Bouet Guenaelle, Cabanettes Frédéric, Bidron Guillaume, Guignandon Alain, Peyroche Sylvie, Bertrand Philippe, Vico Laurence, Dumas Virginie
Ecole Nationale d'Ingénieurs de Saint-Etienne, Laboratoire de Tribologie et Dynamique des Systèmes, UMR 5513 CNRS, University of Lyon, 58, rue Jean Parot, 42023 Saint-Etienne, France.
GIE Manutech-USD (Ultrafast Surface Design), 20 Rue Professeur Benoît Lauras, 42000 Saint-Etienne, France.
ACS Biomater Sci Eng. 2019 Sep 9;5(9):4376-4385. doi: 10.1021/acsbiomaterials.9b00769. Epub 2019 Jul 24.
Additive manufacturing (AM) is becoming increasingly important in the orthopedic and dental sectors thanks to two major advantages: the possibility of custom manufacturing and the integration of complex structures. However, at smaller scales, surface conditions of AM products are not mastered. Numerous non-fused powder particles give rise to roughness values (Sa) greater than 10 μm, thus limiting biomedical applications since the surface roughness of, e.g., metal implants plays a major role in the quality and rate of osseointegration. In this study, an innovative hybrid machine combining AM and a femtosecond laser (FS) was used to obtain Ti6Al4V parts with biofunctional surfaces. During the manufacturing process, the FS laser beam "neatly" ablates the surface, leaving in its path nanostructures created by the laser/matter interaction. This step decreases the Sa from 11 to 4 μm and increases the surface wettability. The behavior of human mesenchymal stem cells was evaluated on these new AM+FS surfaces and compared with that on AM surfaces and also on polished surfaces. The number of cells attached 24 h after plating is equivalent on all surfaces, but cell spreading is higher on AM+FS surfaces compared with their AM counterparts. In the longer term (days 7 and 14), fibronectin and collagen synthesis increase on AM+FS surfaces as opposed to AM alone. Alkaline phosphatase activity, osteocalcin production, and mineralization, markers of osteogenic differentiation, are significantly lower on raw AM surfaces, whereas on the AM+FS specimens they display a level equivalent to that on the polished surface. Overall, these results indicate that using an FS laser beam during the fabrication of AM parts optimizes surface morphology to favor osteoblastic differentiation. This new hybrid machine could make it possible to produce AM implants with functional surfaces directly at the end of AM, thereby limiting their post-treatments.
由于两大主要优势，增材制造（AM）在骨科和牙科领域正变得越来越重要：定制制造的可能性以及复杂结构的集成。然而，在较小尺度下，增材制造产品的表面状况尚未得到很好的控制。大量未熔合的粉末颗粒导致粗糙度值（Sa）大于10μm，从而限制了生物医学应用，因为例如金属植入物的表面粗糙度在骨整合的质量和速率中起着重要作用。在本研究中，一种结合了增材制造和飞秒激光（FS）的创新型混合机器被用于制造具有生物功能表面的Ti6Al4V零件。在制造过程中，飞秒激光束“整齐地”烧蚀表面，在其路径上留下由激光与物质相互作用产生的纳米结构。这一步骤将Sa从11μm降低到4μm，并提高了表面润湿性。在这些新的增材制造+飞秒激光表面上评估了人间充质干细胞的行为，并与增材制造表面以及抛光表面上的行为进行了比较。接种24小时后，所有表面上附着的细胞数量相当，但与增材制造表面相比，增材制造+飞秒激光表面上的细胞铺展情况更好。从长期来看（第7天和第14天），与单独的增材制造表面相反，增材制造+飞秒激光表面上的纤连蛋白和胶原蛋白合成增加。碱性磷酸酶活性、骨钙素产生和矿化是成骨分化的标志物，在原始增材制造表面上显著较低，而在增材制造+飞秒激光样品上它们显示出与抛光表面相当的水平。总体而言，这些结果表明，在增材制造零件的制造过程中使用飞秒激光束可优化表面形态，有利于成骨细胞分化。这种新型混合机器有可能在增材制造结束时直接生产出具有功能表面的增材制造植入物从而减少其后处理。
