Extreme makeovers: body-bits and injectable scaffolds

New Melbourne-based biotechnology company PolyNovo Biomaterials has gone into the body-bits business -- with a material straight from the surgery of the Starship Enterprise.

PolyNovo, founded in May this year, is owned in equal partnership by new Perth-based biotechnology investment company Xceed Biotechnology (ASX:XBL) and CSIRO.

The company aims to provide present-day orthopaedic surgeons with an injectable, biocompatible polymer for repairing fractured limbs, reconstructing facial bones, or patching holes in the cranial vault, without the need for bone screws or metal scaffolds to secure the repairs.

The remarkable polymer, developed by researchers at CSIRO Materials Science in Clayton, Victoria, hardens rapidly in the ‘wet’ environment of the body, to produce strong, stable but temporary repairs. It subsequently serves as a porous, biocompatible scaffold that allows cells to recolonise the injury, and rebuild or repair missing bone.

As living bone gradually replaces the polymer ‘glue’, it biodegrades from the outside in, leaving a harmless residue of small molecules that disappear harmlessly from the body.

PolyNovo CEO Dr Ian Griffiths said rival biocompatible materials tend to degrade all at once, leading to macroscopic loss of its properties, accompanied by release of high molecular weight substances into the body.

Griffiths said the polymer ‘glue’ is in late-stage development, and the early stages of commercialisation, after eight years of fundamental research by CSIRO.

“It has many potential applications,” Griffiths said. “The main focus is its bone repair and bone glue applications. It can be used as a minimally invasive way to fix linear bone fractures, by injecting it into the fracture site.

“It can also be used to replace large missing segments of bone up to a centimetre in diameter in cranial surgery. The repair is self-supporting, so the patient can come straight off the operating table with minimal external fixation to support the injury.

“The material persists long enough to allow hard bone tissue to regenerate through its porous structure.”

PolyNovo announced this week that it had formed an alliance with Imperial College, London (ICL) to develop orthopaedic applications for the polymer.

Stent, bone potential

The alliance involves Dr Molly Stevens’ research group. Stevens, a world expert in tissue engineering, was recently recruited from the Massachusetts Institute of Technology.

“We believe that there is great potential for these new materials in the regeneration of complex hard tissues such as bone, due to the optimised environment they provide for tissue formation,” Stevens said.

Griffiths said PolyNovo was also receiving inquiries from potential commercial partners to develop the polymer for cardiovascular stents for minimally invasive coronary bypass repair.

“There’s lots of money going into developing minimally invasive alternatives to conventional coronary bypass surgery, which requires surgeons to crack the chest,” Griffiths said.

“It’s being driven by big players like Johnson and Johnson and Boston Scientific. Using stents to reopen blocked coronary arteries would be more like going to the dentist than undergoing major surgery.

“The polymer stent is implanted in a crushed state then mechanically expanded to reopen the blocked artery.

“At the moment our stents tend to block up again over time -- but conventional stents have the same problem. The next generation of materials will be formulated with slow-release drugs that will prevent re-stenosis. We believe we’re ideally placed to compete in that market.”

Griffiths said that while the short-term objective was to use the polymer in bone-repair, CSIRO could also formulate its specialised polymers to create a relatively soft, rubbery polymer that would be flexible enough to repairing soft-tissue injuries, including surgical cavities and breast-tissue replacement after surgery.

Look out for our focus on PolyNovo and other unlisted life science companies in upcoming issues of Australian Biotechnology News.