Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Researchers engineer new polymers to change their stiffness and strength when exposed to liquids

 Sea cucumbers inspired the design of chemo-responsive nanocomposite with adaptive mechanical properties.

Credit: F. Carpenter
Sea cucumbers inspired the design of chemo-responsive nanocomposite with adaptive mechanical properties.
Credit: F. Carpenter

Abstract:
Case Western Reserve University, VA researchers publish findings in Science

Researchers engineer new polymers to change their stiffness and strength when exposed to liquids

CLEVELAND, OH | Posted on March 6th, 2008

An interdisciplinary team of researchers from the departments of macromolecular science and engineering and biomedical engineering at the Case School of Engineering and the Louis Stokes Cleveland Department of Veterans Affairs Medical Center has published ground-breaking work on a new type of polymer that displays chemoresponsive mechanic adaptability -- meaning the polymer can change from hard to soft plastic and vice versa in seconds when exposed to liquid -- in the March 7, 2008, issue of Science, one of the world's most prestigious scholarly journals covering all aspects of science.

Jeffrey R. Capadona, associate investigator at the VA's Advanced Platform Technology (APT) Center, graduate student Kadhiravan Shanmuganathan, and Case Western Reserve University professors and APT investigators Dustin Tyler (biomedical engineering), Stuart Rowan (macromolecular science) and Christoph Weder (macromolecular science) have unveiled a radically new approach for developing polymer nanocomposites which alter their mechanical properties when exposed to certain chemical stimuli.

"We can engineer these new polymers to change their mechanical properties -- in particular stiffness and strength -- in a programmed fashion when exposed to a specific chemical," says Weder, one of the senior authors of the paper.

"The materials on which we reported in Science were designed to change from a hard plastic -- think of a CD case -- to a soft rubber when brought in contact with water," adds Rowan, who has been Weder's partner on the project for almost six years.

"Our new materials were tailored to respond specifically to water and to exhibit minimal swelling, so they don't soak up water like a sponge," saud Shanmuganathan.

In their new approach, the team used a biomimetic approach -- or mimicking biology -- copying nature's design found in the skin of sea cucumbers.

"These creatures can reversibly and quickly change the stiffness of their skin. Normally it is very soft, but, for example, in response to a threat, the animal can activate its 'body armor' by hardening its skin," explains Capadona, who has a sea cucumber in his aquarium. Marine biologists have shown in earlier studies that the switching effect in the biological tissue is derived from a distinct nanocomposite structure in which highly rigid collagen nanofibers are embedded in a soft connective tissue. The stiffness is mediated by specific chemicals that are secreted by the animal's nervous system and which control the interactions among the collagen nanofibers. When connected, the nanofibers form a reinforcing network which increases the overall stiffness of the material considerably, when compared to the disconnected (soft) state.

Building on their recent success on the fabrication of artificial polymer nanocomposites containing rigid cellulose nanofibers, which earned them the December 2007 cover of Nature Nanotechnology, the team mimicked the architecture nature 'designed' for the sea cucumbers and created artificial materials that display similar mechanical morphing characteristics.

The Case Western Reserve/VA team is specifically interested in using such dynamic mechanical materials in biomedical applications, for example as adaptive substrates for intracortical microelectrodes. These devices are being developed as part of 'artificial nervous systems' that have the potential to help treat patients that suffer from medical conditions such as Parkinson's disease, stroke or spinal cord injuries, i.e., disorders in which the body's interface to the brain is compromised. A problem observed in experimental studies is that the quality of the brain signals recorded by such microelectrodes usually degrades within a few months after implantation, making chronic applications challenging. One hypothesis for this failure is that the high stiffness of these electrodes, which is required for their insertion, causes damage to the surrounding, very soft brain tissue over time. "We believe that electrodes that use mechanically adaptive polymer as substrate could alleviate this problem" explains Dustin Tyler, who specializes in neural interfacing and functional electrical stimulation. The development and testing of experimental microelectrodes that involve the new adaptive materials is currently underway. "That's why we designed our first materials to respond to water" explains Weder. "This allows the rigid electrodes to become soft when implanted into the water-rich brain" he adds.

