Influence of Chemical Composition and Structure on the Blood Compatibility of Titanium Oxide Films Prepared by E-beam Evaporation

摘要

Since titanium oxide has been known to be biocompatible, they were coated additionally by supplying oxygen gases on the titanium plates for the tests of their applications in blood-contacting implants. Different layers of titanium oxides were deposited on the Ti plates by electron (E)-beam evaporation of titanium oxide under different flow rates of oxygen gases. The surface morphology, chemical composition and crystal structure of the obtained titanium oxide films were analyzed by FE-SEM, XPS and XRD, respectively. In dependence on the deposition parameters employed, the obtained surface layers were affected by the effects of the rutile phase as well as different titanium oxides (such as Ti_2O_3 and TiO). Contact angles were measured by using distilled water as test liquid. To study the correlation between the structures of the coated layers and their biocompatibility, cellular interaction on their surfaces was investigated by employing porcine aortic smooth muscle cells. The cellular activity on the modified Ti plates was superior to those on the untreated Ti plates. A process of the post-deposition annealing was also an important factor to achieve advantageous biocompatibility in this study. Furthermore, their hemocompatibility was investigated by observing adhesion of blood platelets on their surfaces. Little platelet adhesion was observed on the titanium oxide films. These results showed that the resultant TiO_(2-x) films had good biocompatibility as judged by the tests of modest cellular interaction but nearly no platelet adhesions, indicating that the method of the E-beam treatment could be used as a useful method for the surface modification of the metal stent. The relationship between the chemical states and blood compatibility of the E-beam treated surfaces was further discussed. The existence of Ti~(2+) and Ti~(3+) seemed to be beneficial for their blood compatibility.