Surface treatments for modifications at the nanoscale of biomaterials for tissue integration

Tissue integration of biomaterials can be increased by several modifications at the nanoscale: we explored surface texturing (topography at the nanoscale), structuring (microstructure at the nanoscale) and nanofiber deposition. Nano-texturing of the surface can be useful to get bioactive behaviour and mineralization ability (apatite precipitation) on titanium alloys, as well as better cell differentiation for osseointegration, enhanced cell proliferation and contact guidance effect on soft tissues, tailored inflammatory response. Both nano-texturing and -structuring can reduce bacteria adhesion and biofilm formation. We tested nano-textured titanium obtained both through chemical and e-beam surface treatments. The first shows nano-porous and isotropic topography and modified surface chemistry (degree of hydroxylation). In this way, the integration of the implant to the hard or soft tissues can be increased and inflammatory response as well as adhesion of bacteria can be reduced. On the other side, e-beam surface directional texturing (grooves) can be useful for contact guidance effect on fibroblasts and reduced adhesion of bacteria because of a refinement of the microstructure (nano-structuring). Also, nanofiber deposition can be useful in order to enhance soft tissues adhesion (e.g. gum) and to direct fibroblasts into a specific direction. We tested both random and oriented keratin nanofibers. Biological (bacterial and cell cultures) and chemical characterization (FTIR, XPS, FESEM, EDS, zeta potential) of the modified surfaces is described. All the obtained results are discussed to get an overall understanding of the potential applications of biomaterials surfaces modified at the nanoscale with a focus on the dental and orthopaedic implants.