Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > A shiny new tool for imaging biomolecules: Berkeley Lab researchers embed artificial membranes with billions of nanoantennas for enhanced optical studies

Gold triangle nanoparticles paired tip-to-tip in a bow-tie formation, serve as optical antennas. When a protein (green) bound to a fluorescently labeled SOS-catalyst passes through the the gaps between opposing tips of the triangles (plasmonic hot spots) fluorescence is amplified.

Credit: (Image by Groves, et. al., Berkeley Lab)
Gold triangle nanoparticles paired tip-to-tip in a bow-tie formation, serve as optical antennas. When a protein (green) bound to a fluorescently labeled SOS-catalyst passes through the the gaps between opposing tips of the triangles (plasmonic hot spots) fluorescence is amplified.

Credit: (Image by Groves, et. al., Berkeley Lab)

Abstract:
At the heart of the immune system that protects our bodies from disease and foreign invaders is a vast and complex communications network involving millions of cells, sending and receiving chemical signals that can mean life or death. At the heart of this vast cellular signaling network are interactions between billions of proteins and other biomolecules. These interactions, in turn, are greatly influenced by the spatial patterning of signaling and receptor molecules. The ability to observe signaling spatial patterns in the immune and other cellular systems as they evolve, and to study the impact on molecular interactions and, ultimately, cellular communication, would be a critical tool in the fight against immunological and other disorders that lead to a broad range of health problems including cancer. Such a tool is now at hand.

A shiny new tool for imaging biomolecules: Berkeley Lab researchers embed artificial membranes with billions of nanoantennas for enhanced optical studies

Berkeley, CA | Posted on March 24th, 2012

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, have developed the first practical application of optical nanoantennas in cell membrane biology. A scientific team led by chemist Jay Groves has developed a technique for lacing artificial lipid membranes with billions of gold "bowtie" nanoantennas. Through the phenomenon known as "plasmonics," these nanoantennas can boost the intensity of a fluorescent or Raman optical signal from a protein passing through a plasmonic "hot-spot" tens of thousands of times without the protein ever being touched.

"Our technique is minimally invasive since enhancement of optical signals is achieved without requiring the molecules to directly interact with the nanoantenna," Groves says. "This is an important improvement over methods that rely on adsorption of molecules directly onto antennas where their structure, orientation, and behavior can all be altered."

Groves holds joint appointments with Berkeley Lab's Physical Biosciences Division and UC Berkeley's Chemistry Department, and is also a Howard Hughes Medical Institute investigator. He is the corresponding author of a paper that reports these results in the journal NanoLetters. The paper is titled "Single Molecule Tracking on Supported Membranes with Arrays of Optical Nanoantennas." Co-authoring the paper were Theo Lohmuller, Lars Iversen, Mark Schmidt, Christopher Rhodes, Hsiung-Lin Tu and Wan-Chen Lin.

Fluorescent emissions, in which biomolecules of interest are tagged with dyes that fluoresce when stimulated by light, and Raman spectroscopy, in which the scattering of light by molecular vibrations is used to identify and locate biomolecules, are work-horse optical imaging techniques whose value has been further enhanced by the emergence of plasmonics. In plasmonics, light waves are squeezed into areas with dimensions smaller than half-the-wavelength of the incident photons, making it possible to apply optical imaging techniques to nanoscale objects such as biomolecules. Nano-sized gold particles in the shape of triangles that are paired in a tip-to-tip formation, like a bow-tie, can serve as optical antennas, capturing and concentrating light waves into well-defined hot spots, where the plasmonic effect is greatly amplified. Although the concept is well-established, applying it to biomolecular studies has been a challenge because gold particle arrays must be fabricated with well-defined nanometer spacing, and molecules of interest must be delivered to plasmonic hot-spots.

"We're able to fabricate billions of gold nanoantennas in an artificial membrane through a combination of colloid lithography and plasma processing," Groves says. "Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The result is well-defined spacing between each pair of gold triangles in the final array with a tip-to-tip distance between neighboring gold nanotriangles measuring in the 5-to-100 nanometer range."

Until now, Groves says, it has not been possible to decouple the size of the gold nanotriangles, which determines their surface plasmon resonance frequency, from the tip-to-tip distance between the individual nanoparticle features, which is responsible for enhancing the plasmonic effect. With their colloidal lithography approach, a self-assembling hexagonal monolayer of polymer spheres is used to shadow mask a substrate for subsequent deposition of the gold nanoparticles. When the colloidal mask is removed, what remains are large arrays of gold nanoparticles and triangles over which the artificial membrane can be formed.

