In situ molecular imaging of the biofilm and its matrix
Reference: Analytical Chemistry (2016) 88:11244-11252

Molecular mapping of live biofilms at submicron resolution presents a grand challenge. Here, we present the first chemical mapping results of biofilm extracellular polymeric substance (EPS) components in biofilms using correlative imaging be-tween super resolution florescence microscopy and liquid time-of-flight secondary ion mass spectrometry (ToF-SIMS). Shewanella oneidensis is used as a model organism. Heavy metal anions chromate (Cr2O72-) consisting of chromium Cr (VI) was a model environmental stressor used to treat the biofilms. Of particular interest, biologically relevant water clusters have been first observed in the biofilms. Characteristic fragments of biofilm matrix components such as proteins, polysaccharides, and lipids can be spatially imaged. Furthermore, characteristic fatty acids (e.g., palmitic acid), quinolone signal, and riboflavin fragments are found to respond after the biofilm is treated with Cr (VI), leading to biofilm dispersion. Significant changes in water clusters and quorum sensing signals indicative of inter-cellular communication in the aqueous environment are observed, suggesting that they might result in fatty acid synthesis and inhibit riboflavin production. The Cr (VI) reduction seems to follow the Mtr pathway leading to Cr (III) formation. Our approach potentially opens a new avenue for mechanistic insight of microbial community processes and communications using in situ imaging mass spectrometry and superresolution optical microscopy.


Link to article



Published By
Ding Y., Zhou Y., Yao J., Szymanski C., Fredrickson J. K., Shi L., Cao B., Yu X.-Y.