3.3. Scanning Electron Microscopy (SEM) Imaging of Bacterial Cells Exposed to IntegroPectins

Stationary grown cells of either P. aeruginosa or S. aureus strains were independently inoculated 1% (v/v) on fresh LB medium and grew for 2 h prior to their exposure (for 2 additional hours) to 15 mg mL⁻¹ of either lemon or grapefruit IntegroPectins. Then, bacterial cells were pelleted at 8000x g for 10 min, washed twice with sterile saline (0.9% w/v) solution, and resuspended in 2.5% (v/v) glutaraldehyde solution. The samples were stored overnight (ca. 18 h) at 4 °C to fix bacterial cells. The day after, bacterial cells were pelleted as described above, being then dehydrated through three washing steps (10 min each) with increasing concentration (30, 40, 50, 60, 70, 80, 90% v/v, and absolute) of ice-cold ethanol. Right after, the cells were opportunely diluted and deposited onto carbon-coated copper grids (300 mesh) and observed through an FEG-SEM FEI versa 3D microscope, using an accelerating voltage of 10kV, as previously described [75].