# Characterization of Biofilms by Correlated Mass Spectrometric and Raman Imaging

> **NIH NIH R01** · UNIVERSITY OF NOTRE DAME · 2020 · $500,779

## Abstract

PROJECT SUMMARY
 Most bacteria in natural and clinical settings grow as surface-attached biofilms, which are bacterial
communities that have self-assembled into an encased matrix of extracellular polymeric substances (EPS). To
form these bacterial biofilm communities and infect host cells, an intercellular signaling process described as
quorum sensing (QS) is very important. For the opportunistic pathogens Pseudomonas aeruginosa and
Staphylococcus aureus, QS regulates the expression of many genes important to biofilm initiation, EPS
production, and virulence. While much has been learned about select factors that regulate biofilm formation in
vitro and in animal models, the specific mechanisms by which multispecies groups of cells form biofilms are not
understood. Furthermore, the therapeutic capabilities needed to treat the increasingly virulent infections of the
coming decades will require deeper insight into multi-species interactions and their regulation of multiple gene
expression profiles as represented over extended spatial and temporal scales during host cell infection.
 The correlated mass spectrometric and Raman chemical imaging approaches that have been developed
by our combined research group circumvent the limitations imposed by previous technology which allowed
examination of either a small number of cells or entire cell populations that had been removed from the
conditions of interest. In contrast our correlated chemical imaging methods allow the determination and spatial
mapping of individual bacterial species and their microbial products within a mixed bacterial community
growing in situ on surfaces.
 One of our long-term goals is the design of detection and diagnostic strategies informed by an
understanding of bacterial interactions and signature biomolecule production. We will continue our work toward
this goal by conducting mono-culture and co-culture experiments using Pseudomonas aeruginosa and
Staphylococcus aureus as model pathogens. Correlated chemical imaging will be used to define the onset and
range of intercellular quorum sensing signaling in space and time. The biosecretome and interactions of
specific species in co-culture biofilms will be characterized for both intra- and inter-species interactions. Also,
an ex vivo lung assay will be created to study the spatial biofilm secretome. This research will exploit the
ability to spatially map specific chemical products produced by these and other pathogenic bacteria thereby
yielding deep and therapeutically informative insights into host colonization, infection, and virulence.

## Key facts

- **NIH application ID:** 10021393
- **Project number:** 5R01AI113219-07
- **Recipient organization:** UNIVERSITY OF NOTRE DAME
- **Principal Investigator:** Joshua Shrout
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $500,779
- **Award type:** 5
- **Project period:** 2014-06-01 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10021393

## Citation

> US National Institutes of Health, RePORTER application 10021393, Characterization of Biofilms by Correlated Mass Spectrometric and Raman Imaging (5R01AI113219-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10021393. Licensed CC0.

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