Effect of various concentrations of Ti in hydrocarbon plasma polymer films on the adhesion, proliferation and differentiation of human osteoblast-like MG-63 cells

•Hydrocarbon plasma polymer films with Ti in concentration of 0–20at.% were prepared.•The Ti concentration was positively correlated with the material surface wettability.•The optimum Ti concentrations for the MG-63 cells behavior were identified.•The Ti concentration also influenced the cell immune activation. Hydrocarbon polymer films (ppCH) enriched with various concentrations of titanium were deposited on microscopic glass slides by magnetron sputtering from a Ti target. The maximum concentration of Ti (about 20at.%) was achieved in a pure argon atmosphere. The concentration of Ti decreased rapidly after n-hexane vapors were introduced into the plasma discharge, and reached zero values at n-hexane flow of 0.66sccm. The decrease in Ti concentration was associated with decreasing oxygen and titanium carbide concentration in the films, decreasing wettability (the water drop contact angle increased from 20° to 91°) and decreasing root-mean-square roughness (from 3.3nm to 1.0nm). The human osteoblast-like MG-63 cells cultured on pure ppCH films and on films with 20at.% of Ti showed relatively high concentrations of ICAM-1, a marker of cell immune activation. Lower concentrations of Ti (mainly 5at.%) improved cell adhesion and osteogenic differentiation, as revealed by higher concentrations of talin, vinculin and osteocalcin. Higher Ti concentrations (15at.%) supported cell growth, as indicated by the highest final cell population densities on day 7 after seeding. Thus, enrichment of ppCH films with appropriate concentrations of Ti makes these films more suitable for potential coatings of bone implants.