Abstract: Biofilm infections represent a critical global health threat, characterized by high mortality and significant resistance to conventional therapies. Chemodynamic therapy (CDT), which harnesses Fenton or Fenton-like reactions to generate bactericidal hydroxyl radicals (·OH), has emerged as a promising approach for combating planktonic bacterial infections. Nevertheless, its effectiveness against biofilms remains limited because of the protective extracellular polymeric substance (EPS) matrix and low endogenous H₂O₂ concentrations. To overcome these challenges, a cascade-activatable nanoplatform was developed, integrating deoxyribonuclease-mimetic components with self-sustaining H₂O₂ generation. The platform consists of Ce⁴⁺/nitrilotriacetic acid (NTA) complexes immobilized on amino-functionalized SiO₂ shells encapsulating CuO₂ nanodots. In the acidic microenvironment of biofilms, this nanoplatform initiates a two-pronged approach: First, the Ce⁴⁺/NTA complexes selectively degrade extracellular DNA within the EPS matrix, disrupting biofilm structure and facilitating deeper penetration; Second, CuO₂ decomposition releases substantial H₂O₂ and Cu²⁺ ions, the latter catalyzing a Fenton-like reaction that converts H₂O₂ into cytotoxic ·OH radicals, inducing bacterial membrane lipid peroxidation. This combined strategy demonstrated outstanding antibiofilm performance in vitro, eliminating over 99.9 % of both Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa)biofilms. In vivo testing using an S. aureus-infected murine wound model demonstrated a substantial decrease in bacterial colonization alongside enhanced tissue repair kinetics, with no detectable toxicological effects. By simultaneously overcoming matrix penetration barriers and autonomously generating H₂O₂, this approach offers a robust enhancement of CDT efficacy against persistent biofilm infections.

Key words: Bacterial biofilm, Antibiofilm, Chemodynamic therapy, Dnase-mimetic activity, H₂O₂ supplying