Bionic Soft Anisotropic Metamaterials for Replicating Tissue-Like Large-Deformation Mechanics under Diverse Loadings

The development of mechanical metamaterials that replicate the anisotropic mechanical behavior of biological tissues is pivotal for applications in flexible electronics, tissue engineering, and biointegrated technologies. Existing efforts have primarily focused on replicating biomechanical responses under simple uniaxial tension, thereby limiting their applicability under realistic multiaxial deformation scenarios involving complex loading modes such as biaxial tension and shear. To bridge this gap, a class of Bionic Soft Anisotropic Metamaterials (BSAMs) is introduced, featuring a modular architectural strategy that enables tissue-like responses across diverse loading conditions. By combining a quasi-isotropic matrix with directional reinforcements, BSAMs achieve strain energy-level similarity with anisotropic soft tissues, thereby removing dependence on specific loading modes for mechanical compatibility. Numerical simulations and experimental validations demonstrate that BSAMs replicate a wide range of tissue mechanics—from soft organs such as the kidney (tens of kPa) to stiffer tissues like skin (approaching MPa)—and accurately capture varying degrees of anisotropy. Furthermore, the architectural tunability of BSAMs allows for the realization of spatially graded and regionally partitioned structures, enabling precise replication of biomechanical distributions at the organism level. These results highlight the potential of BSAMs as versatile platforms for next-generation prosthetics, soft robotics, and other biointegrated technologies.