Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists use alfalfa plants to harvest nanoparticles of gold

15.08.2002


Ordinary alfalfa plants are being used as miniature gold factories that one day could provide the nanotechnology industry with a continuous harvest of gold nanoparticles.



An international research team from the University of Texas-El Paso (UTEP) and Mexico advanced the work at the Stanford Synchrotron Radiation Laboratory (SSRL) - part of the Stanford Linear Accelerator Center (SLAC) in Menlo Park, Calif. The researchers are using, as tiny factories, the alfalfa’s natural, physiological need to extract metals from the medium in which they are growing. Of most value here is that the alfalfa extracts gold from the medium and stores it in the form of nanoparticles - specks of gold less than a billionth of a meter across. Their findings are published in the April issue of Nano Letters, a publication of the American Chemical Society.

’’This study is just one of hundreds of innovative research projects that take advantage of the unique properties of synchrotron X-rays provided by SSRL,’’ said Keith Hodgson, the director of SSRL and a professor of chemistry at Stanford University.


The semiconductor industry has long valued the oxidation resistance and the thermal and electrical conductivity of gold. Now, the relentless and accelerating drive toward ever-smaller wires, connectors and through-holes on ever-smaller semiconductor devices makes those properties even more important to the folks who make very small things. Consequently, the nanotechnology industry is very interested in processes that make gold nanoparticles for nano-scale electronic and optical devices.

Gold factories

Some processes for making high concentrations of solid nanoparticles use chemistry. However, many of the chemical methods used are cumbersome and lead to poisonous end products that could endanger public health. A better method is needed. Ordinary plants, acting as tiny factories, may provide a better means of production.

All ordinary plants use their roots to extract nutrients - water and minerals, even heavy metals - from the soil they grow in. In this case, alfalfa was chosen as a model plant system for studying the ability of plants to extract gold from various growth media. If it worked, using plants to produce gold nanoparticles would eliminate the need for harsh chemicals or chemical reducing agents. As this would be a significant environmental advantage, the Environmental Protection Agency, the Department of Energy (DOE) and the National Institutes of Health provided funding.

The researchers needed answers to such questions as: Will plants make gold nanoparticles? And if they will, how then do we determine the presence, size and physical distribution of nanoparticles within the plant? And how will we extract the nanoparticles from the alfalfa?

A University of Texas (UT) team from the El Paso and Austin campuses is working on those answers in Texas and at SSRL. Work to date demonstrates answers to the first two of those questions, and the team is working on answering the third.

Subatomic scale

The alfalfa plants were germinated and grown on an artificial, gold-rich, ’’soil’’ at UTEP. At special SSRL facilities, a UT team led by chemistry and environmental sciences Professor Jorge Gardea-Torresdey analyzed the samples using X-ray absorption spectroscopy (XAS), which allows for selective study of metals and their chemical environments in biological samples on a subatomic scale. Because metals play an important role in biological systems - many are beneficial or even essential - XAS is a powerful tool for accurate characterization of the metal environment in metalloproteins and for a better understanding of their function.

The researchers also analyzed the samples using high-resolution transmission electron microscopy. The advantage electron microscopes offer over light microscopes is about a thousand-fold increase in resolution and a hundred-fold increase in the depth of field. All the electron microscope work was done at UT-Austin.

The UT-Austin microscopy team, directed by chemical engineering Professor Miguel Jose Yacaman, formerly of the Institute of Physics at UNAM in Mexico, produced the first answer when electron microscopy images of the alfalfa shoots confirmed the existence of gold nanoparticles in the roots and along the entire shoot of the alfalfa plants. The second answer appeared when SSRL imaging equipment corroborated the presence of gold and determined that the particles have physical properties that are similar to gold nanoparticles formed using chemical techniques. The answer to the third question - how to extract the nanoparticles from the plants - may be by centrifuge, which may turn out to be easier than expected.

International collaboration

’’This collaboration between two important universities in the UT system - the team conducting microscopy work at UT-Austin collaborates with the phytoremediation group at UTEP to investigate nanotechnology issues through the XAS capability at SSRL - is great,’’ Gardea-Torresdey and Yacaman said. Phytoremediation uses plants for the biological remediation of environmental problems.

Two international postdoctoral fellows participated in the Yacaman group: Patricia Santiago from the Instituto Nacional De Investigaciones Nucleares de Mexico (ININ), and Horacio Troiani from the Balseiro Institute in Bariloche, Argentina.

’’The work has demonstrated that using alfalfa is a cost effective and environmentally friendly method of producing gold nanoparticles. Future work will involve the full physical characterization of the nanoparticles and the development of methods to extract them from the plants,’’ Gardea-Torresdey added.

’’Last year, more than 1,700 scientists from better than 200 universities and companies used SSRL resources for 775 individual experiments that were carried out at our national user facility, which is funded by the DOE Office of Basic Energy Sciences,’’ Hodgson noted. ’’What they learned advanced frontiers of knowledge in fields from computer chip manufacturing to advancing drug discovery.’’


The project is funded through the DOE/SSRL Gateway program and the beam time is funded by SSRL. The synchrotron aspects of this project are supported by the DOE/SSRL Gateway program, which is a joint cooperative research and training effort by SSRL and UT-El Paso to engage Mexican- American students and students belonging to ethnic minorities in frontier scientific research using advanced facilities.

By Tom Mead

News Service website:
http://www.stanford.edu/news/

Stanford Report (university newspaper):
http://news.stanford.edu

Most recent news releases from Stanford:
http://www.stanford.edu/dept/news/html/releases.html

To change contact information for these news releases:
news-service@lists.stanford.edu Phone: 650-723-2558

COMMENT: Jorge Gardea-Torresdey, University of Texas-El Paso
915-747-5359; jgardea@utep.edu

EDITORS: Images for this article can be found at:
http://www.slac.stanford.edu/slac/media-info/pressphoto_ssrl.html

Relevant Web URL:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/alfalfa.html
http://www2.slac.stanford.edu/vvc


Neil Calder | EurekAlert1

More articles from Interdisciplinary Research:

nachricht New approach: Researchers succeed in directly labelling and detecting an important RNA modification
30.04.2018 | Westfälische Wilhelms-Universität Münster

nachricht Start of work for the world's largest electric truck
20.04.2018 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>