A vial of the
clear hydrogel turns to a white semi-solid as it's heated to body
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Rice team created a hydrogel containing a polymer known as poly
(N-isopropylacrylamide), which has also recently been put forward as a
"reversible glue" for temporarily sealing eye injuries while patients are in
transit. As long as it's kept below body temperature, the polymer remains in a
liquid state. Once heated by the body, however, it becomes a semi-solid.
scientists envision the gel being injected into the body in areas where bone has
been lost to injury or disease. As it solidifies, it will fill the void,
providing a scaffold for cells from the adjacent natural bone to grow into.
the case of some other "thermogelling polymers,"
however, they expel their own water content while solidifying. This causes them
to shrink to as little as one-third their original size, thus
negating their whole void-filling function. The team got
around that problem by adding chemical cross-linkers to the gel. These stabilize
the material, keeping it from shrinking as it sets.
added benefit, the bonds formed by the cross-links are gradually degraded by
alkaline phosphatase, which occurs in high levels when new bone is being formed.
This means that as natural bone grows into the material, the material itself
will disintegrate to make way for the bone. It's believed that the rate of
degradation could be tweaked to allow for different bone growth rates, as they
vary between individuals and different parts of the body.
paper on the research was recently published in the journal Biomacromolecules.
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