Home > Press > Taking the 3D Measure of Macromolecules
|The 3D plasmon ruler is constructed from five gold nanorods in which one nanorod (red) is placed perpendicular between two pairs of parallel nanorods (yellow and green).|
Berkeley Lab 3D plasmon rulers may offer unprecedented view of critical biological events
Taking the 3D Measure of Macromolecules
Berkeley, CA | Posted on June 16th, 2011
The world's first three-dimensional plasmon rulers, capable of measuring nanometer-scale spatial changes in macromolecular systems, have been developed by researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab), in collaboration with researchers at the University of Stuttgart, Germany. These 3D plasmon rulers could provide scientists with unprecedented details on such critical dynamic events in biology as the interaction of DNA with enzymes, the folding of proteins, the motion of peptides or the vibrations of cell membranes.
"We've demonstrated a 3D plasmon ruler, based on coupled plasmonic oligomers in combination with high-resolution plasmon spectroscopy, that enables us to retrieve the complete spatial configuration of complex macromolecular and biological processes, and to track the dynamic evolution of these processes," says Paul Alivisatos, director of Berkeley Lab and leader of this research.
Alivisatos, who is also the Larry and Diane Bock Professor of Nanotechnology at the University of California (UC), Berkeley, is the senior author of a paper in the journal Science describing this research. The paper is titled "Three-Dimensional Plasmon Rulers." Co-authoring this paper were Laura Na Liu, who at the time the work was done was a member of Alivisatos' research group but is now with Rice University, and Mario Hentschel, Thomas Weiss and Harald Giessen with the University of Stuttgart.
The nanometer scale is where the biological and materials sciences converge. As human machines and devices shrink to the size of biomolecules, scientists need tools by which to precisely measure minute structural changes and distances. To this end, researchers have been developing linear rulers based on the electronic surface waves known as "plasmons," which are generated when light travels through the confined dimensions of noble metal nanoparticles or structures, such as gold or silver.
"Two noble metallic nanoparticles in close proximity will couple with each other through their plasmon resonances to generate a light-scattering spectrum that depends strongly on the distance between the two nanoparticles," Alivisatos says. "This light-scattering effect has been used to create linear plasmon rulers that have been used to measure nanoscale distances in biological cells."
Compared to other types of molecular rulers, which are based on chemical dyes and fluorescence resonance energy transfer (FRET), plasmon rulers neither blink nor photobleach, and also offer exceptional photostability and brightness. However, until now plasmon rulers could only be used to measure distances along one dimension, a limitation that hampers any comprehensive understanding of all the biological and other soft-matter processes that take place in 3D.
"Plasmonic coupling in multiple nanoparticles placed in proximity to each other leads to light scattering spectra that are sensitive to a complete set of 3D motions," says Laura Na Liu, corresponding author of the Science paper. "The key to our success is that we were able to create sharp spectral features in the otherwise broad resonance profile of plasmon-coupled nanostructures by using interactions between quadrupolar and dipolar modes."
Liu explains that typical dipolar plasmon resonances are broad because of radiative damping. As a result, the simple coupling between multiple particles produces indistinct spectra that are not readily converted into distances. She and her co-authors overcame this problem with a 3D ruler constructed from five gold nanorods of individually controlled length and orientation, in which one nanorod is placed perpendicular between two pairs of parallel nanorods to form a structure that resembles the letter H.
"The strong coupling between the single nanorod and the two parallel nanorod pairs suppresses radiative damping and allows for the excitation of two sharp quadrupolar resonances that enable high-resolution plasmon spectroscopy," Liu says. "Any conformational change in this 3D plasmonic structure will produce readily observable changes in the optical spectra."
Not only did conformational changes in their 3D plasmon rulers alter light scattering wavelengths, but the spatial freedom afforded its five nanorods also enabled Liu and her colleagues to distinguish the direction as well as the magnitude of structural changes.
"As a proof of concept, we fabricated a series of samples using high-precision electron beam lithography and layer-by-layer stacking nanotechniques, then embedded them with our 3D plasmon rulers in a dielectric medium on a glass substrate," Liu says. "Experimental results were in excellent agreement with the calculated spectra."
