Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Twinkling nanostars cast new light into biomedical imaging

Research team members stand with equipment used for gyromagnetic imaging of gold nanostars. From left are graduate students Hyon-Min Song, Qingshan Wei and Dongmyung Oh; chemistry professor Alexander Wei; graduate student Jacob Hale; and associate professor of physics Kenneth Ritchie. (Purdue University photo/Andrew Hancock)
Research team members stand with equipment used for gyromagnetic imaging of gold nanostars. From left are graduate students Hyon-Min Song, Qingshan Wei and Dongmyung Oh; chemistry professor Alexander Wei; graduate student Jacob Hale; and associate professor of physics Kenneth Ritchie. (Purdue University photo/Andrew Hancock)

Abstract:
Purdue University researchers have created magnetically responsive gold nanostars that may offer a new approach to biomedical imaging

Twinkling nanostars cast new light into biomedical imaging

West Lafayette, IN | Posted on July 21st, 2009

The nanostars gyrate when exposed to a rotating magnetic field and can scatter light to produce a pulsating or "twinkling" effect. This twinkling allows them to stand out more clearly from noisy backgrounds like those found in biological tissue.

Alexander Wei, a professor of chemistry, and Kenneth Ritchie, an associate professor of physics, led the team that created the new gyromagnetic imaging method.

"This is a very different approach to enhancing contrast in optical imaging," said Wei, who also is a member of the Purdue University Center for Cancer Research and the Oncological Sciences Center. "Brighter isn't necessarily better for imaging; the real issue is background noise, and you can't always overcome this simply by creating brighter particles. With gyromagnetic imaging we can zero in on the nanostars by increasing signal strength while cutting down on background noise."

The gold nanostars are about 100 nanometers from tip to tip and contain an iron-oxide core that causes them to spin when exposed to a rotating magnet. The arms of the nanostar are designed to respond to a light source and reflect light to a camera when properly aligned. This gives nanostars the appearance of twinkling at rates that can be precisely controlled by the speed of the rotating magnetic field. The unique signature of the twinkling nanostars enables them to be picked out easily from a field of stationary particles, some of which can be brighter than the nanostars.

Any signal that doesn't have the frequency corresponding to the rotating magnetic field can be suppressed in the images, eliminating background noise, Ritchie said.

"It was surprising how well this method enhanced the imaging," he said. "It can improve the contrast of the particles to the background noise by more than 20 decibels and can clearly reveal a gyrating nanostar, where with existing direct imaging methods in many cases you wouldn't be able to definitively find a particle."

Gold nanostars and other gold nanoparticles have recently been examined as contrast agents for biomedical imaging because of their brightness at near-infrared wavelengths, which can penetrate through tissue better than visible light. However, giving them the ability to twinkle was key to developing a novel dynamic imaging method, Wei said.

"Gyromagnetic nanostars combine strong optical signaling with a unique mechanism for reducing noise, allowing one to pick out the proverbial needle from the haystack," Wei said. "The key is to enable the nanostars to twinkle at a frequency of our choosing. Our analysis picks out signals at that frequency and translates that information into images of remarkable clarity."

A paper detailing the team's work is featured on the cover of the July 22 issue of the Journal of the American Chemical Society. In addition to Wei and Ritchie, co-authors include graduate students Qingshan Wei, Hyon-Min Song, Jacob A. Hale, Dongmyung Oh, Quy K. Ong and postdoctoral research associate Alexei P. Leonov.

The National Institutes of Health funded the research.

To perform gyromagnetic imaging, the team placed a sample of cells containing nanostars under a standard microscope equipped with a white light source and a rotating magnet. Light was sent through a polarizing beam splitter and into the sample, then reflected back through the beam splitter and to the camera. The camera collected images at 120 frames per second, capturing the signal from the nanostars as they spun at approximately five revolutions per second.

The set-up is simple and practical for general laboratory use, Ritchie said.

"To translate a new imaging technique into something practical for broad use, it needs to be done without specialized equipment," he said. "Many other imaging techniques require expensive equipment or lasers, but this method can be done with a halogen lamp and a $10,000 camera."

After initial data is collected, mathematical operations such as Fourier transforms can be applied to obtain frequency information from the pulsating light signals, allowing the twinkling nanostars to be easily picked out.

The use of Fourier transforms in imaging techniques, often referred to as Fourier-domain imaging, is already known to be useful for reducing noise, but the research team's method allows a mechanical frequency to be used as input for selective Fourier-based imaging, Wei said.

"We have external control over the speed of rotation, so we will always know what frequency to focus on when looking for nanostars," he said.

In testing whether nanostars might harm cells during the imaging process, the researchers found that the particles were not only biocompatible, but could actually promote cell growth, Wei said. The team is continuing to investigate the biological effects of nanostars inside cells.

####

About Purdue University
Purdue University, located in West Lafayette, Indiana, U.S., is the flagship university of the six campuses within the Purdue University System. Purdue currently ranks 9th among America's Best Undergraduate Engineering Programs according to U.S. News & World Report, and is often regarded as one of the top engineering schools in the world. While Purdue offers many diverse majors, it is perhaps best known for the Purdue University College of Engineering. With its highly competitive engineering curriculum and its leading programs in aerospace, electrical, and mechanical, Purdue is consistently regarded as one of the top technology schools in the world. The university was responsible for developing several innovations, such as the Wiki, and produced pioneers of robotics and remote control technology.

From Wikipedia, the free encyclopedia

For more information, please click here

Contacts:
Writer: Elizabeth K. Gardner, (765) 494-2081,

Sources: Alexander Wei, 765-494-5257,

Kenneth Ritchie, 765-496-8315,

Purdue News Service: (765) 494-2096;

Copyright © Purdue University

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

Fonon Announces 3D Metal Sintering Technology: Emerging Additive Nano Powder Manufacturing Technology August 28th, 2014

Ultra-Low Frequency Vibration Isolation Stabilizes Scanning Tunneling Microscopy at UCLA’s Nano-Research Group August 28th, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

Possible Futures

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

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

Local girl does good March 22nd, 2014

Nanomedicine

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

PetLife Comments on CNN Story on Scorpion Venom Health Benefits August 27th, 2014

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Introducing the multi-tasking nanoparticle: Versatile particles offer a wide variety of diagnostic and therapeutic applications August 26th, 2014

Announcements

Leading European communications companies and research organizations have launched an EU project developing the future 5th Generation cellular mobile networks August 28th, 2014

Ultra-Low Frequency Vibration Isolation Stabilizes Scanning Tunneling Microscopy at UCLA’s Nano-Research Group August 28th, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

Nanobiotechnology

The channel that relaxes DNA: Relaxing DNA strands by using nano-channels: Instructions for use August 20th, 2014

Сalculations with Nanoscale Smart Particles August 19th, 2014

Interaction between Drug, DNA for Designing Anticancer Drugs Studied in Iran August 17th, 2014

Scientists fold RNA origami from a single strand: RNA origami is a new method for organizing molecules on the nanoscale. Using just a single strand of RNA, this technique can produce many complicated shapes. August 14th, 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