A Thin Polymer Membrane, the NanoSuit^®, for the Observation of Living and Wet Organisms in High-Vacuum Scanning Electron Microscope

Scanning electron microscopy (SEM) has become an essential tool for observing the biological materials, however, various complex procedures preclude observation of living organisms to date. Here we present a new method to observe living organisms by a SEM. We observed the active movements of animals in vacuo (10−5—10−7 Pa) by coating them with a thin polymer membrane, NanoSuit®, made by polyoxyethylene (20) sorbitan monolaurate and found that the surface fine structure of the living organism is very different from that of traditionally fixed samples. After observation of the larvae of mosquitos, despite the high vacuum, we could rear them in normal culture conditions. We also found that the NanoSuit® and self-standing biocompatible films were able to produce by plasma polymerization from various monomer solutions. Our method will be useful for numerous applications, particularly in the electron microscopic observation of life sciences.