In Situ Hardening Cellular Constructs for Craniofacial Bone Regeneration

描述(由申请人提供)：拟议的项目旨在开发可注射的、原位硬化的细胞-聚合物构建物，用于修复颅面部骨缺损。除了开发适合这一应用的生物材料外，该项目还将调查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。这些水凝胶还将包含钙结合结构域，假设在注射后使材料变硬，并在基质矿化后诱导包裹的骨髓基质细胞成骨分化。将使用各种方法来评估水凝胶的物理化学特性，并将进行体外和体内测试来评估水凝胶的细胞相容性、稳定性和降解性。第二个具体目标是研究不同的水凝胶配方和由此产生的物理参数对已建立的临界大鼠颅骨缺损模型中被包裹的细胞活性和骨再生的影响。最后，第三个具体目的是研究不同的细胞参数，如初始种植密度和包裹的骨髓基质细胞的成骨分化阶段对水凝胶构建物的骨再生能力的影响。活体研究被纳入到该项目的每个目标中，以便与开发适合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与骨再生和构建生物相容性有关的效果。

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.