Featured Research

from universities, journals, and other organizations

New Technique Sees Into Tissue At Greater Depth, Resolution

Date:
September 26, 2008
Source:
Duke University
Summary:
By coupling a kicked-up version of microscopy with miniscule particles of gold, Duke University scientists are now able to peer so deep into living tissue that they can see molecules interacting.

Joseph Izatt, professor of biomedical engineering in Duke's Pratt School of Engineering.
Credit: Image courtesy of Duke University

By coupling a kicked-up version of microscopy with miniscule particles of gold, Duke University scientists are now able to peer so deep into living tissue that they can see molecules interacting.

If future studies in animal models prove fruitful, the researchers believe that their new approach can have a wide spectrum of clinical applications, from studying the margins of a tumor as it is removed from the body to assessing the effects of anti-cancer agents on the blood vessels that nourish tumors.

The Duke bioengineers combined tightly focused heat with optical coherence tomography (OCT), which has often been called the optical equivalent of ultrasound. OCT is commonly used in medical clinics where imaging at the highest resolution is critical, such as in the retina. These experiments represent the first time the technique has been extended to the functional imaging of cells expressing particular molecular receptors.

"This technique could possibly augment traditional methods of deep-tissue molecular imaging with a relatively high resolution," said Melissa Skala, a postdoctoral fellow working in the laboratory of Joseph Izatt, professor of biomedical engineering in Duke's Pratt School of Engineering. "Not only were we able to get better images, we were able to specifically target the types of cells we were looking for."

The results of the Duke research were posted on line by Nano Letters, a journal published by the American Chemical Society. The research was supported by the National Institutes of Health.

For their experiments, the Duke team attached nanospheres of gold to a targeting molecule known as a monoclonal antibody.

Gold is a metal that not only is an efficient conductor of heat, but whose effects in the body are well known. The antibody they used targets epidermal growth factor receptor (EGFR), a cell-surface receptor implicated in cancer.

These "tagged" antibodies were then applied to the surface of a three-dimensional tissue model composed of human cells – both cancerous and non-cancerous. Skala hoped that these antibodies would home in on cells that were overproducing EGFR on their surfaces, an indicator of cancerous activity. Then the photothermal OCT would be able to detect them by showing where the gold spheres were concentrated.

"When we directed the photothermal OCT at the tissue, we found that the cells that were overexpressing EGFR gave off a signal 300 percent higher than cells with low expressions of EGFR," Skala said.

Adding heat to this form of microscopy technique created a phenomenon much like that seen on very hot days, when portions of the pavement far in the distance seem to float or hover above the road.

"The heat causes a distortion in the way light is reflected off the gold nanospheres in a characteristic way," Skala explained. "As we changed the temperature, the light pathways would change in measurable ways."

In this manner, Skala explained, they were not only able to "see" cells within the tissue, but they were able to capture the molecular function of an antibody attaching to a receptor.

"The use of metal nanoparticles as contrast agents with photothermal OCT technology could lead to a host of potential clinical applications," Izatt said. "Organically-based contrast agents can cause damage or death to the targeted cells, while metal nanospheres are relatively safer."

"Also, given the wide range of nanoparticle shapes and sizes, coupled with the ability to 'tune" the optical wavelength of the OCT, we can customize our approach to many different target types," Izatt said.

Skala plans to expand the use of this approach in animal models to better understand the role of different cancer therapies. Tumors with elevated levels of EGFR are known to have a poor prognosis, and she plans to use photothermal OCT to measure how these tumor types react to different therapies.

Other members of the Duke team were Adam Wax, professor of biomedical engineering and his graduate student Matthew Crow. Skala also worked with Mark Dewhirst, a cancer researcher at Duke University Medical Center, and plans further collaborations with the Dewhirst laboratory to apply this technique better understand the fundamentals of cancer.


Story Source:

The above story is based on materials provided by Duke University. Note: Materials may be edited for content and length.


Cite This Page:

Duke University. "New Technique Sees Into Tissue At Greater Depth, Resolution." ScienceDaily. ScienceDaily, 26 September 2008. <www.sciencedaily.com/releases/2008/09/080917095400.htm>.
Duke University. (2008, September 26). New Technique Sees Into Tissue At Greater Depth, Resolution. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2008/09/080917095400.htm
Duke University. "New Technique Sees Into Tissue At Greater Depth, Resolution." ScienceDaily. www.sciencedaily.com/releases/2008/09/080917095400.htm (accessed September 18, 2014).

Share This



More Health & Medicine News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Cost of Ebola

The Cost of Ebola

Reuters - Business Video Online (Sep. 18, 2014) As Sierra Leone prepares for a three-day "lockdown" in its latest bid to stem the spread of Ebola, Ciara Lee looks at the financial implications of fighting the largest ever outbreak of the disease. Video provided by Reuters
Powered by NewsLook.com
What HealthKit Bug Means For Your iOS Fitness Apps

What HealthKit Bug Means For Your iOS Fitness Apps

Newsy (Sep. 18, 2014) Apple has delayed the launch of the HealthKit app platform, citing a bug. Video provided by Newsy
Powered by NewsLook.com
Residents Vaccinated as Haiti Fights Cholera Epidemic

Residents Vaccinated as Haiti Fights Cholera Epidemic

AFP (Sep. 18, 2014) Haitians receive the second dose of the vaccine against cholera as part of the UN's vaccination campaign. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Artificial Sweetener Could Promote Diabetes

Artificial Sweetener Could Promote Diabetes

Newsy (Sep. 17, 2014) Doctors once thought artificial sweeteners lacked the health risks of sugar, but a new study says they can impact blood sugar levels the same way. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins