Convex vs concave surface nano-curvature of Ta2O5 thin films for tailoring the osteoblast adhesion

In certain medical interventions, temporally introduced bone implants are required to exhibit high biocompatibility, yet combined with low osseointegration, to allow for their easy removal afterwards. In this work, Ta2O5 surfaces are developed with good biocompatibility and with the osteoblast adhesion regulated by the nano-topography. The surfaces with convex nano-curvature are produced by applying reactive magnetron sputtering of tantalum over sub-monolayers of hydrocarbon plasma polymer particles. Subsequent ultrasonication leads to the removal of the particles from the coatings and results in the formation of the surfaces with concave nano-curvature. Primary human osteoblasts are found to sustain the viability and the mineralization ability on all kinds of these surfaces; however, Ta2O5 with the concave topography shows restrained adhesion of the cells. The limited cell adhesion is associated with a closed nature of the concave cavities which poses additional potential barriers for protein-mediated cell-surface interactions.