the pressures on frog populations, there’s a lethal fungus which has affected some 200 species of frogs. A March 23, 2015 news item on ScienceDaily describes some recent research into the bacterial communities present on frog skin,

A team of scientists including Virginia Tech researchers is one step closer to understanding how bacteria on a frog’s skin affects its likelihood of contracting disease.

A frog-killing fungus known as Batrachochytrium dendrobatidis, or Bd, has already led to the decline of more than 200 amphibian species including the now extinct-in-the-wild Panamanian golden frog.

In a recent study, the research team attempted to apply beneficial bacteria found on the skin of various Bd-resistant wild Panamanian frog species to Panamanian golden frogs in captivity, to see if this would stimulate a defense against the disease.

A March 23, 2015 Virginia Tech University news release on EurekAlert, which originated the news item, provides a twist and a turn in the story (Note: Links have been removed),

They found that while the treatment with beneficial bacteria was not successful due to its inability to stick to the skin, there were some frogs that survived exposure to the fungus.

These survivors actually had unique bacterial communities on their skin before the experiments started.

The next step is to explore these new bacterial communities.

“We were disappointed that the treatment didn’t work, but glad to have discovered new information about the relationship between these symbiotic microbial communities and amphibian disease resistance,” said Lisa Belden, an associate professor of biological sciences in the College of Science, a Fralin Life Science Institute affiliate, and a faculty member with the new Global Change Center at Virginia Tech. “Every bit of information gets us closer to getting these frogs back into nature.”

Studying the microbial communities of Panamanian golden frogs was the dissertation focus of Belden’s former graduate student Matthew Becker, who graduated with a Ph.D. in biological sciences from Virginia Tech in 2014 and is now a fellow at the Smithsonian Conservation Biology Institute.

“Anything that can help us predict resistance to this disease is very useful because the ultimate goal of this research is to establish healthy populations of golden frogs in their native habitat,” Becker told Smithsonian Science News. “I think identifying alternative probiotic treatment methods that optimize dosages and exposure times will be key for moving forward with the use of probiotics to mitigate chytridiomycosis.”

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

Composition of symbiotic bacteria predicts survival in Panamanian golden frogs infected with a lethal fungus by Matthew H. Becker , Jenifer B. Walke , Shawna Cikanek , Anna E. Savage , Nichole Mattheus , Celina N. Santiago , Kevin P. C. Minbiole , Reid N. Harris , Lisa K. Belden , Brian Gratwicke. April 2015 Volume: 282 Issue: 1805 DOI: 10.1098/rspb.2014.2881 Published 18 March 2015

This is an open access paper.

For anyone curious about the article in the Smithsonian mentioned in the news release, you can find it here.