Villapún Victor M, Carter Luke N, Cox Sophie C
School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
Biomater Adv. 2025 Apr;169:214186. doi: 10.1016/j.bioadv.2025.214186. Epub 2025 Jan 14.
Laser-powder bed fusion (PBF-LB) has enabled production of customised skeletal implants that incorporate porous lattices structures to enable bone ingrowth. However, the inherent surface roughness of PBF-LB, characterised by partially adhered particles and undulating sub-topography, remains a barrier to adoption. As such PBF-LB surfaces require several time-consuming post-processing steps, nevertheless, conventional finishing techniques are often limited by geometrical part complexity, making them unsuitable for porous PBF-LB parts. Herein we explore the possibility to utilise plasma-electrolytic oxidation (PEO) as a rapid, single step surface finishing method not constrained by implant design. Specifically, PEO treatment was performed in a phosphate-based electrolyte on as-printed and polished Ti-6Al-4V PBF-LB samples with complete surface coverage and chemical functionalisation, as observed by optical profilometry, SEM-EDX, XRD and XRF, achieved after only 20 min. To test the lack of geometric constraints brought by PEO, clinically relevant BCC porous lattices were also successfully PEO treated accomplishing a coating that either masked or removed surface adhered particles throughout the structure. Promisingly for medical application, no cytotoxicity was noted for MC3T3-E1 murine osteoblasts over 7 days and significantly more (p < 0.05) mineralisation was observed after 21 days compared with as-printed and polished PBF-LB controls. Still, an enhanced pro-inflammatory response, iNOS and TNF-α, was observed in murine RAW261 macrophages seeded on PEO surfaces, indicating further optimisation is required to guide the inflammatory process. Overall, these findings showcase the widespread opportunity to robustly ensure PBF-LB implant safety by using PEO to tackle partially adhered particles while also offering new avenues to enhance functionality through variations in coating chemistry.
激光粉末床熔融（PBF-LB）技术已能够生产定制的骨骼植入物，这些植入物包含多孔晶格结构以促进骨长入。然而，PBF-LB固有的表面粗糙度，其特征在于部分附着的颗粒和起伏的亚表面形貌，仍然是其被采用的障碍。因此，PBF-LB表面需要几个耗时的后处理步骤，然而，传统的精加工技术通常受到零件几何复杂性的限制，使其不适用于多孔PBF-LB零件。在此，我们探索了将等离子体电解氧化（PEO）用作一种不受植入物设计限制的快速单步表面精加工方法的可能性。具体而言，在磷酸盐基电解质中对打印后和抛光后的Ti-6Al-4V PBF-LB样品进行PEO处理，通过光学轮廓仪、扫描电子显微镜-能谱仪（SEM-EDX）、X射线衍射仪（XRD）和X射线荧光光谱仪（XRF）观察到，仅20分钟后就实现了完全的表面覆盖和化学功能化。为了测试PEO带来的不受几何限制的特性，还成功地对具有临床相关性的骨小梁多孔晶格进行了PEO处理，形成了一种涂层，该涂层在整个结构中掩盖或去除了表面附着的颗粒。对于医学应用而言，有希望的是，在7天内未观察到MC3T3-E1小鼠成骨细胞的细胞毒性，并且与打印后和抛光后的PBF-LB对照相比，在21天后观察到显著更多（p < 0.05）的矿化。尽管如此，在接种于PEO表面的小鼠RAW261巨噬细胞中观察到促炎反应增强，诱导型一氧化氮合酶（iNOS）和肿瘤坏死因子-α（TNF-α）升高，这表明需要进一步优化以引导炎症过程。总体而言，这些发现展示了通过使用PEO处理部分附着的颗粒来有力确保PBF-LB植入物安全性的广泛机会，同时也为通过涂层化学变化增强功能提供了新途径。
