Bioelectrodynamics is a branch of
medical physics
Medical physics deals with the application of the concepts and methods of physics to the prevention, diagnosis and treatment of human diseases with a specific goal of improving human health and well-being. Since 2008, medical physics has been incl ...
and
bioelectromagnetism
Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the e ...
which deals with rapidly changing
electric
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...
and
magnetic
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particle ...
fields in biological systems, i.e. high frequency
endogenous
Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell.
In contrast, exogenous substances and processes are those that originate from outside of an organism.
For example, es ...
electromagnetic phenomena in living cells. Unlike the events studied by the
electrophysiology
Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , '' -logia'') is the branch of physiology that studies the electrical properties of b ...
, the generating mechanism of bioelectrodynamic phenomenon is not connected with currents of ions and its frequency is typically much higher. Examples include vibrations of electrically polar intracellular structures and non-thermal emission of
photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
s as a result of
metabolic
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
activity.
Theories and Hypotheses
Plenty of theoretical work was published on theories and hypotheses describing generation of
electromagnetic field
An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical c ...
by living cells in very broad frequency range. The most influential one was once probably the Fröhlich's hypothesis of
coherence
Coherence, coherency, or coherent may refer to the following:
Physics
* Coherence (physics), an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference
* Coherence (units of measurement), a deriv ...
in biological systems introduced by
Herbert Fröhlich
Herbert Fröhlich (9 December 1905 – 23 January 1991) FRS was a German-born British physicist.
Career
In 1927, Fröhlich entered Ludwig-Maximilians University in Munich to study physics, and received his doctorate under Arnold Sommerfeld i ...
in the late 1960s. Despite the fact that experimental evidence for Fröhlich's hypothesis does not exist yet, numerical estimates indicate biological feasibility of at least Fröhlich's weak condensation.
Recent theoretical considerations predict generation of
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
electromagnetic field in cells as a result of vibrations of electrically polar intracellular structures, e. g.,
microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 an ...
s. Emission in optical part of
electromagnetic spectrum
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.
The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...
is usually attributed to
reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen () p ...
(ROS).
Experimental evidence
Bioelectrodynamic effects were experimentally proven in optical range of electromagnetic spectrum.
Spontaneous emission of photons by living cells, with intensity significantly higher than corresponds to emission by thermal radiation, was repeatedly reported by several authors over decades. These observations exhibit experimental simplicity and good reproducibility. Although non-thermal emission of photons from living cells is generally accepted phenomenon, much less is known about its origin and properties. On the one hand, it is sometimes attributed to
chemiluminescent
Chemiluminescence (also chemoluminescence) is the emission of light (luminescence) as the result of a chemical reaction. There may also be limited emission of heat. Given reactants A and B, with an excited intermediate ◊,
: + -> lozenge -> ...
metabolic reactions (including for instance
reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen () p ...
(ROS) ), on the other hand, some authors relate this phenomenon to far-from-equilibrium thermodynamics.
Indirect evidence exists on acoustic and radio frequencies; however, direct measurement of field quantities is missing. Pohl and others observed force effect on dielectric particles which were attracted to cells and repulsed from cells, respectively, depending on particles' dielectric constant. Pohl attributed this behavior to
dielectrophoresis
Dielectrophoresis (DEP) is a phenomenon in which a force is exerted on a dielectric particle when it is subjected to a non-uniform electric field.
This force does not require the particle to be charged. All particles exhibit dielectrophoretic ac ...
caused by electromagnetic field of cells. He estimated the frequency of this field as about hundreds of MHz. Other indirect evidence comes from the fact that mechanical vibrations were experimentally proven in very broad frequency range in cells. Since many structures in cells are electrically polar, they will generate electromagnetic field if they vibrate.
Controversy
As a question opened for decades, bioelectrodynamics was not always part of scientific mainstream and thus it was sometimes treated with poor scientific standards. This is particularly true for:
# - overestimation of the significance of experimental data obtained (Kucera argues that claims by several authors about direct measurement of cellular electromagnetic activity in radio-frequency band should be accepted with skepticism since technical properties of experimental setups have not even met criteria arising from optimistic theoretical biophysical predictions. Firstly, spatial resolution of used sensors was too low with respect to expected spatial complexity of electromagnetic field in cells. Secondly, the sensitivity of experimental setups was not high enough compared to power available in living cell.),
# - misinterpretation of experimental data (
Fritz-Albert Popp
Fritz-Albert Popp (11 May 1938 – 4 August 2018) was a German researcher in biophysics, particularly in the study of biophotons.
Biography
Popp was born in 1938 in Frankfurt. He has a diploma in Experimental Physics (1966, University Würzbur ...
's claim about
coherence
Coherence, coherency, or coherent may refer to the following:
Physics
* Coherence (physics), an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference
* Coherence (units of measurement), a deriv ...
of photo-emission from cells
[Popp FA (1999]
About the Coherence of Biophotons 1999
''Proceedings of an International Conference on Macroscopic Quantum Coherence'', Boston University. is based on statistical distribution of photon counts; however, this is not proof of coherence. Coherent emission (see
coherent states
In physics, specifically in quantum mechanics, a coherent state is the specific quantum state of the quantum harmonic oscillator, often described as a state which has dynamics most closely resembling the oscillatory behavior of a classical harmo ...
) has
Poisson distribution
In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if these events occur with a known co ...
, but Poisson distribution is not exclusively related only to coherent processes.) and
# - development of uncorroborated hypotheses .
See also
*
Medical physics
Medical physics deals with the application of the concepts and methods of physics to the prevention, diagnosis and treatment of human diseases with a specific goal of improving human health and well-being. Since 2008, medical physics has been incl ...
*
Bioelectromagnetism
Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the e ...
References
{{Reflist
External links
Groups
Bioelectrodynamics research team, Institute of Photonics and Electronics of the Czech Academy of Sciences, Czech Republic
Bioelectromagnetics
Electrodynamics