“The intensity of biophotons produced
by this mouse rapidly faded after death”
BIOCHEMILUMINESCENSE
https://en.wikipedia.org/wiki/Biophoton
https://en.wikipedia.org/wiki/Chemiluminescence
https://pubs.acs.org/doi/10.1021/acs.jpclett.4c03546
https://newscientist.com/living-things-emit-glow-snuffed-upon-death
All living things emit an eerie glow that is snuffed out upon death
by Alex Wilkins / 9 May 2025
“All living things, including humans, constantly emit a ghostly glow – and it appears to vanish almost as soon as we die. Monitoring this signal could one day help track forest health or even detect diseases in people. The existence of this barely perceptible glow has been controversial, but it is thought to be the result of a process called ultraweak photon emission. Mitochondria and other energy-producing machinery in our cells involve molecules gaining and losing energy, in turn emitting the equivalent of a few photons a second per square centimetre of skin tissue. However, these “biophotons” are extremely difficult to detect and disentangle from other biological processes or light sources, such as the radiation produced by any warm object.
Now, Daniel Oblak at the University of Calgary in Canada and his colleagues have isolated what happens to these biophotons when an animal dies, imaging ultraweak photon emission across an entire mouse before and after its death. “The fact that ultraweak photon emission is a real thing is undeniable at this point,” says Oblak. “This really shows that this is not just an imperfection or caused by other biological processes. It’s really something that comes from all living things.”
Oblak and his team used digital cameras that could detect single photons to produce two hour-long exposure images of four hairless mice, one before and one after death. The animals were kept at the same temperature to exclude heat as a factor and in a dark box to avoid light pollution. They found that biophoton emission significantly decreased after death across the whole mouse. They also took pictures of umbrella tree (Heptapleurum arboricola) leaves they had cut, and found that the plant’s injury repair mechanism increased biophoton emission, while various drugs applied to the plant surface, such as the numbing drug benzocaine, also appeared to do the same.
“Emissions of UPE from four umbrella tree leaves”
(Salari et al., J. Phys. Chem. Lett., 2025).
It isn’t surprising that biophotons stop being emitted when you die because they are a byproduct of metabolic cellular processes that cease after death, says Alasdair Mackenzie at the Central Laser Facility in Oxford, UK, and previous research has shown this for individual cells and smaller body parts. However, it hasn’t been done for a whole animal before, and because Oblak and his team have been careful to exclude other potential light sources, we can be confident that we are really seeing biophotons, says Mackenzie.
Michal Cifra at the Czech Academy of Sciences in Prague says the absence of biophotons after death is mainly due to the lack of blood flow around the body, because oxygen-rich blood is one of the key drivers of metabolism, which produces biophotons. If the blood had been kept artificially circulating, then they would still observe the same biophoton emission, he says. “It’s not related to the systemic liveliness, it’s related to the liveliness of the optically accessible tissue.” The technology could one day be used to monitor living tissue without performing invasive tests, or monitoring forest health from afar at night, says Oblak. “The nice thing about ultraweak photon emission is it’s a complete passive monitoring process.”
ULTRAWEAK PHOTON EMISSIONS
https://nature.com/articles/s41598-024-80469-0
https://pmc.ncbi.nlm.nih.gov/articles/PMC9981976/
https://frontiersin.org/journals/physiology/articles/10.3389/fphys.2024.1348915/full
https://phys.org/news/2025-05-emit-faint-extinguishes-death.html
Living beings emit a faint light that extinguishes upon death
by Sanjukta Mondal / May 17,2025
“The light of someone’s life might not be just another person, but light in the literal sense. According to a recent study by researchers from University of Calgary, every living system emits light without requiring external excitation due to a biological phenomenon known as ultraweak photon emission (UPE). In mice, UPE was linked to vitality as live mice emitted significantly higher UPE intensity compared to recently dead mice.
In plants, however, UPE varied depending on exposure to stress factors like temperature changes, injury and chemical treatments, as reported in The Journal of Physical Chemistry Letters. Living organisms are compact biochemical labs where complex chemical reactions keep the system up and running. Cellular metabolism, a series of chemical reactions that fuel life-sustaining processes, produces a group of highly reactive oxygen-containing molecules produced as a natural byproduct called reactive oxygen species or ROS.
Studies suggest that ROS plays a central role in UPE. When organisms encounter stress, they activate biochemical pathways that generate ROS, which act as signaling molecules in the cellular stress response. However, excessive ROS production can lead to oxidative stress, overwhelming the cell’s antioxidant defenses. This oxidative stress can induce electron excitation and transfer processes, ultimately resulting in UPE.
Unlike bioluminescence, which produces high-intensity light visible to the naked eye, UPE, also known as biophoton emission, is a spontaneous release of extremely low-intensity light that is invisible to the human eye and falls within the spectral range of 200–1,000 nm. This faint light has been detected in a wide range of life forms—from single-celled organisms and bacteria to plants, animals, and even humans. Despite being so widely observed, not much is known about the impact of mortality and stress factors on UPE.
Furthermore, the ability to monitor UPE in response to stress factors and injuries could be a powerful, non-invasive tool for diagnostics and medical research. The researchers used advanced imaging techniques to explore the biological significance of UPE by directly comparing emissions in living versus dead animals, while also systematically visualizing the effects of temperature, injury, and chemical treatments on UPE in plants.
“High-sensitivity EMCCD and CCD cameras for
imaging UPE in dark, controlled environments”
To carry out the experiments, the researchers designed ultradark enclosures to eliminate environmental light interference. They then used an Electron-Multiplying Charge-Coupled Device (EMCCD) camera for imaging plants and a Charge-Coupled Device (CCD) camera with IVIS system to image UPE changes in mice. The results revealed that despite both groups having the same body temperature of 37°C, the live mice showed robust emissions, whereas the UPE from the euthanized mice was nearly extinguished.
“Effect of the temperature on the intensity of UPE in plants”
In plants, an increase in temperature and injuries led to an increase in UPE intensity. Injured sites were consistently brighter than uninjured parts—a change in the former was observed once the site received any chemical treatment. This study establishes that UPE can act as a sensitive indicator of vitality in animals and of stress responses in plants. The researchers suggest that these findings could catalyze the application of UPE imaging as a non-invasive technique for both basic biological research and clinical diagnostics.”
More information: V. Salari et al, Imaging Ultraweak Photon Emission from Living and Dead Mice and from Plants under Stress, The Journal of Physical Chemistry Letters (2025). DOI: 10.1021/acs.jpclett.4c03546