W. M. Keck Biomedical Materials Research Lab, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA.
W. M. Keck Biomedical Materials Research Lab, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA.
Acta Biomater. 2021 Mar 15;123:379-392. doi: 10.1016/j.actbio.2020.12.060. Epub 2021 Jan 12.
Titanium has been used in various biomedical applications; however, titanium exhibits poor wear resistance, and its bioinert surface slows osseointegration in vivo. In this study, directed energy deposition (DED)-based additive manufacturing (AM) was used to process hydroxyapatite (HA) reinforced Ti6Al4V (Ti64) composites to improve biocompatibility and wear resistance simultaneously. Electron micrographs of the composites revealed dense microstructures where HA was observed at the β-phase grain boundaries. Hardness increased by 57% and 71% for 2 and 3 wt.% HA in Ti64 composites, respectively. XRD analysis revealed no change in the phases with the addition of HA, when compared to the control. Tribological studies displayed an increase in contact resistance (CR) due to an in situ formed HA-based tribofilm, reduction in wear rate when testing in Dulbecco's Modified Eagle Medium (DMEM) with a ZrO counter wear ball, <1% wear ball volume loss, and suppression of cohesive shear failure of the Ti matrix. Histomorphometric analysis from a rat distal femur study revealed an increase in the osteoid surface over the bone surface (OS/BS) for 3 wt.% HA composite over the control Ti64 from 9 ± 1% to 14 ± 1%. Additionally, from push-out testing, the shear modulus was observed to increase from 17 ± 3 MPa for control Ti64 to 32 ± 5 MPa for the 3 wt.% HA composite after 5-weeks in vivo. The present study demonstrates that the addition of HA in Ti64 can simultaneously improve bone tissue-implant response and wear resistance.
钛已被应用于各种生物医学领域，但钛表现出较差的耐磨性，且其惰性生物表面会减缓体内的骨整合。在这项研究中，使用定向能量沉积（DED）增材制造（AM）工艺来处理羟基磷灰石（HA）增强 Ti6Al4V（Ti64）复合材料，以同时提高生物相容性和耐磨性。复合材料的电子显微镜图像显示出致密的微观结构，在 β 相晶粒边界处观察到 HA。Ti64 复合材料中，2 和 3 wt.% HA 的硬度分别提高了 57%和 71%。与对照相比，加入 HA 后，XRD 分析未发现相的变化。摩擦学研究显示，由于原位形成的基于 HA 的摩擦膜，接触电阻（CR）增加，在含有 ZrO 对磨球的 Dulbecco 改良 Eagle 培养基（DMEM）中测试时，磨损率降低，磨损球体积损失<1%，并且抑制了 Ti 基体的内聚剪切失效。来自大鼠股骨远端的组织形态计量学分析显示，3 wt.% HA 复合材料的类骨质表面相对于骨表面（OS/BS）的增加，从对照 Ti64 的 9±1%增加到 14±1%。此外，从推出试验来看，剪切模量观察到从对照 Ti64 的 17±3 MPa 增加到 3 wt.% HA 复合材料的 32±5 MPa，体内 5 周后。本研究表明，在 Ti64 中添加 HA 可以同时提高骨组织-植入物的反应和耐磨性。
