Titanium is a very biocompatible material, which is why it's so often used for medical implants. That said, chemical compounds in the metal sometimes do result in implants being rejected by the body. Scientists at Australia's RMIT University are attempting to address the problem, by coating such implants with diamonds.

Led by Dr. Kate Fox, an RMIT research team has been 3D-printing titanium implants using a technique known as selective laser melting, in which a high power-density laser is used to melt and fuse together particles of titanium powder in order to form a three-dimensional object.

Utilizing a microwave plasma process, those implants are subsequently covered in a coating consisting of more titanium combined with synthetic diamonds. On a microscopic level, the coating has a scaffold-like structure which encourages cells from the surrounding biological tissue to grow into it.

Diamonds were chosen because the carbon of which they're composed is also a major component of the human body, making them extremely biocompatible. And while diamonds may sound like an expensive way to go, the detonation nanodiamonds that are used actually cost less than the titanium powder.

In lab tests conducted so far, the scientists have been concentrating on how the technology could be used to improve orthopedic implants – and although it may be a number of years before the implants are suitable for use in humans, the results have been promising.

"The diamond enhances the integration between the living bone and the artificial implant, and reduces bacterial attachment over an extended period of time," says Fox. "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."

A paper on the research was recently published in the journal ACS Applied Materials and Interfaces.