Structural flexibility in the optical design of the arthopod cornea

节肢动物角膜光学设计的结构灵活性

• 批准号: 286895536
• 负责人: Professor Dr. Gerhard Scholtz
• 金额: --
• 依托单位: B CUBE - Center for Molecular Bioengineering
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/286895536?language=en
• 关键词: Structural; flexibility; optical; design; arthopod

The arthropod cuticle is a versatile biocomposite made of chitin fibers embedded in a protein matrix. The cuticle also forms the cornea of the arthropod compound eye, a characteristic feature of the phylum that has largely contributed to its incredible evolutionary success. In the compound eye structure each photoreceptor unit (ommatidium) carries its own optics. Arthropod compound eyes are homologous and show a similar general structure. However, in particular the basic dioptric unit underwent considerable evolutionary modifications. Here we propose to study the different structural solutions observed in the cornea cuticle, all of which were successful for the animals in their respective lifestyle. The goal is to improve our understanding of how the corneas optical performance emerges from their shape and the underlying chitin architecture. A large body of previous work has focused on understanding the compound eye optics in relation to the animals habitat, diurnal adaptations, ontogeny and evolutionary adaptations. Much less effort has been taken to understand the fundamental relation between the cuticle structure and chitin fiber organization and the emerging optical properties. In our approach, we have selected three species: a horseshoe crab, a crayfish and an amphipod, and we characterize their structure and composition and monitor the optical and mechanical properties of the cornea exploiting diverse advanced techniques developed within the collaborating groups. In the ommatidia found in the horseshoe crab Limulus polyphemus (Chelicerata) each cornea possesses a cone-like process, made entirely of chitin-based cuticle. In the Mandibulata (myriapods, crustaceans, hexapods), in contrast, this process is replaced by an intracellular crystalline cone and the ommatidial cornea is either lentiform or smooth, as exemplified by the chosen crayfish and amphipod. The cornea has to serve both an optical and a mechanical function leading to adjusted structures between these constraints. We wish to draw correlations between the underlying chitin-structure, the cuticle composition of the cornea and the emerging materials properties in order to draw conclusions relevant for polymer materials design. We shall exploit the diverse expertise of the partners in biological characterization and histology, as well as analytical techniques such as diffuse X ray scattering and microdiffraction, Raman spectroscopy, cryo electron microscopy and more. The significance of this proposal is in the attempt to explore the boundaries of structural flexibility as observed in biology as a source of design strategies for bioinspired material synthesis.

节肢动物角质层是由嵌入蛋白质基质中的几丁质纤维制成的多功能生物复合材料。角质层还形成了节肢动物化合物眼的角膜，这是门的一个特征，在很大程度上有助于其令人难以置信的进化成功。在复合眼睛结构中，每个光感受器单元（Ommatidium）具有自己的光学元件。节肢动物化合物的眼睛是同源的，并且显示出相似的一般结构。但是，尤其是基本的屈光单元进行了相当大的进化修饰。在这里，我们建议研究角膜角质层中观察到的不同结构溶液​​，所有这些溶液在各自的生活方式中都成功。目的是提高我们对角膜光学性能如何从其形状和基础几丁质体系结构中出现的理解。以前的大量工作集中在了解与动物栖息地，昼夜适应性，本体发育和进化适应性相关的复合眼镜。了解角质层结构与几丁质纤维组织与新兴光学特性之间的基本关系所花费的努力要少得多。在我们的方法中，我们选择了三种物种：一个马蹄蟹，小龙虾和两栖动物，我们表征了它们的结构和组成，并监测角膜的光学和机械性能，从而在协作组中开发了多种高级技术。在马蹄蟹limulus polyphemus（chelicerata）中发现的蛋黄酱中，每个角膜都具有类似锥形的过程，完全由基于几丁质的角质层制成。相比之下，在下颌骨（Myriapods，甲壳类动物，六脚架）中，此过程被细胞内晶锥取代，并且羊皮角膜是壁壁或光滑的，是由所选择的小龙虾和放大器构成的。角膜必须既有光学和机械函数，从而导致这些约束之间的调整结构。我们希望在基础几丁质结构，角膜的角质层组成和新兴材料特性之间提出相关性，以得出与聚合物材料设计相关的结论。我们将利用合作伙伴在生物表征和组织学方面的多元化专业知识，以及分析技术，例如弥漫性X射线散射和微屈光度，拉曼光谱，冷冻电子显微镜等。该提案的意义在于试图探索在生物学中观察到的结构灵活性的边界，作为生物启发材料合成的设计策略的来源。