Complex mechanical changes in response to an external trigger are pervasive in natural soft materials and often sought for applications. Be it the reversible stiffening of sea cucumber, the failure of a polymeric or colloidal gel under load, or the dissolution of a biosensing hydrogel upon target binding, mechanical transitions are typically enabled, and critically affected, by heterogeneous structures and reversible bonds. New possibilities to monitor evolving properties and to gain access to stress propagation with temporal and spatial resolution are being disclosed by mechanochromic molecules and molecular complexes, which transduce a mechanical stress into a light signal and act as built-in stress reporters. I will review recent strategies and identify future directions for the design of mechanically responsive soft networks and for their optical mapping, focusing particular attention on the emerging class of hydrogels based on DNA self-assembly.

响应外部触发的复杂机械变化在天然软质材料中无处不在，并且经常寻求应用。无论是海参的可逆变硬，负载下聚合物或胶体凝胶的失效，还是靶结合后生物传感水凝胶的溶解，异质结构和可逆键通常都能实现且严重影响机械转换。机械致变色分子和分子复合物揭示了监视演化的特性并获得具有时间和空间分辨率的应力传播的新可能性，它们将机械应力转化为光信号并充当内置的应力报告物。