DEVELOPMENT OF STRONG AND MACROPOROUS BIOMATERIALS

描述（由申请人提供）：随着世界人口老龄化，对生物材料的需求不断增加。磷酸钙骨水泥 (CPC) 由于其骨传导性和骨替代能力而在临床应用中极具前景。然而，其强度较低，限制了 CPC 仅限于非应力用途。文献检索未发现对CPC纤维增强的研究。初步研究表明，CPC 增强材料的强度可提高 2 至 5 倍，断裂韧性可提高 6 倍，断裂功可提高两个数量级。在这个项目中，目标1将使用可吸收纤维来强化CPC，然后溶解并产生微处理器血管向内生长；将研究纤维长度、体积分数和纤维-基体界面的影响。目标2将研究可吸收纤维性能的变化对复合材料性能的影响，并建立预测方程。在目标 3 中，将使用具有广泛属性范围的 CPC 矩阵来建立矩阵和复合材料属性之间的关系。研究非刚性CPC、速溶CPC、流动CPC、大孔CPC；将确定基本结构-性能关系的模型。目标 4 将研究控制大孔形成速率并定制植入物强度历史的新方法。较快吸收的纤维和较慢吸收的纤维将结合在 CPC 中以获得较高的初始强度。然后，较快的纤维溶解并产生用于骨骼向内生长的大孔，而较慢的纤维则提供长期的强度。将进行建模以将复合材料性能变化与每根纤维的性能变化联系起来。在目标 5 中，可吸收网格将用于 CPC 以获得强度，然后用于高度互连的大孔。将研究浸入时网格厚度和强度变化的影响并建立预测方程。将使用网格和纤维来研究功能梯度多层植入物，以控制强度和大孔形成梯度。这些研究将： 1）产生用于牙科和颅面修复的新型复合材料，具有优异的强度、自定能力、支架结构以及新骨吸收和替代的能力； (it) 建立植入物的微观结构设计方法，以通过定制的强度历史和大孔形成率实现高强度和韧性； (iii) 提供新的强化机制、基本的复合成分关系、预测模型和加工指导，以形成新一代生物材料的基础。

DESCRIPTION (provided by applicant): The need for biomaterials has increased as the world population ages. Calcium phosphate cements (CPC) are highly promising for wide clinical applications due to their osteoconductivity and bone replacement capability.Their low strength, however, limits CPC to only non-stress uses. A literature search revealed no study on fiber reinforcement of CPC. In preliminary studies, the promise for CPC reinforcement was shown with a 2- to 5-fold increase in strength, 6-fold increase in fracture toughness, and two orders of magnitude increase in work-of-fracture. In this project, Aim 1 will use absorbable fibers to strengthen CPC and then to dissolve and create microprocessor vascular ingrowth; the effects of fiber length, volume fraction and fiber-matrix interface will be studied. Aim 2vill study the effects of changes in the absorbable fiber properties on the composite properties, and establish predictive equations. In Aim 3, CPC matrices with wide property ranges will be used to establish the relationships between matrix and composite properties. Non-rigid CPC, fast-dissolution CPC, flow able CPC and macroporous CPC will be studied; models on fundamental structure-property relationships will be determined. Aim 4 will investigate novel methods to control the macropore formation rate and tailor the strength history of the implant. Faster-absorbable fibers and slow-absorbable fibers will be combined in CPC for a high initial strength. Then the faster fibers dissolve and create macropores for bony ingrowth, while the slow fibers provide longer-term strength. Modeling will be performed to relate the composite property change to that of each fiber. In Aim 5, absorbable meshes will be used in CPC for strength and then highly interconnected macropores. The effects of mesh thickness and strength changes in immersion will be investigated and predictive equations will be established. Functionally graded multilayer implants will be investigated using mesh and fibers for controlled strength and macropore formation gradient. These studies will: 1) Yield novel composites for Dental and craniofacial repairs with superior strength, self-setting ability, scaffold structures, and capability of resorption and replacement by new bone; (it) Establish microstructural design methods for implants to achieve high strength and toughness with tailored strength history and macropore formation rates; (iii) Provide new reinforcement mechanisms, fundamental composite-constituent relationships, predictive models, and processing guidance to form the basis for a new generation of biomaterials.