Featured Research

from universities, journals, and other organizations

A hydrogel that knows when to go

Date:
May 7, 2014
Source:
Rice University
Summary:
Bioengineers have created a hydrogel that instantly turns from liquid to semisolid at close to body temperature -- and then degrades at precisely the right time. 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.

A new hydrogel invented at Rice University turns from liquid to semisolid as it moves from room temperature to near body temperature in an experiment. The material inside the tube quickly turns white as it gellates. Chemical links in the gel take longer to form, but help it hold its size and shape as a scaffold for growing new tissue.
Credit: Jeff Fitlow/Rice University

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.

Related Articles


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 the gel," he said. The links begin to form at the same time as the gel, but crosslinking takes up to a half-hour to complete.

The hydrogel is designed for stability over its long-term use as a scaffold for cells to take root and proliferate. But it's also designed for its own timely destruction.

"I came up with the idea a few years ago, but it's finally all come together," said Watson, who is pursuing both a Rice doctorate and a medical degree in a joint program with nearby Baylor College of Medicine. "These chemical crosslinks are attached by phosphate ester bonds, which can be degraded by catalysts -- in particular, alkaline phosphatase -- that are naturally produced by bone tissue.

"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 fine balancing act took a lot of expertise from his colleagues and co-authors, including Paul Engel, chair of Rice's Department of Chemistry, and F. Kurtis Kasper, a senior faculty fellow in bioengineering. "It looks like we may have just decided to try something and found that, hey, it worked! But that wasn't the case," said Watson, describing the months and years it took to refine the hydrogel. Engel's help with the sophisticated chemistry was especially valuable, he said.

Watson expects that the material degradation can be tuned to match various bone growth rates.

"Optimizing the degradation kinetics is nontrivial and may be better suited for a biotech company," he said. "We focus more on the performance of the hydrogels and the underlying molecular mechanisms"

The National Institutes of Health, the Keck Center Nanobiology Training Program of the Gulf Coast Consortia and the Baylor College of Medicine Medical Scientist Training Program supported the research.


Story Source:

The above story is based on materials provided by Rice University. The original article was written by Mike Williams. Note: Materials may be edited for content and length.


Journal Reference:

  1. Brendan M. Watson, F. Kurtis Kasper, Paul S. Engel, Antonios G. Mikos. Synthesis and Characterization of Injectable, Biodegradable, Phosphate-Containing, Chemically Cross-Linkable, Thermoresponsive Macromers for Bone Tissue Engineering. Biomacromolecules, 2014; 140430083851000 DOI: 10.1021/bm500175e

Cite This Page:

Rice University. "A hydrogel that knows when to go." ScienceDaily. ScienceDaily, 7 May 2014. <www.sciencedaily.com/releases/2014/05/140507114757.htm>.
Rice University. (2014, May 7). A hydrogel that knows when to go. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/05/140507114757.htm
Rice University. "A hydrogel that knows when to go." ScienceDaily. www.sciencedaily.com/releases/2014/05/140507114757.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Nurse Nina Pham Cured of Ebola

Texas Nurse Nina Pham Cured of Ebola

AFP (Oct. 25, 2014) An American nurse who contracted Ebola while caring for a Liberian patient in Texas has been declared free of the virus and will leave the hospital. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins