Controlling crystalline phase of TiO₂ thin films to evaluate its biocompatibility

This paper describes studies performed to understand the biocompatibility of TiO2 thin films with controlled crystalline phases using human pigment epithelium cells (ARPE-19). TiO2 films were deposited by radio frequency magnetron sputtering using different gas pressure, oxygen partial pressure and magnetron power. Thermal annealing was used to control the microstructure and crystalline phase of the resulting films. Results show that films deposited at low power (75 and 100 W) developed anatase phase and as power increases (>125 W), a mixture of rutile and anatase is observed. For films deposited at higher power (>150 W), only rutile phase was obtained. These results indicate that plasma power is a critical parameter to control TiO2 crystalline phase. Finally, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay showed that there is no significative difference in cell proliferation among TiO2 crystalline phases and indicates that the biocompatibility is mostly defined by the surface chemistry of the films.