Waveguide evanescent field fluorescence (WEFF) microscopy is a new development that allows the imaging of contact regions between biological cells and their substratum, as well as imaging of ultrathin films such as monomolecular Langmuir–Blodgett (LB) films. Mixed-lipid monolayer systems mimicking lung surfactant were fabricated on waveguides using the LB technique and imaged by both WEFF and standard wide field epifluorescence microscopy. These two technologies were compared with respect to contrast, photobleaching, and sensitivity. It was found that WEFF microscopy produced images with a much higher contrast, lower photobleaching, and higher sensitivity. In addition, fine structures in the lipidic domains were observed for the first time.
