Plasmonic heterojunction on dental implant abutments for enhanced antibacterial activity and soft tissue integration

Peri-implantitis, a leading cause of dental implant failure, is characterized by bacterial infection, immune dysregulation and inadequate soft tissue integration. To address those challenges, this study proposes a novel plasmonic heterojunction coating on titanium-based abutments. The introduction of tungsten doping and lattice defects significantly increases the free electron density, thereby inducing a strong LSPR effect in the titanium oxide matrix within the near-infrared region. Under 808 nm laser irradiation, the coating demonstrates good antibacterial activity through a dual-mode mechanism: it generates energetic “hot holes” that participate in the “electron hijacking” process, which disrupts bacterial energy metabolism and redox balance; concurrently, the non-radiative relaxation of surface plasmons produces a controlled and mild photothermal effect, which induces bacterial thermal stress and increases bacterial membrane permeability. The plasmonic heterojunction also promotes the adhesion, proliferation, and collagen secretion of human gingival fibroblasts and modulates the immune microenvironment, thereby facilitating the formation of a stable biological seal. In vivo experiments in rats and beagle dogs confirm its good antibacterial activity and biocompatibility, as well as its therapeutic potential in treating peri-implantitis. This work presents a promising potential of plasmonic heterojunction coatings in developing next-generation smart, multifunctional implants to improve long-term clinical success.