The Department of Veterans Affairs and the VA Rehabilitation R&D Center of Excellence in Advanced Platform Technology (APT) played an important role in uniting Weder and Rowan with Capadona and Tyler, to conduct research in the area of adaptive nanocomposite materials, which are now fabricated by the new process. The APT center is a cohesive intellectual community that offers its investigators the opportunity to meet regularly, have discussions within and outside of their fields, participate in list-servs, and attend educational and scientific conferences. It allows access to state-of-the-art facilities including MEMS design and fabrication, mixed signal and wireless communication laboratories, telemetry laboratories, support staff and other technical and clinical resources.

Science is the world's leading multidisciplinary, peer-reviewed journal that publishes significant original scientific research, plus reviews and analyses of current research and science policy.

####

About Case Western Reserve University
Case is among the nation's leading research institutions. Founded in 1826 and shaped by the unique merger of the Case Institute of Technology and Western Reserve University, Case is distinguished by its strengths in education, research, service, and experiential learning. Located in Cleveland, Case offers nationally recognized programs in the Arts and Sciences, Dental Medicine, Engineering, Law, Management, Medicine, Nursing, and Social Work.

About research at the Louis Stokes Cleveland VA Medical Center

The Cleveland VA Medical Center has several large, well-funded research and development programs in:

* biomedical research

* health services research

* clinical and cooperative studies

* rehabilitation research

There are also two VA-funded centers of excellence:

* Functional Electrical Stimulation (FES) Center

* Advance Platform Technology Center

For more information, please click here

Contacts:
Laura M. Massie

216-368-4442

Copyright © Case Western Reserve 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

Bosch announces high-performance MEMS acceleration sensors for wearables June 27th, 2017

Nanometrics to Participate in the 9th Annual CEO Investor Summit 2017: Accredited investor and publishing research analyst event held concurrently with SEMICON West and Intersolar 2017 in San Francisco June 27th, 2017

NMRC, University of Nottingham chooses the Quorum Q150 coater for its reliable and reproducible film thickness when coating samples with iridium June 27th, 2017

Picosunís ALD solutions enable novel high-speed memories June 27th, 2017

Nanomedicine

Researchers developed nanoparticle based contrast agent for dual modal imaging of cancer June 21st, 2017

Learning with light: New system allows optical ďdeep learningĒ: Neural networks could be implemented more quickly using new photonic technology June 12th, 2017

Mussels add muscle to biocompatible fibers: Rice University chemists develop hydrogel strings using compound found in sea creatures June 9th, 2017

Making vessels leaky on demand could aid drug delivery:Rice University scientists use magnets and nanoparticles to open, close gaps in blood vessels June 8th, 2017

Discoveries

Picosunís ALD solutions enable novel high-speed memories June 27th, 2017

Atomic imperfections move quantum communication network closer to reality June 25th, 2017

Research accelerates quest for quicker, longer-lasting electronics: UC Riverside-led research makes topological insulators magnetic well above room temperatures June 25th, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Materials/Metamaterials

Atomic imperfections move quantum communication network closer to reality June 25th, 2017

Rice U. chemists create 3-D printed graphene foam June 22nd, 2017

Alloying materials of different structures offers new tool for controlling properties June 19th, 2017

Smart materials used in ultrasound behave similar to water, Penn chemists report June 16th, 2017

Announcements

Bosch announces high-performance MEMS acceleration sensors for wearables June 27th, 2017

Nanometrics to Participate in the 9th Annual CEO Investor Summit 2017: Accredited investor and publishing research analyst event held concurrently with SEMICON West and Intersolar 2017 in San Francisco June 27th, 2017

NMRC, University of Nottingham chooses the Quorum Q150 coater for its reliable and reproducible film thickness when coating samples with iridium June 27th, 2017

Picosunís ALD solutions enable novel high-speed memories June 27th, 2017

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