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Abstract Biofilms can increase pathogenic contamination of drinking water, cause biofilm‐related diseases, alter the sediment erosion rate, and degrade contaminants in wastewater. Compared with mature biofilms, biofilms in the early‐stage have been shown to be more susceptible to antimicrobials and easier to remove. Mechanistic understanding of physical factors controlling early‐stage biofilm growth is critical to predict and control biofilm development, yet such understanding is currently incomplete. Here, we reveal the impacts of hydrodynamic conditions and microscale surface roughness on the development of early‐stagePseudomonas putidabiofilm through a combination of microfluidic experiments, numerical simulations, and fluid mechanics theories. We demonstrate that early‐stage biofilm growth is suppressed under high flow conditions and that the local velocity for early‐stageP. putidabiofilms (growth time < 14 h) to develop is about 50 μm/s, which is similar toP. putida's swimming speed. We further illustrate that microscale surface roughness promotes the growth of early‐stage biofilms by increasing the area of the low‐flow region. Furthermore, we show that the critical average shear stress, above which early‐stage biofilms cease to form, is 0.9 Pa for rough surfaces, three times as large as the value for flat or smooth surfaces (0.3 Pa). The important control of flow conditions and microscale surface roughness on early‐stage biofilm development, characterized in this study, will facilitate future predictions and managements of early‐stageP. putidabiofilm development on the surfaces of drinking water pipelines, bioreactors, and sediments in aquatic environments.
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Plasma‐induced inactivation of Staphylococcus aureus biofilms: The role of atomic oxygen and comparison with disinfectants and antibiotics
Abstract Microbial biofilms are of critical concern because of their recalcitrance to antimicrobials. Cold atmospheric plasmas (CAP) represent a promising biofilm remediation strategy as they generate reactive oxygen and nitrogen species (RONS), but mechanisms underpinning CAP‐biofilm interactions remain unknown. We assess the impact of treatment modality on biofilm inactivation and show that CAP killing ofStaphylococcus aureusbiofilms is dependent on treatment conditions, including solution chemistry. In dry treatments, biofilms are locally ablated due to plasma‐produced O flux. For saline‐submerged biofilms, while we show that ClO−is generated at high concentrations in larger treatment volumes, CAP inactivation at low ClO−concentrations implicates other reaction pathways. Finally, we demonstrate CAP efficacy over conventional antimicrobials, underscoring its promise as a biofilm treatment approach.
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- Award ID(s):
- 2020695
- PAR ID:
- 10376013
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Plasma Processes and Polymers
- Volume:
- 20
- Issue:
- 1
- ISSN:
- 1612-8850
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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