Figure 4. Enhanced fluorescence contrast of actin filament in nanochannel.

a) An actin filament labelled with RhPh was imaged using a TRITC filter. The approximately l = 2.5 μm long filament passed over the w = 2 μm wide Au lines, with d₂ = 240 nm (see Fig. 3), and there became brighter. b) fluorescence profile along the actin-guiding channel (dashed white lines in (a)) and below channel region (red line in (a)). A single pixel line along the centre of the channel was used to create the profiles shown.