Chemical etching of Ti‐6Al‐4V biomaterials fabricated by selective laser melting enhances mesenchymal stromal cell mineralization

Abstract

Porous titanium scaffolds fabricated by powder bed fusion additive manufacturing techniques have been widely adopted for orthopedic and bone tissue engineering applications. Despite the many advantages of this approach, topological defects inherited from the fabrication process are well understood to negatively affect mechanical properties and pose a high risk if dislodged after implantation. Consequently, there is a need for further post‐process surface cleaning. Traditional techniques such as grinding or polishing are not suited to lattice structures, due to lack of a line of sight to internal features. Chemical etching is a promising alternative; however, it remains unclear if changes to surface properties associated with such protocols will influence how cells respond to the material surface. In this study, we explored the response of bone marrow derived mesenchymal stem/stromal cells (MSCs) to Ti‐6Al‐4V whose surface was exposed to different durations of chemical etching. Cell morphology was influenced by local topological features inherited from the SLM fabrication process. On the as‐built surface, topological nonhomogeneities such as partially adhered powder drove a stretched anisotropic cellular morphology, with large areas of the cell suspended across the nonhomogeneous powder interface. As the etching process was continued, surface defects were gradually removed, and cell morphology appeared more isotropic and was suggestive of MSC differentiation along an osteoblastic‐lineage. This was accompanied by more extensive mineralization, indicative of progression along an osteogenic pathway. These findings point to the benefit of post‐process chemical etching of additively manufactured Ti‐6Al‐4V biomaterials targeting orthopedic applications.

Comparative study of cell interaction and bacterial adhesion on titanium of different composition, structure and surfaces with various laser treatment

“…It has been found that materials with a combination of micro-and nanostructured surfaces with a certain roughness can show improved levels of cell attachment [13]. Methods such as sandblasting and acid etching [14,15], anodic oxidation [16], plasma spraying [17], magnetron sputtering [18], or meniscus-dragging deposition [19] are commonly used for surface modification. These methods assume contact with the material, so they have some limitations to their universal use such as limitations in substrate size or contamination with hazardous chemicals [20].…”