Reduced TiO2 Nanotubes/Silk Fibroin/ZnO as a Promising Hybrid Antibacterial Coating

The current research aims to elucidate the influence of reduction process of TiO2 nanostructures on the surface properties of a bioinspired Ti modified implant, considering that the interface between a biomaterial surface and the living tissue plays an important role for this interaction. The production of reduced TiO2 nanotubes (RNT) with lower band gap is optimized and their performance is compared with those of simple TiO2 nanotubes (NT). The more conductive surfaces provided by the presence of RNT on Ti, allow a facile deposition of silk fibroin (SF) film using the electrochemical deposition method. This hybrid film is then functionalized with ZnO nanoparticles, to improve the antibacterial effect of the coating. The modified Ti surface is evaluated in terms of surface chemistry, morphology and roughness, wettability, surface energy, surface charge and antibacterial properties. Surface analysis such as SEM, AFM, FTIR and contact angle measurements were performed to obtain topographical features and wettability. FT-IR analysis confirms that SF was effectively attached to TiO2 nanotubes surfaces. The electrochemical deposition of SF and SF-ZnO reduced the interior diameter of nanotubes from similar to 85 nm to approx. 50-60 nm. All modified surfaces have a hydrophilic character.

Automated summary

This research focuses on the influence of the reduction process of TiO2 nanostructures on the surface properties of a bioinspired Ti modified implant. By optimizing the production of reduced TiO2 nanotubes (RNT) and comparing them with simple TiO2 nanotubes (NT), it was found that the presence of RNT on Ti allows for easy deposition of silk fibroin (SF) film. The hybrid film was then functionalized with ZnO nanoparticles to improve the antibacterial effect of the coating. Surface analysis confirmed that SF was effectively attached to the TiO2 nanotube surfaces. Evaluation of the modified Ti surface showed hydrophilic characteristics.