A biophoton (from the Greek βίος meaning "life" and φῶς meaning "light") is a photon of non-thermal origin in the visible and ultraviolet spectrum emitted from a biological system. Emission of biophotons is technically a type of bioluminescence, but the latter term is generally reserved for higher luminance luciferin/luciferase systems. The term biophoton used in this narrow sense should not be confused with the broader field of biophotonics, which studies the general interaction of light with biological systems. The typical observed radiant emittance of biological tissues in the visible and ultraviolet frequencies ranges from 10−19 to 10−16 W/cm2 (approx 1-1000 photons/cm2/second). This light intensity is much weaker than that seen in the perceptually visible and well-researched phenomenon of normal bioluminescence but is detectable above the background of thermal radiation emitted by tissues at their normal temperature. While detection of biophotons have been reported by several groups,[1][2][3] hypotheses that such biophotons indicate the state of biological tissues and facilitate a form of cellular communication are controversial. Their supposed discoverer, Alexander Gurwitsch, was awarded the Stalin Prize.[4] Detection and measurementBiophotons may be detected with photomultipliers or by means of an ultra low noise CCD camera to produce an image, using an exposure time of typically 15 minutes for plant materials.[5][6] The typical observed radiant emittance of biological tissues in the visible and ultraviolet frequencies ranges from 10−19 to 10−16 W/cm2.[7] Proposed physical mechanismsChemi-excitation via oxidative stress by reactive oxygen species and/or catalysis by enzymes (i.e., peroxidase, lipoxygenase) is a common event in the biomolecular milieu.[8] Such reactions can lead to the formation of triplet excited species, which release photons upon returning to a lower energy level in a process analogous to phosphorescence. That this process is a contributing factor to spontaneous biophoton emission has been indicated by studies demonstrating that biophoton emission can be attenuated by depleting assayed tissue of antioxidants[9] or by addition of carbonyl derivatizing agents.[10] Further support is provided by studies indicating that emission can be increased by addition of reactive oxygen species.[11] PlantsImaging of biophotons from leaves has been used as a method for Assaying R Gene Responses. These genes and their associated proteins are responsible for pathogen recognition and activation of defense signaling networks leading to the hypersensitive response,[12] which is one of the mechanisms of the resistance of plants to pathogen infection. It involves the generation of reactive oxygen species (ROS) which have crucial roles in signal transduction or as toxic agents leading to cell death.[13] AnimalsEnhanced biophoton emission along with the growth of tumor has been observed in mice and biophoton emission has been correlated with EEG activity in rats.[14] Speculative theories on the biological function of biophotonsAcademic speculationHypothesized involvement in cellular communicationIn the 1970s the then assistant professor Fritz-Albert Popp and his research group at the University of Marburg (Germany) showed that the spectral distribution of the emission fell over a wide range of wavelengths, from 200 to 800 nm. Popp proposed that the radiation might be both semi-periodic and coherent. Russian, German, and other biophotonics experts, often adopting the term "biophotons" from Popp, have theorized, like Gurwitsch, that they may be involved in cell functions, such as mitosis, or even that they may be produced and detected by the DNA in the cell nucleus. In 1974 Dr. V.P. Kaznacheyev announced that his research team in Novosibirsk had detected intercellular communication by means of these rays.[15] Kaznacheyev and his team carried out about 12 000 experiments up to the 1980s. Details of experiments are described in his book (in Russian).[16] Proponents additionally claim that studies have shown that injured cells will emit a higher biophoton rate than normal cells and that organisms with illnesses will likewise emit a brighter light, which has been interpreted as implying a sort of distress signal. These ideas tend to support Gurwitsch's original idea that biophotons may be important for the development of larger structures such as organs and organisms. However, injured cells are under higher levels of oxidative stress, which ultimately is the source of the light, and whether this constitutes a "distress signal" or simply a background chemical process is yet to be demonstrated.[17] The difficulty of teasing out the effects of any supposed biophotons amid the other numerous chemical interactions between cells makes it difficult to devise a testable hypothesis. Most organisms are bathed in relatively high-intensity light that ought to swamp any signaling effect, although biophoton signaling might manifest through temporal patterns of distinct wavelengths or could mainly be used in deep tissues hidden from daylight (such as the human brain, which contains photoreceptor proteins). A 2010 review article[18] discusses various published theories on this kind of signaling and identifies around 30 experimental scientific articles in English in the past 30 years which show evidence of electromagnetic cellular interactions. PseudoscienceMany claims with no scientific proof have been made for cures and diagnosis using biophotons.[19] An appraisal of "biophoton therapy" by the IOCOB[20] notes that biophoton therapy claims to treat a wide variety of diseases, such as malaria, Lyme disease, multiple sclerosis, schizophrenia, and depression, but that all these claims remain unproven. Dr. F.Popp, a researcher who investigates biophoton emission, concludes that the complexity of cellular chemical reactions in living systems is such that it excludes the possibility to create a machine to selectively heal systems using biophotons, and that "there are always charlatans who believe in these miracles."[20][21] Quantum medicineThis claims:
A review of the American Academy of Quantum Medicine[19] concludes that many quantum medicine practitioners are not licensed as health care professionals, that quantum medicine uses scientific terminology but is nonsense, and that the practitioners have created "a nonexistent 'energy system' to help peddle products and procedures to their clients." Esoteric claimsIt has been proposed that biophotons play an important role in consciousness.[23] See alsoNotes
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