Keratin nanofibers as coating for titanium transmucosal implants

Even if surface coatings and modifications of titanium for bone contact applications have been widely investigated, few literature can be found concerning coatings aimed at soft tissue contact. However, soft tissue healing represents a crucial step for the positive outcome of percutaneous/transmucosal titanium implants. Fibroblasts, the soft tissues most representative cells, are known to be sensitive to surface topography (contact guidance effect). Anyhow, fibroblasts adhesion and spread can be influenced by the presence of attractive macromolecules, such as keratin. As last, bacteria penetration through soft tissues and consequent biofilm formation on the implants is a great issue of percutaneous/transmucosal implants. Accordingly, this work aims at a coating of keratin aligned nanofibers on a Ti-substrate with nanogrooves, in order to impart additive topographical plus biochemical signals in stimulating fibroblasts repopulation. Antibacterial inorganic agents (such as Ag or Cu ions) can be added to the nanofibers by soaking in salt solutions. The aim is challenging because despite the very promising cells guidance provided by keratin nanofibers, the strong limitation to their synthesis is related to the macromolecules high sensitivity to environmental parameters (temperature, humidity, pH) which seriously compromise the feasibility and reproducibility of the final nanofiber layer. Moreover, ion release must be optimize in order to get an antibacterial behavior without compromise biocompatibility. The coating is characterized by means of FESEM, FTIR and AFM analysis, adhesion tests, degradation rate tests, biological evaluation (fibroblasts and bacteria cultures).