3-Mercaptopropionic acid functionalization of titanium dioxide thin films

• Published in: Materials chemistry and physics 2019-02, Vol.223, p.32-38
• Main Authors: Gomes, Orisson P., Azevedo Neto, Nilton F., Bronze-Uhle, Erika S., Trino, Luciana D., dos Santos, Cássio M., da Silva, José H.D., Lisboa-Filho, Paulo N.
• Format: Article
• Language: English
• Subjects: Anatase; Atomic beam spectroscopy; Atomic force microscopy; Bacterial corrosion; Biocompatibility; Biomaterials; Dental materials; Hydroxyl groups; Magnetron sputtering; Organic chemistry; Photoelectrons; Rutile; Surface functionalization; Surgical implants; Thin films; Titanium; Titanium dioxide; Transplants & implants; X ray photoelectron spectroscopy
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.10.041

Nanostructured titanium dioxide (TiO2) films are commonly employed as surface modifiers on medical and dental metallic implants, presenting promising results related to interactions with living tissues, promoting improvements in the in vivo biocorrosion resistance and increased bioactivity when compared to non-coated metallic materials. In addition to these properties, titanium dioxide is also well recognized for its biocompatibility. However, considering the necessary integration with surrounding tissues when this oxide is applied as implant coatings, there are many aspects of the adhesion mechanisms located at the interface between the biological environment and the oxide surface that still need to be addressed. Specifically regarding the surface chemistry, these oxides are mainly terminated by hydroxyl groups (-OH) that are readily functionalized by different molecules, such as the 3-mercaptopropionic acid (MPA). In this contribution, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to examine the adsorption of MPA on anatase- and rutile-phase forms of TiO2 thin film surfaces grown by RF magnetron sputtering. According to the obtained results, both anatase and rutile TiO2 films present similarities in roughness and thickness. However, different responses to interaction with the MPA molecules were observed, wherein the functionalization was seen to occur only for the rutile phase. •Nanostructured titanium dioxide films are commonly employed as surface modifiers.•Monophasic anatase and rutile TiO2 films were grown onto Ti substrates.•The surfaces of these oxides are mainly terminated by -OH groups.•The -OH groups can be readily functionalized by bifunctional molecules.•The functionalization with MPA was seen to occur only for the rutile phase.