This study demonstrates that the fate of human mesenchymal stem cells (hMSCs) can be controlled solely by altering the dimensions of nanotubular titanium oxide (TiO₂) surface structures. By adjusting the nanotube sizes, the researchers observed significant changes in hMSC behavior, including adhesion and differentiation into osteoblasts, without the need for osteogenic inducing media. Small nanotubes (≈30 nm diameter) promoted adhesion without noticeable differentiation, while larger nanotubes (≈70–100 nm diameter) induced dramatic cell elongation and selective differentiation into osteoblast-like cells. This suggests that nanotopography can be used to guide stem cell differentiation, offering a promising nanotechnology-based approach for orthopedic applications. The study highlights the importance of nanoscale surface structures in influencing cell behavior. The unique nanotopographical features of TiO₂ nanotubes enhance biocompatibility and promote cell adhesion, proliferation, and differentiation. The researchers found that the size of the nanotubes significantly affects hMSC behavior, with larger nanotubes leading to increased cell elongation and osteogenic differentiation. This is attributed to the mechanical stress induced by the nanotube geometry, which influences the cytoskeletal structure and cellular function. The study also shows that the adhesion and elongation of hMSCs are strongly correlated with the size of the nanotubes. Cells on larger nanotubes exhibited more pronounced elongation and differentiation into osteoblast-like cells, while cells on smaller nanotubes remained more rounded and less differentiated. The results indicate that the nanotopography can be used to control stem cell fate, providing a new approach for directing stem cell differentiation without the need for chemical inducers. The findings have important implications for stem cell research and regenerative medicine. By controlling the nanotopography of surfaces, it is possible to guide stem cell differentiation into specific cell lineages, which could lead to new therapeutic applications in bone regeneration and tissue engineering. The study also highlights the potential of TiO₂ nanotubes as a biomaterial for osseointegration and bone regeneration, as they promote strong bone integration and reduce soft tissue trapping. The results suggest that nanotopography can be a powerful tool for controlling stem cell behavior and differentiation, offering a promising avenue for future research and clinical applications.This study demonstrates that the fate of human mesenchymal stem cells (hMSCs) can be controlled solely by altering the dimensions of nanotubular titanium oxide (TiO₂) surface structures. By adjusting the nanotube sizes, the researchers observed significant changes in hMSC behavior, including adhesion and differentiation into osteoblasts, without the need for osteogenic inducing media. Small nanotubes (≈30 nm diameter) promoted adhesion without noticeable differentiation, while larger nanotubes (≈70–100 nm diameter) induced dramatic cell elongation and selective differentiation into osteoblast-like cells. This suggests that nanotopography can be used to guide stem cell differentiation, offering a promising nanotechnology-based approach for orthopedic applications. The study highlights the importance of nanoscale surface structures in influencing cell behavior. The unique nanotopographical features of TiO₂ nanotubes enhance biocompatibility and promote cell adhesion, proliferation, and differentiation. The researchers found that the size of the nanotubes significantly affects hMSC behavior, with larger nanotubes leading to increased cell elongation and osteogenic differentiation. This is attributed to the mechanical stress induced by the nanotube geometry, which influences the cytoskeletal structure and cellular function. The study also shows that the adhesion and elongation of hMSCs are strongly correlated with the size of the nanotubes. Cells on larger nanotubes exhibited more pronounced elongation and differentiation into osteoblast-like cells, while cells on smaller nanotubes remained more rounded and less differentiated. The results indicate that the nanotopography can be used to control stem cell fate, providing a new approach for directing stem cell differentiation without the need for chemical inducers. The findings have important implications for stem cell research and regenerative medicine. By controlling the nanotopography of surfaces, it is possible to guide stem cell differentiation into specific cell lineages, which could lead to new therapeutic applications in bone regeneration and tissue engineering. The study also highlights the potential of TiO₂ nanotubes as a biomaterial for osseointegration and bone regeneration, as they promote strong bone integration and reduce soft tissue trapping. The results suggest that nanotopography can be a powerful tool for controlling stem cell behavior and differentiation, offering a promising avenue for future research and clinical applications.