Thermodynamic aspects of fibroblastic spreading on diamond-like carbon films containing titanium dioxide nanoparticles

Abstract

The combination of low friction, wear resistance, high hardness, biocompatibility, and chemical inertness makes diamond-like carbon (DLC) films suitable in numerous applications in biomedical engineering. The cytotoxicity of DLC films containing TiO2 nanoparticles was practical and theoretically evaluated. The films were grown on 316L stainless steel substrates from a dispersion of TiO2 nanopowder in hexane. Raman spectroscopy shows that the presence of TiO2 increased the graphite-like bonds in the films. The incorporation of TiO2 nanoparticles into DLC films increases surface roughness, decreases water contact angle (increased hydrophilic character), and increases the total free surface energy due to the higher polar component. As the concentration of TiO2 increased, the films increased the cell viability (MTT assay), becoming more thermodynamically favorable to cell spreading (ΔF Adh values became more negative). This was evidenced through the increasing number of projections (philopodia and lamellipodia), indicating a higher adhesion between the L929 cells and the films. The practical and theoretical findings of this study show that the incorporation of TiO2 into DLC films is effective in enhancing cell viability. These results show the potential use of DLC and TiO2-DLC films in biomedical applications.