A team of researchers from Australia’s RMIT University, Melbourne, report that they have been able to enhance the biocompatibility of titanium additively manufactured orthopaedic implants by creating a surface coating of synthetic nanodiamonds.
Leading a research team at RMIT’s School of Engineering, Dr Kate Fox explained that while titanium is the best widely-available solution for the fast and accurate Additive Manufacturing of orthopaedic implants, the human body can still sometimes reject the material. This is due to the chemical compounds of titanium, which may prevent tissue and bone from interacting effectively with biomedical implants.
“Currently, the gold standard for medical implants is titanium but too often titanium implants don’t interact with our bodies the way we need them to,” Fox stated. “To work around this, we have used diamond on 3D scaffolds to create a surface coating that adheres better to cells commonly found in mammals.”
“We are using detonation nanodiamonds to create the coating, which are cheaper than the titanium powder,” she continued. “This coating not only promotes better cellular attachment to the underlying diamond-titanium layer, but encouraged the proliferation of mammalian cells. The diamond enhances the integration between the living bone and the artificial implant, and reduces bacterial attachment over an extended period of time.”
“Not only could our diamond coating lead to better biocompatibility for 3D printed implants, but it could also improve their wear and resistance. It’s an exceptional biomaterial.” The application of the surface coating is reported to have been made possible by recent advances in the AM of titanium scaffolds at RMIT’s Advanced Manufacturing Precinct. The coating itself is created via a microwave plasma process at the Melbourne Centre for Nanofabrication, and the titanium scaffolds and diamond then combined to create the biomaterial.
“It will be a number of years before a technology like this is rolled out, and there are many steps to take until we see it available to patients,” Fox added. “But what we have done is taken the first crucial step in a long and potentially incredible journey.”
Aaqil Rifai, a PhD researcher and part of Fox’s team, states that diamond is so effective because carbon is a major component of the human body. “Carbon has an incredible level of biocompatibility,” Rifai said. “Our body readily accepts and thrives off diamond as a platform for complex material interfacing.”
In addition to orthopaedics, diamond has also been used to coat cardiovascular stents – tubes that help keep the heart’s arteries open – and in bionics and prosthetics. “The scalability of 3D printing is growing rapidly, so we can expect to see diamond coatings to become common in orthopaedics sometime in the near future,” Fox concluded.