Corporate Banner
Satellite Banner
Biomolecular Screening
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Tiny Probes Shine Brightly to Reveal the Location of Targeted Tissues

Published: Friday, November 23, 2012
Last Updated: Friday, November 23, 2012
Bookmark and Share
Called BRIGHTs, the tiny probes described in the online issue of Advanced Materials, bind to biomarkers of disease and, when swept by an infrared laser, light up to reveal their location.

Tiny as they are, the probes are exquisitely engineered objects: gold nanoparticles covered with molecules called Raman reporters, in turn covered by a thin shell of gold that spontaneously forms a dodecahedron.

The Raman reporters are molecules whose jiggling atoms respond to a probe laser by scattering light at characteristic wavelengths.

The shell and core create an electromagnetic hotspot in the gap between them that boosts the reporters’ emission by a factor of nearly a trillion.

BRIGHTs shine about 1.7 x 1011 more brightly than isolated Raman reporters and about 20 times more intensely than the next-closest competitor probe, says Srikanth Singamaneni, PhD, assistant professor of mechanical engineering and materials science in the School of Engineering & Applied Science at Washington University in St. Louis.

Goosing the signal from Raman reporters

Singamaneni and his postdoctoral research associate Naveen Gandra, PhD, tried several different probe designs before settling on BRIGHTS.

Singamaneni’s lab has worked for years with Raman spectroscopy, a spectroscopic technique that is used to study the vibrational modes (bending and stretching) of molecules. Laser light interacts with these modes and the molecule then emits light at higher or lower wavelengths that are characteristic of the molecule.

Spontaneous Raman scattering, as this phenomenon is called, is by nature very weak, but 30 years ago scientists accidently stumbled on the fact that it is much stronger if the molecules are adsorbed on roughened metallic surfaces. Then they discovered that molecules attached to metallic nanoparticles shine even brighter than those attached to rough surfaces.

The intensity boost from surface-enhanced Raman scattering, or SERS, is potentially huge. “It’s well-known that if you sandwich Raman reporters between two plasmonic materials, such as gold or silver, you are going to see dramatic Raman enhancement,” Singamaneni says.

Originally his team tried to create intense electromagnetic hot spots by sticking smaller particles onto a larger central particle, creating core-satellite assemblies that look like daisies.

“But we realized these assemblies are not ideal for bioimaging,” he says, “because the particles were held together by weak electrostatic interactions and the assemblies were going to come apart in the body.”

Next they tried using something called Click chemistry to make stronger covalent bonds between the satellites and the core.

“We had some success with those assemblies,” Singamaneni says, “but in the meantime we had started to wonder if we couldn’t make an electromagnetic hot spot within a single nanoparticle rather than among particles.

“It occurred to us that if we put Raman reporters between the core and shell of a single particle could we create an internal hotspot.”

That idea worked like a charm.

A rainbow of probes carefully dispensing drugs?

The next step, says Singamaneni, is to test BRIGHTS in vivo in the lab of Sam Achilefu, PhD, professor of radiology in the School of Medicine.

But he’s already thinking of ways to get even more out of the design.

Since different Raman reporter molecules respond at different wavelengths, Singamaneni says, it should be possible to design BRIGHTS targeted to different biomolecules that also have different Raman reporters and then monitor them all simultaneously with the same light probe.

And he and Gandra would like to combine BRIGHTS with a drug container of some kind, so that the containers could be tracked in the body and the drug and released only when it reached the target tissue, thus avoiding many of the side effects patients dread.

Good things, as they say, come in small packages.


Further Information

Join For Free

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 3,100+ scientific posters on ePosters
  • More than 4,500+ 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

Midlife Changes in Alzheimer’s Biomarkers May Predict Dementia
Studying brain scans and cerebrospinal fluid of healthy adults, scientists have shown that changes in key biomarkers of Alzheimer's disease during midlife may help identify those who will develop dementia years later, according to new research.
Tuesday, July 07, 2015
Unusual Comparison Nets New Sleep Loss Marker
Paul Shaw, PhD, a researcher at Washington University School of Medicine in St. Louis, uses what he learns in fruit flies to look for markers of sleep loss in humans.
Wednesday, May 08, 2013
Scientific News
Advancing Protein Visualization
Cryo-EM methods can determine structures of small proteins bound to potential drug candidates.
Breast Cancer Drug Hope
A drug for breast cancer that is more effective than existing medicines may be a step closer thanks to new research.
Harnessing Nature’s Vast Array of Venoms for Drug Discovery
Scripps scientists have developed a method for rapidly identifying venoms.
A New Platform for Discovering Antibiotics
Harvard chemists hope to shorten time, difficulty in measuring their effectiveness, potential.
The Need for Speed
Evaluating MALDI-TOF as a high-throughput screening technology for the pharmaceutical industry.
Antarctic Sponge Extract Kills MRSA
New findings may provide opportunity for developing new drugs to fight dangerous bacteria currently highly resistant to treatment.
US-India Collab Finds Molecular Signatures of Severe Malaria
Study may be a significant advancement in understanding the causes of severe malaria.
Novel Way to Prevent Deadly Bacterial Infections
Monash scientists may have found a way to stop deadly bacteria from infecting patients. The discovery could lead to a whole new way of treating antibiotic-resistant “superbugs”
Gene Expression Controls Revealed
Researchers have modelled every atom in a key part of the process for switching on genes, revealing a whole new area for potential drug targets.
An Old-New Weapon Against Emerging Chikungunya Virus
Researchers utilize existing drugs to interfere with host factors required for replication of Chikungunya virus.
SELECTBIO

SELECTBIO Market Reports
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
3,100+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,500+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!