Ruthenium-Anchored Ag₂Se Quantum Dots for Enhanced Near-Infrared Antibacterial Nanotherapeutics

Light-activated nanotherapeutics that generate reactive oxygen species (ROS) offer a resistance-independent antibacterial strategy. However, integrating transition metals with inorganic quantum dots (QDs) to modulate light-matter interactions and extend photoactivity into the near-infrared (NIR) windows remains largely unexplored for antibacterial applications. Here, we develop a colloidal in situ integration strategy to anchor metallic ruthenium (Ru) onto Ag₂Se QDs, enabling broadband-enhanced photoresponse and multimodal generation of superoxide, hydroxyl radicals, and singlet oxygen, alongside a high photothermal conversion efficiency of 66.4%. Moreover, Ru decoration transforms the previously unstable Ag₂Se QDs into highly robust colloidal suspensions. The Ru-decorated Ag₂Se QDs exhibit potent photodynamic and photothermal antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus under near-infrared (NIR-I and NIR-II) irradiation, extending therapeutic photoactivation beyond the visible range. Ultimately, this work introduces an unconventional biomedical nanoplatform that integrates transition metals with inorganic quantum dots for advanced functionality.