A New Approach for Structure-Property Relations in Scaffold Design for Bone Tissue Engineering

这笔赠款为组织工程研究提供了第一年的资金，该研究旨在确定骨生长、初始支架微结构和性能以及支架/组织复合材料性能之间的关系。具体地说，它旨在回答这样一个问题：组织再生后支架中的骨填充百分比以及支架/组织复合材料性能与初始力学性能，更根本地与支架的初始微结构之间是如何关联的？对于最初的研究，将在体外构建一个设计空间，代表支架/组织复合材料可能的机械性能范围。具有四种不同微观结构但都具有相同宏观结构的羟基磷灰石(HA)支架将被硬聚合物和软聚合物渗透，分别代表100%的骨和结缔组织填充。复合支架将接受压缩测试，并将为每个微观结构提供一套机械性能的上限和下限。体外研究的结果将用于未来的体内研究；被检查的微结构的子集将被植入猪的下颌骨，并评估骨向内生长和复合机械性能。这项研究有可能在骨支架结构-性能关系的基础理解方面取得重大进展。这项研究的临床和社会影响是显而易见的。有些人需要大规模的骨骼重建，例如，包括老年人、患有口腔癌的人，或者像在伊拉克受伤的美国士兵那样遭受钝器创伤的人。市场上还没有合适的产品来满足这一需求；因此，这项工作的结果有可能显著提高临界大小骨缺损患者的生活质量。

This grant provides the first year of funding for tissue engineering research that aims to determine relationship between bone ingrowth, initial scaffold microstructure and properties, and scaffold/tissue composite properties. Specifically, it aims to answer the question: How does the percent bone fill in the scaffold after tissue regeneration and the scaffold/tissue composite properties correlate with initial mechanical properties, and more fundamentally with the initial microstructure of the scaffold? For the initial study, a design space will be constructed in vitro that represents the range of possible mechanical properties for the scaffold/tissue composites. Hydroxyapatite (HA) scaffolds with four different microstructures, but all with the same macrostructure, will be infiltrated with hard and soft polymers, representing 100% bone and connective tissue fill, respectively. Composite scaffolds will be tested in compression and will provide a set of upper and lower bounds on mechanical properties for each microstructure. The results from the in vitro study will feed into a future in vivo study; a subset of the microstructures examined will be implanted into a swine mandible and evaluated for bone ingrowth and composite mechanical properties. The research has the potential to make significant advances in the fundamental understanding of the structure-property relationships of bone scaffolds. The clinical and societal impact for the research is evident. There are people who are in need of massive scales of bone reconstruction including, for example, the elderly, those afflicted with oral cancer, or who have suffered blunt force trauma like the American soldiers injured in Iraq. There are no appropriate products on the market to fill this need; therefore, results derived from this work have the potential to significantly improve the quality of life for patients with critical-sized bone defects.