Waveguide evanescent field scattering microscopy: bacterial biofilms and their sterilization response via UV
Qamrun Nahar1, Frederik Fleißner, Jeremiah Shuster
1Department 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.
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.
