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.

节肢动物角质层是一种多功能生物复合材料，由嵌入蛋白质基质的几丁质纤维制成。角质层还形成节肢动物复眼的角膜，这是该门的一个特征，在很大程度上促成了节肢动物令人难以置信的进化成功。在复眼结构中，每个感光单元（小眼）都带有自己的光学器件。节肢动物的复眼是同源的，并表现出相似的总体结构。然而，特别是基本屈光单位经历了相当大的进化修改。在这里，我们建议研究在角膜角质层中观察到的不同结构解决方案，所有这些解决方案对于动物各自的生活方式都是成功的。目标是提高我们对角膜光学性能如何从其形状和底层几丁质结构中产生的理解。之前的大量工作都集中在了解与动物栖息地、昼夜适应、个体发育和进化适应相关的复眼光学。人们很少花精力来理解角质层结构和甲壳素纤维组织之间的基本关系以及新兴的光学特性。在我们的方法中，我们选择了三个物种：鲎、小龙虾和片足类动物，我们利用合作小组开发的各种先进技术来表征它们的结构和组成，并监测角膜的光学和机械特性。在鲎（Chelicerata）的小眼中，每个角膜都有一个圆锥状的突起，完全由几丁质角质层组成。相比之下，在下颌类（多足类、甲壳类、六足类）中，这一过程被细胞内的晶体锥体所取代，小眼角膜要么是豆状的，要么是光滑的，正如所选择的小龙虾和片足类动物所例证的那样。角膜必须同时具有光学和机械功能，从而在这些限制之间调整结构。我们希望得出底层几丁质结构、角膜角质层组成和新兴材料特性之间的相关性，以便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样化专业知识，以及扩散 X 射线散射和微衍射、拉曼光谱、冷冻电子显微镜等分析技术。该提案的意义在于尝试探索生物学中观察到的结构灵活性的边界，作为仿生材料合成的设计策略的来源。