Data from: The microscopic network structure of mussel (Mytilus) adhesive plaques

Marine mussels of the genus Mytilus live in the hostile intertidal zone, attached to rocks, bio-fouled surfaces and each other via collagen-rich threads ending in adhesive pads, the plaques. Plaques adhere in salty, alkaline seawater, withstanding waves and tidal currents. Each plaque requires a force of several newtons to detach. Although the molecular composition of the plaques has been well studied, a complete understanding of supra-molecular plaque architecture and its role in maintaining adhesive strength remains elusive. Here, electron microscopy and neutron scattering studies of plaques harvested from Mytilus californianus and Mytilus galloprovincialis reveal a complex network structure reminiscent of structural foams. Two characteristic length scales are observed characterizing a dense meshwork (approx. 100 nm) with large interpenetrating pores (approx. 1 µm). The network withstands chemical denaturation, indicating significant cross-linking. Plaques formed at lower temperatures have finer network struts, from which we hypothesize a kinetically controlled formation mechanism. When mussels are induced to create plaques, the resulting structure lacks a well-defined network architecture, showcasing the importance of processing over self-assembly. Together, these new data provide essential insight into plaque structure and formation and set the foundation to understand the role of plaque structure in stress distribution and toughening in natural and biomimetic materials.贻贝属（Mytilus）的海洋贻贝栖息于严苛的潮间带生境，通过末端带有黏附斑（plaques）的富含胶原蛋白的丝附着于岩石、生物污损表面及同类个体。该黏附斑可在咸碱性海水中实现稳定附着，抵御海浪与潮汐水流的冲击，单个斑块的剥离所需力可达数牛顿。尽管学界已对黏附斑的分子组成开展了充分研究，但对其超分子（supra-molecular）结构架构及其在维持黏附强度中的作用，仍缺乏完整认知。本研究通过对加州贻贝（Mytilus californianus）与地中海贻贝（Mytilus galloprovincialis）所采集的黏附斑开展电子显微镜与中子散射分析，揭示出一类类似结构泡沫的复杂网状结构。该网状结构存在两个特征长度尺度：一是约100 nm的致密网状骨架，二是约1 µm的大型互穿孔隙。该网状结构可耐受化学变性，提示其内部存在显著的交联作用。在较低温度下形成的黏附斑具有更纤细的网络支柱，据此我们提出了动力学调控的斑块形成机制假说。当人为诱导贻贝生成黏附斑时，所得结构缺乏明确的网状架构，这凸显了加工过程相较于自组装的重要性。综上，本研究的全新数据为黏附斑的结构与形成机制提供了关键认知，并为理解黏附斑结构在天然及仿生材料的应力分布与增韧过程中的作用奠定了基础。