  In electron microscopy, charging of non-conductive biological samples by
focused electron beams hinders their high-resolution imaging. Gold or platinum
coatings have been commonly used to prevent such sample charging, but it
disables further quantitative and qualitative chemical analyses by energy
dispersive spectroscopy (EDS). Here we report that graphene-coating on
biological samples enables non-destructive high-resolution imaging by scanning
electron microscopy (SEM) as well as chemical analysis by EDS, utilizing
graphene's transparency to electron beams, high conductivity, outstanding
mechanical strength, and flexibility. We believe that the graphene-coated
imaging and analysis would provide us a new opportunity to explore various
biological phenomena unseen before due to the limitation in sample preparation
and image resolution, which will broaden our understanding on the life
mechanism of various living organisms.
