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UConn scientist creates artificial tendon (Released: 4/10/987)

by Luis Mocete, Office of University Communications.

Storrs, Conn. -- When senior Nykesha Sales ruptured her right Achilles tendon in late February, it prematurely ended her UConn basketball career.

The injury is all-too-common among athletes. Former New York Giants linebacker Lawrence Taylor and Miami Dolphins quarterback Dan Marino are high-profile athletes who have also torn their Achilles tendon on the job.

Full recovery from an Achilles injury can take six months to a year. The patient may either need surgery or be in a cast for months while the injury heals itself -- not ideal for any athlete, or for their team.

Samuel Huang, a professor of chemistry and materials science at the University of Connecticut, has created an artificial tendon out of biodegradable materials that will assist the body in developing a new tendon and shorten the recovery period. His research is part of the Polymer Science Program, an interdisciplinary graduate program that is part of the Institute of Materials Science.

Several methods have previously been tried to enhance the recovery process, Huang says. One is to remove a tendon from another part of the body to replace the tendon that is damaged. Another is to do a tendon implant. Neither was completely successful.

So he decided to study how a damaged tendon can be reconstructed.

"Tendons are principally composed of a hydrogel, reinforced with protein fibers," he says. "The protein fibers act like springs, supporting the muscle movement, while the hydrogel serves as a lubricant to permit free movement between the muscle and the tendon."

It was difficult to find materials with appropriate biological and mechanical properties that can be used to produce an effective artificial tendon, he says. Many of the artificial tendons developed by other laboratories do not simulate the structure and properties of natural tendons.

"The makeup of the artificial tendons was designed to permanently replace damaged tendons, which is not necessary, because a damaged tendon regenerates itself" Huang says. "These artificial tendons hindered the development of the natural tendon because the regenerated tendon grew into the implanted tendon, preventing proper healing."

Huang discovered that a hydrogel composite would provide a solution to this dilemma, because it degrades slowly after implantation, as new tissue grows in.

To test his discovery, he implanted artificial tendons into the legs of white rabbits. During a three-month period — the period of time it usually takes for a rabbit tendon to regenerate — the artifical tendon "functioned like a natural tendon and served as a scaffold to help nature heal itself," he says. The hydrogel composite degraded in conjunction with the growth of the new tendon and there was no visible scar tissue. In addition, the artificial tendon did not trigger any negative reaction around the area where it was implanted.

Huang notes that this artificial tendon will prevent prolonged immobilization, which can inhibit the return of proper tendon function. "Athletes — or anyone else for that matter — will wait a shorter period of time than they do now before they return to action."

He says the biodegradable tendon, which he expects will be commercially available in the near future after tests on human volunteers, will revolutionize tendon treatment.