The unique artificial membranes, which Groves and his research group developed earlier, are another key to the success of this latest achievement. Made from a fluid bilayer of lipid molecules, these membranes are the first biological platforms that can combine fixed nanopatterning with the mobility of fluid bilayers. They provide an unprecedented capability for the study of how the spatial patterns of chemical and physical properties on membrane surfaces influence the behavior of cells.

"When we embed our artificial membranes with gold nanoantennas we can trace the trajectories of freely diffusing individual proteins as they sequentially pass through and are enhanced by the multiple gaps between the triangles," Groves says. "This allows us to study a realistic system, like a cell, which can involve billions of molecules, without the static entrapment of the molecules."

As molecules in living cells are generally in a state of perpetual motion, it is often their movement and interactions with other molecules rather than static positions that determine their functions within the cell. Groves says that any technique requiring direct adsorption of a molecule of interest onto a nanoantenna intrinsically removes that molecule from the functioning ensemble that is the essence of its natural behavior. The technique he and his co-authors have developed allows them to look at individual biomolecules but within the context of their surrounding community.

"The idea that optical nanoantennas can produce the kinds of enhanced signals we are observing has been known for years but this is the first time that nanoantennas have been fabricated into a fluid membrane so that we can observe every molecule in the system as it passes through the antenna array," Groves says. "This is more than a proof-of-concept we've shown that we now have a useful new tool to add to our repertoire."

This research was primarily supported by the DOE Office of Science.

####

About Berkeley Lab
Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science.

For more information, please click here

Contacts:
Lynn Yarris

510-486-5375

Copyright © Berkeley Lab

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

News and information

JPK announces expansion of its global sales and service activities in China and USA April 15th, 2014

Nanobiotix Appoints Thierry Otin as Head of Manufacturing and Supply April 15th, 2014

PAM-XIAMEN Offers UV LED wafer April 15th, 2014

Engineers develop new materials for hydrogen storage April 15th, 2014

Laboratories

Shiny quantum dots brighten future of solar cells: Photovoltaic solar-panel windows could be next for your house April 14th, 2014

No compromises: JILA's short, flexible, reusable AFM probe April 9th, 2014

Imaging

Catching the (Invisible) Wave: UC Santa Barbara researchers create a unique semiconductor that manipulates light in the invisible infrared/terahertz range, paving the way for new and enhanced applications April 11th, 2014

Agilent Technologies Announces Fourth NanoMeasure Scientific Symposium: National Center for Nanoscience and Technology in Beijing to Host Event April 10th, 2014

Hawk Trade Secures Funding and Development Capital for Nanotec Industries: Nanotec Industries successfully negotiates funding for development of nano-sized treatment and imaging delivery device facility through Hawk Trade April 3rd, 2014

Govt.-Legislation/Regulation/Funding/Policy

Engineers develop new materials for hydrogen storage April 15th, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

A molecular approach to solar power: Switchable material could harness the power of the sun ó even when itís not shining April 15th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Discoveries

Engineers develop new materials for hydrogen storage April 15th, 2014

Nanocrystalline cellulose modified into an efficient viral inhibitor April 15th, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

A molecular approach to solar power: Switchable material could harness the power of the sun ó even when itís not shining April 15th, 2014

Announcements

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

A molecular approach to solar power: Switchable material could harness the power of the sun ó even when itís not shining April 15th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Biologists Develop Nanosensors to Visualize Movements and Distribution of Plant Stress Hormone April 15th, 2014

Tools

JPK announces expansion of its global sales and service activities in China and USA April 15th, 2014

Affordable High Precision XY Nanopositioning Piezo Stage April 15th, 2014

Obducat has launched a new generation of SINDREģ Nano Imprint production system April 11th, 2014

Catching the (Invisible) Wave: UC Santa Barbara researchers create a unique semiconductor that manipulates light in the invisible infrared/terahertz range, paving the way for new and enhanced applications April 11th, 2014

Nanobiotechnology

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Biologists Develop Nanosensors to Visualize Movements and Distribution of Plant Stress Hormone April 15th, 2014

In latest generation of tiny biosensors, size isn't everything: UCLA researchers overturn conventional wisdom on nanowire-based diagnostic devices April 11th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Research partnerships

Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor April 8th, 2014

Carbon nanotubes grow in combustion flames April 1st, 2014

Never say never in the nano-world March 31st, 2014

Diamonds are an oil's best friend: Rice University leads research to find the best nanofluid for heat transfer March 31st, 2014

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 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE