Surface versus Nanocatalyst-Induced Matrix Bubbles Govern Temperature-Dependent Biofilm Removal

Bacterial biofilms protected by viscoelastic extracellular polymeric substances (EPS) are highly resistant to chemical disinfectants and rapidly regenerate after treatment. While bubble-mediated mechanical disruption has emerged as an eco-friendly antifouling strategy, bubbles generated by conventional tools act on biofilm surfaces and fail to disrupt three-dimensional biofilms. Here, we demonstrate that generating bubbles within biofilms, referred to as matrix bubbles, and controlling their dynamics with temperature, enables effective matrix disruption and biofilm removal. Using P. aeruginosa biofilms as a model system, we compared H₂O₂ alone with MnO₂ nanocatalyst-doped biosilica microparticles (MnO₂-biosilica) across a range of temperatures. H₂O₂ alone produced catalase-driven O₂ bubbles localized on the biofilm surface with minimal temperature dependence, resulting in limited biofilm removal. In contrast, MnO₂-biosilica generated temperature-amplified matrix bubbles that formed swarms, penetrated biofilms, disrupted EPS, and suppressed regrowth at elevated temperatures (25 and 40 °C). Kinetic and imaging analyses revealed that this temperature-dependent behavior arises from accelerated MnO₂-catalyzed H₂O₂ decomposition coupled with enhanced bubble expansion and rupture, which deliver strong mechanical perturbation within the biofilm matrix. Importantly, nanocatalyst-induced matrix bubbles effectively removed biofilm from complex surgical instrument geometries and acted synergistically with autoclaving. This study therefore establishes temperature-controlled, nanocatalyst-mediated matrix bubble dynamics as a physical strategy for overcoming biofilm resistance in clinical and industrial settings.