Investigation of the effects of nanoparticles and extracellular vesicles on cells requires direct observation and analysis at nano-level resolution, both in vitro and in living cells. Recently, we have developed a scanning electron assisted dielectric microscope (SE-ADM) that enables the direct observation of living cells and organic materials without staining or fixation. Here, we present an overview of SE-ADM and scanning electron impedance microscopy including our recent results analyzing the effects of extracellular particles on biological specimens. Our system can be easily used to examine unstained biological specimens including bacteria, viruses and protein complexes. Furthermore, it can be used for diverse liquid samples across a broad range of scientific fields, e.g. nanoparticles, nanotubes and organic and catalytic materials.