Protein interaction with tantalum: changes with oxide layer and hydroxyapatite at the interface.

For metallic implants the surface nature is extremely important because blood and tissue interactions with metal depend upon it. Protein adsorption is the initial reaction that takes place when an implant comes in contact with blood or tissue. We attempted to coat different thicknesses of oxide layers and hydroxyapatite on tantalum and examined the changes in water contact angle and adsorption of albumin and fibrinogen. Protein adsorption studies were performed with 125I-labeled proteins. A decrease in water contact angle was observed as the oxide layer thickness of tantalum increased. Fibrinogen adsorption increased on oxide layer coated and hydroxyapatite coated surfaces, compared to bare tantalum.