Titanium oxide with a rutile structure has superior optical properties and blood compatibility and is thermodynamically morestable than other forms. Titanium oxide thin films are deposited on (100) silicon and SiO2 wafers by metal plasma ion implantation and deposition. The substrates are DC biased during the film deposition and the influence of the oxygen pressure on the characteristics of the coatings is investigated. X-ray diffraction indicates the existence of Ti4O7 in the film when the oxygen pressure is lower than 2.0=10-2 Pa. As the oxygen pressure increases, the preferred orientation of the as-deposited titanium oxide film changes to the (200) high-index plane from the (100) low-index plane. The as-deposited titanium oxide films are subsequently annealed at 750℃ for 60 min in vacuum. The microstructure, resistance, composition, and blood compatibility of the films are assessed. Before annealing, the sheet resistance of the titanium oxide increases with higher oxygen pressure, and after vacuum annealing, the sheet resistance of some of the titanium oxide films increases by approximately 60 times. The results of the platelet adhesion experiments acquired from the annealed samples are similar to those from low-temperature isotropic pyrolytic carbon.

Over the past decade, much attention has been paid to anti-thrombotic materials applied in artificial organs. Surface modification has shown potential to improve the anti-coagulation of blood-contacting biomedical devices and materials [1-3]. Our in vitro study of Ti-O thin films has recently shown that Ti-O thin films possess superior blood compatibility to low temperature isotropic pyrolytic carbon (LTI-carbon) [1]. In this work, we have focussed our attention onto the in vivo evaluation of Ti-O thin films, fabricated by plasma immersion ion implantation (PⅢ). The samples of titanium coated by Ti-O thin films were implanted in dogs' hearts for 1 month. The results of the implantation showed that no thrombus was found on the surfaces of the Ti-O thin film, although the coagulation occurred on the surfaces of LTI-carbon.

Titanium metal and titanium alloys are among the most widely used materials in biomedical devices because of their relatively high corrosion resistance and good biocompatibility. It has been suggested that the physiochemical and dielectric properties of the surface native oxide play a crucial role in the biocompatibility. There is increasing evidence that titanium may be extensively released in vivo and, under certain conditions, accumulated in adjacent tissues or transported to distant organs. Therefore, it is necessary to synthesize thicker and denser TiO2 films on titanium to enhance its biomedical properties. In this paper, we discuss our fabrication technique utilizing dual plasma generated by metal vacuum arc and radio frequency. The films fabricated consist of rutile crystal, although the substrates are not heated. As the oxygen partial pressure is raised, the intensity of the (101) and (110) diffraction peaks increases, and that of the (002) diffraction peak decreases. The preferred orientation of the TiO2 film shifts from (002) to (110) as a result of the competition between the surface free energy and ion bombardment. At low oxygen pressure, the TiO2 grain growth is mainly affected by ion bombardment, whereas thermodynamic factors affect the film growth at higher oxygen partial pressure. When the oxygen partial pressure reaches 0.93=10-2 Pa, further increase in the oxygen flow rate does not change the film composition. The film is completely oxidized and only comprises the TiO2 phase. The microhardness of the TiO films increases with the oxygen partial pressure and reaches a maximum value of 19 GPa at 1.7=10-2 Pa.

Plasma immersion ion implantation and deposition (PIIID) provides a novel approach to fabricate high quality films by means of utilizing particle filtrated metal plasma and varying acceleration pulse voltages. In this work, investigation on plastic deformation of TiN films synthesized by PIIID was performed by pulling the TiN film-coated stainless steel sheet samples. The surface morphology during the pulling was observed in situ by scanning electron microscopy. No delaminating, peeling or cracking were found on the coating surfaces. The structure of the films was identified by transmission electron microscopy and atom force microscopy. It is considered that the excellent deformation behavior of the TiN film was related with the nanocrystal structure of the films and the broader film/matrix interface achieved by the PIII process.

