Takemoto Shinji, Yamamoto Tatsuhiro, Tsuru Kanji, Hayakawa Satoshi, Osaka Akiyoshi, Takashima Seisuke
Biomaterials Laboratory, Faculty of Engineering, Okayama University, Tsushima, Okayama-shi 700-8530, Japan.
Biomaterials. 2004 Aug;25(17):3485-92. doi: 10.1016/j.biomaterials.2003.10.070.
The correlations between titanium oxide layers on oxidized titanium (Ti) substrates and platelet adhesion were examined. Ti substrates were prepared by three different oxidation methods: the first one was treated with hydrogen peroxide (H2O2) solution, the second one was heated in air at moderate temperatures, and the third one was processed with both H2O2 and heating. The titanium oxide layers formed on the Ti substrates were characterized by wettability, chemical composition, thickness, and crystal phase. The platelet adhesion on these oxide layers was examined and correlated to the characterizations of the surface layers. The number of adhesive platelets seemingly correlated with the contact angle towards distilled water, because the number increased close to 70-80 degrees of the contact angle. The effect of surface oxidation on platelet adhesion was examined in detail and it was found that the composition and thickness of the oxide layer influenced platelet adhesion rather than wettability. Thick titanium oxide layers formed on Ti substrates by heating displayed less platelet adhesion than thin oxide layers on untreated Ti substrates. The largest number of adhesive platelets was found on H2O2-oxidized substrates; the substrates found on amorphous titanium oxide contained the Ti-peroxide radical species. The number of platelets, on the other hand, could hardly be observed on Ti substrates treated with H2O2 and subsequently heated above 300 degrees C. The titanium oxide layer on the substrate was thick and we found it to consist of only a few radical species. That is, the effect of heat treatment accelerates the growth of the oxide layer, and decomposes or decreases the number of radical species. Ti substrates with H2O2 and heat treatment above 300 degrees C held the least number of platelets, and were concluded to be the most inhibitory for platelet adhesion.
研究了氧化钛（Ti）基底上的氧化钛层与血小板粘附之间的相关性。Ti基底通过三种不同的氧化方法制备：第一种用过氧化氢（H2O2）溶液处理，第二种在空气中适度加热，第三种同时进行H2O2处理和加热。通过润湿性、化学成分、厚度和晶相来表征在Ti基底上形成的氧化钛层。检测了这些氧化层上的血小板粘附情况，并将其与表面层的表征相关联。粘附血小板的数量似乎与对蒸馏水的接触角相关，因为在接触角接近70 - 80度时数量增加。详细研究了表面氧化对血小板粘附的影响，发现氧化层的组成和厚度而非润湿性影响血小板粘附。通过加热在Ti基底上形成的厚氧化钛层比未处理的Ti基底上的薄氧化层显示出更少的血小板粘附。在H2O2氧化的基底上发现粘附血小板的数量最多；在非晶态氧化钛上发现的基底含有过氧钛自由基物种。另一方面，在用H2O2处理并随后加热到300摄氏度以上的Ti基底上几乎观察不到血小板数量。基底上的氧化钛层很厚，我们发现它仅由少数自由基物种组成。也就是说，热处理的效果加速了氧化层的生长，并分解或减少了自由基物种的数量。经过H2O2处理且热处理温度高于300摄氏度的Ti基底上的血小板数量最少，被认为对血小板粘附的抑制作用最强。
