Lin F H, Liao C J, Chen K S, Su J S, Lin C P
Center of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei.
Biomaterials. 2001 Nov;22(22):2981-92. doi: 10.1016/s0142-9612(01)00044-8.
In the present study six types of tricalcium phosphate ceramic were prepared and soaked in distilled water for different periods to investigate whether a surface apatite layer was formed on TCP ceramics or not. X-ray diffractometry (XRD) and Fourier-transformed infrared (FTIR) spectrometer were used to examine the changes in crystalline phases and functional groups of TCP ceramics for different soaking periods. Calcium and phosphate ions released from TCP ceramics during soaking were recorded by atomic absorption analysis and ion-coupled plasma. Results revealed that alphaTCP, alphaTCP/betaTCP mixture (alphabetaTCP) and betaTCP ceramic were gradually dissolved. There was no apatite layer formed on their surface after being immersed in distilled water for different durations of time. Mg-TCP ceramic, tricalcium phosphate doped with Mg ions, exhibited a lower dissolution rate than the other types of TCP ceramics. Apatite crystals were also not formed on the surface of Mg-TCP ceramic when immersed in distilled water. Tribasic calcium phosphate, prepared from wet precipitation method, was converted to betaTCP/HAP (HbetaTCP) or alphaTCP/betaTCP/HAP (HalphabetaTCP) crystalline composition at different sintering temperatures (1,150 degrees C and 1,300 degrees C). The surface apatite layer did not appear on HbetaTCP ceramic after soaking. We observed that petal-like apatite was formed on the HalphabetaTCP ceramic surface after being immersed for 2 weeks. alphaTCP phase of HalphabetaTCP ceramic was not directly converted to apatite during soaking. The surface apatite layer formed on the HalphabetaTCP ceramic surface was due to the precipitation of the calcium and phosphate ions released from alphaTCP dissolution. HAP, which existed in the structure of HalphabetaTCP ceramic, plays a role as apatite-precipitating seed to uptake calcium and phosphate ions. TCP ceramics which lacked alphaTCP and HAP content neither converted to apatite nor formed surface apatite on their surfaces during immersion.
在本研究中，制备了六种类型的磷酸三钙陶瓷，并将其在蒸馏水中浸泡不同时间，以研究磷酸三钙陶瓷表面是否形成磷灰石层。采用X射线衍射仪（XRD）和傅里叶变换红外（FTIR）光谱仪检测不同浸泡时间下磷酸三钙陶瓷晶相和官能团的变化。通过原子吸收分析和离子耦合等离子体记录浸泡过程中从磷酸三钙陶瓷释放的钙和磷酸根离子。结果表明，α - TCP、α - TCP/β - TCP混合物（αβ - TCP）和β - TCP陶瓷逐渐溶解。在不同时间浸入蒸馏水后，其表面未形成磷灰石层。掺镁离子的磷酸三钙（Mg - TCP）陶瓷的溶解速率低于其他类型的磷酸三钙陶瓷。当Mg - TCP陶瓷浸入蒸馏水中时，其表面也未形成磷灰石晶体。通过湿沉淀法制备的磷酸三钙在不同烧结温度（1150℃和1300℃）下转变为β - TCP/HAP（Hβ - TCP）或α - TCP/β - TCP/HAP（Hαβ - TCP）晶体组成。浸泡后，Hβ - TCP陶瓷表面未出现磷灰石层。我们观察到，Hαβ - TCP陶瓷浸泡2周后，其表面形成了花瓣状磷灰石。浸泡过程中，Hαβ - TCP陶瓷的α - TCP相未直接转变为磷灰石。Hαβ - TCP陶瓷表面形成的磷灰石层是由于α - TCP溶解释放的钙和磷酸根离子沉淀所致。Hαβ - TCP陶瓷结构中存在的HAP作为磷灰石沉淀晶种，吸收钙和磷酸根离子。缺乏α - TCP和HAP含量的磷酸三钙陶瓷在浸泡过程中既不转变为磷灰石，其表面也不形成表面磷灰石。
