Mineral particles in bone are interlaced with collagen fibrils, hindering the investigation of bioapatite crystallites (BAp). This study utilized a special whale rostrum (the most highly mineralized bone ever recorded) to measure the crystallites of bone BAp via long-term dissolution in water. The BAp in the rostrum has a low solubility (6.7 ppm Ca and 3.8 ppm P after 150 days dissolution) as well as in normal bones, which leads to its Ksp value of ~10−53. Atomic force microscopy results show tightly compacted mineral crystallites and confirm the low amount of collagen in the rostrum. Additionally, the mineral crystallites demonstrate irregular plate-like shapes with variable sizes. The small crystallites (~11 × 24 nm) are easily detached from BAp prisms, compared with the large crystallites (~50 nm). Moreover, various orientations of crystallites are observed on the edge of the prisms, which suggest a random direction of mineral growth. Furthermore, these plate-like crystallites prefer to be stacked layer by layer under weak regulation from collagen. The morphology of rostrum after dissolution provides new insights into the actual morphology of BAp crystallites.

中文翻译：

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对部分溶解后生物磷灰石超微结构的新见解：基于鲸鱼讲台，最致密的骨头

骨骼中的矿物颗粒与胶原原纤维交织在一起，阻碍了对生物磷灰石微晶 (BAp) 的研究。这项研究利用一种特殊的鲸鱼讲台（有记录以来矿化程度最高的骨头）通过长期溶解在水中来测量骨 BAP 的微晶。主席台中的 BAp 在正常骨骼中的溶解度较低（溶解 150 天后为 6.7 ppm Ca 和 3.8 ppm P），这导致其 Ksp 值约为 10−53. 原子力显微镜结果显示紧密压实的矿物微晶并证实主席台中的胶原蛋白含量低。此外，矿物微晶表现出不规则的板状形状，大小不一。与大微晶（~50 nm）相比，小微晶（~11 × 24 nm）很容易从 BAp 棱镜上脱离。此外，在棱柱的边缘观察到各种取向的微晶，这表明矿物生长的方向是随机的。此外，这些板状微晶更喜欢在胶原蛋白的弱调节下逐层堆叠。溶解后主席台的形态为 Bap 微晶的实际形态提供了新的见解。