Featured Research

from universities, journals, and other organizations

Engineers Improve Plastic's Potential For Use In Implants By Linking It To Biological Material

Date:
May 17, 2005
Source:
University Of Texas At Austin
Summary:
Engineers at The University of Texas at Austin have found a way to modify a plastic to anchor molecules that promote nerve regeneration, blood vessel growth or other biological processes. In the study led by Dr. Christine Schmidt, the researchers identified a piece of protein from among a billion candidates that could perform the unusual feat of attaching to polypyrrole.

Christine Schmidt, associate professor of biomedical engineering, led the study published in Nature Materials that identified a biological material, or peptide, that will allow the plastic polypyrrole to be used to enhance nerve regeneration or other biological processes.
Credit: Photo : Marsha Miller

Engineers at The University of Texas at Austin have found a way to modify a plastic to anchor molecules that promote nerve regeneration, blood vessel growth or other biological processes.

In the study led by Dr. Christine Schmidt, the researchers identified a piece of protein from among a billion candidates that could perform the unusual feat of attaching to polypyrrole, a synthetic polymer (plastic) that conducts electricity and has shown promise in biomedical applications. When the protein piece, or peptide, was linked to a smaller protein piece that human cells like to attach to, polypyrrole gained the ability to attach to cells grown in flasks in the laboratory.

“It will be very useful from a biomedical standpoint to be able to link factors to polypyrrole in the future that stimulate nerve growth or serve other functions,” said Schmidt, an associate professor of biomedical engineering at the university.

Schmidt is the principal author for the study conducted with colleague Dr. Angela Belcher at Massachusetts Institute of Technology. It was published online May 15 by the journal Nature Materials.

Polypyrrole is of interest for tissue engineering and other purposes because it is a non-toxic plastic that conducts electricity. As a result, it could be used to extend previous experiments in Schmidt’s laboratory. The experiments involve wrapping a tiny strip of plastic around damaged, cable-like extensions of nerve cells called neurites to help them regenerate.

“We can apply an electric field to this synthetic material and enhance neurite repair,” said Schmidt. The newly gained ability to attach proteins to polypyrrole, she said, will mean that growth-enhancing factors could also be linked to this plastic wrapping, further stimulating neurite regeneration.

Working with Schmidt and Belcher, the paper’s lead authors, graduate students Archit Sanghvi and Kiley Miller identified the peptide that attaches to polypyrrole from among the billion alternatives initially analyzed. These unique peptides were displayed on the outer surface of a harmless type of virus called a bacteriophage that was purchased commercially.

To hunt for the plastic-preferring peptide, Sanghvi and Miller added a solution containing bacteriophages that displayed different peptides to a container with polypyrrole stuck on its inner surface. The bacteriophages that didn’t wash away when exposed to conditions that hinder attachment were retested on a new polypyrrole-coated container, a process that was repeated four more times.

The sticky peptide selected, known as T59, is a string of 12 amino acids. To make certain that something else on the outer surface of the bacteriophage virus wasn’t responsible for its perceived stickiness, the researchers demonstrated that T59 by itself could attach to immobilized polypyrrole, using synthetic copies of it made at the university’s Institute for Cellular and Molecular Biology. In addition, they determined that a certain amino acid, aspartic acid, had to be a part of T59 for it to attach well to the plastic.

Aspartic acid carries a negative charge, which in T59 appeared to be drawn to the positively charged surface of the polypyrrole the way magnets of opposite charges cling together. Yet other peptides containing aspartic acid didn’t attach to polypyrrole, leading the researchers to speculate that something contributed by the other amino acids in T59 influenced its 3-dimensional shape in a way that augmented its plastic preference.

“This aspartic acid is just one piece of the puzzle,” Sanghvi said. “There are still more pieces to put together.”

The researchers also evaluated how well T59 clings to polypyrrole. They attached copies of the peptide to the tip of an atomic force microscope at the university’s Center for Nano- and Molecular Science and Technology. The tip of this specialized microscope is normally passed across the surface of a material to “map” its peaks and valleys. In this case, the surface was a layer of polypyrrole, and the resistance of the peptide-coated tip to being passed across the surface revealed how well T59 clung to the plastic.

“They had a moderately strong interaction, which is useful to know,” Schmidt said, referring to the need for a stable attachment between polypyrrole and biological molecules that T59 would be used to link to.

Schmidt’s laboratory intends to study T59 as a linker to other molecules in the future, possibly including vascular endothelial growth factor, which stimulates the growth of new blood vessels. In addition, they will use the bacteriophage analysis approach, called high-throughput combinatorial screening, to look for peptide linkers for other plastics such as polyglycolic acid under study for tissue-repair or tissue-engineering purposes.

“This is a powerful technique that can be used for biomaterials modification,” Schmidt said, “and it hasn’t really been explored very much until now.”

This research was funded by the Gillson Longenbaugh Foundation and the Welch Foundation.


Story Source:

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


Cite This Page:

University Of Texas At Austin. "Engineers Improve Plastic's Potential For Use In Implants By Linking It To Biological Material." ScienceDaily. ScienceDaily, 17 May 2005. <www.sciencedaily.com/releases/2005/05/050517112846.htm>.
University Of Texas At Austin. (2005, May 17). Engineers Improve Plastic's Potential For Use In Implants By Linking It To Biological Material. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2005/05/050517112846.htm
University Of Texas At Austin. "Engineers Improve Plastic's Potential For Use In Implants By Linking It To Biological Material." ScienceDaily. www.sciencedaily.com/releases/2005/05/050517112846.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. 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