Tsukimura Naoki, Kojima Norinaga, Kubo Katsutoshi, Att Wael, Takeuchi Kazuo, Kameyama Yoichiro, Maeda Hatsuhiko, Ogawa Takahiro
Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, California 90095-1668, USA.
J Biomed Mater Res A. 2008 Jan;84(1):108-16. doi: 10.1002/jbm.a.31422.
The surface topography and chemistry of titanium are postulated to be two major factors that affect the osseointegration capacity of titanium implants. However, it is extremely difficult to control one factor without changing the other, which prevents the isolation of the genuine effect of one factor. This study aimed to determine whether surface chemistry of titanium alone affects osteoblastic function. Two different titanium surfaces were prepared by sputter depositioning of titanium (Ti; 99.99% purity) or titanium dioxide (TiO2; 99.99% purity) (50-nm thick for each) onto machined commercially pure titanium disks. Rat bone marrow-derived osteoblastic cells were cultured on each of the two surfaces. TiO2 surface showed 4.4 times higher elemental oxygen concentration and higher water wettability than Ti surface. Scanning electron microscopic and atomic force microscopic examination revealed no differences in surface topography and roughness values between the two surfaces. The cell proliferated more on TiO2 than on Ti by up to 60%. Although the expression of collagen I gene increased more rapidly on TiO2 at early culture stage of day 3, the late stage marker genes for osteoblastic differentiation, including osteopontin and osteocalcin, were not modulated between the two cultures. The alkaline phosphatase positive area and mineralized nodule area were approximately two times larger on TiO2 than on Ti. In conclusion, titanium materials having different superficial chemistry, that is, titanium or titanium dioxide, may exert different biological capacity of osteoblasts; titanium dioxide may induce superior osteoconduction, primarily because of the increased osteoblastic proliferation.
钛的表面形貌和化学性质被认为是影响钛植入物骨整合能力的两个主要因素。然而，在不改变另一个因素的情况下控制其中一个因素极其困难，这阻碍了对单一因素真实作用的分离。本研究旨在确定仅钛的表面化学性质是否会影响成骨细胞功能。通过将钛（Ti；纯度99.99%）或二氧化钛（TiO₂；纯度99.99%）（每种厚度为50纳米）溅射沉积到加工过的商业纯钛盘上，制备了两种不同的钛表面。将大鼠骨髓来源的成骨细胞培养在这两种表面上。TiO₂表面的元素氧浓度比Ti表面高4.4倍，且润湿性更高。扫描电子显微镜和原子力显微镜检查显示，两种表面的表面形貌和粗糙度值没有差异。细胞在TiO₂上的增殖比在Ti上多高达60%。虽然在培养第3天的早期阶段，I型胶原基因在TiO₂上的表达增加得更快，但在两种培养物中，成骨细胞分化的晚期标记基因，包括骨桥蛋白和骨钙素，并未受到调节。TiO₂上的碱性磷酸酶阳性面积和矿化结节面积比Ti上大约大两倍。总之，具有不同表面化学性质的钛材料，即钛或二氧化钛，可能对成骨细胞发挥不同的生物学作用；二氧化钛可能诱导更好的骨传导性，主要是因为成骨细胞增殖增加。
