I am looking for peoples' experiences in studying biofilms with Environmental Scanning Electron Microscope. Was preservation needed, or did you find good results without?
Fixation may may be useful - it helps bacteria/cells to keep their shape in a harsh environment of ESEM. I am not a big fan of observation of wet biological specimens (if they are not plants) with ESEM, because you have either water on surface (and see smooth water surface) or they will be dry and deformed. But you may have some success with tough biofilms, such as dental plaque. If bacteria in biofilm is well attached I would rather use standard biological protocol - fixation, dehydration, etc., but if you are not too choosy about quality of micrographs, you certainly may have some success even without special steps in specimen preparation.