. 24/7 Space News .
TECH SPACE
All that is gold is not biochemically stable
by Staff Writers
Durham NC (SPX) Sep 04, 2018

Mark Wiesner stands with rows of mesocosms - small, manmade structures containing different plants and microorganisms meant to represent a natural environment with experimental controls.

It turns out gold isn't always the shining example of a biologically stable material that it's assumed to be, according to environmental engineers at Duke's Center for the Environmental Implications of NanoTechnology (CEINT).

In a nanoparticle form, the normally very stable, inert, noble metal actually gets dismantled by a microbe found on a Brazilian aquatic weed.

While the findings don't provide dire warnings about any unknown toxic effects of gold, they do provide a warning to researchers on how it is used in certain experiments.

The study was published August 13 in the journal Nature Nanotechnology.

CEINT researchers from Duke, Carnegie Mellon and the University of Kentucky were running an experiment to investigate how nanoparticles used as a commercial pesticide affect wetland environments in the presence of added nutrients. Although real-world habitats often receive doses of both pesticides and fertilizers, most studies on the environmental effects of such compounds only look at a single contaminant at a time.

For nine months, the researchers released low doses of nitrogen, phosphorus and copper hydroxide nanoparticles into wetland mesocosms - small, manmade structures containing different plants and microorganisms meant to represent a natural environment with experimental controls. The goal was to see where the nanoparticle pesticides ended up and how they affected the plant and animal life within the mesocosm.

The researchers also released low doses of gold nanoparticles as tracers, assuming the biologically inert nanoparticles would remain stable while migrating through the ecosystem. This would help the researchers interpret data on the pesticide particles that partly dissolve by showing them how a solid metal particle acts within the system.

But when the researchers went to analyze their results, they found that many of the gold nanoparticles had been oxidized and dissolved.

"We were taken completely by surprise," said Mark Wiesner, the James B. Duke Professor and chair of civil and environmental engineering at Duke. "The nanoparticles that were supposed to be the most stable turned out to be the least stable of all."

After further inspection, the researchers found the culprit - the microbiome growing on a common Brazilian waterweed called Egeria densa. Many bacteria secrete chemicals to essentially mine metallic nutrients from their surroundings. With their metabolism spiked by the experiment's added nutrients, the bacteria living on the E. densa were catalyzing the reaction to dissolve the gold nanoparticles.

This process wouldn't pose any threat to humans or other animal species in the wild. But when researchers design experiments with the assumption that their gold nanoparticles will remain intact, the process can confound the interpretation of their results.

"The assumption that gold is inert did not hold in these experiments," said Wiesner. "This is a good lesson that underscores how real, complex environments, that include for example the bacteria growing on leaves, can give very different results from experiments run in a laboratory setting that do not include these complexities."

Research Report: "Gold nanoparticle biodissolution by a freshwater macrophyte and its associated microbiome"


Related Links
Duke University
Space Technology News - Applications and Research


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


TECH SPACE
Chemists make breakthrough on road to creating a rechargeable lithium-oxygen battery
Waterloo, Canada (SPX) Aug 30, 2018
Chemists from the University of Waterloo have successfully resolved two of the most challenging issues surrounding lithium-oxygen batteries, and in the process created a working battery with near 100 per cent coulombic efficiency. The new work, which appears this week in Science, proves that four-electron conversion for lithium-oxygen electrochemistry is highly reversible. The team is the first to achieve four-electron conversion, which doubles the electron storage of lithium-oxygen, also known as ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
Star Gosling took flying lessons for new astronaut film

Heat shield install brings Orion spacecraft closer to space

Students experience the power of controlling satellites in space

Russia's Kalashnikov branches out from rifles to robots and e-cars

TECH SPACE
Space launch training cooperation

Commercial Spaceports 2018

Chinese private space company to launch first carrier rocket

GEOStar-3 mission success enabled by Aerojet Rocketdyne XR-5 Hall Thruster System

TECH SPACE
NASA's InSight passes halfway to Mars, instruments check in

Six Things About Opportunity'S Recovery Efforts

The Science Team Continues to Listen for Opportunity as Storm Diminishes

Planet-Encircling Dust Storm of Mars shows signs of slowing

TECH SPACE
China unveils Chang'e-4 rover to explore Moon's far side

China's SatCom launch marketing not limited to business interest

China to launch space station Tiangong in 2022, welcomes foreign astronauts

China solicits international cooperation experiments on space station

TECH SPACE
Successful capital raising sees Kleos Space Launch on the ASX

Artwork unveiled on exoplanet satellite

Three top Russian space industry execs held for 'fraud'

ISRO to launch GSAT-32 in Oct 2019 to replace GSAT-6A which went incommunicado days after launch

TECH SPACE
Kiel research team increases adhesiveness of silicone using the example of beetles

New laser technique binds aluminum with plastic in injection molding

Access to 3D printing is changing the work in research labs

Game over? China to rein in online games in latest industry setback

TECH SPACE
Infant exoplanet weighed by Hipparcos and Gaia

Infant exoplanet weighed by Hipparcos and Gaia

Discovery of a structurally 'inside-out' planetary nebula

Under pressure, hydrogen offers a reflection of giant planet interiors

TECH SPACE
Study helps solve mystery under Jupiter's coloured bands

Million fold increase in the power of waves near Jupiter's moon Ganymede

New Horizons team prepares for stellar occultation ahead of Ultima Thule flyby

High-Altitude Jovian Clouds









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.