of phosphate buffered saline (PBS;
pH D 7.4, sterilized after preparation). Sucrose, sodium
cacodylate trihydrate approx. 98 wt%, glutaraldehyde solution
(50 wt% in water) and methanol anhydrous 99.8 wt%
(Sigma-Aldrich) were used to fix and dehydrate the cells
before visualization by scanning electron microscopy (SEM).