Interplay of topographical and biochemical cues in regulating osteoblast cellular activity in BMP-2 eluting three-dimensional cellular titanium alloy mesh structures.

The objective of this study is to elucidate the elution response of bone morphogenetic protein (BMP-2) in tuning cellular functions on 3D-printed titanium alloy mesh scaffolds subjected to microarc/plasma electrolytic oxidation process. The microtopographical cues enabled strong interaction with BMP-2 protein, which led to controlled release. Furthermore, the interaction of BMP-2 with the surface microtopographical cue regulated osteoblast cellular activity by contributing to the early phase differentiation and mineralization of osteoblasts. The in vitro BMP-2 release kinetics showed an initial burst of BMP-2 after day 1, followed by a controlled release on plasma electrolytic oxidized mesh structure. The profile represented that the rate of release decreased with increase in time on both as-fabricated and plasma electrolytic oxidized mesh structures after 24 h, with relatively higher degree on plasma electrolytic oxidized mesh structure. Furthermore, the in vitro osteoblast cellular activity indicated enhanced osteogenic induction on BMP-2 adsorbed plasma electrolytic oxidized mesh structure. Cells penetrated into micropores through several filopodia-like cellular extensions by increasing the area of contact, leading to stronger cell adhesion on BMP-2 adsorbed plasma electrolytic oxidized mesh structure. The up-regulation of biochemical markers and quantification of the expression level of cell secreted proteins underscored the determining role of BMP-2 eluting 3D mesh structure in modulating osteoblasts functions. The study emphasizes the potential of BMP-2 in rendering plasma electrolytic oxidized 3D-printed titanium alloy mesh structure osteoinductive and controlled delivery of BMP-2. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 49-60, 2019.