Ion-exchange-driven AgCuO₂-TiO₂hybrid nanocomposites for rapid antibacterial activity in dental sealers

Microbial colonization at the biomaterial-tissue interface remains a primary challenge in restorative dental treatments. While root canal sealers act as physical barriers, their lack of intrinsic antibacterial activity limits the eradication of residual pathogens. In this study, we developed an ion-exchange-driven AgCuO₂-TiO₂ hybrid nanocomposite designed to provide rapid bactericidal activity at the restorative interface. The nanocomposite features AgCuO₂ clusters anchored on a TiO₂ support. Under Na⁺-rich and mildly acidic conditions typical of infection microenvironments, a cation-exchange mechanism accelerates Ag⁺ ion release, while Cu acts as a charge buffer to maintain structural stability. Density functional theory calculations and experimental evaluations validated this rapid ion-release behavior. Furthermore, the nanocomposite exhibits high protein adsorption capacity, which facilitates the local concentration and retention of Ag⁺ at the bacteria-material interface, thereby amplifying the bactericidal effect. When incorporated into commercial resin- and mineral trioxide aggregate-based sealers, the materials achieved rapid and substantial bacterial inactivation against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis within short exposure times. The modified sealers retained essential physicochemical properties complying with ISO 6876 standards, and in vitro cytotoxicity and in vivo dermal tests confirmed their biocompatibility. Collectively, this ion-exchange-driven strategy provides a viable mechanism for rapid initial pathogen eradication, presenting a functional approach to designing responsive antibacterial biomaterials.