(316g) Diatom Microbubbler for Active Biofilm Removal in Confined Spaces

Bacterial biofilms are formed on many living tissues, engineered materials, and medical devices, which threatens human health and sustainability. Although tremendous efforts have been made on biofilm removal, it is still a grand challenge to remove biofilms formed in confined space. One primary cause is extracellular polymeric substances (EPS) of the biofilm, which limit the transport of antibacterial agents into biofilm. In this work, we hypothesized that microparticles engineered to produce microbubbles with self-locomotion would remove biofilms by fracturing the EPS and subsequently enhancing transports of the antiseptic reagent. We examined this hypothesis by doping a porous cylinder-shaped diatom biosilica particle with manganese oxide (MnO₂) nanosheets. In antiseptic H₂O₂ solution, the diatoms doped with MnO₂ nanosheets, denoted as diatom microbubbler, continuously discharged oxygen gas microbubbles and became self-motile. Subsequently, the diatoms penetrated the bacterial biofilm formed on microgrooved poly(dimethylsiloxane) (PDMS) substrates and continued to generate microbubbles. The resulting microbubbles merged and converted surface energy to mechanical energy to fracture the EPS matrix in biofilm. Consequently, H₂O₂ molecules diffused into the biofilm and killed most bacterial cells. Overall, this study provides a powerful and unique tool that can significantly impact current efforts to clean a wide array of biofouled products and devices.