HOUSTON (May 7, 2014) Rice University bioengineers have created a hydrogel that instantly turns from liquid to semisolid at close to body temperature and then degrades at precisely 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.
The hydrogel created in the lab of Rice bioengineer Antonios Mikos is a liquid at room temperature but, when injected into a patient, becomes a gel that would fill and stabilize a space while natural tissue grows to replace it.
The new material detailed in the American Chemical Society journal Biomacromolecules takes the state of the art a few steps further, Rice scientists said.
"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.
A problem with thermogelling polymers is that once they harden, they begin to collapse and then force out water, said Rice graduate student and the paper's lead author, Brendan Watson. That process, known as syneresis, defeats the purpose of defining the space 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," he said.
Watson and his colleagues at Rice's BioScience Research Collaborative 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 th
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