Biomedical polymers

Chinese researchers have developed the first soluble polyurethane (PU) with controllable properties that could make it suitable for biomedical applications.

For biomedical use, a polymer also needs to be non-toxic and compatible with blood and tissue. Although PUs are used for pace-maker wire insulation and artificial hearts, they degrade over time.

If and when the surface of the material becomes damaged, potentially dangerous blood clots can form - a process known as platelet adhesion.

The PU made by Fangxing Li and colleagues at Nankai University and Tianjin Medical University has two advantages.

First, by carefully selecting the length of side chain used to extend from the main polymer chain, platelet adhesion can be minimised.

Second, unlike many PUs, this material is soluble in some common solvents. Li believes that, in future, similar materials could be used to make car tyres that could be recycled or repaired instead of being scrapped.

Peter West, biomaterials project leader at the Smith & Nephew research centre in York, UK, says that the ’mechanical properties appear impressive’. But further tests to determine biological toxicology and long-term durability would be required, he said.

Vikki Allen