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:2/3/2016)... 3, 2016 --> ... report "Automated Fingerprint Identification System Market by Component (Hardware ... (Banking & Finance, Government, Healthcare, and Transportation) and Geography ... market is expected to be worth USD 8.49 Billion ... 2015 and 2020. The transformation and technology evolution from ...
(Date:2/2/2016)... Feb. 2, 2016 This BCC Research ... market by reviewing the recent advances in high ... drive the field forward. Includes forecast through 2019. ... the challenges and opportunities that exist in the ... solution developers, as well as IT and bioinformatics ...
(Date:2/2/2016)... Calif. , Feb. 2, 2016  Based ... market, Frost & Sullivan recognizes US-based Intelligent Retinal ... Frost & Sullivan Award for New Product Innovation. ... in North America , is ... the rapidly growing diabetic retinopathy market. The IRIS ...
Breaking Biology News(10 mins):
(Date:2/10/2016)... DUBLIN , Feb. 10, 2016  Allergan plc ... today announced that Brent Saunders , Allergan,s CEO ... in a fireside chat session at the RBC Capital ... 12:30 p.m. ET at The New York Palace Hotel ... presentation will be webcast live and can be accessed ...
(Date:2/10/2016)... ... February 10, 2016 , ... ... Society of Pharmaceutical Engineering (ISPE) Rocky Mountain Chapter 21st Annual Vendor Exhibition on ... fill more than 100 tables for its annual event, which will run from ...
(Date:2/10/2016)... ... February 10, 2016 , ... PatientCrossroads ... built on the secure online PatientCrossroads platform, has exceeded both its one-year and ... joined the PROMPT study, which seeks to advance understanding of the hereditary risks ...
(Date:2/10/2016)... ... February 10, 2016 , ... Cenna Bioscience Inc., an emerging biopharmaceutical ... Alzheimer’s disease, announced today it has been selected to present at the Cavendish Global ... Palm Beach, Florida. The purpose of the Forum is to help family offices ...
Breaking Biology Technology: