Effects of titania nanotube surfaces on osteogenic differentiation of human adipose-derived stem cells.

The surface of an implant is important for successful osseointegration and long-term stability as it can aid in cell migration and proliferation, cell differentiation and allow extracellular matrix production. Earlier studies have shown that nanostructuring the surface of titanium can enhance mesenchymal stem cell (MSC) migration, proliferation, and differentiation. Although many studies have evaluated MSC response on nanostructured surfaces, there are only a few studies that have explored the response of adipose-derived stem cells (ADSC) on titania nanotube surfaces. Because ADSC exhibit great potential in regenerative medicine and have already proven effective in developing new treatments, this study aims to further understand how ADSC interact with titania nanotube surfaces. The results of this study indicate that titania nanotube surfaces enhance ADSC proliferation and differentiation that is also dependent on the size of nanotubes. Additionally, the favorable response of ADSC on nanotube surfaces suggests a potential application in orthopedic tissue regeneration.

Effect of crystalline phases of titania nanotube arrays on adipose derived stem cell adhesion and proliferation.

The aim of this work was to evaluate the cellular response to titanium nanotube arrays with variable crystalline structure. Cytotoxicity, viability and the ability of the titania nanotube arrays to stimulate adhesion and proliferation of adipose derived stem cells (ADSCs) was evaluated. Titania nanotube arrays were fabricated by electrochemical anodization of titanium in diethyleneglycol/hydrofluoric acid electrolyte at 60 V for 6 h, then annealed at 300, 530 and 630 °C for 5 h. The nanotube arrays were characterized using scanning electron microscopy (SEM), contact angle goniometry, x-ray diffraction (XRD) and protein adsorption. ADSCs were cultured on titania nanotube arrays at a density of 1 × 104 cells/ml. The cells were allowed to adhere and to proliferate for 1, 4 and 7 days. Cell viability was characterized by the CellTiter-Blue® Cell Viability Assay; and cell morphology was characterized by SEM. Cell adhesion, proliferation and morphology were characterized using fluorescence microscopy by staining the cells with DAPI and rhodamine/phalloidin. The results from this study showed that the annealing at 300 and 530 °C formed anatase phase, and annealing at 630 °C formed anatase/rutile phase. The results indicated that the modification of the crystalline structure (i.e. anatase/rutile phase) of titania nanotube arrays influenced the ADSC adhesion and proliferation. Future studies are now directed towards evaluating differentiation of this cellular model in osteoblasts.