Characterization of Pseudomonas Aeruginosa Biofilms Grown on Different Substrates by Means of FT-IR Spectroscopy

Fourier transform infrared spectroscopy (FT-IR) is a vibrational technique largely adopted for the study of bacterial biofilms. FT-IR is a non-destructive method allowing multiple analyses of the same biofilm. Pseudomonas aeruginosa represents a class of bacteria largely investigated since it is an opportunistic pathogen, and it is now considered a primary infectious agent, especially for its ability to form multi-resistant biofilms. In the present investigation, we aimed to characterize P. aeruginosa biofilms grown on different substrates to better define the experimental conditions more useful for investigating the interaction of these biofilms with external agents. In particular, we investigated biofilms grown on Teflon membranes, CaF2 windows, and MirrIR slides (specific reflection FT-IR spectroscopy microscope slides). Different geometries were used for collecting spectra using the microscope stage of a Perkin Elmer Spectrum One spectrometer and a Universal Attenuated Total Reflection (UATR) device. Multiple acquisitions of spectra were conducted, and statistical criteria were applied for monitoring and comparing them. The positive and negative aspects of the different examined substrates for biofilm formation and acquisition modes are presented and discussed.