Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Bio-enabled, Surface-mediated Approach Produces Nanoparticle Composites

Georgia Tech researcher Eugenia Kharlampieva studies the properties of composite materials containing silk and metallic nanoparticles. (Georgia Tech Photo: Gary Meek)
Georgia Tech researcher Eugenia Kharlampieva studies the properties of composite materials containing silk and metallic nanoparticles. (Georgia Tech Photo: Gary Meek)

Abstract:
Thin Films of Silk Produce and Combine with Metallic Particles

Bio-enabled, Surface-mediated Approach Produces Nanoparticle Composites

Atlanta, GA | Posted on August 20th, 2009

Using thin films of silk as templates, researchers have incorporated inorganic nanoparticles that join with the silk to form strong and flexible composite structures that have unusual optical and mechanical properties. This bio-enabled, surface-mediated approach mimics the growth and assembly processes of natural materials, taking advantage of the ability of biomolecules to chemically reduce metal ions to produce nanoparticlesówithout harsh processing conditions.

Less than 100 nanometers thick, silk-silver nanoparticle composite films formed in this process can be used as flexible mirrors. The technique could also be used to create films that reflect light in specific wavelengths, anti-microbial coatings, thin film sensors, self-cleaning coatings, catalytic materials and potentially even flexible photovoltaic cells.

"We are taking advantage of biological molecules that have the ability to bind metallic ions of silver or gold from solution," said Vladimir Tsukruk, a professor in the Georgia Tech School of Materials Science and Engineering. "These molecules can create mono-dispersed metallic nanoparticles of consistent sizes under ambient conditionsóat room temperature and in a water-based environment without high vacuum or high temperatures."

Sponsored by the Air Force Office of Scientific Research and the Air Force Research Laboratory, the research was described August 19 at the Fall 2009 National Meeting of the American Chemical Society.

The nanoparticles produced range in size from four to six nanometers in diameter, surrounded by a biological shell of between one and two nanometers. The silk template permits good control of the nanoparticle placement, creating a composite with equally dispersed particles that remain separate. The optical properties of the resulting film depend on the nanoparticle material and size.

"This system provides very precise control over nanoparticle sizes," said Eugenia Kharlampieva, a postdoctoral researcher in Tsukruk's laboratory. "We produce well-defined materials without the problem of precipitation, aggregation or formation of large crystals. Since the silk fibroin is mono-dispersed, we can create uniform domains within the template."

Fabrication of the nanocomposites begins by dissolving silk cocoons and making the resulting fibroin water soluble. The silk is then placed onto a silicon substrate using a spin-coating technique that produces multiple layers of thin film that is then patterned into a template using a nanolithography technique.

"Because silk is a protein, we can control the properties of the surface and design different kinds of surfaces," explained Kharlampieva. "This surface-mediated approach is flexible at producing different shapes. We can apply the method to coat any surface we want, including objects of complex shapes."

Next, the silk template is placed in a solution containing ions of gold, silver, or other metal. Over a period of time ranging from hours to days, nanoparticles form within the template. The relatively long growth process, which operates at room temperature and neutral pH in a water-based environment, allows precise control of the particle size and spacing, Tsukruk notes.

"We operate at conditions that are suitable for biological activities," he explained. "No reducing agents are required to produce the particles because the biomolecules serve as reducing agents. We don't add any chemicals that could be toxic to the protein."

Use of these mild processing conditions could reduce the cost of producing the composites and their potential environmental impact. When dried, the resulting silk-nanoparticle film has high tensile strength, high elasticity and toughness.

"Silk is almost as strong as Kevlar, but it can be deformed by 30 percent without breaking," said Tsukruk. "The silk film is very robust, with a complicated structure that you don't find in synthetic materials."

For the future, the researchers plan to use the bio-assisted, surface-mediated technique to produce nanoparticles from other metals. They also hope to combine different types of particles to create new optical and mechanical properties.

"If we combine gold-binding and silver-binding peptides, we can make composites that will include a mixture of gold and silver nanoparticles," said Kharlampieva. "Each particle will have its own properties, and combining them will create more interesting composite materials."