Alivisatos, Liu and their collaborators at Stuttgart envision a future in which 3D plasmon rulers would, through biochemical linkers, be attached to a sample macromolecule, for example, to various points along a strand of DNA or RNA, or at different positions on a protein or peptide. The sample macromolecule would then be exposed to light and the optical responses of the 3D plasmon rulers would be measured via dark field microspectroscopy.
"The realization of 3D plasmon rulers using nanoparticles and biochemical linkers is challenging, but 3D nanoparticle assemblies with desired symmetries and configurations have been already been demonstrated," Liu says. "We believe these exciting experimental achievements along with the introduction of our new concept will pave the road toward the realization of 3D plasmon rulers in biological and other soft-matter systems."
This research was supported by grants from the National Institutes of Health NIH Plasmon Rulers Project and the German Ministry of Science.
For more information about the research of Paul Alivisatos: www.cchem.berkeley.edu/pagrp/
For more information about the 3D plasmon ruler research at the University of Stuttgart visit the Website at www.pi4.uni-stuttgart.de
About Lawrence Berkeley National Laboratory
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 12 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov.
For more information, please click here
Copyright © Lawrence Berkeley National Laboratory
If you have a comment, please Contact
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
News and information
Making graphene work for real-world devices: Fundamental research in phonon scattering helps researchers design graphene materials for applications April 24th, 2014
Return on investment for kit and promotion materials April 24th, 2014
Protecting olive oil from counterfeiters April 24th, 2014
NanoSafe, Inc. announces the addition of the Labconco Protector® Glove Box to its NanoSafe Tested™ registry April 23rd, 2014
Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014
Local girl does good March 22nd, 2014
Surface Characteristics Influence Cellular Growth on Semiconductor Material March 12th, 2014
The "Tipping Point" February 12th, 2014
Global leader in solar cell manufacturing eyes New York for major expansion outside of Japan: CNSE and Solar Frontier Explore $700 Million Investment, Job Creation in New York State April 22nd, 2014
University of Waterloo Visits China to Strengthen Bonds With Research Partners April 21st, 2014
Director Wally Pfister joins UC Berkeley neuroengineers to discuss the science behind ‘Transcendence’ April 7th, 2014
First annual science week highlights STEM pipeline and partnerships: UB, SUNY Buffalo State and ECC team up with the City of Buffalo and its schools for April 7-11 events April 3rd, 2014
Characterizing inkjet inks: Malvern Instruments presents new rheological research April 23rd, 2014
MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014
Oxford Instruments Asylum Research Introduces the MFP-3D InfinityTM AFM Featuring Powerful New Capabilities and Stunning High Performance April 18th, 2014
More effective kidney stone treatment, from the macroscopic to the nanoscale April 17th, 2014
National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014
Energy Research Facility Construction Project at Brookhaven Lab Wins U.S. Energy Secretary's Achievement Award April 16th, 2014
IDTechEx Printed Electronics Europe 2014 Award Winners April 1st, 2014
Dais Analytic Wins SBIR Grant: Dais Analytic Receives US Army Small Business Innovation Research Grant to Further Its Demonstrated Successes in Cleaning Most Forms of Wastewater March 28th, 2014
University of Tehran Researchers Invent Non-Enzyme Sensor to Detect Blood Sugar April 23rd, 2014
Gold nanoparticles help target, quantify breast cancer gene segments in a living cell April 23rd, 2014
Guo Lab Shows Potential of RNA as Heat-resistant Polymer Material for Nanoarchitectures April 23rd, 2014
Cloaked DNA nanodevices survive pilot mission: Successful foray opens door to virus-like DNA nanodevices that could diagnose diseased tissues and manufacture drugs to treat them April 22nd, 2014
University of Waterloo Visits China to Strengthen Bonds With Research Partners April 21st, 2014
Novel stapled peptide nanoparticle combination prevents RSV infection, study finds April 17th, 2014
Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014
Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor April 8th, 2014