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Bioengineers at Rice University have created a hydrogel that instantly turns from liquid to semisolid at close to body temperature and then degrades at exactly the right pace. 

The gel shows potential as a bioscaffold to support the regrowth of bone and other three-dimensional tissues in a patient's body using the patient's own cells to seed the process, according to the press release.

The developed hydrogel is a liquid at room temperature but when injected into a patient, it would fill and stabilize a space while natural tissue grows to replace it. 

"This study describes the development of a novel thermogelling hydrogel for stem cell delivery that can be injected into skeletal defects to induce bone regeneration and that can be degraded and eliminated from the body as new bone tissue forms and matures," said Mikos, Rice's Louis Calder Professor of Bioengineering and Chemical and Biomolecular Engineering, in the press release. 

Researchers said the problem with thermogelling polymers is that once they harden, they begin to collapse forcing out water. This ultimately defeats the purpose of defining the space which doctors hope to fill with new tissue. 

"If the transition gellation temperature is one or two degrees below body temperature, these polymers slowly start to expel water and shrink down until they're one-half or one-third the size. Then the defect-filling goal is no longer accomplished," said Rice graduate student and the paper's lead author, Brendan Watson, in the press release.

Researchers solved the problem by adding chemical cross-linkers to the gel's molecules. "It's a secondary mechanism that, after the initial thermogellation, begins to stabilize the gel," Watson added.

"The catalysts are naturally present in your body at all times, in low levels. But in areas of newly formed bone, they actually get to much higher levels," he said. "So what we get is a semismart material for bone-tissue engineering. As new bone is formed, the gel should degrade more quickly in that area to allow even more space for bone to form."

The research has been detailed in the Chemical Society journal Biomacromolecules.