  Due to its ultrahigh electron transmissivity in a wide electron energy range,
molecular impermeability, high electrical conductivity and excellent mechanical
stiffness the suspended graphene membranes appear to be a nearly ideal window
material for in situ (in vivo) environmental electron microscopy of nano- and
mesoscopic objects (including bio-medical samples) immersed in liquids and/or
in dense gaseous media. In this communication, taking advantage of little
modification of the graphene transfer protocol on to metallic and SiN
supporting orifices, the reusable environmental cells with exchangeable
graphene windows have been designed. Using colloidal gold nanoparticles (50 nm)
dispersed in water as model objects for scanning electron microscopy in
liquids, the different imaging conditions through graphene membrane have been
tested. The limiting factors for electron microscopy in liquids such as
electron beam induced water radiolysis and damage of graphene membrane at high
electron doses were discussed.
