Shape-memory polymeric materials lack long-range molecular order that enables more controlled and efficient actuation mechanisms. Here, we develop a hierarchical structured keratin-based system that has long-range molecular order and shape-memory properties in response to hydration. We explore the metastable reconfiguration of the keratin secondary structure, the transition from α-helix to β-sheet, as an actuation mechanism to design a high-strength shape-memory material that is biocompatible and processable through fibre spinning and three-dimensional (3D) printing. We extract keratin protofibrils from animal hair and subject them to shear stress to induce their self-organization into a nematic phase, which recapitulates the native hierarchical organization of the protein. This self-assembly process can be tuned to create materials with desired anisotropic structuring and responsiveness. Our combination of bottom-up assembly and top-down manufacturing allows for the scalable fabrication of strong and hierarchically structured shape-memory fibres and 3D-printed scaffolds with potential applications in bioengineering and smart textiles.

形状记忆聚合物材料缺乏长距离的分子有序性，从而无法实现更有效和受控的致动机制。在这里，我们开发了一种基于分层结构化角蛋白的系统，该系统具有响应水合作用的远程分子顺序和形状记忆特性。我们探索了角蛋白二级结构的亚稳态重构结构，即从α螺旋向β折叠的转变，以此作为驱动机制来设计一种高强度的形状记忆材料，该材料具有生物相容性并且可以通过纤维纺丝和三维（3D）处理）打印。我们从动物毛中提取角蛋白原纤维，并使其受到剪切应力以诱导其自组织成为向列相，从而概括了蛋白质的天然层次结构。可以调整此自组装过程以创建具有所需各向异性结构和响应能力的材料。自下而上组装和自上而下制造的结合，使可伸缩制造坚固，层次结构化的形状记忆纤维和3D打印支架，具有在生物工程和智能纺织品中的潜在应用。