Bones healed and pain numbed at the same time

A material that mimics bone could be used to simultaneously mend and numb the pain of broken limbs, thanks to work by South Korean scientists.

The news is reported in the latest edition of the Royal Society of Chemistry's Journal of Materials Chemistry.

Two teams have created the polymer-ceramic material, led by Dr Jeong Ho Chang at the Korea Institute of Ceramic Engineering and Dr Kyung Sik Oh at Andong National University, Kyunbuk.

They used hydroxyapatite - a major component of bones and teeth - and coated it with a porous silica gel, which was then impregnated with a heat-sensitive polymer and hardened.

Crucially, the polymer does not block the pores of the ceramic - meaning that the movement of bone-forming and bone-absorbing cells is not restricted.

Dr Chang said: "The addition of the polymer means the material can not only be used as a scaffold for regenerating damaged bone, but also as a reservoir for controlled drug release - such as painkillers."

The teams tested the drug releasing abilities of the material by using indomethacin, an abundant painkiller and anti-rheumatism drug. 

As the polymer reaches temperatures close to body temperature, it shrinks - gradually releasing the drug. The rate of drug release can be further controlled by varying the amount of polymer. 

Dr Chang said: "Tests have already revealed the material is not toxic cells and so should be safe for clinical use."

with thanks to Nicola Burton for the original article

References

S Zhang, G Gangal and H Uludag, Chem. Soc. Rev., 2006,
DOI: 10.1039/B512310k