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Title: In situ molecular imaging of hydrated biofilm in a microfluidic reactor by ToF-SIMS

The first results of using a novel single channel microfluidic reactor to enable Shewanella biofilm growth and in situ characterization using time-of-flight secondary ion mass spectrometry (ToF-SIMS) in the hydrated environment are presented. The new microfluidic interface allows direct probing of the liquid surface using ToF-SIMS, a vacuum surface technique. The detection window is an aperture of 2 m in diameter on a thin silicon nitride (SiN) membrane and it allows direct detection of the liquid surface. Surface tension of the liquid flowing inside the microchannel holds the liquid within the aperture. ToF-SIMS depth profiling was used to drill through the SiN membrane and the biofilm grown on the substrate. In situ 2D imaging of the biofilm in hydrated state was acquired, providing spatial distribution of the chemical compounds in the biofilm system. This data was compared with a medium filled microfluidic reactor devoid of biofilm and dried biofilm samples deposited on clean silicon wafers. Principle Component Analysis (PCA) was used to investigate these observations. Our results show that imaging biofilms in the hydrated environment using ToF-SIMS is possible using the unique microfluidic reactor. Moreover, characteristic biofilm fatty acids fragments were observed in the hydrated biofilm grown in the microfluidicmore » channel, illustrating the advantage of imaging biofilm in its native environment.« less
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Publication Date:
OSTI Identifier:
Report Number(s):
36601; 48143; 42330; 47299; 47740
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Analyst, 139:1609-1613
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
Shewanella biofilm; molecular imaging; microfluidic flow reactor; hydrated state; ToF-SIMS; in situ; Principle Component Analysis; Environmental Molecular Sciences Laboratory