Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Nanoparticles Reach New Peaks

Published: Wednesday, January 09, 2013
Last Updated: Wednesday, January 09, 2013
Bookmark and Share
Rice University researchers show short laser pulses selectively heat gold nanoparticles.

Plasmonic gold nanoparticles make pinpoint heating on demand possible. Now Rice University researchers have found a way to selectively heat diverse nanoparticles that could advance their use in medicine and industry.

Rice scientists led by Dmitri Lapotko and Ekaterina Lukianova-Hleb showed common gold nanoparticles, known since the 19th century as gold colloids, heat up at near-infrared wavelengths as narrow as a few nanometers when hit by very short pulses of laser light. The surprising effect reported in Advanced Materials appears to be related to nonstationary optical excitation of plasmonic nanoparticles. Plasmons are free electrons on the surface of metals that become excited by the input of energy, typically from light. Moving plasmons can transform optical energy into heat.

“The key idea with gold nanoparticles and plasmonics in general is to convert energy,” Lapotko said. “There are two aspects to this: One is how efficiently you can convert energy, and here gold nanoparticles are world champions. Their optical absorbance is about a million times higher than any other molecules in nature.

“The second aspect is how precisely one can use laser radiation to make this photothermal conversion happen,” he said. Particles traditionally respond to wide spectra of light, and not much of it is in the valuable near-infrared region. Near-infrared light is invisible to water and, more critically for biological applications, to tissue.

“This was the problem,” Lapotko said. “All nanoparticles, beginning with solid gold colloids and moving to more sophisticated, engineered gold nanoshells, nanorods, cages and stars, have very wide spectra, typically about 100 nanometers, which means we were allowed to use only one type of nanoparticle at a time. If we tried to use different types, their spectra overlapped and we did not benefit from the high tunability of lasers.”

The discovery allows controlled laser pulses to tune the absorbance spectrum of plain gold colloids, Lapotko said. “This novel approach is counter to the established paradigm that assumes optical properties of nanoparticles are pre-set during their fabrication and stay constant during their optical excitation,” he said.

The Rice lab showed basic colloidal gold nanoparticles could be efficiently activated by a short laser pulse at 780 nanometers, with an 88-fold amplification of the photothermal effect seen with a continuous laser. The researchers repeated their experiment with nanoparticle clusters in water, in living cancer cells and in animals, with the same or better results: they showed spectral peaks two nanometers wide. Such narrow photothermal spectra had never been seen for metal nanoparticles, either singularly or in clusters.

The effect appears to depend on vapor nanobubbles that form when the particles heat liquid in their immediate environment. The nanobubbles grow and burst in an instant. “Instead of using the nanoparticle as a heat sink with a continuous, stationary laser, we’re creating a transient, nonstationary situation in which the particle interacts with the incident laser in a totally different way,” Lapotko said. He said the effect is repeatable and works with laser pulses shorter than 100 picoseconds.

Even better, an experiment with mixed nanorods and nanoshells found they responded to laser pulses with strong, distinct signals at wavelengths 10 nanometers apart. That means two or more types of nanoparticles in the same location can be selectively activated on demand.

“The nanoparticles we used were nothing fancy; they were used in the 19th century by Michael Faraday, and it was believed they could do nothing in the near-infrared,” he said. “That was the major motivation for people to invent nanorods, nanoshells and the other shapes. Here, we prove these inexpensive particles can behave quite well in near-infrared.” He said the discovery opens the possibility that many metal nanoparticles could be used in biomedical and industrial applications where spectral selectivity and tuning would provide “unprecedented” precision.

“This is still more a phenomenon rather than a firmly established mechanism, with a nice theoretical basis,” Lapotko said. “But when fully clarified, it could become a universal tool.”

Co-authors of the paper are Alexey Volkov, a research scientist at the University of Virginia, and Xiangwei Wu, an associate professor in the Department of Head and Neck Surgery at the University of Texas MD Anderson Cancer Center. Lapotko is a faculty fellow in biochemistry and cell biology, and Lukianova-Hleb is a research scientist at Rice.

The National Institutes of Health supported the research.


