Nanostructured titanium dioxide layer combined with reactive functional groups as a promising biofunctional surface for biomedical applications

In the present study, low-temperature plasma combined with allylamine polymerization approach was used to coat amino-groups on oxide layer of plasma-oxidized biomedical titanium (Ti) for protein immobilization. Scanning electron microscopy, X-ray diffractometer, transmission electron microscopy, X-ray photoemission spectroscopy, secondary ion mass spectrometer and 2, 4, 6-trinitrobenzenesulfonic acid assay were utilized to investigate the surface and microstructural properties of the plasma-oxidized, plasma-polymerized and protein-immobilized samples. Analytical results indicated that the presence of a nanostructured rutile-TiO ₂ thin layer could be found on the plasma-oxidized samples. The thickness of nanostructured rutile-TiO ₂ layer increased with increasing plasma treatment power and period. As the plasma-oxidized samples underwent plasma polymerization with allylamine, amino-groups (NH ₂ ) were uniformly coated on nanostructured rutile-TiO ₂ layer. It was also found that Ti surface with thick oxide layer exhibited higher amounts of amino-groups deposition. After protein immobilization, the plasma-polymerized samples presented a formation of uniform streak-like immobilized protein clusters. Therefore, biomedical Ti with nanostructured rutile-TiO ₂ layer is a promising biomaterial that can be applied to cross-link with other biomolecules for promoting the bone healing and regeneration.