Multi-scale composite Ag-TiO₂ nanoreactor for long-lasting antibacterial and immunomodulatory therapy of periodontitis

Periodontitis is a prevalent chronic inflammatory disease driven by biofilms formed by common oral pathogens, leading to the progressive destruction of periodontal tissues. However, conventional antimicrobial therapies often neglect the clearance of bacterial endotoxins such as lipopolysaccharide (LPS), a potent pro-inflammatory mediator that exacerbates tissue inflammation. To address this problem, we developed a multifunctional nanoreactor featuring both antibacterial and LPS-scavenging capabilities. Utilizing a photochemical synthesis strategy, Ag-TiO₂ nanoparticles with diameters below 10 nm were grown in situ onto micro-scale carriers 13X zeolite and activated carbon (AC). The 13X matrix enhances photocatalytic oxidative activity, while AC offers a high specific surface area for the adsorption of LPS and hydrogen sulfide (H₂S). The Ag-TiO₂ photocatalyst further endows the system with self-cleaning ability and improved degradation efficiency of harmful agents. Under 405 nm blue light emitting diode (LED) light irradiation, the composite efficiently generates reactive oxygen species (ROS), achieving > 98% bactericidal rates against Actinobacillus Actinomycetemcomitans (A. actinomycetemcomitans), Streptococcus mutans (S. mutans), and Porphyromonas gingivalis (P. gingivalis), with up to 80% biofilm removal. Additionally, AC-Ag-TiO₂ effectively adsorbs and degrades LPS, significantly reducing the secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in macrophages. In a mouse model of periodontitis, the material not only stabilized the oral microbiota but also promoted periodontal tissue repair. Taken together, this study introduces a multi-scale catalytic platform that synergistically combines photocatalysis and adsorption to achieve dual antibacterial and anti-inflammatory effects, offering a highly efficient and long-lasting therapeutic strategy for periodontitis.