Researchers from Seoul National University and the University of Manchester have found that a graphene coating on biological samples helps dissipate the charge build-up that tends to occur on the surface of these samples during non-destructive electron microscopy imaging. Such build-ups are often damaging and prevent high-resolution images from being obtained.
Currently used gold or platinum coatings mean that researchers cannot obtain high-resolution images of the samples or perform further quantitative and qualitative chemical analyses with techniques such as energy dispersive spectroscopy (EDS). Now, the research team discovered that a layer of graphene on biological samples can dissipate the charge accumulation on the non-conducting surfaces of biological samples thanks to the high electrical conductivity of graphene. The researchers explain that as soon as excessive charges appear on the sample surfaces, the graphene membrane provides conducting channels for these charges to disappear quickly and so allows to obtain high-resolution EM images. Furthermore, the high thermal conductivity of graphene allows it to dissipate excess heat produced by the high-energy electrons in the microscope, thus preventing thermal damage or deformation of biological specimens as well.