Understanding Nano-Microbial Interactions In A Bacterial Biofilm

<p>Previously established unpublished data show that biofilm cells are more resistant to silver nanoparticles (AgNPs) than planktonic cells. The goal of this research is to determine the fate and transport of AgNPs in a single species biofilm system and to examine the role of AgNPs in the proliferation of antibacterial resistance in attached growth systems. The specific objectives and associated tasks include (1) characterizing AgNPs and examining microbially induced particle aggregation/dissolution and determining the spatial/temporal distribution of AgNPs in biofilms, (2) examining the spatial and temporal variation of microbial activity within the biofilm exposed to AgNPs, and (3) evaluating the impact of AgNPs on gene expression of the stress related genes and antimicrobial resistance genes in biofilms. The research will use microrespirometry, two-photon laser scanning fluorescence microscopy (2P-LSM) and laser capture microdissection microscopy to determine bacterial activity, AgNPs and cell activity within the biofilm, and the levels of antimicrobial resistance gene expression at different biofilm depth, respectively. The research will further examine particle dissolution/aggregation/transformation by microorganisms using advanced electron microscopy (TEM/SEM/ESEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Two bacterial species Escherichia coli and Pseudomonas aeruginosa will be used for single species biofilm studies because P. aeruginosa is a well-studied opportunistic pathogen that is commonly found in the environment to form biofilms while E. coli is still used as the principle indicator for drinking water pollution monitoring. Significant broader impacts involve student support.</p>