Bone implants that dissolve in the body

Someone somewhere in the world breaks a bone every three seconds. In some cases, to fix the fractures, doctors add a metallic plate to keep the bone in place. This plate has to be removed in a second operation. 

Dr Sina Naddaf Dezfuli has developed an alternative material for fixation devices that dissolves in the body after the bone has healed, avoiding second invasive surgery for patients. He received a doctorate for his research on 13 June 2018. 

Finding a suitable material for bone implants wasn’t easy. The material can’t be toxic, has to dissolve, and has to be strong enough to sustain load without breaking. “There is only one material that meets these criteria: magnesium,” concluded Dezfuli.

Although magnesium is weak, Dezfuli found that it gets stronger when combined with bioceramics (a mixture of silicate, calcium and magnesium). Adding this component to the implant has another advantage: it induces the process of bone formation. While the implant dissolves inside the body, it releases chemicals that stimulate the bone cells to ‘work harder’ and help the bone heal faster.

‘Surgeons are looking forward to seeing these implants in action’

To make the implants, magnesium powder and bioceramics are mixed, heated and pressed inside a machine that Dezfuli designed himself, until the particles turn into one integrated composite.

Magnesium implants are suitable for all kinds of bone fractures because their strength and degradation rates can be adjusted. For example, implants for the femur should be stronger than those for the cheekbone, but they should dissolve more slowly. The microstructure of the material is adapted to the needs of the patient by adjusting the quantity of each component, the size of the particles and the pressing procedure.

After receiving his doctorate, Dezfuli founded a start-up at YES!Delft to continue developing magnesium implants. He is now working with orthopaedic and maxillofacial surgeons at Amsterdam and Leiden University Medical Centres. Their next step is to test the implants on animals to observe how their immune system and body fluids react to magnesium.

Dezfuli’s final goal is to manufacture the implants in his recently founded company, Phoenix Bone Tech. “The good news is that surgeons are looking forward to seeing these implants in action, but it will take at least five more years until they are ready to be used.” 

• Sina Naddaf Dezfuli, Biodegradable magnesium matrix composites for bone fixation devices, PhD supervisors Frans van der Helm and Jie Zhou, Faculty of 3mE, June 13 2018

Maria Rubal / science editor