Plasma sprayed hydroxyapatite (HA) coating is known to improve the osteoconductivity of metallic implants. However, the adhesive bond strength of the coating is affected due to a mismatch in coefficients of thermal expansion (CTE) between the metal and HA ceramic. In this study, a gradient HA coating was prepared on Ti6Al4V by laser engineered net shaping (LENS™) followed by plasma spray deposition. In addition, 1 wt% MgO and 2 wt% Ag2O were mixed with HA to improve the biological and antibacterial properties of the coated implant. Results showed that the presence of an interfacial layer by LENS™ enhanced adhesive bond strength from 26 ± 2 MPa for just plasma spray coating to 39 ± 4 MPa for LENS™ and plasma spray coatings. Presence of MgO and Ag2O did not influence the adhesive bond strength. Also, Ag+ ions release dropped by 70% less with a gradient HA LENS™ layer due to enhanced crystallization of the HA layer. In vitro human osteoblast cell culture revealed presence of Ag2O had no deleterious effect on proliferation and differentiation when compared to pure HA as control and provided antibacterial properties against E. coli and S. aureus bacterial strands. This study presents an innovative way to improve interfacial mechanical and antibacterial properties of plasma sprayed HA coating for load-bearing orthopedic as well as dental implants. STATEMENT OF SIGNIFICANCE: Implants are commonly composed of metals that lack osteoconductivity. Osteoconductivity is a property where bone grows on the surface meaning the material is compatible with the surrounding bone tissue. Plasma sprayed hydroxyapatite (HA) coating improves the osteoconductivity of metallic implants, however, the adhesive bond strength can be weak. This study incorporates a gradient HA coating by using an additive manufacturing technique, laser engineered net shaping (LENS™), followed by plasma spray deposition to enhance the adhesive bond strength by incorporating a thermal barrier. The proposed system has not been well studied in the current literature and the results presented bring forth an innovative way to improve the interfacial mechanical and antibacterial properties of plasma sprayed HA coating for load-bearing orthopedic implants.

中文翻译：

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使用激光和等离子喷涂沉积在钛上进行成分梯度掺杂羟基磷灰石涂层，用于骨植入物。

众所周知，等离子喷涂羟基磷灰石（HA）涂层可以提高金属植入物的骨传导性。然而，由于金属和 HA 陶瓷之间的热膨胀系数 (CTE) 不匹配，涂层的粘合强度受到影响。在本研究中，通过激光工程净成形 (LENS™) 和等离子喷涂沉积在 Ti6Al4V 上制备梯度 HA 涂层。此外，将 1 wt% MgO 和 2 wt% Ag2O 与 HA 混合，以提高涂层植入物的生物和抗菌性能。结果表明，LENS™ 界面层的存在将粘合强度从仅等离子喷涂涂层的 26 ± 2 MPa 提高到 LENS™ 和等离子喷涂涂层的 39 ± 4 MPa。MgO 和 Ag2O 的存在不影响粘合强度。此外，由于 HA 层的结晶增强，梯度 HA LENS™ 层的 Ag+ 离子释放量减少了 70%。体外人成骨细胞培养显示，与作为对照的纯 HA 相比，Ag2O 的存在对增殖和分化没有有害影响，并且对大肠杆菌和金黄色葡萄球菌细菌链具有抗菌特性。这项研究提出了一种创新方法来改善用于承载骨科和牙科植入物的等离子喷涂 HA 涂层的界面机械和抗菌性能。意义声明：植入物通常由缺乏骨传导性的金属组成。骨传导性是骨骼在表面生长的一种特性，意味着该材料与周围的骨组织相容。等离子喷涂羟基磷灰石（HA）涂层可改善金属植入物的骨传导性，但粘合强度可能较弱。这项研究通过使用增材制造技术、激光工程净成形 (LENS™) 来整合梯度 HA 涂层，然后进行等离子喷涂沉积，通过结合热障来增强粘合强度。目前的文献中尚未对所提出的系统进行充分研究，所提出的结果提出了一种创新方法来提高用于承载骨科植入物的等离子喷涂HA涂层的界面机械和抗菌性能。