Spongy polymers for broken bones

American researchers at Texas A&M University have developed a spongy polymer that could help regenerate broken bones. Thanks to its honeycomb structure, it could fill in missing bone sections while encouraging natural reconstruction.
This new material is made from an elastic and biodegradable shape memory polymer (SMP) which is already used in certain medical implants; it is coated in a second polymer, called polydopamine, which is known to stimulate bone growth.

When heated to 60°C, it becomes soft and spongy and can easily be molded to the exact shape of the missing section of bone. Once it has been placed, the polymer cools and stiffens, much like sponge drying out. Its porous structure enables bone cells to grow naturally and to gradually replace the artificial graft that is absorbed by the body. The research team estimates that full bone regrowth would take around a year.

Currently, the most widely-used method involves harvesting bone from the patient's body and grafting it back to repair broken bones. This technique does not produce an immune rejection since the graft comes from the patient's own body, although it does require an additional operation which can lead to complications. 
For the time being, this new polymer has only been tested in laboratory conditions. The next step will consist of investigating how it will set the bone in a living organism.

More information
www.gizmag.com/shape-memory-polymer-bone-defects/33373/