Jan 10, 2026 04:20 PM
https://www.psypost.org/scientists-just-...or-coffee/
EXCERPTS: Researchers have identified a common household beverage as an effective, non-toxic substitute for the hazardous chemicals traditionally used in high-resolution microscopic imaging. A new study demonstrates that ordinary espresso coffee can stain biological samples for electron microscopy with clarity and detail comparable to industry-standard radioactive solutions. The findings were published in the journal Methods.
[...] The current “gold standard” for this process is a chemical called uranyl acetate. It is a salt derived from uranium. It is exceptionally effective at binding to biological lipids and proteins, providing sharp definition to cell membranes and DNA.
However, uranyl acetate comes with severe downsides. It is both highly toxic to the kidneys and chemically radioactive. The use of such dangerous material requires strict safety protocols, expensive waste disposal, and complex regulatory paperwork.
Some laboratories are even banned from possessing it entirely. Consequently, the scientific community has been searching for a “green” alternative that is safe, cheap, and effective. This search led a team of researchers in Austria to the kitchen break room.
Claudia Mayrhofer, a specialist in ultramicrotomy at the Graz Centre for Electron Microscopy, spearheaded the investigation [...] Mayrhofer noticed that coffee left in a cup for too long created persistent rings that were difficult to clean. She hypothesized that the compounds responsible for these stubborn stains might also bind effectively to biological tissues.
[...] The visual results were immediate and striking. The samples treated with the espresso solution produced high-quality images. The mitochondrial membranes were clearly visible and well-defined.
When analyzed with the objective software, the coffee stain performed admirably. Mayrhofer noted the success of the household beverage in the press release. “Espresso provided comparatively very good contrast values, in some cases they were even better than with uranyl acetate,” she explained.
[...] Furthermore, coffee poses no health risk to the scientists handling it. It requires no special ventilation, radiation shielding, or government licenses. It simplifies the workflow of the laboratory considerably. ... Despite being lighter, the density of the coffee stain was sufficient to create the necessary image. This challenges the assumption that only heavy metals can serve as effective electron microscopy stains. It opens the door to organic chemistry solutions.
There are, of course, caveats to this research. The study focused specifically on zebrafish mitochondria. Biological tissues vary greatly in their chemical composition. [...] Validation across a wider range of biological specimens is necessary... (MORE - missing details)
EXCERPTS: Researchers have identified a common household beverage as an effective, non-toxic substitute for the hazardous chemicals traditionally used in high-resolution microscopic imaging. A new study demonstrates that ordinary espresso coffee can stain biological samples for electron microscopy with clarity and detail comparable to industry-standard radioactive solutions. The findings were published in the journal Methods.
[...] The current “gold standard” for this process is a chemical called uranyl acetate. It is a salt derived from uranium. It is exceptionally effective at binding to biological lipids and proteins, providing sharp definition to cell membranes and DNA.
However, uranyl acetate comes with severe downsides. It is both highly toxic to the kidneys and chemically radioactive. The use of such dangerous material requires strict safety protocols, expensive waste disposal, and complex regulatory paperwork.
Some laboratories are even banned from possessing it entirely. Consequently, the scientific community has been searching for a “green” alternative that is safe, cheap, and effective. This search led a team of researchers in Austria to the kitchen break room.
Claudia Mayrhofer, a specialist in ultramicrotomy at the Graz Centre for Electron Microscopy, spearheaded the investigation [...] Mayrhofer noticed that coffee left in a cup for too long created persistent rings that were difficult to clean. She hypothesized that the compounds responsible for these stubborn stains might also bind effectively to biological tissues.
[...] The visual results were immediate and striking. The samples treated with the espresso solution produced high-quality images. The mitochondrial membranes were clearly visible and well-defined.
When analyzed with the objective software, the coffee stain performed admirably. Mayrhofer noted the success of the household beverage in the press release. “Espresso provided comparatively very good contrast values, in some cases they were even better than with uranyl acetate,” she explained.
[...] Furthermore, coffee poses no health risk to the scientists handling it. It requires no special ventilation, radiation shielding, or government licenses. It simplifies the workflow of the laboratory considerably. ... Despite being lighter, the density of the coffee stain was sufficient to create the necessary image. This challenges the assumption that only heavy metals can serve as effective electron microscopy stains. It opens the door to organic chemistry solutions.
There are, of course, caveats to this research. The study focused specifically on zebrafish mitochondria. Biological tissues vary greatly in their chemical composition. [...] Validation across a wider range of biological specimens is necessary... (MORE - missing details)