Osteoderms of Heloderma suspectum - A new nano-micro hierarchical biomineralized structure in vertebrates

作者：Alexander Kirby 1合作者：Michael Jossi1 Mehran Moazen2，Susan Evans3，Sergio Bertazzo11伦敦大学学院医学物理和生物医学工程系，伦敦WC1E 6BT，UK2机械工程系，伦敦大学学院Torrington Place，London WC1E 7JE，UK 3细胞与发育生物系，伦敦大学学院，Gower Street，London WC1E 6BT，英国摘要：Helodermatdae是一种有毒蜥蜴家族，它在皮肤内进化了骨皮。自首次报道以来，骨皮通常被描述为骨或骨样结构，这一概念从未受到彻底的挑战。在这个项目中，我们评估了疑似螺旋藻(Gila Monster)骨皮肤的纳米/微观特征，并将其与同一动物的骨和牙齿样本进行了比较。这项表征研究将使用先进的物理化学分析，例如与聚焦离子束(FIB)相关的电子显微镜。在微观尺度上，扫描电子显微镜的结果将证明或否定Gila怪物的骨真皮可以分为三个区域：存在于骨皮上部的高度矿化的致密物质；贯穿骨皮的骨样材料，明显包围着血管；以及矿化区，直径约10微米的胶原纤维排列成三维网状结构。X射线衍射仪表明，在纳米尺度上，FIB制备的样品的透射电子显微镜将证明或反驳这三个不同区域的每个区域都是唯一的假设，呈现出不同的纳米结构和不同的结晶度。我们还假设，与同一动物的骨骼和牙齿样本相比较，骨皮确实是一种独特的矿化组织，而不是简单的类骨组织。这些结果可能证明，在脊椎动物中，自然的非病理硬组织比人们想象的更多样化，这表明存在全新的细胞和生化生物矿化系统。进一步的初步结果表明，这里描述的Gila怪物的三个结构是蜥蜴骨皮的基本成分，这三个结构的形状和比例在不同物种之间存在差异。最后，除了在脊椎动物中发现的一种新的硬组织的生物学、进化和生态意义外，这里描述的迄今未知的纳米/微结构可能在未来的翻译应用中被证明是有价值的，包括创造具有特殊性质的仿生和生物灵感材料。出于这些原因，这项研究与EPSRC生物材料研究领域以及开发未来疗法、物理干预前沿和先进材料的战略/重大挑战很好地结合在一起。作者声明，这项研究不需要伦理批准。

Author:Alexander Kirby1Collaborators:Michael Jossi1 Mehran Moazen2, Susan Evans3, Sergio Bertazzo11Department of Medical Physics & Biomedical Engineering, University College London, London WC1E 6BT, UK2Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK 3Department of Cell & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UKSummary:Helodermatidae is a family of venomous lizards that has evolved osteoderms within the skin. Since they were first reported, osteoderms have generally been described as bone or bone-like structures, and this concept has never been thoroughly challenged. In this project, the nano/micro characteristics of the osteoderms of Heloderma suspectum (Gila monster) are evaluated and compared to bone and tooth samples from the same animal. This characterization study is to be done using advanced physical-chemical analyses, such as electron microscopy associated with focused ion beam (FIB). At the micro scale, scanning electron micrograph results will prove or disprove that the osteoderm of the Gila monster can be divided into three regions: a highly mineralised dense material present in the upper region of the osteoderm; a bone-like material that runs through the osteoderm, apparently surrounding vasculature; and a mineralised region, with collagen fibers of approximately 10 microns of diameter organized in a three-dimensional mesh. At the nano scale, transmission electron micrographs of samples prepared by FIB will prove or disprove the hypothesis that each of the three different regions is unique, presenting different nanostructures and different crystallinity, as demonstrated by x-ray diffractometry. We also hypothesise that comparison with samples of bone and teeth taken from the same animal reveal that the osteoderm is indeed a unique mineralised tissue and not a simple bone-like tissue. These results then may prove an indication that in vertebrates, natural non-pathological hard tissues are more diverse than suspected, suggesting the existence of completely novel cellular and biochemical biomineralization systems. Further preliminary results indicate that the three structures described here for the Gila monster are the fundamental components of osteoderms in lizards, with variations in the shape and proportion of these three structures between species. Finally, beyond the biological, evolutionary and ecological significance of a new hard tissue discovered in vertebrates, the hitherto unknown nano/micro structures described here may potentially prove valuable in future translational applications, including the creation of biomimetic and bioinspired materials with special properties. For these reasons, this study is well aligned to the EPSRC research area of biomaterials and the strategies/grand challenges of developing future therapies, frontiers of physical intervention and advanced materials.The authors declare that no ethical approval was required for this study.