Oscillations of ultra-weak photon emission from cancer and non-cancer cells stressed by culture medium change and TNF-α

Abstract

Cells spontaneously emit photons in the UV to visible/near-infrared range (ultra-weak photon emission, UPE). Perturbations of the cells' state cause changes in UPE (evoked UPE). The aim of the present study was to analyze the evoked UPE dynamics of cells caused by two types of cell perturbations (stressors):(i) a cell culture medium change, and (ii) application of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α). Four types of human cell lines were used (squamous cell carcinoma cells, A431; adenocarcinomic alveolar basal epithelial cells, A549; p53-deficient keratinocytes, HaCaT, and cervical cancer cells, HeLa). In addition to the medium change, TNF-α was applied at different concentrations (5, 10, 20, and 40 ng/mL) and UPE measurements were performed after incubation times of 0, 30, 60, 90 min, 2, 5, 12, 24, 48 h. It was observed that (i) the change of cell culture medium (without added TNF-α) induces a cell type-specific transient increase in UPE with the largest UPE increase observed in A549 cells, (ii) the addition of TNF-α induces a cell type-specific and dose-dependent change in UPE, and (iii) stressed cell cultures in general exhibit oscillatory UPE changes.Cells and tissues spontaneously emit photons in the UV to visible/near-infrared spectral range (approx. 200-1300 nm) even without photoexcitation (for a review see [1][2][3][4] ). This spontaneous ultra-weak photon emission (UPE) with an intensity in the order of 10 1 -10 4 photons/s cm 2 3 is not thermal radiation 1 , but considered to be mainly due to the de-excitation of energetically excited species (atoms, molecules) to a deeper energy level that is accompanied by the emission of photons. The energetic state of a molecule of atom (E total ) is, according to the Born-Oppenheimer approximation, given as E total = E electronic + E vibrational + E rotational + E nuclear , with E electronic the electronic energies (i.e., kinetic energies, electron-nuclear attraction as well as interelectronic and internulear repulsive forces), E vibrational the vibrational energies, and E nuclear the nuclear spin energy. Energy transitions of atoms or molecules are quantized involving the resonant absorption of incident energy and the subsequent quantized emission of it. In case of UPE, the excited energy levels involved refer to transitions regarding changes in E vibrational and E rotational , associated with luminescence in the UV-IR optical spectrum. According to the conventional view, the energetically excited species are formed by oxidation reactions caused by radical or non-radical reactive oxygen (ROS) and nitrogen (RNS) species with lipids, proteins and nucleic acids 1,5 . Especially the UPE in the visible/near-infrared region can be attributed to lipid peroxidation, protein and nucleic acid oxidation. As summarized nicely by Pospíšil et al. 5 the chain reactions leading to UPE can be initiated by the oxidation of biomolecules that yield peroxyl and alkoxyl radicals. These radicals then recombine/cyclize to form dioxetanes or tetraoxides, whic...

Stochastic light concentration from 3D to 2D reveals ultraweak chemi- and bioluminescence

“…Our observation of the spontaneous luminescence of S. cerevisiae yeast cells is congruent with a series of reports that clearly demonstrate that most cells and tissues including yeasts 15 , 18 – 22 do spontaneously emit an ultraweak bioluminescence related to their oxidative metabolism and to basic mechanisms of radical-based chemiluminescence 15 , 19 , 22 , 23 , 51 , 52 . In this field, the most quantitative papers have essentially reported luminescence intensities in terms of photon fluxes with values in the range of – 19 .…”

“…The production of light by living organisms and by chemical reactions has been known for a very long time and used for a broad range of applications across various scientific and technological fields 6 – 14 , and CL and BL are generally thought to require catalytic or enzymatic activity respectively. However, numerous reports since the 1950s show that living cells and tissues in general spontaneously emit ultraweak light 15 – 23 , in the absence of any of the known light-producing enzymes, and probably as a consequence of the oxidative metabolic activity. It has also been known for decades that a large number of very simple oxidation and neutralization reactions in water do produce UV–visible photons with extremely small quantum efficiencies ( to ) 15 , 24 , 25 .…”

Mechanism of the Formation of Electronically Excited Species by Oxidative Metabolic Processes: Role of Reactive Oxygen Species

“…The electronic transition from the excited state to the ground state is accompanied by ultra-weak photon emission. Several lines of evidence indicate that ultra-weak photon emission is an intrinsic property of all biological systems, including microorganisms, plants, and animals [21,22,23,24,25,26,27]. The intensity of ultra-weak photon emission is considerably low and is generally considered to be within the order of several units or tens photons s −1 cm −2 [28].…”

Triplet Excited Carbonyls and Singlet Oxygen Formation During Oxidative Radical Reaction in Skin

“…During the last few decades, ultra-weak photon emission (UPE) detection techniques have been extensively used to study the oxidative metabolic processes in the different living system in vivo , ex vivo , and in vitro ( Kobayashi, 2005 ; Cifra and Pospíšil, 2014 ; Ou-Yang, 2014 ; Poplova et al, 2017 ). Keratinocytes, fibroblast, skin homogenate, ex vivo skin tissues as well as malignant skin cells have been measured in vitro ( Torinuki and Miura, 1981 ; Niggli et al, 2008 ; Madl et al, 2017 ). Spontaneous and induced UPE under exposure to stress factors such as ultra-violet irradiations, smoke and toxic chemicals have also been documented for human skin/animals cells model/organism and have been well-summarized in recent reviews ( Sauermann et al, 1999 ; Ou-Yang, 2014 ).…”