Diamond-like carbon (DLC) is an attractive biomedical material due to its high inertness and excellent mechanical properties. Using plasma immersion ion implantation-deposition (PIII-D), DLC films are fabricated on silicon substrates at room temperature. By changing the C2H2 to Ar(FC2/H2/FAr) flow ratio during deposition, the effects of the reactive gas pressure and flow ratio on the characteristics of the DLC films are systematically examined to correlate to the blood compatibility. The thickness, surface morphology, composition, structure, sp3/sp2 content, as well as carbon–hydrogen bonding are studied using alpha-step profilometry, atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR), respectively. The blood compatibility of the film is evaluated using in vitro platelet adhesion investigation, and the quantity and morphology of the adherent platelets are investigated employing optical microscopy and scanning electron microscopy (SEM). The Raman D-band to G-band intensity ratio is consistent with the adherent platelet quantity. Both first increase and then decrease with higher FC2/H2/FAr flow ratios. This implies that the blood compatibility of the DLC films is influenced by the ratio of sp3 to sp2, not by the absolute sp3 or sp2 content. Our study suggests that DLC films with the proper sp3 to sp2 ratio and good blood compatibility can be fabricated by C2H2-Ar PIII-D using a suitable C H yAr gas ratio.

The biomedical properties of tantalum nitride thin films synthesized by reactive magnetron sputtering employing orthogonal design technology are investigated. The adhesion properties between the film and substrate can be enhanced by optimizing the sputtering gas pressure and substrate temperature. The hardness of the tantalum nitride films is greatly affected by the nitrogen partial pressure, and our results show that films deposited under the optimal conditions can achieve a hardness value of approximately 40 GPa. The blood compatibility of the tantalum nitride films, as evaluated by clotting time measurement and platelet adhesion tests, is compared to that of TiN, Ta and low-temperature isotropic pyrolytic carbon (LTIC). Our data reveal that the blood compatibility of our tantalum nitride films is better, and tantalum nitride is thus an excellent material for the fabrication of commercial artificial heart valves.

Ti-O/Ti-N duplex coatings were fabricated on titanium alloys by metal plasma immersion ion implanta tion and reactive plasma nitriding/oxidation. The purpose of Ti-O is to improve the blood compatibility, and that of Ti N is to improve the mechanical properties. X-Ray diffraction (XRD), microhardness tests, pin-on-disk wear experiments, and platelet adhesion investigation were conducted to evaluate the properties and blood compatibility of the coatings. The results reveal that the blood compatibility of the Ti-O/Ti-N duplex coatings is better than that of low temperature isotropic pyrolytic carbon (LTIC). The microhardness of Ti-O/Ti-N duplex coatings can reach 14 GPa. The wear resistance is also much better than that of Ti6Al4V alloy. The semiconductor nature of non-stoichio-metric titanium oxide may be responsible for the observed improvement in the blood compatibility.

Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper, we describe our work of improving hemocompatibility with Ti-O thin films prepared by plasma immersion ion implantation and deposition and by sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, Auger electron spectroscopy, atomic force microscopy (AFM), contact angle measurement, and Hall effect measurement. The behavior of fibrinogen adsorption was investigated by 125I radioactive isotope labeling and AFM. Systematic evaluation of hemocompatibility, including in vitro clotting time, thrombin time, prethrombin time, platelet adhesion, and in vivo implantation into dog's ventral aorta or right auricle from 17 to 90 days, proved that Ti-O films have excellent hemocompatibility. It is suggested that the significantly lower interface tension between Ti-O films and blood and plasma proteins and the semiconducting nature of Ti-O films give them their improved hemocompatibility.

采用等离子体浸没离子注八技术（PⅢ），用乙炔时医用聚氨醢材料进行表面改性，对改性后材料表面的X光电子能谱（XPS）、衰减全反射红外光谱（ATR-FTIR）和接触角测试分析表明。医用聚氨酯材料表面的化学健发生断裂，碳元素含量增加，彤成新的无定形碳相，表面的浸润性刖随处理时间的增加而增加。血小板粘附实验的结果表明，乙烧等离子漫没离子注八表面改性医用聚氨酯能哆提高材料的抗凝血性。