Skip to main content
It is well known that analysis using transmission electron microscopes (TEM) yields very high resolution images of thin specimens. However, the applicability of TEM analysis is not universal due to the requirement that a high internal vacuum is required. This high vacuum precludes the TEM study of living specimens or specimens in a gas or liquid environment. In order to tackle this problem, L. Marton of Universite Libre in Brussels, Belgium was the first to design an environmental cell (E-cell) in 1935 that was sealed in the tip of a TEM sample holder. Marton's design included two 0.5 μm aluminum foils as upper and lower windows sandwiching a biological sample to sustain a living environment. The electron transparent windows permitted the confined biological objects to be imaged in TEM mode. Since then, environmental TEM (E-TEM) has received increasing attention from biological scientists and eventually from materials scientists as well.