Supporting fractured bones during healing
We are developing resorbable materials which can support a fractured bone whilst it is healing and gradually degrade until all that is left is the healed bone.
Currently, fractured bones which require surgical intervention are supported by metal implants, pins and screws. Metals are far stiffer than bone and this can affect the healing process and lead to repeat surgeries.
Polymers are a much closer match to the mechanical properties of bones, and once the bone is healed, polymer pins and screws will degrade naturally within the body.
We have studied the processes by which polymer degrades, and the influence this has on the mechanical properties during degradation.
Through the use of subtle interplay between crystallisation and degradation, it is possible to maintain relatively steady properties for extended periods of time, prior to a sudden collapse and degradation at a specified time - this is ideal for medical implant applications. During the £1.2m EPSRC-funded BENcH project, we investigated bioresorbable nanocomposites.
Davide de Focatiis, one of the lead investigators, said
Following on from the BEncH project, we have developed a number of materials using hydroxyapatite platelets and rods. When we add the nano particles, we can change the rate of degradation. Our goal is to achieve gradual degradation. Whilst the bone is still healing, the scaffold needs to be strong, but once healed, the bone needs to start doing the work on its own. The gradual degradation can achieve this – slowly allowing the bone to take on more of the load.
The team can currently manufacture materials these using injection moulding techniques, so complex shapes can be created. They are now exploring the viability of making these on a commercial scale.
Davide de Focatiis David Grant Ed Lester Andy Parsons Derek Irvine