Broad-spectrum utilization and direct energy transfer from lanthanide nanoparticles for sunlight-triggered low-dose, highly efficient photodynamic therapy

Abstract

Antibacterial photodynamic therapy (aPDT) is an emerging and promising approach for addressing microbial contamination and antibiotic resistance. However, achieving efficient aPDT at reduced doses and under low light-intensity light remains a significant challenge. In this study, an aPDT strategy using solar irradiance intensity was proposed by designing a multifunctional antibacterial nanoplatform, denoted as YVO₄:Bi^3 +,Eu³⁺/TiO₂-Ce6 (YTiC), based on rare-earth nanomaterials (YVO₄:Bi³⁺,Eu³⁺) loaded with Ce6 and TiO₂. The YVO₄:Bi³⁺,Eu³⁺ serves as a carrier for Ce6 and TiO₂, modulating aggregation state, optimizing light absorption, and suppressing electron-hole recombination in TiO₂. The important innovation in this design is that YVO₄:Bi³⁺,Eu³⁺ can convert UV light to red light to activate Ce6 and directly sensitize its triplet state via the ⁵D₀–⁷F₂ transition of Eu³⁺, thereby significantly boosting reactive oxygen species (ROS) production. This strategy reduces the required Ce6 dose by 46 % and light power density by 50 %, substantially enhancing ROS generation efficiency. Furthermore, combining aPDT with sonodynamic therapy (SDT) achieved near-complete bactericidal efficacy against Staphylococcus aureus, Salmonella typhimurium, and Botrytis cinerea, by inhibiting bacterial glycogen metabolism and disrupting the arginine and proline metabolism pathways. Based on this platform, the multifunctional antibacterial film YTiC-CMC is developed, enabling UV irradiation and sunlight to extend the shelf life of strawberries and chicken by 4 and 3 days, respectively, achieving outdoor antibacterial action and food preservation. This rare-earth nanomaterial-enhanced synergistic strategy offers a novel and powerful pathway for combating microbial contamination in both clinical applications and food preservation.