title: Waveguide evanescent field scattering microscopy: bacterial biofilms and their sterilization response via UV irradiation.
abstract: Waveguide Evanescent Field Scattering (WEFS) microscopy is introduced as a new and simple tool for label-free, high contrast imaging of bacteria and bacteria sensors. Bacterial microcolonies and single bacteria were discriminated both by their bright field images and by their evanescent scattering intensity. By comparing bright field images with WEFS images, the proportion of planktonic: sessile (i.e., "floating": attached) bacteria were measured. Bacteria were irradiated with UV light, which limited their biofilm forming capability. A quantitative decrease in attachment of individual, sessile bacteria and in attached, microcolony occupied areas was easily determined within the apparent biofilms with increasing UV dose. WEFS microscopy is an ideal tool for providing rapid quantitative data on biofilm formation.
authors.affiliation: Department of Electrical and Computer Engineering, The University of Western Ontario Western University, London, Ontario, N6A 5B9, Canada; Department of Physics and Astronomy, The University of Western Ontario Western University, London, Ontario, N6A 3K7, Canada.
authors.forename: Qamrun
authors.initials: Q
authors.lastname: Nahar
authors.forename: Frederik
authors.initials: F
authors.lastname: Fleißner
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Shuster
authors.forename: Michael
authors.initials: M
authors.lastname: Morawitz
authors.forename: Christopher
authors.initials: C
authors.lastname: Halfpap
authors.forename: Mihaela
authors.initials: M
authors.lastname: Stefan
authors.forename: Uwe
authors.initials: U
authors.lastname: Langbein
authors.forename: Gordon
authors.initials: G
authors.lastname: Southam
authors.forename: Silvia
authors.initials: S
authors.lastname: Mittler
mesh_terms: D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects; D018441:Biofilms / Q000254:growth & development* / Q000528:radiation effects*; D002470:Cell Survival / Q000502:physiology / Q000528:radiation effects; D007089:Image Enhancement / Q000379:methods*; D008029:Lighting / Q000379:methods; D008853:Microscopy / Q000379:methods*; D009576:Nitrobacter / Q000502:physiology / Q000528:radiation effects*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013242:Sterilization / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*; D014466:Ultraviolet Rays
keywords: UV sterilization; biofilm; evanescent field; microscopy; scattering; waveguide