Coffee as a Staining Agent Substitute in Electron Microscopy
1st February 2026
To ensure that the tissue structures of biological samples are easily recognizable under the electron microscope, they are treated with a staining agent. The standard staining agent for this is uranyl acetate. However, some laboratories are not allowed to use this highly toxic and radioactive substance for safety reasons.
A research team at the Institute of Electron Microscopy and Nanoanalysis (FELMI-ZFE) at Graz University of Technology (TU Graz) has now found an environmentally friendly alternative: ordinary espresso.
Images of the samples treated with it were of equally good quality as images of comparative samples, which were prepared with uranyl acetate. The researchers have published their findings in the journal Methods.
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