Hydrogels are excellent mimetics of mammalian extracellular matrices and have found widespread use in tissue engineering. Nanoporosity of monolithic bulk hydrogels, however, limits mass transport of key biomolecules. Microgels used in 3D bioprinting achieve both custom shape and vastly improved permissivity to an array of cell functions, however spherical‐microbead‐based bioinks are challenging to upscale, are inherently isotropic, and require secondary crosslinking. Here, bioinks based on high‐aspect‐ratio hydrogel microstrands are introduced to overcome these limitations. Pre‐crosslinked, bulk hydrogels are deconstructed into microstrands by sizing through a grid with apertures of 40–100 µm. The microstrands are moldable and form a porous, entangled structure, stable in aqueous medium without further crosslinking. Entangled microstrands have rheological properties characteristic of excellent bioinks for extrusion bioprinting. Furthermore, individual microstrands align during extrusion and facilitate the alignment of myotubes. Cells can be placed either inside or outside the hydrogel phase with >90% viability. Chondrocytes co‐printed with the microstrands deposit abundant extracellular matrix, resulting in a modulus increase from 2.7 to 780.2 kPa after 6 weeks of culture. This powerful approach to deconstruct bulk hydrogels into advanced bioinks is both scalable and versatile, representing an important toolbox for 3D bioprinting of architected hydrogels.

中文翻译：

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基于缠结水凝胶微丝的大孔材料3D生物打印

水凝胶是哺乳动物细胞外基质的优异模拟物，并在组织工程中得到广泛应用。然而，整体水凝胶的纳米孔隙度限制了关键生物分子的传质。3D生物打印中使用的微凝胶既可以实现定制形状，又可以大大提高对一系列细胞功能的允许性，然而基于球形微珠的生物墨水难以升级，本质上是各向同性的，并且需要二次交联。在这里，引入基于高纵横比水凝胶微丝的生物墨水来克服这些限制。通过孔径为 40-100 µm 的网格调整尺寸，将预交联的块状水凝胶解构为微丝。微丝是可模制的，形成多孔的缠结结构，在水介质中稳定，无需进一步交联。缠结的微丝具有用于挤出生物打印的优异生物墨水的流变特性。此外，各个微丝在挤压过程中对齐并促进肌管的对齐。细胞可以放置在水凝胶相内部或外部，存活率 >90%。与微链共同打印的软骨细胞沉积了丰富的细胞外基质，导致培养 6 周后模量从 2.7 kPa 增加到 780.2 kPa。这种将块状水凝胶解构为先进生物墨水的强大方法既具有可扩展性又具有多功能性，是构建水凝胶 3D 生物打印的重要工具箱。