Figure 1.

Surface characterization, cell morphology, and osteoinductive ability of TiO₂ nanotubes.

Notes: (A) Scanning electron microscopic (SEM) observation of TiO₂ nanotubes and smooth Ti surfaces. (B) Atomic force microscopy (AFM) images of TiO₂ nanotubes and Ti surfaces. (C) Photographs of contact-angle measurement of water. (D) Confocal micrographs of human adipose-tissue-derived stem cells (hASCs) on TiO₂ nanotubes and Ti surfaces after 2, 4, and 24 hours of culture. (E) SEM observation of cell morphology on TiO₂ nanotubes and Ti surfaces after 2, 4, and 24 hours of culture. (F) Cell spreading area on TiO₂ nanotubes and Ti surfaces after 2, 4, and 24 hours of culture. (G) Gene expression of osteogenic-related genes quantified by quantitative real-time PCR. *P<0.05. (H) Immunofluorescent staining of RUNX2 and osteocalcin (OCN) in hASCs cultured on TiO₂ nanotubes and Ti surfaces after 7 days of osteoinduction. OCN and RUNX2 are colored green, while nuclei are blue.

Abbreviations: OM, osteoinduction medium; PM, proliferation medium.