Oxygen generating bioinks for 3D printed bone implants

摘要 肌肉骨骼组织损伤是美国残疾的主要原因，然而， 对于患有骨退化的患者来说，只有少数可行的选择。之一 该领域的主要挑战是骨不连的形成，这是骨的永久性失效 骨折愈合目前的治疗如骨固定或骨移植通常是无效的， 疼痛的、侵入性的、昂贵的，并且不会导致完全功能的恢复。为了克服这个巨大的 挑战，许多研究一直致力于开发工程三- 三维（3D）骨组织，其通常由包含人骨的生物材料组成。 间充质干细胞（hMSCs）用于骨形成和血管内皮细胞 阵尽管这些方法加速了植入物吻合，但其本质上仍然是 与血管前阶段相关，导致大量饥饿诱导的细胞 死亡在这里，我们提出了一个创新的解决方案来解决这个重要的问题。我们的目标是 通过开发可用于3D生物打印的氧气生成生物材料来实现这一目标。 血管化骨植入物用于严重骨缺损治疗。为此，我们开始探索 我们最近开发的两项技术：氧气生成生物材料和嵌入式 牺牲3D生物打印为了在植入物的吻合前阶段维持细胞存活， 我们将开发疏水微材料，其中含有释放氧气的分子， 水解，这可以通过调节微材料的疏水性来控制。这些 微粒将与我们的3D打印和骨形成纳米颗粒相结合， 掺入的生物材料基质（硅酸盐纳米颗粒/GelMA），其负载有人 间充质干细胞以有效地产生充氧骨形成生物墨水。这个生物墨水 将被用作粘性介质，其中3D血管结构将使用 嵌入式生物打印;我们正在开创的一种新型3D生物打印技术。我们特别 将赋予构建体内皮细胞负载藻酸盐生物墨水的3D血管结构。 使用低水平的UV光交联氧化生物墨水将产生完全固体的3D 构建体在牺牲内部藻酸盐结构后，将形成开放的3D血管网络。 瞬间形成。预负载的内皮细胞将覆盖3D网络，从而提供一种新的内皮细胞。 功能性早期血管分布，这将加速吻合，从而最大限度地减少植入物的 血管前期在使用常氧和低氧培养物进行深入的体外表征后， 我们将使用皮下和临界缺损研究该结构的体内行为 模型

Abstract Musculoskeletal tissue injuries are a leading cause of disability in the United States (US), yet there are only a few viable options for patients suffering from bone degeneration. One of the major challenges in this field is nonunion formation, which is the permanent failure of bone fracture healing. Current therapies such as bone fixation or bone grafting are often ineffective, painful, invasive, costly, and do not result in recovery of full function. To overcome this grand challenge, much research has been dedicated to the development of engineered three- dimensional (3D) bone tissue, which typically is composed of a biomaterial containing human mesenchymal stem cells (hMSCs) for bone formation and endothelial cells for blood vessel formation. Although these approaches accelerate implant anastomosis, it is inherently still associated with a prevascular phase that causes significant amounts of starvation induced cell death. Here, we propose an innovative solution to solve this important problem. We aim to achieve this by developing an oxygen generating biomaterial that can be used to 3D bioprint a vascularized bone implant for critical bone defect treatments. To this end, we set-out to explore two of our recently developed technologies: oxygen generating biomaterials and embedded sacrificial 3D bioprinting. To maintain cell survival during the implant’s pre-anastomosis phase, we will develop hydrophobic micromaterials containing molecules that release oxygen upon hydrolysis, which can be controlled via tuning the micromaterial’s hydrophobicity. These microparticles will be combined with our 3D printable and bone forming nanoparticle incorporated biomaterial matrix (Silicate-nanoparticles/GelMA) that is laden with human mesenchymal stem cells to effectively create an oxygenating bone forming bioink. This bioink will be used as a viscous medium in which a 3D vascular structure will be printed using embedded bioprinting; a novel 3D bioprinting technique that we are pioneering. Specifically, we will endow constructs with a 3D vascular structure of endothelial cell laden alginate bioink. Crosslinking the oxygenating bioink using low levels of UV light will yield a fully solid 3D construct. Upon sacrificing the internal alginate structure, an open 3D vascular network will be instantly formed. The pre-laden endothelial cells will coat the 3D network and thus provide a functional early vascularity that will accelerate anastomosis and thus minimize the implant’s prevascular phase. After in depth in vitro characterization using normoxic and hypoxic cultures, we will investigate the construct’s in vivo behavior using a subcutaneous and a critical defect model.