毛发是功能梯度复合材料，而非均匀纤维
Hair is a functionally graded composite, not a uniform fiber
浏览论文内容
中文总结 AI 辅助
研究毛发结构功能关系，发现家猫体毛和胡须有三种分层结构沿毛发显著变化，其形态、成分和元素富集改变，产生功能梯度复合结构，揭示毛发非均匀特性及相关机制。
中文摘要 AI 辅助
毛发为哺乳动物带来多种益处，如保护、体温调节和增强感官感知。与生物矿化的肌腱和牙齿不同，毛发被认为仅通过角蛋白实现结构-功能关系。近期研究表明毛发力学性能在类型内和类型间差异大，如亚洲象的胡须从基部到尖端刚度降两个数量级，而象体毛发近乎均匀。本文证明家猫的体毛和胡须有三种分层结构沿毛发显著变化：分层的外层角蛋白壁、皮层中直径250纳米的黑素体样颗粒以及这些颗粒的钙富集。长方形颗粒排列在纵向通道中可能增强皮层，其分布与毛发长度上的局部力学性能相关。对体毛的长期化学处理会去除颗粒中的钙，破坏外层角质层和内部皮层，使基部变硬、尖端裂开。此前认为均匀的毛发，其形态、成分和元素富集沿毛发会改变，产生具有功能梯度的复合结构。
英文摘要
Hair provides mammals with diverse benefits, including protection, thermoregulation, and enhanced sensory perception. Unlike tendons and teeth, which are biomineralized, hair is hypothesized to accomplish its structure-function relationship purely through keratin, a fibrous protein that provides structural integrity. Recent research showed that mechanical properties can vary substantially both within and across hair types: the whiskers of Asian elephant (Elephas maximus) exhibit a two-order-of-magnitude material stiffness reduction from base to tip, whereas elephant body hairs are nearly homogenous. Here, we demonstrate that three hierarchical structures vary significantly along the body hairs and whiskers of domestic cat (Felis catus): the layered outer keratin wall, 250-nm-diameter melanosome-like granules in the cortex, and calcium enrichment of these granules. As occasionally described for human hair, the oblong granules are arranged in longitudinal channels, potentially reinforcing the cortex; their prevalence correlates with local mechanical properties along the hair's length. Prolonged chemical treatment of body hairs removes calcium from the granules while breaking down the outer cuticle and internal cortex, hardening bases and splitting tips. Though previously assumed uniform, morphology, composition, and elemental enrichment can change along hairs, producing composite structures with functional gradients.
