title: Real-time mapping of a hydrogen peroxide concentration profile across a polymicrobial bacterial biofilm using scanning electrochemical microscopy.
abstract: Quantitative detection of hydrogen peroxide in solution above a Streptococcus gordonii (Sg) bacterial biofilm was studied in real time by scanning electrochemical microscopy (SECM). The concentration of hydrogen peroxide was determined to be 0.7 mM to 1.6 mM in the presence of 10 mM glucose over a period of 2 to 8 h. The hydrogen peroxide production measured was higher near the biofilm surface in comparison to Sg grown planktonically. Differential hydrogen peroxide production was observed both by fluorometric as well as by SECM measurements. The interaction between two different species in a bacterial biofilm of Sg and Aggregatibacter actinomycetemcomitans (Aa) in terms of hydrogen peroxide production was also studied by SECM. One-directional y-scan SECM measurements showed the unique spatial mapping of hydrogen peroxide concentration across a mixed species biofilm and revealed that hydrogen peroxide concentration varies greatly dependent upon local species composition.
authors.affiliation: Center for Electrochemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165, USA.
authors.forename: Xiuhui
authors.initials: X
authors.lastname: Liu
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Ramsey
authors.forename: Xiaole
authors.initials: X
authors.lastname: Chen
authors.forename: Dipankar
authors.initials: D
authors.lastname: Koley
authors.forename: Marvin
authors.initials: M
authors.lastname: Whiteley
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard
mesh_terms: D018441:Biofilms; D003198:Computer Simulation; D004563:Electrochemistry / Q000379:methods*; D005470:Fluorometry; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism*; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D008991:Monitoring, Physiologic / Q000379:methods*; D015661:Pasteurellaceae / Q000378:metabolism*; D013045:Species Specificity; D054773:Streptococcus gordonii / Q000378:metabolism*
chemical_list: D006861:Hydrogen Peroxide