Abstract

Lab-on-a-Chip Studies of Bacterial Communities -- Spatiotemporal Characterization of Chemical Signaling and Virulence Agents

Paul Bohn, Arthur J. Schmitt Professor of Chemical and Biomolecular Engineering and Professor of Chemistry and Biochemistry, University of Notre Dame

Despite the fact that most microorganisms occupy 2- and 3-dimensional space in heterogeneous ways and do not exist in monoculture, much of our current knowledge about the relation of bacteria to disease processes is derived from homogenizing, then analyzing, the chemical content of monocultures - an approach that yields no information about the 3D production and dispersal of secreted factors.  To address this need, we are developing lab-on-a-chip (LOC) methods involving nanofluidics and spectroelectrochemistry to characterize the spatiotemporal evolution of secreted chemical factors used by bacteria to organize their community structures. LOC approaches are ideal for these studies, because they facilitate: (a) characterization of different mobility conditions, e.g. swarm, twitch, biofilm, etc.; (b) development and subsequent analysis of co-cultures of antagonistic bacterial species; (c) analysis of microbial communities in the presence of antibiotics; and (d) protein (mucin) templating of regulated surface communities. We have characterized the phenotypic responses and spatial variability of alkyl quinolones, including the Pseudomonas quinolone signal (PQS) and members of the alkyl hydroxyquinoline (AQNO) subclass, in P. aeruginosa swarming communities as well as the electrochemical and spectroscopic behavior of the phenazine class of virulence factors used by this species.