At a Glance
- Researchers have discovered that all living organisms emit a faint, invisible light called ultraweak photon emission, which provides insights into biological vitality and stress responses.
- Unlike visible bioluminescence, UPE is linked to low-intensity biochemical reactions and is triggered by reactive oxygen species produced during cellular metabolism.
- Using advanced imaging tools, scientists observed that live mice emitted significantly more UPE than dead ones and that stressed or injured plants showed elevated UPE levels, especially at affected sites.
- These findings suggest that UPE is sensitive to physiological changes and could serve as a real-time, non-invasive indicator of health in animals and plants.
- UPE imaging offers a new tool for assessing stress and vitality in living systems, with potential future applications in medicine, agriculture, and environmental monitoring.
Researchers have uncovered a fascinating biological phenomenon in which living organisms emit light, even without external excitation. This ultraweak photon emission (UPE) light is a very low-intensity light that can be detected in all living systems, from single-celled organisms to humans. In a recent study, scientists used advanced imaging technology to track the UPE from various living organisms, including mice and plants. Their findings, published in The Journal of Physical Chemistry Letters, show that UPE can provide insight into the vitality of animals and how plants respond to stress.
UPE is distinct from bioluminescence, which involves organisms emitting visible light that can be seen with the naked eye. Instead, UPE is a faint, invisible light that falls in the 200–1,000 nm wavelength range. While bioluminescence results from high-intensity reactions, UPE occurs at much lower intensities and is associated with the biochemical reactions inside living organisms. One important factor contributing to UPE is the production of reactive oxygen species (ROS), which are byproducts of cellular metabolism. When organisms experience stress, ROS levels rise, leading to UPE due to electron excitation and transfer within the cells.
In their study, the researchers focused on how UPE varies in response to factors such as the health of an organism and stress factors like temperature, injury, and chemical treatments. By using Electron-Multiplying Charge-Coupled Device (EMCCD) cameras and Charge-Coupled Device (CCD) cameras, the team could capture detailed images of UPE in living and dead mice and plants. The results were striking: live mice exhibited much higher UPE emissions than dead mice, even when both groups had the same body temperature. In plants, UPE intensity increased when subjected to higher temperatures or injuries, and the intensity was significantly higher at the injury sites.
This study suggests that UPE could be a valuable tool for noninvasive diagnostics in medical and ecological research. Since UPE is sensitive to changes in vitality and stress, it could be used to monitor the health of plants and animals in real-time. UPE imaging could open up new opportunities for research in medicine, agriculture, and environmental science by providing a way to observe these biological processes without the need for invasive procedures.
References
- Salari, V., Seshan, V., Frankle, L., England, D., Simon, C., & Oblak, D. (2025). Imaging ultraweak photon emission from living and dead mice and from plants under stress. The Journal of Physical Chemistry Letters, 16(17), 4354–4362. https://doi.org/10.1021/acs.jpclett.4c03546
- Mondal, S. & Phys.org. (2025, May 17). Living beings emit a faint light that extinguishes upon death, according to a new study. Phys.Org; Phys.org. https://phys.org/news/2025-05-emit-faint-extinguishes-death.html
