Liu Xuanyong, Xie Youtao, Ding Chuanxian, Chu Paul K
Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China.
J Biomed Mater Res A. 2005 Sep 1;74(3):356-65. doi: 10.1002/jbm.a.30273.
Dicalcium silicate coating was deposited onto a Ti-6Al-4V substrate using plasma-spraying technology. The coating was immersed in simulated body fluid (SBF) for 1, 3, 6, 12, 24, and 48 h to investigate early apatite formation on the coating. Osteoblasts were also seeded onto the surface of the dicalcium silicate coating to evaluate its biocompatibility. Cold field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry were used to evaluate the morphologies and determine the chemical composition of the coatings. The surface structural changes caused by immersion in SBF were analyzed using thin-film X-ray diffraction. After the dicalcium silicate coating was soaked in SBF solution 1-6 h, two types of particles containing calcium and phosphorus were formed on the surface. One type consisted of relatively larger particles (P1) precipitated on the surface of the coating from the precursor cluster formed in the SBF solution. The second type was composed of particles (P2) nucleated on the surface of the coating. With increasing immersion time, the particles coalesced to form a surface Ca-P layer. The Ca-P layer was composed of amorphous calcium phosphate that was not transformed to crystalline apatite until the immersion time in SBF exceeded 24 h. The formation mechanism of the Ca-P layer and apatite on the surface of the coating is believed to be involved in the formation of the Si 3-ring active surface site with negative charge. The cell-seeding test revealed that osteoblasts grew and proliferated very well on the surface of the dicalcium silicate coating.
采用等离子喷涂技术在Ti-6Al-4V基体上沉积硅酸二钙涂层。将涂层浸入模拟体液（SBF）中1、3、6、12、24和48小时，以研究涂层上早期磷灰石的形成。还将成骨细胞接种到硅酸二钙涂层表面，以评估其生物相容性。使用冷场发射扫描电子显微镜和能量色散X射线光谱仪评估涂层的形貌并确定其化学成分。利用薄膜X射线衍射分析浸泡在SBF中引起的表面结构变化。硅酸二钙涂层在SBF溶液中浸泡1-6小时后，表面形成了两种含钙和磷的颗粒。一种是由SBF溶液中形成的前驱体簇沉淀在涂层表面的相对较大的颗粒（P1）。第二种是在涂层表面成核的颗粒（P2）。随着浸泡时间的增加，颗粒聚结形成表面Ca-P层。Ca-P层由无定形磷酸钙组成，直到在SBF中的浸泡时间超过24小时才转变为结晶磷灰石。涂层表面Ca-P层和磷灰石的形成机制被认为与带负电荷的Si 3环活性表面位点的形成有关。细胞接种试验表明，成骨细胞在硅酸二钙涂层表面生长和增殖良好。
