Biomimetics-Innovation-Centre, Hochschule Bremen - City University of Applied Sciences, Neustadtswall 30, 28199, Bremen, Germany.
Arthropod Struct Dev. 2022 Jan;66:101139. doi: 10.1016/j.asd.2021.101139. Epub 2022 Jan 29.
One of the most versatile and complex biological composite materials, the insect exoskeleton shows a huge range in biomechanical properties. The cuticle exoskeleton can be differentiated into two main histologically different layers with distinct properties: the outer, more sclerotized exocuticle and inner, softer endocuticle. For most biomechanical research questions, it is of great importance to be able to selectively characterize geometrical features of these layers. However, most conventional preparation methods (cross-sections, histological staining, SEM) require complex and destructive sample preparation, which provides only two-dimensional information. Here, we present a novel, simple staining method using X-ray microtomography to distinguish between exo- and endocuticle in a 3D environment without sample destruction. We illustrate the power of our method using locust (Locusta migratoria) hindleg tibia, a well characterized biomechanical sample. Our method allows an easy and direct measurement of exo- and endocuticle and their respective geometric features. Applying our method will help to understand the biomechanical role of exo- and endocuticle within an insect exoskeleton and will allow us to understand its composition and morphological features in more detail.
昆虫外骨骼是一种用途广泛且复杂的生物复合材料，具有巨大的生物力学性能差异。外骨骼可以分为两个组织学上明显不同、具有不同特性的主要层：外层更硬化的外角质层和内层较软的内角质层。对于大多数生物力学研究问题，能够有选择性地对这些层的几何特征进行特征化是非常重要的。然而，大多数传统的制备方法（切片、组织学染色、SEM）需要复杂和破坏性的样品制备，只能提供二维信息。在这里，我们提出了一种新颖的、简单的染色方法，使用 X 射线微断层扫描在 3D 环境中区分外角质层和内角质层，而不会破坏样品。我们使用经过很好表征的生物力学样本——蝗虫（Locusta migratoria）后肢胫骨来说明我们方法的强大功能。我们的方法允许对外角质层和内角质层及其各自的几何特征进行简单和直接的测量。应用我们的方法将有助于了解昆虫外骨骼中外角质层和内角质层的生物力学作用，并使我们能够更详细地了解其组成和形态特征。
