A strategy to optimize the strength and degradation rate of calcium polyphosphates biomaterials

优化聚磷酸钙生物材料强度和降解率的策略

• 批准号: 250629-2012
• 负责人: Grynpas, Marc
• 金额: $ 3.57万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=525065
• 关键词: strategy; optimize; strength; degradation; rate

Hip and knee replacements are increasingly used to replace joints where the cartilage has been destroyed by arthritis. A novel alternative approach to total joint replacement by artificial materials (metals, ceramics or polymers) is tissue engineering where new cartilage tissue is grown in vitro. One of the main problems with this approach is the anchorage of the newly formed cartilage tissue into bone. Our group (Drs. Kandel, Pilliar and Grynpas) has developed a method to form biphasic constructs consisting of tissue engineered cartilage anchored on top of a calcium polyphosphate (CPP) porous solid. A small biphasic construct has been implanted in a sheep knee for up to 9 months at which point the cartilage of the construct has integrated with the surrounding cartilage. Bone has grown into the pores of the CPP solid, which has been shown to be biocompatible and to degrade slowly. It is essential to ensure that this CPP material has sufficient mechanical properties to support a whole joint or to be used as a bone substitute in load bearing applications where only metal cages are currently used. In addition the rate of degradation of the CPP is lower than desired. The mechanism by which the polyphosphate chains of CPP hydrolyze into shorter chains, polyphosphate rings and orthophosphates is still not well understood. The aim of this project is to maximize the mechanical properties of the CPP biomaterial and to understand its mechanisms of degradation.

髋关节和膝关节置换术越来越多地用于替换关节软骨已被关节炎破坏的关节。人工材料（金属、陶瓷或聚合物）全关节置换的一种新的替代方法是组织工程，其中新的软骨组织在体外生长。这种方法的主要问题之一是新形成的软骨组织锚定到骨中。我们的团队（Kandel，Pilliar和Grynpas博士）开发了一种形成双相结构的方法，该结构由锚定在聚磷酸钙（CPP）多孔固体顶部的组织工程软骨组成。将小的双相结构植入绵羊膝关节中长达9个月，此时结构的软骨已与周围软骨整合。骨已经生长到CPP固体的孔隙中，CPP固体已被证明具有生物相容性并且降解缓慢。必须确保这种CPP材料具有足够的机械性能，以支撑整个关节或在目前仅使用金属融合器的承重应用中用作骨替代物。此外，CPP的降解速率低于期望的。CPP的多磷酸盐链水解成较短链、多磷酸盐环和正磷酸盐的机理仍然没有很好地理解。该项目的目的是最大限度地提高CPP生物材料的机械性能，并了解其降解机制。