Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
Acta Biomater. 2019 Feb;85:263-271. doi: 10.1016/j.actbio.2018.12.030. Epub 2018 Dec 22.
A wide variety of animals-from insects to snakes-crucially depend on their ability to inject venom into their target, be it their prey or their predator. To effectively deliver their venom, venomous animals use a specialized biomechanical element whose tip must penetrate through the integument of the target. During this process, the tip of the venom-injection element (VIE) is subject to local forces, which may deform it and cause considerable structural damage to the VIE, with devastating consequences for the survival of the animal or, in the case of eusocial insects, to the colony. Hence, it is plausible that millions of years of evolution have carefully 'shaped' the architecture of VIEs across different taxa toward a similar mechanical function, namely, to effectively resist the mechanical forces exerted on the tip. The present study aims to identify such a common architecture by analyzing the form-function relationships in various biological VIEs. A universal structural modeling, which quantifies the fundamental geometrical characteristics of a wide range of VIEs is constituted, and a theoretical mechanical framework that analytically correlates these characteristics with the material stress fields is introduced. This investigation reveals that the architecture of biological VIEs reduces the magnitude of applied stresses and confines the maximal stress to the near-tip region of the element. The presented analytical approach and modeling can be straightforwardly applied to various other types of bio-mechanical elements and can potentially be employed for developing a new class of microscopic injection elements for bio-medical and engineering applications. STATEMENT OF SIGNIFICANCE: Venomous animals-both vertebrate and invertebrate-use an extremely wide variety of venom-injection elements to incapacitate their prey or predator. Despite the clear differences in their typical dimensions, shapes, and evolutionary paths, all venom-injection elements have evolved to perform a single mechanical function, namely, to penetrate a target surface. Accordingly, the architecture of many such elements appears to follow similar principles and their material exhibits similar stress characteristics upon biologically relevant mechanical loadings. The current study introduces a theoretical model that draws connections between the 'universal' structural characteristics of such elements and their bio-mechanical functions. It is found that all examined venom-injection elements provide extreme load-bearing capabilities and unusual post-failure functionalities, which are in good agreement with the wide range of numerical and experimental findings from the literature. The emerging theoretical insights from this study thus shed light on the biomechanical origins of the naturally evolved forms of various biological organisms, including bee and wasp stingers, spider and snake fangs, porcupine fish spines, and scorpion stingers.
从昆虫到蛇等各种各样的动物，它们的生存都严重依赖于将毒液注入目标的能力，无论是它们的猎物还是捕食者。为了有效地输送毒液，有毒动物使用一种专门的生物力学元素，其尖端必须穿透目标的体被。在这个过程中，毒液注射元件（VIE）的尖端会受到局部力的作用，这可能会使它变形，并对 VIE 造成相当大的结构损坏，对动物的生存造成毁灭性的后果，或者在群居昆虫的情况下，对蚁群造成毁灭性的后果。因此，可以合理地假设，数百万年来的进化已经精心“塑造”了不同分类群中 VIE 的结构，使其具有相似的机械功能，即有效地抵抗施加在尖端的机械力。本研究旨在通过分析各种生物 VIE 的形式-功能关系来确定这种共同的结构。本研究构成了一个通用的结构建模，它量化了广泛的 VIE 的基本几何特征，并引入了一个理论力学框架，该框架分析地将这些特征与材料应力场相关联。这项研究表明，生物 VIE 的结构降低了施加的应力的大小，并将最大应力限制在元件的近尖端区域。所提出的分析方法和建模可以直接应用于各种其他类型的生物力学元件，并有可能用于开发用于生物医学和工程应用的新型微观注射元件。
有毒动物——包括脊椎动物和无脊椎动物——使用极其广泛的毒液注射元件来使它们的猎物或捕食者丧失能力。尽管它们的典型尺寸、形状和进化路径有明显的差异，但所有的毒液注射元件都进化到执行一个单一的机械功能，即穿透目标表面。因此，许多这样的元件的结构似乎遵循类似的原则，并且它们的材料在受到生物相关的机械载荷时表现出相似的应力特征。本研究引入了一个理论模型，该模型在这些元件的“通用”结构特征与其生物力学功能之间建立了联系。研究发现，所有被检查的毒液注射元件都提供了极端的承载能力和异常的失效后功能，这与文献中的大量数值和实验结果非常吻合。本研究得出的理论见解因此揭示了各种生物有机体的自然进化形式的生物力学起源，包括蜜蜂和黄蜂的蛰刺、蜘蛛和蛇的毒牙、豪猪鱼的刺和蝎子的蛰刺。
