Drumming up better hearing

Already they have been the first in the world to successfully harvest and grow eardrum cells - called keratinocytes - in a test tube.

Now a team led by institute molecular geneticist Reza Ghassemifar will take the next step towards completing the tissue engineering process.

Over the next three years they hope to recreate the best biological chemical conditions so the cells grow into a sheet of eardrum that can be transplanted.

"In the next five years we hope to be able to replace a hole in an eardrum with a functional, artificial eardrum," Dr Ghassemifar said.

This would be done by taking a small piece of a patient's own damaged eardrum tissue - to reduce chances of later rejection - and from it growing new cells on a mesh in the laboratory, he said.

Within a few weeks, the new tissue could be given to a surgeon who could use it to patch the hole.

But first, the challenge was to stimulate the harvested cells to grow into the appropriate structure, outside the body.

"Every eardrum is a very thin, translucent, three-layered membrane around 10 microns thick," Dr Ghassemifar said.

"Using a particular chemical mix - which remains closely guarded - we are trying to stimulate the cells to grow and differentiate into the three layers similar to normal eardrums."

Gene therapy will be used to keep the harvested cells alive and improve their ability to "sit tightly" and adhere to their supporting mesh, he said.

Before being trialled in humans, the engineered eardrums will be tested in animals.

The work will be funded by a $240,000 grant from the Garnett Passe and Rodney William Memorial Foundation, which is dedicated to funding leading-edge research in the areas of ear, nose and throat surgery.