Roy Mangal, Bandyopadhyay Amit, Bose Susmita
W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA.
Surf Coat Technol. 2011 Jan 25;205(8-9):2785-2792. doi: 10.1016/j.surfcoat.2010.10.042.
This paper reports preparation of a highly crystalline nano hydroxyapatite (HA) coating on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray and their in vitro and in vivo biological response. HA coatings were prepared on Ti using normal and supersonic plasma nozzles at different plate powers and working distances. X-ray diffraction (XRD) and Fourier transformed infrared spectroscopic (FTIR) analysis show that the normal plasma nozzle lead to increased phase decomposition, high amorphous calcium phosphate (ACP) phase formation, and severe dehydroxylation of HA. In contrast, coatings prepared using supersonic nozzle retained the crystallinity and phase purity of HA due to relatively short exposure time of HA particles in the plasma. In addition, these coatings exhibited a microstructure that varied from porous and glassy structure at the coating-substrate interface to dense HA at the top surface. The microstructural analysis showed that the coating was made of multigrain HA particles of ~200 nm in size, which consisted of recrystallized HA grains in the size range of 15- 20 nm. Apart from the type of nozzle, working distance was also found to have a strong influence on the HA phase decomposition, while plate power had little influence. Depending on the plasma processing conditions, a coating thickness between 300 and 400 μm was achieved where the adhesive bond strengths were found to be between 4.8 MPa to 24 MPa. The cytotoxicity of HA coatings was examined by culturing human fetal osteoblast cells (hFOB) on coated surfaces. In vivo studies, using the cortical defect model in rat femur, evaluated the histological response of the HA coatings prepared with supersonic nozzle. After 2 weeks of implantation, osteoid formation was evident on the HA coated implant surface, which could indicate early implant- tissue integration in vivo.
本文报道了使用电感耦合射频（RF）等离子体喷涂技术在工业纯钛（Cp-Ti）上制备高度结晶的纳米羟基磷灰石（HA）涂层及其体外和体内生物学反应。使用普通和超音速等离子体喷嘴在不同的平板功率和工作距离下在钛上制备HA涂层。X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析表明，普通等离子体喷嘴导致相分解增加、高无定形磷酸钙（ACP）相形成以及HA的严重脱羟基。相比之下，使用超音速喷嘴制备的涂层由于HA颗粒在等离子体中的暴露时间相对较短，保留了HA的结晶度和相纯度。此外，这些涂层呈现出一种微观结构，从涂层-基体界面处的多孔和玻璃状结构到顶面处的致密HA结构各不相同。微观结构分析表明，涂层由尺寸约为200 nm的多晶HA颗粒组成，这些颗粒由尺寸在15 - 20 nm范围内的再结晶HA晶粒组成。除了喷嘴类型外，还发现工作距离对HA相分解有很大影响，而平板功率影响较小。根据等离子体处理条件，实现了300至400μm的涂层厚度，其中发现粘结强度在4.8 MPa至24 MPa之间。通过在涂层表面培养人胎儿成骨细胞（hFOB）来检测HA涂层的细胞毒性。在体内研究中，使用大鼠股骨皮质缺损模型评估了用超音速喷嘴制备的HA涂层的组织学反应。植入2周后，在HA涂层植入物表面明显可见类骨质形成，这可能表明体内早期植入物与组织的整合。
