Blood compatibility of titanium based coatings prepared by metal plasma immersion ion implantation and deposition
Tsyganov I., Maitz M.F., Wieser E.
Appl Surf Sci 235(1-2): 156-163 (2004).
Titanium based materials are known to be good hemocompatible, therefore they are suggested as coating for blood contacting implants. Layers of pure Ti, Ti oxynitrides (TiN1-xOx with x = 0.25, 0.50, and 0.75) and Ti oxides were deposited on oxidised Si from a plasma produced by cathodic arc evaporation under addition of N2 and/or O2 to the ambient near the substrate. The oxynitrides are crystalline with the fcc structure of TiN up to x = 0.25. For x = 0.5 a two phase system of fcc TiN and fcc TiO has been found. In dependence on the deposition parameters amorphous and crystalline layers (anatase + brookite, or rutile) of TiO2 have been obtained. The rutile layers were doped by implantation of P. The amorphous TiO2 layers were implanted mit Cr. To study the correlation between structure of the coating and blood compatibility the clotting time of blood plasma as well as the adhesion and activation of blood platelets on the surface was investigated. TiN and oxynitrides show the longest clotting time compared to rutile. Minimum platelet adhesion has been observed for pure TiO2.
Contrasting tendencies in the dependence of clotting time and platelet adhesion on the microstructure have been stated. However, for P+-doped rutile both, enhanced clotting time and improved platelet adhesion, are observed. Platelet adherence and activation always show similar trends.