In Situ Hardening Cellular Constructs for Craniofacial Bone Regeneration

描述（由申请人提供）： 该项目旨在开发可注射的原位硬化细胞聚合物结构，用于修复颅面骨缺损。除了开发非常适合这种应用的生物材料外，该项目还将研究一些关键材料和细胞参数对骨再生的影响，以便从所述研究中阐明的知识可以广泛应用于组织工程的其他领域。该项目的第一个具体目标是合成和表征在体温下经历物理凝胶化和化学交联的新型可注射水凝胶。这些水凝胶还将含有钙结合结构域，假设其在注射后硬化材料并在基质矿化后诱导包封的骨髓基质细胞的骨分化。将使用各种方法评估水凝胶的理化特性，并进行体外和体内试验，以评价水凝胶的细胞相容性、稳定性和降解。第二个具体目标涉及调查不同的水凝胶配方和所得的物理参数对包封的细胞活力和骨再生的影响，在完善的临界尺寸大鼠颅骨缺损模型。最后，第三个具体目标是研究不同的细胞参数，如初始接种密度和包封骨髓基质细胞的骨分化阶段对水凝胶结构的骨再生潜力的影响。将体内研究纳入项目的每个目标中，以便与开发适用于临床应用的材料的长期目标保持一致，在研究的每个阶段评估骨再生和结构生物相容性方面的有效性。

DESCRIPTION (provided by applicant): The proposed project aims to develop injectable, in situ hardening cell-polymer constructs for the repair of craniofacial bone defects. In addition to developing biomaterials well suited to this application, the project will also investigate the effect on bone regeneration of a number of critical material and cellular parameters, such that knowledge elucidated from the described studies can be broadly applied to other areas of tissue engineering. The first specific aim of the project is to synthesize and characterize novel injectable hydrogels that undergo physical gelation and chemical crosslinking at body temperature. These hydrogels will also contain calcium-binding domains that are hypothesized to both harden the material after injection and induce osteodifferentiation of encapsulated marrow stromal cells following matrix mineralization. A variety of methods to assess the physicochemical characteristics of the hydrogels will be used, and both in vitro and in vivo testing will be performed to evaluate cytocompatibility, stability, and degradation of the hydrogels. The second specific aim involves investigations of the effect different hydrogel formulations and the resultant physical parameters have on both encapsulated cell viability and bone regeneration within the well-established critical size rat calvarial defect model. Finally, the third specific aim is to investigate the effects that varying cellular parameters such as initial seeding density and the stage of osteodifferentiation of encapsulated marrow stromal cells have on the bone regenerative potential of the hydrogel constructs. In vivo studies are incorporated into each aim of the project such that, in keeping with the long-term goal of developing materials appropriate for clinical applications, efficacy with respect to bone regeneration and construct biocompatibility is assessed at each stage of the study.