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

Authors: 
Deng, Y. H., University of Illinois at Urbana-Champaign
Seo, Y., University of Illinois, Urbana-Champaign
Leong, J., University of Illinois at Urbana-Champaign
Park, J. D., University of Illinois at Urbana-Champaign
Hong, Y. T., University of Illinois, Urbana-Champaign
Chu, S. H., National Institute of Aerospace
Park, C., NASA Langley Research Center
Kim, D. H., Korea Institute of Industrial Technology
Dushnov, V., University of Illinois at Urbana-Champaign
Soh, J., University of Illinois at Urbana-Champaign
Rogers, S., University of Illinois, Urbana-Champaign
Yang, Y. Y., Institute of Bioengineering and Nanotechnology
Kong, H., University of Illinois, Urbana-Champaign
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.
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