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,400+ scientific posters on ePosters
  • More Than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Bacteria Use DNA Replication to Time Key Decision
Rice University researchers have found that in spore-forming bacteria, chromosomal locations of genes can couple the DNA replication cycle to critical decisions about whether to reproduce or form spores.
Monday, July 13, 2015
Massive Genome Shift in one Generation
A team of biologists has discovered that an agricultural pest that began plaguing U.S. apple growers in the 1850s likely did so after undergoing extensive and genome-wide changes in a single generation.
Tuesday, June 16, 2015
DNA Mutations get Harder to Hide
Rice University researchers have developed a method to detect rare DNA mutations with an approach hundreds of times more powerful than current methods.
Wednesday, May 27, 2015
Amniotic Stem Cells Demonstrate Healing Potential
Rice University, Texas Children’s Hospital study proves cells promote vasculature in hydrogel therapy.
Friday, April 10, 2015
Cells Exercise Suboptimal Strategy to Survive
Rice University study shows it’s not always good for cells’ metabolism to work at peak efficiency.
Thursday, April 09, 2015
Designing A Better Way To Study Stomach Flu
Texas Medical Center team aims to improve research of gastrointestinal disease.
Wednesday, March 18, 2015
Worm Virus Details Come to Light
Rice University scientists have won a race to find the crystal structure of rare nematode virus, known to infect the most abundant animal on Earth.
Wednesday, August 20, 2014
Flu’s Mechanisms Clues Uncovered
Researchers from Rice University and Baylor College of Medicine have analyzed how influenza-related proteins help infect cells.
Tuesday, August 05, 2014
Water-cleanup Catalysts Tackle Biomass Upgrading
Rice University researchers register 4th ‘volcano plot’ for palladium-gold catalysts.
Tuesday, July 01, 2014
Researchers Tune in to Protein Pairs
Rice University team quantifies how mutations affect cell signaling in bacteria.
Tuesday, January 28, 2014
Rice Scientists ID New Catalyst for Cleanup of Nitrites
Gold-palladium nanocatalysts set new mark for breakdown of nitrites.
Monday, December 02, 2013
New Statistical Tools Being Developed for Mining Cancer Data
Team from Rice, BCM, UT Austin tackling big data variety.
Monday, December 02, 2013
Bad Proteins Branch Out
Rice researchers find misfolded proteins are capable of forming tree-like aggregates.
Monday, December 02, 2013
Have iPod, Will Test for Drug Toxicity
Rice students help Houston-based start-up create drug toxicity app.
Thursday, October 31, 2013
Physicists Decode Decision Circuit of Cancer Metastasis
Rice U. research reveals three-way genetic switch for cancer metastasis.
Thursday, October 31, 2013
Scientific News
Study Finds Brain Chemicals that Keep Wakefulness in Check
Researchers to develop new drugs that promote better sleep, or control hyperactivity in people with mania.
Sorting Through Cellular Statistics
Aaron Dinner, professor in chemistry, and his graduate student Herman Gudjonson are trying to read the manual of life, DNA, as part of the Dinner group’s research into bioinformatics—the application of statistics to biological research.
Playing 'Tag' with Pollution lets Scientists See Who's It
Using a climate model that can tag sources of soot from different global regions and can track where it lands on the Tibetan Plateau, researchers have determined which areas around the plateau contribute the most soot — and where.
Women’s Immune System Genes Operate Differently from Men’s
A new technology reveals that immune system genes switch on and off differently in women and men, and the source of that variation is not primarily in the DNA.
Long Telomeres Associated with Increased Lung Cancer Risk
Genetic predisposition for long telomeres predicts increased lung adenocarcinoma risk.
First Artificial Ribosome Designed
Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins and enzymes within the cell.
High-Resolution 3D Images Reveal the Muscle Mitochondrial Power Grid
NIH mouse study overturns scientific ideas on energy distribution in muscle.
Expanding the Brain
A team of researchers has identified more than 40 new “imprinted” genes, in which either the maternal or paternal copy of a gene is expressed while the other is silenced.
Identifying a Key Growth Factor in Cell Proliferation
Researchers discover that aspartate is a limiter of cell proliferation.
Study Uncovers Target for Preventing Huntington’s Disease
Scientists from Cardiff University believe that a treatment to prevent or delay the symptoms of Huntington’s disease could now be much closer, following a major breakthrough.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!