Strong
Gel for Artificial Cartilage
Researchers at the National Institute of Standards and Technology
(NIST) are studying an unusually pliant yet strong synthetic
cartilage replacement in hopes of providing people with arthritis
an alternative to total joint replacement. Scientists created
a gel that, while having the pliancy of gelatin, won’t
break apart even when deformed more than 1,000 percent. By
using NIST’s neutron research facility to show how the
molecules in the gel sustain such large deformations, the
research team hopes to make it easier to design materials
with even better mechanical properties.
Known
as double-network hydrogels, the incredible strength of these
new materials was a happy surprise when first discovered by
researchers at Hokkaido University in Japan in 2003. Most
conventionally prepared hydrogels—materials that are
80 to 90 percent water held in a polymer network—easily
break apart like a gelatin. The Japanese team discovered that
the addition of a second polymer to the gel made it so tough
that it rivaled cartilage. A combination of a brittle hydrogel
and a soft polymer solution led to a surprisingly tough material.
Work
using NIST’s neutron scattering techniques is exploring
the structure of the gel to discover the molecular-level toughening
mechanism found in this unique hydrogel. Establishing the
details of the molecular structure will allow for more precise
design of the next generation of hydrogels to be tough and
rigid at the same time. Real cartilage goes through a process
of constant daily destruction and regeneration under everyday
stresses; the researchers hope a good synthetic cartilage
could endure year after year under the rigors of the body
before needing to be replaced.
To
learn more about cartilage engineering, read about the work
being done by Arthritis Foundation-funded scientists Jennifer
H. Elisseeff, PhD, and Farshid Guilak, PhD.
Reference:
Wu
WL, Tirumala VR, Tominaga T, et al. A molecular model for
toughening in double-network hydrogels. Presented at the March
Meeting of the American Physical Society, March 11, 2008,
New Orleans, La.
This
article was adapted from a press release issued by National
Institute of Standards and Technology.
Source: http://www.arthritis.org/gel-artificial-cartilage.php
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