LL-37 - biofunctionalized titanium improves soft tissue seal surrounding the dental implant from the perspective of optimizing a race to the surface

The bacterial oral environment poses a significant challenge to the long-term stability of dental implants due to vulnerability of peri-implant soft tissues to pathogenic infiltration. Therefore, the rapid formation of a dense soft tissue barrier in the transgingival mucosal area surrounding the implant is essential. In this study, we engineer a biofunctionalized titanium (Ti) material by leveraging polydopamine (PD) as an intermediate coating to immobilize the peptide LL-37 onto nanostructured Ti substrates (LL-37-PD@NT). Material characterization shows that LL-37 is successfully loaded onto Ti substrate, and although the roughness of LL-37-PD@NT increases within a certain extent, the overall biological activity is still better than that of smooth Ti, which is considered to be traditional abutment material; meanwhile, LL-37 can be released stably for more than 1 week. Furthermore, the in vitro experiments demonstrate dual functionality of LL-37-PD@NT: the modified Ti samples significantly promote the migration, adhesion, proliferation and ECM synthesis of human gingival fibroblasts (hGFs), while exhibiting potent antibacterial efficacy against Pg and Sm. In a rat model of implantation immediately after tooth extraction, a peri-implant epithelial structure resembling the junctional epithelium of natural teeth is observed surrounding dental implant of LL-37-PD@NT at 4 weeks, and the prevention for HRP penetration exhibits the potent sealing capacity of peri-implant soft tissues. Collectively, our findings validate that the LL-37 - biofunctionalized Ti can simultaneously enhance hGFs biological functions and bacteriostatic performance, thus promoting formation and strength of soft tissue seal, holding promise as a novel option for implant abutment material.