The researchers also hope to find additional applications for the films in such areas as photovoltaics, medical technology and anti-microbial films that utilize the properties of silver nanoparticles.

Beyond Tsukruk and Kharlampieva, the research team has included Dmitry Zimnistky, Maneesh Gupta and Kathryn Bergman of Georgia Tech; David Kaplan of the Department of Biomedical Engineering at Tufts University, and Rajesh Naik of the Materials and Manufacturing Directorate of the Air Force Research Laboratory at Wright-Patterson Air Force Base.

"Nanomaterials grown under environmentally friendly conditions can be as good as synthetic materials that are produced under harsh conditions," Tsukruk added. "This technique allows us to grow very useful materials under natural conditions."

####

About Georgia Institute of Technology
The Georgia Institute of Technology is one of the nation's premier research universities. Ranked seventh among U.S. News & World Report's top public universities, Georgia Tech's more than 19,000 students are enrolled in its Colleges of Architecture, Computing, Engineering, Liberal Arts, Management and Sciences. Tech is among the nation's top producers of women and African-American engineers. The Institute offers research opportunities to both undergraduate and graduate students and is home to more than 100 interdisciplinary units plus the Georgia Tech Research Institute.

For more information, please click here

Contacts:
Media Relations Contacts
John Toon
404-894-6986


Abby Vogel
404-385-3364


Technical Contact
Vladimir Tsukruk
404-894-6081

Copyright © Georgia Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Thin films

Electronic circuits with reconfigurable pathways closer to reality January 26th, 2015

News and information

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Nanomedicine

Engineering self-assembling amyloid fibers January 26th, 2015

Promising use of nanodiamonds in delivering cancer drug to kill cancer stem cells: NUS study shows that delivery of Epirubicin by nanodiamonds resulted in a normally lethal dosage of Epirubicin becoming a safe and effective dosage for treatment of liver cancer January 26th, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

2nd International Conference on Infectious Diseases & Nanomedicine (December 15-18, 2015, Kathmandu, NEPAL) January 22nd, 2015

Sensors

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Announcements

Nanoparticles Increase Durability of Concrete Decorations in Cold Areas January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Environment

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Magnetic Nanosorbents Able to Eliminate Chemical Contaminants January 19th, 2015

Malaysian Nanotechnology Company Nanopac Innovation Ltd. lists on the NSX January 19th, 2015

Iran Designs Magnetic Nano-Absorbents Cleaning Chemical Pollutants January 11th, 2015

Energy

Visualizing interacting electrons in a molecule: Scientists at Aalto University and the University of Zurich have succeeded in directly imaging how electrons interact within a single molecule January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

New technique helps probe performance of organic solar cell materials January 23rd, 2015

Industrial

Detection of Heavy Metals in Samples with Naked Eye January 26th, 2015

Iranian Scientists Produce Graphene-Based Oxygen Sensor January 23rd, 2015

Teijin to Participate in Nano Tech 2015 January 22nd, 2015

Materials - Next-generation insulation ... January 13th, 2015

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

OCSiAl supports NanoART Imagery Contest January 23rd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

Laser-generated surface structures create extremely water-repellent metals: Super-hydrophobic properties could lead to applications in solar panels, sanitation and as rust-free metals January 20th, 2015

NREL Scientist Brian Gregg Named AAAS Fellow: Gregg honored for distinguished contributions to the field of organic solar photoconversion January 20th, 2015

Nanobiotechnology

Nanoshuttle wear and tear: It's the mileage, not the age January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

DNA 'glue' could someday be used to build tissues, organs January 14th, 2015

Photonic crystal nanolaser biosensor simplifies DNA detection: New device offers a simpler and potentially less expensive way to detect DNA and other biomolecules through changes in surface charge density or solution pH January 13th, 2015

Solar/Photovoltaic

Visualizing interacting electrons in a molecule: Scientists at Aalto University and the University of Zurich have succeeded in directly imaging how electrons interact within a single molecule January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

New technique helps probe performance of organic solar cell materials January 23rd, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE