3D-printed eardrum patch to repair damage and aid regeneration

August 24, 2021
3D-printed eardrum patch to repair damage and aid regeneration

A multidisciplinary research team at Harvard’s Wyss Institute for Biologically Inspired Engineering have fashioned a novel 3D-printed, biocompatible graft that could be used to repair a damaged eardrum. The Phonograft device, as it is called, is also intended to mitigate the pain, drainage, and hearing loss associated with a damaged eardrum.

The eardrum – or tympanic membrane – is a thin but intricate membrane that conducts sound in the ear. The eardrum is however easily perforated by blasts, traumatic injuries, and chronic ear infections, that require reconstructive surgical interventions; surgical failures are common with this type of delicate surgery, making revision surgeries necessary.

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Additionally, patient-derived tissue grafts used as repair very often have imperfect sound-conducting abilities because their structure does not match that of the native eardrum.

After extensive research, the PhonoGraft device was made to mimic the domed shape of the natural eardrum, replete with patterned “wheels and spokes” like a bike wheel. This pattern enables it to vibrate in response to auditory stimulation, and to transmit the sound for further processing by the brain. The Phonograft is composed of a specially developed synthetic polymer-based ink, for 3D printing.

Not only does the implant itself work to restore hearing, but it provides a scaffold for the recipient’s own cells to regenerate. Tests in chinchillas, which have similar ear anatomy and hearing ranges to humans, proved promising.

The researchers believe the novel technology used in the Phonograft could eventually enable permanent repair by first mimicking and then restoring the eardrum’s sound-conducting mechanical properties and barrier functions.

As a bonus, the PhonoGraft can be inserted through the ear canal, thus doing away with invasive surgical repair.

“Three months after implanting our optimised graft into the chinchilla’s ear, we had a genuine eureka moment,” said Dr. Aaron Remenschneider, from the Massachusetts Eye and Ear teaching hospital. “The hearing tests indicated full restoration of sound conduction, which has been a big hurdle. Then we took our first peek down the ear canal with the endoscope. What we were seeing was merely the ghost of our graft that was being replaced with new tissue – a beautifully reconstructed eardrum with its radial-circular pattern.”

According to the researchers, the technology is now entering commercial development as part of high-priority institute project.

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Category: Features, Technology & Devices

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