Biophoton

A biophoton (from the Greek βιο meaning "life" and φωτο meaning "light") is a photon of light emitted in some fashion from a biological system. From a scientific point of view, there is no difference between such a photon and a photon emitted by any other physical process. One might then argue that it is more correct to attach the attribute biological to the emission process, as in bioluminescence, because no specific biologicalness can be attributed to the photons themselves, once they are emitted. However, the term "bioluminescence" is generally reserved for higher intensity luciferin/luciferase systems, while "biophoton emission" refers to the more general phenomena of low-intensity photon emission from living systems.

It is universally accepted that biological systems emit photons. The term "biophoton", however, has come to be associated in particular with photons emitted by certain processes that are not yet well understood. Loose terminology has caused some confusion as to what is actually known about the phenomena of emission of photons from biological systems. There are several associated definitions of the term biophoton, some of which are unscientific, and some of which generate confusion among those who are not scientists.

Scientific usage

In general scientific usage, "biophotonics" is the science, research and applications of photons in their interactions within and on biological systems. Topics of research pertain more generally to basic questions of biophysics and related subjects (for example, the regulation of biological functions, cell growth and differentiation, connections to so-called delayed luminescence, and spectral emissions in supermolecular processes in living tissues, etc.).

The term biophoton is used more specifically to denote those photons that are detected by biological probes as part of the general weak electromagnetic radiation of living biological cells. Further terms in science for this phenomenon are ultra-weak bioluminescence, dark luminescence, and ultraweak chemiluminescence.

The typical magnitude of "biophotons" in the visible and ultraviolet spectrum ranges from a few up to several hundred photons per second per square centimeter of surface area. This is much weaker than in the openly visible and well-researched phenomenon of normal bioluminescence, but much stronger than in the thermal, or black body radiation that so-called perfect black bodies demonstrate.

Very vaguely, though qualitatively, this amount of light has been compared to that observed from a candle viewed at a distance of 10 kilometers. The detection of these photons has been made possible due to the development of sensitive modern photomultipliers. Because of this, the existence of this radiation is no longer disputed, while its interpretation is still very much an open question.

Scientifically, this does not mean that the biophoton is any different from a normal photon, only that the way in which it is generated might be unique to biological systems. Though this far-reaching research question is often implicated in the usage of the term biophoton, most biologists have not yet seen the evidence that would justify such an implication (see below).

History

In the 1920s, the Russian embryologist Alexander Gurwitsch reported "ultraweak" photon emissions from living tissues in the UV-range of the spectrum. He named them "mitogenetic rays", because he assumed that they had a stimulating effect on cell division rates of nearby tissue. However, common biochemical techniques as well as the fact that cell growth can generally be stimulated and directed by radiation, though at much higher amplitudes, evoked a general skepticism about Gurwitsch´s assumption. Consequently, the mitogenetic radiation hypothesis was largely ignored.

However, after the end of World War II some Western scientists such as Colli (Italy), Quickenden (Australia), Inaba (Japan) returned to the subject of "mitogenetic radiation", but referred to the phenomenon as "dark luminescence", "low level luminescence", "ultraweak bioluminescence", or "ultraweak chemiluminescence". Their common basic hypothesis was that the phenomenon was induced from rare oxidation processes and radical reactions. While they added some general chemistry to the hypothesis of photon emission, they did not address the more mysterious assumption of Gurwitsch that the photons themselves, forming the so-called mitogenic rays, stimulated cellular responses.

In the 1970s the then assistant professor Fritz-Albert Popp, and his research group, at the University of Marburg (Germany) offered a slightly more detailed analysis of the topic. They showed that the spectral distribution of the emission fell over a wide range of wavelengths, from 200 to 800 nm. Popp further proposed the surprising and unprecedented hypothesis that the radiation might be both semi-periodic and coherent in the quantum mechanical sense. This hypothesis is still regarded as an outsider hypothesis in the scientific community.

A model for random emissions

In statistical mechanics and modern biology, the favored model of many systems has to do with ensemble phenomena due to a large number of interacting molecules, etc. In chaos theory, for example, it is often suggested that the appearance of randomness in systems is due to a lack of understanding of the larger scheme under which the system responds. Regardless, this has led many who deal with large systems to employ statistics to explain seemingly random events as outlying effects in probability distributions. In this way, since there is normal and openly visible bioluminescence in both many bacteria and other cells (see bioluminescence article) which emit light by particular chemical reactions due to proteins, then it can be inferred that due to the extremely small number of photons in ultra-weak bioluminescence (the numbers given above correspond to roughly a single photon per cell per month, assuming a typical cell diameter of 10 micrometers) that these emissions are simply a random by-product of cellular metabolism, in much the same way that solar flares on some coarse level are thought of as simply random byproducts of nuclear fusion on the surface of stars.

Slightly more specifically, cellular metabolism is thought to occur in a chain of steps (which leads to dynamic cycles) in which each step involves small energy exchanges (See ATP). Thus, due to a certain degree of randomness according to the laws of thermodynamics (or statistical mechanics), it must then be expected that, very rarely, some irregular steps can occur. These are referred to as "outlying states." Thus due to occasional physiochemical energy imbalance, a photon is occasionally emitted.

