Functionally Graded HA Coatings for Biological Response

产品说明：本项目的目的是开发功能梯度，薄膜羟基磷灰石涂层，以提高牙种植体的骨结合。涂层将被分级，使得它们从薄膜内的不同层引起定制的生物反应。涂层/基材界面附近的高度结晶区域将缓慢转变为膜表面处的非常细粒度的、几乎无定形的HA。第I阶段将评估具有分级结晶度的羟基磷灰石涂层加速并最终增强器械固定的假设。 在最近的工作中，我们已经证明，优化羟基磷灰石涂层的结晶度可以增强生物活性和骨整合，从而实现更快速、更牢固的骨固定。晶粒更细或接近无定形的羟基磷灰石具有更高的Ca和P溶解率，因此具有更高的生物活性。涂层表面的这种结构非常适合在器械整合的早期阶段促进快速骨生长。薄膜中更深的结晶区域将吸收得更慢，确保涂层长时间保持功能，直到实现完全整合和固定。 通过改变涂层沉积工艺和随后的微观结构分析（透射电子显微镜），将开发出优化的结晶分级剖面。将在小动物（大鼠）胫骨中评价涂层有效性。将评估早期和长期骨反应。将性能与常规等离子喷涂羟基磷灰石涂层以及完全结晶的HA和完全无定形的CaP涂层进行比较。

DESCRIPTION: The objective of this project is to develop functionally graded, thin film hydroxyapatite coatings to enhance osseointegration of Dental implants. The coatings will be graded such that they elicit tailored biological response from different layers within the thin film. Highly crystalline regions near the coating/substrate interface will slowly transition to very fine-grained, nearly amorphous HA at the surface of the film. Phase I will evaluate the hypothesis that hydroxyapatite coatings with graded crystallinity both speed up and ultimately enhance device fixation. In recent work, we have demonstrated that optimizing crystallinity of hydroxyapatite coatings enhances bioactivity and osseointegration, leading to more rapid and stronger bone fixation. Finer grained or near-amorphous hydroxyapatite has higher rates of Ca and P dissolution, and therefore, higher bioactivity. Such structures at the coating surface are ideally suited for promoting rapid bone growth during early stages of device integration. More crystalline regions deeper in the film will resorb much slower, ensuring that the coating remains functional for long time periods, until complete integration and fixation is achieved. Optimized crystalline grading profiles will be developed via variation of coating deposition processes and subsequent microstructural analysis (transmission electron microscopy). Coating efficacy will be evaluated in the tibia of a small animal (rat). Both early and long-term bone response will be assessed. Performance will be compared to that of conventional plasma spray hydroxyapatite coatings and also with fully crystalline HA and fully amorphous CaP coatings.