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This article presents an experimental study to determine the tensile properties of the envelope fabric Uretek3216A under mono-uniaxial, uniaxial cyclic, and biaxial cyclic loading. First, the mono-uniaxial, uniaxial cyclic, and biaxial cyclic tests were carefully carried out on the envelope fabric, and the corresponding stress–strain behaviors were discussed. Then, the elastic constants were calculated from the experimental data of these tests and the influences of the uniaxial loading cycle and the determination options with different stress ratios were discussed. For the biaxial tests, the elastic constants were determined with and without the constraint of the reciprocal relationship to investigate its significance. Finally, a comparison of the elastic moduli between uniaxial and biaxial tensile tests was presented. Results show that the nonlinearity and orthotropy of the envelope fabric could be attributed to the mechanical properties and unbalanced crimp of their constitutive yarns, respectively. The elastic constants vary noticeably with the experimental protocols, as well as the determination options for biaxial tests, and then in the real design practice, elastic constants should be determined for specific loading conditions and stress distributions depending on the project’s needs.

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Anisotropic microarchitectures arising from an aligned organization of threadlike extracellular matrix (ECM) components or cells are ubiquitous in the human body, such as skeletal muscle, corneal stroma, and meniscus, for executing tissue-specific physiological functions. It is widely recognized that tissue engineering, whereby growing the implanted or endogenous cells in anisotropic scaffolds with geometrical resemblance to the ECM of targeted tissues, represents a promising solution for the structural and functional restoration of these anisotropic tissues. However, remarkable challenges remain in recapitulating the anisotropic complexities of native tissues beyond simply uniaxial alignment. Through unremitting endeavors over the past decade, some innovative bioengineering approaches are developed to tackle these challenges. This review focuses on the recent progress in modular assembly and 3D printing techniques exploited to construct complex anisotropic scaffolds with a key highlight on their accessibility and features for different types of anisotropies, based on understanding the whole picture of anisotropies beyond simply uniaxial alignment in native tissues, which are geometrically divided into three categories. Finally, the applications of these complex scaffolds in anisotropic tissue engineering, either in vitro modeling or in vivo regeneration, are explored.

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