According to this model there is no need to adopt a mysterious hypothesis, like the mitogenetic radiation hypothesis. But, of course, it cannot exclude it.

Hypothesized involvement in cellular communication

In the absence of definite knowledge about the mechanisms that produce these photons, some of the groups around F.A. Popp in Neuss/Germany, who adopted the term "biophotons", have speculated that they may be involved in various cell functions, such as mitosis, or even that they may be produced and detected by the DNA in the cell nucleus. These speculations have not yet resulted in a testable hypothesis.

Some groups have further speculated that these emissions may be part of a system of cell-to-cell communication, which may be of greater complexity than the modes of cell communication already known, such as chemical signaling. These ideas even suggest that biophotons may be important for the development of larger structures, such as organs and organisms.

Studies have shown that injured cells will let off a higher photon rate than normal cells, and organisms with illnesses will likewise emit a brighter light, implying a sort of distress signal being given off. ^* It's possible that this minor form of communication first became common as single-cell organisms began to cooperate to form complex organisms, using biophotons as a less effective neural system.

References

J.J.Chang and F.A.Popp: "Biological Organization: A Possible Mechanism based on the Coherence of Biophotons". In: Biophotons (J.J.Chang, J.Fisch and F.A.Popp, eds.), Kluwer Academic Publisher, Dordrecht-London 1998, pp. 217-227.
A.G. Gurwitsch: "Über Ursachen der Zellteilung". Arch. Entw. Mech. Org. 51 (1922), 383-415.
H.Fröhlich: "Long Range Coherence and Energy Storage in Biological Systems". Int. J. Quant. Chem. 2 (1968), 641-649.
Radiofrequency and microwave radiation of biological origin – their possible role in biocommunication. Psychoenergetic Systems, Vol.3 (1979), pp.133-154.
F.A.Popp, Q.Gu, and K.H.Li: Biophoton emission: Experimental background and theoretical approaches. Modern Physics Letters B8:1269-1296.
Ruth,B. and F.A.Popp: Experimentelle Untersuchungen zur ultraschwachen Photonenemission biologischer Systeme. Z.Naturforsch.31
Ruth, B. In: Electromagnetic Bio-Information (F.A.Popp, G.Becker, H.L.König and W.Peschka, eds.), Urban &Schwarzenberg, München-Wien-Baltimore 1979. This paper contains the historical background of biophotons.
Popp, F.A.: Biophotonen. Ein neuer Weg zur Lösung des Krebsproblems. Schriftenreihe Krebsgeschehen, Vol.6, Verlag für Medizin, Dr.Ewald Fischer,Heidelberg 1976.
Popp,F.A., Ruth,B., Bahr,W., Böhm,J., Grass,P., Grolig,G., Rattemeyer,M., Schmidt,H.G., and Wulle,P.:Emission of visible and ultraviolet radiation by active biological systems. Collective Phenomena (Gordon&Breach), Vol.3 (1981), pp.187-214.
Rattemeyer, M., Popp,F.A., and Nagl,W.: Evidence of photon emission from DNA in living systems. Naturwissenschaften 68 (1981), 572-573.
Popp,F.A., Gurwitsch,A.A., Inaba, H., Slawinski, J., Cilento G., van Wijk, R., Chwirot B., and Nagl,W.: Biophoton Emission (Multi-Author Review), Experientia 44 (1988), 543-600.
Popp,F.A., Gu,Q., and Li, K.H.:Biophoton Emission: Experimentell Background and Theoretical Approaches. Modern Physics Letters B8 (1994), 1269-1296.
Chang, J.J., Fisch, J., and Popp,F.A.:Biophotons. Kluwer Academic Publishers, Dordrecht-Boston-London 1998.
Bajpai, R.P., Popp,F.A., van Wijk, R., Niggli,H., Beloussov, L.V., Cohen,S., Jung, H.H., Sup-Soh, K., Lipkind, M., Voiekov, V.L., Slawinski, J., Aoshima, Y., Michiniewicz, Z., van Klitzing,L., Swain,J.:Biophotons (Multi-Author-Review). Indian Journal of Experimental Biology 41 (2003), Vol 5, 391-544.
Popp,F.A., Yan,Yu: Delayed luminescence of biological systems in terms of coherent states. Physics Letters A 293 (2002), 93-97.
Yan, Y., Popp,F.A., Sigrist,S., Schlesinger,D., Dolf,A., Yan,Z., Cohen,S., and Chotia, A.:Further analysis of delayed luminescence of plants, Journal of Photochemistry and Photobiology 78 (2005),229-234.

External links

Marco Bischof's Bibliography on biophoton research and related subjects
G.J. Hyland's Fundaments of Coherence in Biology
Photonics TechnologyWorld, "Our Bodies, Our Photons". October 1998 Edition.
Tilbury, Gregg, Percival, Matich: "Ultraweak Cheminluminescence from Human Blood Plasma"
F.A. Popp, et al, Recent Advances in Biophoton Research and its Application
F.A. Popp, Biophotonics
International Institute of Biophysics

Biology | Photonics | Metaphysics | Pseudophysics | Bioluminescence