ALD to prevent metal transfer from implants

Atomic layer deposition (ALD) coatings are used in this work to achieve beneficial effects on the surface of CoCrMo alloys used for biomedical applications. Model experiments of implantation into animal bone tissue are performed with uncoated and TiO2 coated samples. Micro X-ray fluorescence is used to map the elemental composition of samples. Results show barrier effect of the coating against the movement of metals from the implant toward the surrounding tissue, increasing with thickness. Moreover, the presence of TiO2 increase the corrosion resistance of the implant. Additional experiments proof that the transfer of ionic species through the same coating, in liquid environment may be exemplified as diffusion through continuous layer, which is also strictly controlled by the coating layer thickness. These evidences open several possibilities for the development of layer by layer structures, with tunable properties, making ALD a powerful tool for biomedical applications.