The development paves the way for customised implants that could be created at the time of surgery, eliminating the need to harvest cartilage and grow it for weeks in a lab as a replacement for damaged or diseased material.

Researchers from the Australian Research Council Centre of Excellence for Electromaterials Science, based at the University of Wollongong, yesterday unveiled a prototype of the BioPen, which is now bound for Melbourne for further development by clinical partners at St Vincent's Hospital.

Professor Peter Choong is leading efforts at St Vincent's to optimise the cell material, which is ejected from the pen in a method similar to 3D printing, for clinical trials.

Prof Choong said the cell material, and the scaffolding set down in the 3D printing method, would provide a more perfect and predictable result than existing orthopaedic implants, which "don't always form the sort of cartilage we want. We're [aiming] not only to reproduce the same structure of cartilage, but to get cells that actually become that type of cartilage," Prof Choong said.

"Through a device such as this, the surgeon is able to sculpt and reconstruct - personalise in many respects - the sort of tissue that's required to make a repair."

The device has two side-by-side reservoirs filled with "hydrogels" rather than ink.

The gel provides embedded cells with a hydrated environment and protection from the build-up of pressure as they are pushed towards the nozzle tip.

A low-powered ultra-violet light is cast over the material as it emerges, causing the gel to form a hard, protective layer over the embedded cells.

These cells later multiply and differentiate into nerve, muscle or bone cells.

All components of the implantable material are non-toxic and built to biodegrade as the cells fill in the injured bone area.

Prof Choong said the light weight and portability of the device made it ideal for surgeons.

The BioPen was designed and built using the large, bulky 3D printing machines at the University of Wollongong.

Professor Gordon Wallace, who heads the Wollongong research team, said the prototype took several hundred thousand dollars to develop.

But it was outwardly simple, costing several thousand dollars in materials.

"It's a very rudimentary device. All the fine engineering is in the tip, where the polymers are mixed," he said.