A hydrogel that knows when to go
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.
“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 Latest on: Bioscaffold
via Google News
The Latest on: Bioscaffold
- Small Intestinal Submucosa as a Potential Bioscaffold for Intervertebral Disc Regenerationon September 30, 2019 at 5:00 pm
Study Design. To evaluate the capacity of porcine small intestine submucosa to support the in vitro proliferation of human disc cells and the synthesis of extracellular matrix that could restore the ...
- Wyss researchers develop bioscaffold to recruit T cells for blood vessel repairon August 8, 2019 at 5:00 pm
The Wyss Institute for Biologically Inspired Engineering at Harvard University works in a range of cutting-edge med-tech fields. Only a few years ago, it opted to incorporate one focus specifically on ...
- FDA clears bioscaffold from Tela Bio for soft tissue use in plastic, reconstructive surgeryon April 22, 2019 at 5:00 pm
LONDON – It’s no secret that American citizens pay the most for drugs, but the extent of the disparity is laid bare in a new index of the prices of 13... DUBLIN – Crispr Therapeutics AG has delivered ...
- CAREER: Graphene as a Bioscaffold for Musculoskeletal Tissue Engineeringon March 25, 2019 at 5:00 pm
Broader Impacts: By integrating graphene into the tissue engineering cycle, potentially transformational outcomes will likely include new instrumentation for stem cell culture, new multifunctional ...
- Admedus receives European CE Mark for CardioCel 3D® and VascuCel®on March 9, 2019 at 4:00 pm
The first phase of the commercial launch of CardioCel 3D® in Europe begins later this month Admedus Ltd (ASX:AHZ) has received regulatory approval in the form of the CE Mark for its CardioCel® 3D ...
- Nerves repaired using bioscaffold fitted with “radio” antennaon July 23, 2018 at 8:59 am
The body’s ability to repair damaged nerves is something of a mystery. For neurologists, it seems clear that damage to the central nervous system—the brain and spinal cord—cannot be repaired. However, ...
- 3D Bioscaffold Mimics Antigen-Presenting Cells for Improved T-Cell Expansionon January 16, 2018 at 1:27 am
Researchers in the U.S. have developed a 3D biomaterial scaffold that can promote much faster ex vivo expansion of functional T cells than currently available technologies. The new scaffold is ...
- Cryopreservation of Human Mesenchymal Stem Cells in an Allogeneic Bioscaffold based on Platelet Rich Plasma and Synovial Fluidon November 15, 2017 at 4:00 pm
An allogeneic and biomimetic bioscaffold composed of Platelet Rich Plasma and synovial fluid that preserve and mimics the natural environment of MSCs isolated from knee has also been developed. We ...
- Acellular Urethra Bioscaffold: Decellularization of Whole Urethras for Tissue Engineering Applicationson February 5, 2017 at 4:00 pm
We established the decellularization of porcine urethras to produce acellular urethra bioscaffolds for future tissue engineering applications, using bioscaffolds or bioscaffold-derived soluble ...
- Chester County bioscaffold products developer settles patent disputeon November 21, 2016 at 2:54 am
TELA Bio Inc., a Chester County company specializing in biomaterials used for soft tissue repair, said Monday it has settled its legal dispute with LifeCell Corp. The terms of the agreement are being ...
via Bing News