• Researchers at MIT and MGH have developed a polymer gel that mimics the vibrations of human vocal cords.

    Researchers at MIT and MGH have developed a polymer gel that mimics the vibrations of human vocal cords.

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New material could offer hope to those with no voice

Researchers at MIT and MGH have developed a polymer gel that mimics the vibrations of human vocal cords.

MIT and Harvard researchers are developing a synthetic material to revitalize damaged vocal cords.

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Marta Buczek
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In 1997, the actress and singer Julie Andrews lost her singing voice following surgery to remove noncancerous lesions from her vocal cords. She came to Steven Zeitels, a professor of laryngeal surgery at Harvard Medical School, for help.

Zeitels was already starting to develop a new type of material that could be implanted into scarred vocal cords to restore their normal function. In 2002, he enlisted the help of MIT’s Robert Langer, the David H. Koch Institute Professor in the Department of Chemical Engineering, an expert in developing polymers for biomedical applications.

The team led by Langer and Zeitels has now developed a polymer gel that they hope to start testing in a small clinical trial next year. The gel, which mimics key traits of human vocal cords, could help millions of people with voice disorders — not just singers such as Andrews and Steven Tyler, another patient of Zeitels’.

About 6 percent of the U.S. population has some kind of voice disorder, and the majority of those cases involve scarring of the vocal cords, says Sandeep Karajanagi, a former MIT researcher who developed the gel while working as a postdoc in the Langer lab. Many of those are children whose cords are scarred from intubation during surgery, while others are victims of laryngeal cancer.

Other people who could benefit are those with voices strained from overuse, such as teachers. “This would be so valuable to society, because every time a person loses their voice, say, a teacher or a politician, all of their contributions get lost to society, because they can’t communicate their ideas,” Zeitels says.

‘A mechanical problem’

When Langer and his lab joined the effort in 2002, they considered two different approaches: creating a synthetic material that would mimic the properties of vocal cords, or engineering artificial vocal-cord tissue. Both approaches have potential, Langer says, but the team decided to pursue a synthetic material because it would likely take less time to reach patients. “Making a totally natural vocal cord is a more long-term project,” he says.

Some doctors treat vocal-fold scars with materials normally used in dermatology or plastic surgery, in hopes of softening the vocal cords, but those don’t work for everyone, and the effects don’t last long, says Nathan Welham, assistant professor of otolaryngology at the University of Wisconsin School of Medicine.

“Scarred vocal cords are really hard to fix,” says Welham, who is not involved in this project. “People have tried this and that, but there’s really no commonly used, available approach that treats the inherent problem of scarring in the vocal folds.”

Other researchers have tried developing drugs that would dissolve the scar tissue, but the MIT/Harvard team decided on a different approach.

“What we did differently is we looked at this as a mechanical problem that we need to solve. We said, ‘Let’s not look at the scar itself as a problem, let’s think of how we can improve the voice despite the presence of the scar tissue,’” says Karajanagi, who is now an instructor of surgery at Harvard Medical School and a researcher at the Center for Laryngeal Surgery and Voice Rehabilitation at Massachusetts General Hospital.

The team chose polyethylene glycol (PEG) as its starting material, in part because it is already used in many FDA-approved drugs and medical devices.

By altering the structure and linkage of PEG molecules, the researchers can control the material’s viscoelasticity. In this case, they wanted to make a substance with the same viscoelasticity as human vocal cords. Viscoelasticity is critical to voice production because it allows the vocal cords to vibrate when air is expelled through the lungs.

For use in vocal cords, the researchers created and screened many variations of PEG and selected one with the right viscoelasticity, which they called PEG30. In laboratory tests, they showed that the vibration that results from blowing air on a vocal-fold model of PEG30 is very similar to that seen in human vocal folds. Also, tests showed that PEG30 can restore vibration to stiff, non-vibrating vocal folds such as those seen in human patients suffering from vocal-fold scarring.

Under FDA guidelines, the gel would be classified as an injectable medical device, rather than a drug. The researchers, who have published more than a dozen papers on their voice-restoration efforts, have applied for a patent on the material and are working toward FDA approval. If approved for human use, the gel would likely have to be injected at least once every six months, because it eventually breaks down.

The project is funded by the Institute of Laryngology and Voice Restoration, which consists of patients whose mission is to support and fund research and education in treating and restoring voice. Julie Andrews is the foundation’s honorary chairwoman.

Safety tests

In a study recently published in the Annals of Otology, Rhinology & Laryngology, the researchers tested the biocompatibility of the gel by injecting it into the healthy vocal folds of dogs. After four months, the treated dogs showed no damage to their vocal cords.

“That gives us exciting data that this has a real good chance of working in people without creating damage,” Karajanagi says, adding that clinical trials will be needed to confirm this.

The researchers are now working on developing a manufacturing process that will generate enough of the material, in high quality, for human trials. They hope to run a trial of about 10 patients next year. They are also working on developing methods for injecting the material at the right location to treat human vocal cords.

Such gels could find other medical applications, by varying the chemical properties of the PEG, Langer says. “We think of what we do as ‘designer polymers,’” he says. “We can modify them depending on the problem we’re trying to solve.”

Topics: Biological engineering, Biology, Chemistry and chemical engineering, Collaboration, Vocal cords, Voice


I know someone who has lost their voice due to numerous operations on their throat and I would like to be contacted to discuss the possible candidacy for implanting this device. Please contact me at flowersmedia - at - gmail - dot - com, with thanks.

Congratulations Researchers!

My father has been suffering from the disorder for over 6 years, we tried everything, this forced him for early retirement and his mental health is detioriating. This is much needed development in medical science. I would like to be in touch with you and be contacted when you decide to run a trial for which my father is a possible candidate. I am in east coast. My email is rvanand at gmail dot com. Thanks!

I would be a good candidate for this proceedure due to vocal scarring. Pleasr contact me to discuss. lnevill2@comcast.net

thank you

I have had thyroid cancer and have had several surguries resulting in the paralysis of half of my vocal cords. Would this kind of problem be considered?

Could this material be injected into, or painted on the surfaces of lenses in the eyes of people suffering from presbyopia to make the lenses more flexible so that accomodative vision is restored? Can this material become discolored after lengthy exposure to light of particular wavelengths? Is it completely absorbed into the tissue with which it comes into contact, or does it leave a residue?

I am very interested in this procedure. I have a 13 yr old that has one vocal cord that does not move and one that barely moves. He has a lot of scar tissue that narrows his airway and causes him to get short of breathe very easily. He has had laser surgery many times to remove some of the scar tissue but that takes more away from his voice. If there is a possibiliy that this could help... I would love to get more information about it!!

I have polyps removed from my vocal cords 4+ years ago - since then and most recently in the last year I lose my voice. I saw my doctor again this year over a few month period and nothing was really done. I believe I have scar tissue and when asked the doctor if this could be causing my problem today he said maybe - voice therapy was suggested and I was told that is all I can do. My loss of voice often goes with pain and causes problems for me communicating at work and with family. I tend to talk a lot and am told to rest my voice - this year has been so hard - in the last 7 months I have lost my voice for days at a time on at least 15-20 separate occasions and two times in the past 5 days for a day each. Please contact me at msmegbc@gmail.com to see if I can participate. Thank you so much - this could change my life.

This is Incredible news!1 I have wished for this for a long time..Diagnosed with Laryngeal Cancer I did not want to die..I fought hard with checmo and radiation and have been cancer free for 2 years..I know I should just feel good to be alive and I do but there is a part of me that misses my voice so badly that I call my cell phone just to hear it again...My younger Grandkids are petrified of me when they hear my voice..The older ones say I sound like a monster..I am So Isolated as people cannot understand me on the phone and I cannot get out much due to my health...I would Love to be considered for a trial...And to have a chance at being ME again..I can be reached at 6177701377 or by email pashell@aol.com...Thanks So Much! Peggy Shellenberger

I would just like to get updates on this.

I do not have scarred cords. Although I have had hemorrhages, nodules, and laser surgery over the last 3 decades, my cords still move. According to my ENT, my neurologist and my voice therapist, I have superior laryngeal neuralgia and fibromyalgia. This started in my 20s, after a bout of complete laryngitis. I am now 54. Despite 3 decades of medication, voice therapy and very careful usage, I have pain and voice fatigue that comes on AFTER speaking. It is very debilitating. It can take days to get over the pain and discomfort. I need someone who is pursuing research that relates to voice-related pain, neuralgia, or fibromyalgia. I don't think that the gel is relevant to me. However, this is another type of severe voice disorder.

To other people with vocal cord problems, I recommend Dr. Robert Sataloff (Philadelphia -- ENT) and Dr. Linda Carroll (NY, Speech pathology).

I have had a paralyzed vocal cord for 39+ years. Would this be a procedure for my condition?

I have been diagnosed with Spasmodic Dysphonia (adductor type). However, my vocal chords are also atrophied. That means regardless of what is going on with the dyphonia my voice is also weak.

I don't have scarred chords, but couldn't this be used to add to or "beef up" the chords themselves? If my chords were thicker they would come together better and thereby produce more sound.

I would love to have someone contact me as I need my voice desperately for my work as an Orthodox Christian Priest -- michaelmak@aol.com, 509-263-6441.

they lose their voice and then how deaf people could acheive the sense controlled by their socond nature being given control after intence practice. Firstly, we seem to lose our voice when we used it extensively and we should sleep as much as possible or strain it least possible and for the deaf person, they could be eather drawing their voice samples as to create a template to follow for practicing as such as when they speak; they would be able to compare the spoken to their goal voice. I did think of something for my friend about two weeks ago; it was a two part keyboard that slipped out of the inner sleave so that they could type a then read message by the other person from the top of the other or converted to audio. And to accomodate listening to others; ausio could be translate to text and be read at the top inner part of the glasses. But it may be too close and likely is and maybe on their wris****ch. Then again bad spot, maybe an inconspicuous screen at tip of cap.

I have been diagnosed bilateral Sulcus Vocalis. Is this material applicable in this case? If yes, I would like to be considered for your trials. I can be contacted at jhcelis@gmail.com or at +1 305 9389972

I would be a good candidate. I would like to be contacted. I have unilateral vocal cord paralysis of my right vocal cord. I am otherwise healthy. I am a teacher and would be so excited to get my voice back. I also have 3 kids. I miss being able to do the normal things mothers do like read books to my kids.

My mom is having surgerty tomal and will lose the loss of her voice completely, I was VERY interested in seeing If she is a candidate for this..786-380-0216..thank you and god bless.

My daughter, Trinity, was in a terrible car accident July 2008. Brain damaged resulted in vocal paralysis which resulted in a tracheostomy, facial paralysis, and weakess of her entire left side. She's had about 3 surgeries on her throat, and its the same outcome. Her doctor is hoping for decanulation, but I'm not sure if she is ready. Her stats stay at 97 & above with her trach being capped off, but there is still heavy breathing. I am a confused and concerned mother trying to figure out a way to help my 8 year old daughter. She loves the water and wants to learn how to swim, but because of her tracheostomy its not possible. She does not understand, please help. What do I have to do for her to become a candidate?

I was diagnosed with pollyps on my vocal cords when I was nine months old. Due to scar tissue I have never ever been able to talk normal. I am 18 now and am hoping one day there will be a solution. I feel so alone.

I am a 63 year old woman. My voice has gotten so bad that people hang up when I answer the phone and little children back away when they hear my voice. I would very much like to learn more about participating in your Human Trials for vocal cord restoration. I use a cortisone inhaler now, but that does not seem to help.

my husbond was operated for cancer to vocal cords. a part of vocal cord was cut. now he has to talk with lot of pressure, to bring out the voice. it is affecting his other organs such as chest, back ,stomoch. lungs ect. is there any solution for this. he would like to be a candidate for testing this new gel treatment

I notice the messages here are from 2011. Have the trials been done? Were they successful? Where can I get more information about this?

Iv sufferred from lanringal papilloma since birth...and due to many operations it has left my voice extremly horse, am in need of this procedure..

Please post an update to this article. has the study been completed? I have bilateral vocal cord paralysis and now have a tracheostomy. I need an alternate solution to make me healthy, not something to accommodate my condition.

I am a professional singer with a partially paralyzed vocal cord. No one has been able to tell me why it happened. This is amazing and I want to learn more.

Could this material be used to treat Sulcus vocalis.. I mean pathologically their is no difference between scarring and Sulcus vocalis.

I have had vocal cord damage since December 2008. Scar tissue from a tracheal resection (idiopathic tracheal stenosis) basically "tethered" my vocal cords and now I have only partial movement. I can speak, but very low volume and I sound like I have the worst laryngitis ever. I would LOVE to be considered for human trials. Does anyone know where I can get more info?

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