Acellular soft hydrogels are not ideal for hard tissue engineering given their poor mechanical stability, however, in combination with cellular components offer significant promise for tissue regeneration. Indeed, nanocomposite bioinks provide an attractive platform to deliver human bone marrow stromal cells (HBMSCs) in three dimensions producing cell-laden constructs that aim to facilitate bone repair and functionality. Here we present the in vitro, ex vivo and in vivo investigation of bioprinted HBMSCs encapsulated in a nanoclay-based bioink to produce viable and functional three-dimensional constructs. HBMSC-laden constructs remained viable over 21 d in vitro and immediately functional when conditioned with osteogenic media. 3D scaffolds seeded with human umbilical vein endothelial cells (HUVECs) and loaded with vascular endothelial growth factor (VEGF) implanted ex vivo into a chick chorioallantoic membrane (CAM) model showed integration and vascularisation after 7 d of incubation. In a pre-clinical in vivo application of a nanoclay-based bioink to regenerate skeletal tissue, we demonstrated bone morphogenetic protein-2 (BMP-2) absorbed scaffolds produced extensive mineralisation after 4 weeks (p < 0.0001) compared to the drug-free and alginate controls. In addition, HBMSC-laden 3D printed scaffolds were found to significantly (p < 0.0001) support bone tissue formation in vivo compared to acellular and cast scaffolds. These studies illustrate the potential of nanoclay-based bioink, to produce viable and functional constructs for clinically relevant skeletal tissue regeneration.

中文翻译：

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基于纳米粘土的 3D 打印支架促进体外血管向内生长并在体外和体内生成骨矿物质组织。

由于其机械稳定性差，无细胞软水凝胶不适用于硬组织工程，然而，与细胞成分结合为组织再生提供了重要的前景。事实上，纳米复合生物墨水提供了一个有吸引力的平台，可以在三个维度上提供人类骨髓基质细胞 (HBMSC)，从而产生旨在促进骨骼修复和功能的载细胞结构。在这里，我们介绍了封装在基于纳米粘土的生物墨水中的生物打印 HBMSC 的体外、离体和体内研究，以产生可行的和功能性的三维结构。载有 HBMSC 的构建体在体外 21 天后仍保持活力，并在用成骨培养基调节时立即起作用。接种人脐静脉内皮细胞 (HUVEC) 并装载血管内皮生长因子 (VEGF) 的 3D 支架离体植入小鸡绒毛尿囊膜 (CAM) 模型，孵育 7 天后显示整合和血管化。在基于纳米粘土的生物墨水再生骨骼组织的临床前体内应用中，我们证明与无药物相比，骨形态发生蛋白 2 (BMP-2) 吸收的支架在 4 周后产生了广泛的矿化 (p < 0.0001)和藻酸盐对照。此外，与无细胞和铸型支架相比，负载 HBMSC 的 3D 打印支架被发现显着（p < 0.0001）支持体内骨组织形成。这些研究说明了基于纳米粘土的生物墨水的潜力，