Brès E F, Hutchison J L
Laboratoire de Structure et Propriétés de l'Etat Solide, LSPES ESA CNRS 8008, Université de Sciences et Technologies de Lille, Bâtiment C6, 59655 Villeneuve d'Ascq Cedex, France.
J Biomed Mater Res. 2002;63(4):433-40. doi: 10.1002/jbm.10254.
A surface-structure study of human tooth enamel crystals has been carried out by high-resolution electron microscopy (HREM). The surfaces of several crystals have been examined and the surfaces of a single crystal are described here. The observations made on this crystal are similar to the observations made on the other crystals, although the difference of morphology in the crystals observed indicates that the growth control by matrix proteins takes only place on the [011 macro 0] surfaces of the crystals. The crystal described here is oriented along the [112 macro 0] direction, and the following surfaces have been analyzed: (11 macro 00), (011 macro 1), (01 macro 11) and (0001). A subsurface reconstruction is observed just below the surface of the crystal not bonded to the matrix and lying above the supporting film. Observation of the matrix surrounding the crystal shows the existence of poorly crystalline phases with a structure close to that of hydroxyapatite (OHAP). Finally, a comparison of the images of the (011 macro 0) surface with computer-simulated images calculated for several models of the OHAP surface structure shows that the surface itself is stoichiometric and contains both calcium and phosphate groups. The knowledge of the binding sites of proteins on biomineral crystals such as the ones found in human tooth enamel is of prime importance for the understanding of their growth process. In this study, the first structure determination of the surface of human tooth enamel crystals is presented.
利用高分辨率电子显微镜（HREM）对人类牙釉质晶体进行了表面结构研究。已检查了几种晶体的表面，此处描述的是单个晶体的表面。尽管观察到的晶体形态差异表明基质蛋白对晶体生长的控制仅发生在晶体的[011宏观0]表面上，但对该晶体的观察结果与对其他晶体的观察结果相似。此处描述的晶体沿[112宏观0]方向取向，并分析了以下表面：（11宏观00）、（011宏观1）、（01宏观11）和（0001）。在未与基质结合且位于支撑膜上方的晶体表面下方观察到亚表面重构。对晶体周围基质的观察表明存在结构与羟基磷灰石（OHAP）相近的结晶性较差的相。最后，将（011宏观0）表面的图像与针对几种OHAP表面结构模型计算的计算机模拟图像进行比较，结果表明该表面本身是化学计量的，同时含有钙和磷酸基团。了解蛋白质在生物矿物晶体（如人类牙釉质中的晶体）上的结合位点对于理解其生长过程至关重要。在本研究中，首次展示了人类牙釉质晶体表面的结构测定。
