Featured Research

from universities, journals, and other organizations

Shape-memory Polymers Designed For Biomedical Applications

Date:
January 10, 2008
Source:
Georgia Institute of Technology
Summary:
Researchers are developing unique shape-memory polymers, which change shape upon heating, to open blocked arteries, probe neurons in the brain and engineer a tougher spine.

Ken Gall, a professor in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering, reaches inside a thermo-mechanical test frame, which is designed to measure properties of the polymers under environmental conditions simulating the human body.
Credit: Gary Meek

Researchers at the Georgia Institute of Technology are developing unique polymers, which change shape upon heating, to open blocked arteries, probe neurons in the brain and engineer a tougher spine.

These so-called shape-memory polymers can be temporarily stretched or compressed into forms several times larger or smaller than their final shape. Then heat, light or the local chemical environment triggers a transformation into their permanent shape.

"My focus has been to optimize these polymers for many different biomedical applications. My lab studies how altering the chemistry and structure of the polymers affects their chemical, biological and mechanical properties," said Ken Gall, a professor in the George W. Woodruff School of Mechanical Engineering and School of Materials Science and Engineering.

The mechanical properties of these polymers make them extremely attractive for many biomedical applications, according to Gall, who described his research in this area during two presentations at the Materials Research Society's fall meeting in November.

Engineers are always searching for materials that display unconventional properties able to satisfy the severe requirements for implantation in the body. Particular attention must be paid to the biofunctionality, biostability and biocompatibility of these materials, which come into contact with tissue and body fluids.

With funding from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health (NIH), Gall proposed replacing metallic cardiovascular stents with plastic ones because polymers more closely resemble soft biological tissue. Plus, polymers can be designed to gradually dissolve in the body.

"Metal stents are frequently covered in plastic anyway, so we set out to remove the metal leaving just a polymer sheath," explained Gall. "Also, polymers are more flexible and do not stress the artery walls like the metals."

Gall's research group has designed a shape-memory polymer stent that can be compressed and fed through a tiny hole in the body into a blocked artery, just like a conventional stent. Then, the warmth of the body triggers the polymer's expansion into its permanent shape, resulting in natural deployment without auxiliary devices. This work was published in the journal Biomaterials earlier this year.

For another project, Gall and graduate student David Safranski have been investigating how altering a polymer's chemistry changes its properties, such as stretchiness. This project was funded by MedShape Solutions, an Atlanta company that Gall co-founded to develop medical devices primarily for use in minimally invasive surgery.

"You can tailor the polymer to moderate its strength, stiffness, stretchiness and expansion rate," noted Gall.

They found that by changing the chemistry of the polymer backbone to include special side groups, they could increase of the amount of strain the polymer could withstand before failing without sacrificing stiffness. This discovery enabled the creation of polymers that could stretch farther and also push harder during recovery.

Gall and graduate student Scott Kasprzak are exploring how these polymers might be used as a deployable neuronal probe, with funding from the National Institute of Neurological Disorders and Stroke of the NIH.

"We're looking for smart materials that can be synthesized in the size range of 100 microns -- similar to the size of a strand of hair -- and then be inserted into brain tissue," explained Gall. "This type of probe would need to slowly change shape inside the brain as to not disturb any surrounding tissue."

Another project in Gall's laboratory is examining the use of these polymers for the spine. Most spinal surgeries are currently not performed arthroscopically, so Gall sees benefits in using these shape-memory materials to enable minimally invasive spinal surgery.

With funding from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), Gall and graduate student Kathryn Smith are developing shape-memory polymers for the spine that are tough -- meaning they stretch far and support a lot of weight like native spinal disks.

"This would improve the deliverability and life of artificial disks currently used in the spine. Essentially, we're just trying to engineer tougher synthetic polymers that can be easily delivered," explained Gall, who is collaborating on this project with Barbara Boyan and Johnna Temenoff, both of the Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

In addition to exploring different biomedical applications for shape-memory polymers, Gall has also turned his attention to manufacturing them. Walter Voit, a graduate student in the Technological Innovation: Generating Economic Results (TI:GER) program, is investigating how to produce shape-memory polymers at a low cost. More specifically, Voit is examining different types of materials and processing methods that can be used to commercially produce quality polymers for lower cost medical applications.

The NIAMS-funded project was supported by Grant R21AR054339. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIAMS or the NIH.


Story Source:

The above story is based on materials provided by Georgia Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Georgia Institute of Technology. "Shape-memory Polymers Designed For Biomedical Applications." ScienceDaily. ScienceDaily, 10 January 2008. <www.sciencedaily.com/releases/2008/01/080103101124.htm>.
Georgia Institute of Technology. (2008, January 10). Shape-memory Polymers Designed For Biomedical Applications. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2008/01/080103101124.htm
Georgia Institute of Technology. "Shape-memory Polymers Designed For Biomedical Applications." ScienceDaily. www.sciencedaily.com/releases/2008/01/080103101124.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. 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