Dysphonia is speech impairment due to any physical disorder of the mouth, tongue, throat, or vocal cords, and affects 20 million people in the United States alone. For decades, scientists searched for ways to fix dysphonia– but from Botox injections to acupuncture therapy, none of the solutions have been ideal. In recent years, scientists have turned to bioengineering as a more high-tech solution, but vocal cords in particular are difficult to replicate since they must be pliable yet sturdy in order to achieve the necessary vibration rate and performance.
In November of 2015, scientists from the University of Wisconsin School of Medicine and Public Health successfully grew fully-functional vocal cord tissue by culturing cells from the connective vocal tissue of cadavers on 3-D collagen scaffolds. Collagen scaffolding, which uses scaffolds to promote cell migration and formation of tissue, is one of the most widely used techniques to bioengineer tissue. After two weeks, the cells formed a strong vocal cord tissue and could be tested in animals. When University of Wisconsin scientists grafted their bioengineered tissues into dogs’ native vocal fold, they found that the engineered tissue produced a similar sound and vibration rate as the native tissue.
Engineered vocal cords are an example of bioartificial organs, which are grown from both synthetic and biological material, like scaffolds and human vocal tissue cells. In the case of the University of Wisconsin scientists, the vocal cord tissue had proven functional, but they had yet to test its compatibility with the human immune system. For this test, the vocal cord tissue was grafted into mice with immune systems similar to those of humans, to see if it would be accepted or rejected. The immune system did not reject the tissue, and the tissue was able to grow.
The engineered tissue functioned similarly to the native tissue, but it was not fully developed like the complex adult tissue. Natural vocal cord tissue develops over the lifetime of an individual, whereas engineered tissue does not have much time to grow. The engineered vocal cord tissue still has to go through clinical testing before it is approved, but once it is perfected, may be a breakthrough treatment for the 20 million dysphonia patients in the United States.
Biomedical engineering has been taking flight in recent years, with the successful growths of tracheas, bladders, pancreases, livers, kidneys, hearts, and now vocal cords in the labs of brilliant researchers. Today, thanks to these monumental achievements, millions of people are just an FDA approval, clinical testing, and an implantation away from living their lives with more ease and fully functioning artificial organs. Because of innovative scientists like those of University of Wisconsin School of Medicine and Public Health, the feats of biomedical engineering are ever-growing.