OBJECTIVETo study the effect of Ti-TiO2 nanotubes with different diameters on the adhesion of fibroblast and osteoblast, and to find which diameter was more favorable for cells' respective adhesion.

METHODSPure titanium sheets were polished and then anodized at different potentials for 1 h with Ti as anode and Pt as cathode. TiO2 nanotubes formed at 1, 5, 10 and 20 V potentials served as experimental groups and polished pure titanium served as control group. Field emission scanning electron microscopy (Fe-SEM) was used to analyze the surface topography. Stained nucleus with Hoechst33342 were used to measure the cell adhesion. The cell shape on the sample surface were analyzed with Fe-SEM.

RESULTSTiO2 nanotube array of different inner diameters from 15 nm to 100 nm were grown on titanium sheets by anodization at potentials from 1 to 20 V. At 30, 60 and 120 min, fibroblast adhesion at nanotubes anodized at 5 V was (141 ± 9), (388 ± 14) and (489 ± 15) respectively, significantly less than any other nanotube surface at the same time (P < 0.01). Nanotubes anodized at 20 V had the least inhibitory effect for fibroblast adhesion with a number of (579 ± 14) at 120 min, and the cell shape was also inhibited. At 30, 60 and 120 min, osteoblast had a significant better adhesion on nanotubes formed at 5 V than it did on any other surface at the same time (P < 0.01), except the control group at 30 min, with the adhesion number of (198 ± 10), (431 ± 10) and (501 ± 10) respectively, and osteoblast had a abundant spread on nanotubes formed at 5 V; while osteoblast adhesion on nanotubes anodized at 20 V was (152 ± 11), (403 ± 9) and (465 ± 12) respectively, less than on any other nanotube surface within the same time (P < 0.05), and the cell shape on the surface changed to be more elongate.

CONCLUSIONSFibroblast adhesion is inhabited more or less on Ti-TiO2 nanotubes of different diameters. Nanotubes formed at 5 V have the most osteoblast adhesion, and inhibit fibroblast adhesion.