The Humble Silkworm.
A team with researchers based in Perth and Melbourne is moving towards clinical trials of a device that incorporates silkworm silk in an ear implant.
Named “ClearDrum”, it looks like a contact lens, but is instead a device on which the patient’s cells can grow.
Australian Perth-based surgeon Professor Marcus Atlas, said silk was the preferred choice because it was flexible.
“We felt that it had shown previously to support cell growth and proliferation, and the ability to be able to change into various forms was a really appealing thing for us, particularly when we started to mix it with other products to create different mechanical and acoustic criteria,” Professor Atlas said.
“The skin cells are there, it’s getting them to come across and heal, so it’s sort of a scaffold.”
The silk is degummed by removing sericin (the sticky stuff).
The derivative fibroin (the protein present in the silk) is then heated into a liquid and combined with other materials including glycerol and polyurethane to create the “scaffold”.
Chief Executive of the Ear Science Institute Sandra Bellekom said ClearDrum was the first implant which actually mimicked a human ear drum.
“What we find is that the cells, which are called keratinocytes, they love to thrive and migrate and move across this scaffold which helps the healing process,” she said.
“That’s why we want to use silk because we know that it works.”
She said it needed to be strong and flexible with acoustic properties and preferably transparent.
“The middle ear space is a very noxious environment, particularly when there’s disease present, there’s a lot of pressure changes occurring, it’s a very moist environment.
“So it’s not the easiest place to create an implant that’s going to be effective in the long term.”
The implant is placed under the eardrum.
For a “simple” or small perforation, it is expected it would dissolve over time, while for more complex or larger perforations, the implant would remain.
There would be a need for no more than one operation.
Ms Bellekom said surgeons around the world had been harvesting tissue for patches for eardrum perforations, and many organisations have been trying to develop a suitable device.
“We have extensively researched our technology over the past decade, and we’ve been able to produce 34 peer-reviewed journal articles which attest to the quality of our science. But the real truth of the matter is in translating that into human patients.”
That is set to happen with the grant of nearly $4 million from the UK-based charity, the Wellcome Trust.
“We are looking at recruiting patients that have chronic middle ear disease, active and inactive, so patients who have more simple perforations and also patients that have far more complex perforations with disease state present,” Ms Bellekom said.
Recruiting was expected to take place across Australia, but probably not until 2018.
The not-for-profit Ear Science Institute has been working on the project with Deakin University’s Future Fibres Hub.
Professor Atlas and Deakin’s Professor Xungai Wang had gone to London to present to the Wellcome Trust.
Professor Atlas said it has been a very rewarding joint effort.
“We saw that silk had this ability to become a really strong biological membrane that would support cell growth. And then we made contact with Deakin who had this really extensive experience in silk and silk fibroin and it grew from there, it grew from that relationship,” Professor Atlas said.
“Geography has made absolutely no difference, it’s just because the people really want to work together, it’s been very productive.
“It’s one of the best collaborations in science that I’ve worked in and I think it’s because the people are right and they want it to work.”