Figure 5. In situ detection and imaging of pyocyanin produced by P. aeruginosa PA14 biofilms grown on mesostructured Au@TiO₂ thin films.

a) Optical image of the bacterial biofilm (dark central region) captured with the Raman microscope and superimposed pyocyanin SERRS mapping (418 cm⁻¹) acquired with excitation laser wavelength of 785 nm, 5× objective and a laser power of 0.94 mW for 10 s. b) Graphical representation of the SERRS intensity mapping shown in a. c) Representative SEM images of bacterial biofilm formed on Au@TiO₂.