Due to their unique optical properties, diamonds are the most valued gemstones. However, beyond the sparkle, diamonds have a number of unique properties. Their extreme hardness gives them outstanding performance as abrasives and cutting tools. Similar to many materials, their nanometer‐sized form has yet other unique properties. Nanodiamonds are very inert but still can be functionalized on the surface. Additionally, they can be made in very small sizes and a narrow size distribution. Nanodiamonds can also host very stable fluorescent defects. Since they are protected in the crystal lattice, they never bleach. These defects can also be utilized for nanoscale sensing since they change their optical properties, for example, based on temperature or magnetic fields in their surroundings. In this Review, in vivo applications are focused upon. To this end, how different diamond materials are made and how this affects their properties are discussed first. Next, in vivo biocompatibility studies are reviewed. Finally, the reader is introduced to in vivo applications of diamonds. These include drug delivery, aiding radiology, labeling, and use in cosmetics. The field is critically reviewed and a perspective on future developments is provided.

中文翻译：

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体内纳米金刚石

由于其独特的光学特性，钻石是最有价值的宝石。但是，除了闪闪发光，钻石还具有许多独特的属性。极高的硬度使其具有出色的磨料和切削工具性能。与许多材料相似，它们的纳米尺寸形式还具有其他独特的特性。纳米金刚石是非常惰性的，但仍可以在表面上进行功能化。另外，它们可以制成非常小的尺寸和狭窄的尺寸分布。纳米金刚石还可以具有非常稳定的荧光缺陷。由于它们在晶格中受到保护，因此它们永远不会漂白。这些缺陷也可以用于纳米级传感，因为它们会根据其周围环境的温度或磁场而改变其光学特性。在本综述中，着重于体内应用。为此，首先讨论如何制造不同的金刚石材料以及如何影响其性能。接下来，对体内生物相容性研究进行了综述。最后，向读者介绍了钻石的体内应用。这些包括药物输送，辅助放射学，标签和在化妆品中的使用。对该领域进行了严格审查，并提供了有关未来发展的观点。