Tendons are the body's marionette strings, connecting bones to muscles that raise an eyebrow or propel us into a full run.
That is, until an unusually forceful or awkward pull on the strings leaves us with a sprain, strain or tear. Surgeons attempt to repair over 300,000 of these injuries every year, and doctors visits for sore tendons run into the millions.
Using a combination of nanoscience and biomedical and civil engineering to explore tendon structure from atoms on up, researchers have unraveled part of the mystery behind why we have problems with our tendons.
A new study led by scientists at Case Western Reserve University examines single threads of these essential connectors and found the weakest links potential targets for imaging techniques to detect problems before a tendon fails and for drugs to increase flexibility and heal damage. Their work is published in the September issue of Biophysical Journal.
The threads are fibrils of collagen, a tougher form of the soft tissue implanted in models' pouty lips.
"The fibrils are about five times stronger and can strain about five times farther than a tendon," said Steven Eppell, a professor of biomedical engineering and senior author of the study.
"About 80 to 90 percent of a tendon is collagen but mechanical properties like strength are probably controlled by the other stuff."
The other stuff is a cement that holds the bundles of fibrils together; it's made of molecules called proteoglycans. This cement or the interface between collagen fibrils and proteoglycans, is most likely the weakest link in the system, the researchers say.
The scientists suspected that's the case but direct testing of cement, which is more complex and less available than fibrils, was difficult. So, they decided to test the strength of just the collagen fibrils and then compare this with the strength of whole tendons.
To test the tensile stren
|Contact: Kevin Mayhood|
Case Western Reserve University