Implanting a 3D printing scaffold is an effective therapeutic strategy for personalized bone repair. As the key factor for the success of bone tissue engineering, the scaffold should provide an appropriate bone regeneration microenvironment and excellent mechanical properties. In fact, the most ideal osteogenic microenvironment is undoubtedly provided by natural bone extracellular matrix (ECM), which exhibits liquid crystalline and viscoelastic characteristics. However, mimicking a bone ECM-like microenvironment in a 3D structure with outstanding mechanical properties is a huge challenge. Herein, we develop a facile approach to fabricate a bionic scaffold perfectly combining bone ECM-like microenvironment and robust mechanical properties. Creatively, 3D printing a poly(l-lactide) (PLLA) scaffold was effectively strengthened via layer-by-layer electrostatic self-assembly of chitin whiskers. More importantly, a kind of chitin whisker/chitosan composite hydrogel with bone ECM-like liquid crystalline state and viscoelasticity was infused into the robust PLLA scaffold to build the bone ECM-like microenvironment in 3D structure, thus highly promoting bone regeneration. Moreover, deferoxamine, an angiogenic factor, was encapsulated in the composite hydrogel and sustainably released, playing a long-term role in angiogenesis and thereby further promoting osteogenesis. This scaffold with bone ECM-like microenvironment and excellent mechanical properties can be considered as an effective implantation for bone repair.

中文翻译：

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用于骨再生的具有液晶和粘弹性微环境的类 ECM 骨 3D 打印支架

植入 3D 打印支架是个性化骨修复的有效治疗策略。作为骨组织工程成功的关键因素，支架应提供适宜的骨再生微环境和优异的力学性能。事实上，最理想的成骨微环境无疑是由具有液晶和粘弹性特征的天然骨细胞外基质（ECM）提供的。然而，在具有出色机械性能的 3D 结构中模拟类似骨 ECM 的微环境是一个巨大的挑战。在此，我们开发了一种简便的方法来制造完美结合骨 ECM 样微环境和稳健机械性能的仿生支架。创造性地，3D 打印聚 ( l-丙交酯）（PLLA）支架通过几丁质晶须的逐层静电自组装得到有效强化。更重要的是，将一种具有类骨 ECM 液晶态和粘弹性的几丁质晶须/壳聚糖复合水凝胶注入坚固的 PLLA 支架中，以在 3D 结构中构建类骨 ECM 微环境，从而高度促进骨再生。此外，血管生成因子去铁胺被包裹在复合水凝胶中并持续释放，在血管生成中发挥长期作用，从而进一步促进成骨。这种具有类骨 ECM 微环境和优异机械性能的支架可以被认为是一种有效的骨修复植入物。