AVS 62nd International Symposium & Exhibition
    In-Situ Spectroscopy and Microscopy Focus Topic Wednesday Sessions
       Session IS+SS+NS+BI+VT+MN+AS-WeA

Paper IS+SS+NS+BI+VT+MN+AS-WeA4
Investigating Shewanella Oneidensis Biofilm Matrix in a Microchannel by In Situ Liquid ToF-SIMS

Wednesday, October 21, 2015, 3:20 pm, Room 211B

Session: In situ Imaging of Liquids using Microfluidics
Presenter: Yuanzhao Ding, Nanyang Technological University, Singapore
Authors: Y. Ding, Nanyang Technological University, Singapore
X. Hua, Pacific Northwest National Laboratory
Y. Zhou, Pacific Northwest National Laboratory
J. Yu, Pacific Northwest National Laboratory
X. Sui, Pacific Northwest National Laboratory
J. Zhang, Pacific Northwest National Laboratory
Z. Zhu, Pacific Northwest National Laboratory
B. Cao, Nanyang Technological University, Singapore
X.-Y. Yu, Pacific Northwest National Laboratory
Correspondent: Click to Email
Biofilms consist of a group of micro-organisms attached onto surfaces or interfaces and embedded with a self-produced extracellular polymeric substance (EPS) in natural environments. The EPS matrix, like the “house of the cells”, provides bacteria cells with a more stable environment and makes them physiologically different from planktonic cells. Shewanella oneidensis MR-1 is a metal-reducing bacterium, forming biofilms that can reduce toxic heavy metals. This capability makes S. oneidensis biofilms very attractive in environmental applications. To better understand the biofilm EPS matrix composition at the interface, in situ chemical imaging with higher spatial resolution and more molecular level chemical information is strongly needed. Traditionally, electron microscopy and fluorescence microscopy are common imaging tools in biofilm research. However, the bottlenecks in these imaging technologies face the limitations that it is difficult for them to provide chemical information of small molecules (e.g., molecule weight <200). In this study, we use an emerging technology liquid Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to observe S. oneidensis biofilm cultured in a vacuum compatible microchannel of the System for Analysis at the Liquid Vacuum Interface (SALVI) device. Chemical spatial distributions of small organic molecules that are considered to be the main building components of EPS in live biofilms are obtained. Principal component analysis is used to determine differences among biofilms sampled along the microchannel. This new approach overcomes previous limitations in live biofilm analysis and provides more chemical information of the EPS relevant to biofilm formation. Better understanding of the biofilm matrix will potentially fill in the knowledge gap in biofilm surface attachment and detachment processes and improve the engineering and design of S. oneidensis biofilms with high efficiencies in heavy metal reduction.