Navigation Links
Silver cycle: New evidence for natural synthesis of silver nanoparticles
Date:5/11/2011

Nanoparticles of silver are being found increasingly in the environmentand in environmental science laboratories. Because they have a variety of useful properties, especially as antibacterial and antifungal agents, silver nanoparticles increasingly are being used in a wide variety of industrial and consumer products. This, in turn, has raised concerns about what happens to them once released into the environment. Now a new research paper* adds an additional wrinkle: Nature may be making silver nanoparticles on its own.

A team of researchers from the Florida Institute of Technology (FIT), the State University of New York (SUNY), Buffalo, and the National Institute of Standards and Technology (NIST) reports that, given a source of silver ions, naturally occurring humic acid will synthesize stable silver nanoparticles.

"Our colleague, Virender Sharma, had read an article in which they were using wine to form nanoparticles. He thought that, based on the similar chemistry, we should be able to produce silver nanoparticles with humic acids," explains FIT chemist Mary Sohn. "First we formed them by traditional methods and then we tried one of our river sediment humic acids. We were really excited that we could see the characteristic yellow color of the nanoparticles." Samples were sent to Sarbajit Banerjee at SUNY Buffalo and Robert MacCuspie at NIST for detailed analyses to confirm the presence of silver nanoparticles.

"Humic acid" is a complex mixture of many organic acids that are formed during the decay of dead organic matter. Although the exact composition varies from place to place and season to season, humic acid is ubiquitous in the environment. Metallic nanoparticles, MacCuspie explains, have characteristic colors that are a direct consequence of their size.** Silver nanoparticles appear a yellowish brown.

The team mixed silver ions with humic acid from a variety of sources at different temperatures and concentrations and found that acids from river water or sediments would form detectable silver nanoparticles at room temperature in as little as two to four days. Moreover, MacCuspie says, the humic acid appears to stabilize the nanoparticles by coating them and preventing the nanoparticles from clumping together into a larger mass of silver. "We believe it's actually a similar process to how nanoparticles are synthesized in the laboratory," he says, except that the lab process typically uses citric acid at elevated temperatures.

"This caught us by surprise because a lot of our work is focused on how silver nanoparticles may dissolve when they're released into the environment and release silver ions," MacCuspie says. Many biologists believe the toxicity of silver nanoparticles, the reason for their use as an antibacterial or antifungal agent, is due to their high surface area that makes them an efficient source of silver ions, he says, but "this creates the idea that there may be some sort of natural cycle returning some of the ions to nanoparticles." It also helps explain the discovery, over the past few years, of silver nanoparticles in locations like old mining regions that are not likely to have been exposed to man-made nanoparticles, but would have significant concentrations of silver ions.


'/>"/>

Contact: Michael Baum
michaek.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology news :

1. Nanosilver: A new name -- well-known effects
2. Antibacterial silver nanoparticles are a blast
3. Ultrasensitive imaging method uses gold-silver nanocages
4. Silver nanoparticles may one day be key to devices that keep hearts beating strong and steady
5. Nanophysics: Serving up Buckyballs on a silver platter
6. Audience Selected as Silver Winner in This Years Wall Street Journal Technology Innovation Awards and Winner of the Semiconductors Category
7. Chimpanzees contagious yawning evidence of empathy, not just sleepiness, study shows
8. Precedent-setting evidence of the benefits of biodiversity
9. Tree resin the key evidence of current and historic insect invasions
10. Further research needed to develop evidence-based nutrition guidelines for cancer survivors
11. Jefferson researchers provide genetic evidence that antioxidants can help treat cancer
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Silver cycle: New evidence for natural synthesis of silver nanoparticles
(Date:1/21/2017)... Research and Markets has announced the addition of the ... offering. ... global voice recognition biometrics market to grow at a CAGR of ... the present scenario and the growth prospects of the global voice ... report considers the revenue generated from the sales of voice recognition ...
(Date:1/18/2017)... Md. , Jan. 18, 2017  In vitro ... respect to mergers and acquisitions (M&A), and Kalorama Information ... for such acquisitions have been shifting. Generally, uncertainty in ... and the U.S. has changed the acquisitions landscape. ... has resulted in companies buying partners outside of their ...
(Date:1/12/2017)... , Jan. 12, 2017  Trovagene, Inc. (NASDAQ: ... DNA (ctDNA) technologies, today announced that it has signed ... and the Middle East ...  This milestone marks the first wave of international distribution ... urine and blood samples. The initial partners ...
Breaking Biology News(10 mins):
(Date:2/17/2017)... ... ... Academy of Model Aeronautics (AMA), the nation’s leading voice ... systems (UAS), are launching a joint program to promote safe and responsible drone ... efforts. , AMA and DJI will collaborate on other potential opportunities to mutually ...
(Date:2/16/2017)... ... February 16, 2017 , ... Avomeen & MichBio will be hosting a ... held at Avomeen Analytical Services (4840 Venture Dr., Ann Arbor, Michigan 48108). BioMixers ... an opportunity to interact with peers, make new connections and talk bio biz. , ...
(Date:2/16/2017)... , Feb. 16, 2017  MDNA Life ... the development of liquid biopsy tests based on ... into an exclusive license agreement with its first ... proprietary liquid biopsy test for prostate cancer, the ... Korea . This is the first overseas ...
(Date:2/16/2017)... 16, 2017   Capricor Therapeutics, Inc. ... company developing first-in-class biological therapies for cardiac and ... elected to terminate its license agreement with the ... including Cenderitide. "Our decision to return ... prioritize our efforts to advance our core cell ...
Breaking Biology Technology: