Scientists have discovered a previously unrecognized way that degradation can occur in silicone-urethane plastics that are often considered for use in medical devices. Their study, published in ACS' journal Macromolecules, could have implications for device manufacturers considering use of these plastics in the design of some implantable devices, including cardiac defibrillation leads.
Kimberly Chaffin, Marc Hillmyer, Frank Bates and colleagues explain that some implanted biomedical devices, such as pacemakers and defibrillators, have parts made of a plastic consisting of polyurethane and silicone. While these materials have been extensively studied for failure due to interaction with oxygen, no published study has looked at interaction with water as a potential failure mechanism in this class of materials. In a cardiac lead application, these materials may be used as a coating on the electrical wires or "leads" that carry electric current from the battery in the device to the heart. Surgeons implant pacemakers in 600,000 people worldwide and defibrillators in 100,000 people in the United States each year. Since these implants must function reliably for years, the scientists wanted to determine whether the plastic material was suitable for long-term implants.
Their laboratory tests, including accelerated aging of the materials under conditions that simulated the inside of the human body, found indications that the material begins to break down within 3-6 years. "By making the conclusions of this novel, scientific research public in a respected peer-reviewed journal, device manufacturers may now consider these important findings in their device designs," says Chaffin, distinguished scientist and lead author of the manuscript.
American Chemical Society: http://www.acs.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
The presenter and physicist Brian Cox says he supports the idea that many universes may exist.
Ripples in space touted as proof of the Big Bang theory might simply be cosmic interference, a new study finds
The eruption has been going for weeks. So far it hasn't been catastrophic, but it has been creating new ground.
The human eye has inspired physicists to create a processor that can analyse particle collisions 400 times faster than currently possible.
Adjusting the numbers of various types of molecule in the environment seem to improve the chances of self-replicating life generating spontaneously
Geologists must navigate precarious terrain to give the public an accurate picture of the lava's progress
Ben Allanach on the impure fun of rapid-response physics
Squid and other cephalopods control their skin displays by contracting color-filled cells. A team of engineers attempted the same using elastomer and electrical pulses.
Quakes and rockfalls at Mount Mayon have sparked serious concern
Ceramics break rather than bend under pressure, but nano-lattices have been used to produce resilient ceramics that could help make ultralight, tough materials