Stem cell capsules to target broken bones

A new way of delivering stem cells could one day lead to a single injection to mend broken or diseased bones and joints, French and Australian scientists say.

Dr Frank Caruso of the Centre for Nanoscience and Nanotechnology at the University of Melbourne and colleagues report their findings this week in the Proceedings of the National Academy of Sciences.

"It is growth factor and stem cells in an injectable format," says Caruso.

"This would be used wherever you would like to regenerate bone."

Bone and joint problems are particularly challenging for medical scientists because bone cells sometimes don't heal themselves very well.

For this reason researchers are exploring ways to effectively transplant stem cells that will regenerate bones and joints.

Caruso and colleagues have designed a capsule made of synthetic polymers, which they have impregnated with growth factors that stimulate the differentiation of stem cells into bone cells.

He says the capsules are very tiny - ranging from about 100 nanometres to tens of microns.

The researchers have then combined these capsules with embryonic stem cells in a matrix of alginate gel. They injected the mixture into lab animals and demonstrated they can stimulate bone regrowth.

If ongoing experiments prove positive, Caruso says the development may lead to treatments in 5 to 10 years.