Resorbable Calcium Phosphate Ceramics for Bone Graft.

描述（由申请人提供）：磷酸钙（CaP）基陶瓷因其优异的生物相容性而被用于硬组织工程。有必要开发具有可控降解动力学的可生物降解陶瓷材料，以作为支架和支持骨重塑。我们的长期目标是阐明CaP基材料和支架的强度损失机制，以开发特定应用的骨移植物。基于CaP基材料的受控降解行为的基本信息可以帮助我们根据应用需求设计和定制可吸收组织工程骨替代物。本研究的目的是验证我们的中心假设，即CaP基陶瓷的化学和微观结构可以改变这些材料的强度损失。我们的初步数据表明，微量元素（掺杂剂）的少量可以对cap的物理力学性能产生显著的影响。微量元素的存在也会影响细胞-物质的相互作用。1)通过钙磷比分别为1.25:1、1.33:1和1.5:1的纳米级CaP的合成、加工、表征以及体外和体内骨细胞与材料的相互作用，研究其在钙磷比为1.25:1、1.33:1和1.5:1条件下的作用。2)测定单、多元素组成中锌、镁、硅、锶四种掺杂剂以及Ca:P = 1.25:1、1.33:1和1.5:1的三种CaP陶瓷对体外和体内吸收的影响。3)利用快速成型技术开发平均孔径为300微米、体积率为30%和60%的三维互联定制孔隙度CaP结构，验证孔隙度对其性能的影响，并研究其体外和体内相互作用。为了实现这些目标，我们将进行一系列的研究，包括合成单元素和多元素掺杂的纳米cap，表征其化学、物理和机械性能，以及在大鼠和兔子模型中体外和体内强度损失行为。预计这项研究的结果将导致具有定制降解动力学的cap的发展，可用于脊柱融合，颌骨和颅面植入物以及小型骨缺损应用。

DESCRIPTION (provided by applicant): Calcium phosphate (CaP) based ceramics are used in hard tissue engineering because of their excellent biocompatibility. There is a need for the development of biodegradable ceramic materials with controlled degradation kinetics that will act as a scaffold and support bone remodeling. Our long range goal is to elucidate strength loss mechanism in CaP based material and scaffold to develop bone graft for specific application. Fundamental information on controlled degradation behavior of CaP based materials to identify optimal material composition can help us design and tailor resorbable tissue engineered bone replacement based on application needs. The objective of this research is to test our central hypothesis, which is chemistry and microstructure in CaP based ceramics can modify strength loss in these materials. Our preliminary data indicate that a minimum amount of trace elements (dopants) can have significant effects on physical and mechanical properties of CaPs. Cell-materials interactions can also be influenced by the presence of trace elements. The specific aims are 1) To investigate effects of nanoscale CaP with three different Ca to P ratios, 1.25:1, 1.33:1 and 1.5:1, through synthesis, processing, characterization and in vitro and in vivo bone cell-materials interactions. 2) To determine the effects of four dopants, Zinc, Magnesium, Silicon, and Strontium oxides in single and multi-element composition, along with three CaP ceramics with Ca:P = 1.25:1, 1.33:1 and 1.5:1 on in vitro and in vivo resorption. 3) To develop 3D interconnected tailored porosity CaP structures using rapid prototyping, with an average 300 microns pore size, and, 30 and 60 volume % porosity and verify the influence of porosity on their properties and study in vitro and in vivo interactions. In order to accomplish these aims, we will conduct a series of studies including synthesis of nanoscale CaPs with single and multi element dopants, characterize their chemical, physical and mechanical properties, and in vitro and in vivo strength loss behavior in rat and rabbit models. It is envisioned that results from the proposed study will lead to the development of CaPs with tailored degradation kinetics that can be used in spinal fusion, maxillo- and cranio-facial implants and small scale bone defect applications. PUBLIC HEALTH RELEVANCE Resorbable Calcium Phosphate Ceramics for Bone Graft Calcium phosphate (CaP) based ceramics are used in hard tissue engineering because of their excellent biocompatibility. The objective of this research is to test our central hypothesis, which is chemistry and microstructure in Calcium phosphate (CaP) based ceramics can modify strength loss in these materials. It is envisioned that results from the proposed study will lead to the development of CaPs with tailored degradation kinetics that can be used in spinal fusion, maxillo- and cranio-facial implants and small scale bone defect applications.