Bone Setting Glue

Researchers at the University of Utah have developed a new glue that sticks to bone and other wet surfaces. The glue, based on the adhesive used by sandcastle worms building their underwater homes, turns from liquid to solid as it is exposed to higher pH levels. The result is a glue as strong as superglue that doesn’t dissolve in liquids.
 Professor Russell Stewart with a chunk from a sandcastle worm colony (Source: Fred Hayes for the University of Utah)
Professor Russell Stewart 
with a chunk from a 
sandcastle worm colony 
(Source: Fred Hayes 
for the University of Utah)

Using glue in surgical procedures is a difficult and complex process; standard glues tend to slide off or dissolve in the liquids within the body. While screws and plates work well to fit large pieces of bone together, they aren’t effective for small bits that must be fit together perfectly to avoid arthritis and other future problems with the bone. Having a glue that allows even the smallest fragments of bone to be accurately placed and held until fixed would greatly improve the reliability of many orthopedic procedures while reducing non-weight bearing time and other side effects of the traditional healing process. The glue could also be infused with medication, providing anti-inflammatories, pain killers, and antibiotics directly at the site of an injury.

After an extensive study of how the sandcastle worms apply glue, the physical structure of the glue, and chemical analysis, Stewart’s team developed their own version with many of the same properties. Composed of one acidic (negatively charged) and one neutral polymer protein chain augmented by positively charged calcium and magnesium ions, the backbone of the glue works in conjunction with side chains of other materials. The backbone polymer in the synthetic glue is made from water-soluble polyacrylates, a material used in commercial glues, floor wax, nail polish, and Plexiglass among other things. The side chains are polymers that mimic the positive and negative charges of the worm glue. These chains condense into a heavy substance called coacervate which then hardens when the two types of side chains intermingle.

 An electron microscope image of two glass beads glued together by a sandcastle worm (Source: Russell Stewart)
An electron microscope image 
of two glass beads glued 
together by a sandcastle worm 
(Source: Russell Stewart)

Announced at a recent American Chemical Society conference, the new glue has been under development for several years. Head researcher Russell Stewart has yet to test his product extensively in the presence of blood, but it has performed well in laboratory tests using cow bones obtained from grocery stores and in early tests using live rats where there have been no signs of side effects from the glue. Stewart hopes the glue will be available for real surgical use within 10 years. It could also be used for ship repairs that currently require a drydock and other underwater construction and repairs.

TFOT has previously reported on a new material that could be used for artificial bones and on a new process for turning connective tissue stem cells into bone and cartilage. TFOT has also reported on a new adhesive inspired by geckos that could eventually replace surgical staples and sutures and on the strongest known naturally produced glue generated by a particular strain of underwater bacteria.

Read more about the early research efforts prior to animal testing in this University of Utah press release. Background information about the project and additional photographs and movies can be found at the University of Utah Department of Bioengineering website.