Wavelength Articles Summary: Effects of monochromatic low‐intensity light and laser irradiation on adhesion of HeLa cells in vitro
https://pubmed.ncbi.nlm.nih.gov/8833286/
- This study evaluated HeLa cell adhesion in vitro after low-level irradiation with red and near-infrared light across the 580-860 nm range.
- Lymphocyte growth and the percentage of attached cells (indicating cell adhesion) both increased, illustrating that light in this range directly influences biological processes, including embryogenesis, cell growth, differentiation, morphogenesis, and the formation of metastasis..
- The results also indicate the fact that there is a receptor in cells that reacts to light in a significant and consequential manner.
Interplay of Photoacceptors: Amplification and Transduction in Mitochondria to Nucleus Signaling
“In Figure 7, the signal from electronically excited photoacceptors in mitochondria amplifies and transduces to the nucleus through a cascade of biochemical reactions in the cytoplasm and cell membrane, a crucial aspect for this study.”
- These include the increase in the synthesis of DNA and RNA
Melatonin modulates the action of near infrared radiation on cell adhesion
https://pubmed.ncbi.nlm.nih.gov/12614475/
- Study that finds that increased melatonin inhibits the effects of LLLT on cells, specifically on the wavelengths of near-infrared light. Study done on in vitro cells.
- “Melatonin modifies the light action spectrum significantly in the near IR region (760–840 nm only). Thus, the peak at 820–830 nm characteristic for the light action spectrum is fully reduced.”
- We can possibly, according to this paper, extend the in vitro effects of this study to in vivo studies. This means that at wavelengths near-infrared, humans with higher levels of melatonin might be less susceptible to the positive benefits of red light therapy.
- Thus, especially if we use high wavelengths, we should figure out how one might try to optimize their melatonin levels. This would include thinking of factors such as sleep, time of day, foods, age, etc.
Absorption measurements of a cell monolayer relevant to phototherapy: Reduction of cytochrome c oxidase under near IR radiation
https://pubmed.ncbi.nlm.nih.gov/16125966/
- “A similarity is established between the peak positions at 616, 665, 760, 813, and 830 nm in the absorption spectra of the cellular monolayers and the action spectra of the long-term cellular responses (increase in the DNA synthesis rate and cell adhesion to a matrix).”
- Once more, measured attached cells and determined maximum percentage occurred at the aforementioned peaks
- Discusses the fact that near-infrared light is a key driver in changes in cytochrome c oxidase
Cellular Effects of Low Power Laser Therapy Can be Mediated by Nitric Oxide
https://pubmed.ncbi.nlm.nih.gov/15739174/
- “The well-structured action spectrum for the increase of the adhesion of the cells, with maxima at 619, 657, 675, 740, 760, and 820 nm, points to the existence of a photoacceptor responsible for the enhancement of this property (supposedly cytochrome c oxidase, the terminal respiratory chain enzyme), as well as signaling pathways between the cell mitochondria, plasma membrane, and nucleus.”
- In terms of NO and its affects on light therapy, it seems
A Novel Mitochondrial Signaling Pathway Activated by Visble-to-near Infrared Radiation
https://pubmed.ncbi.nlm.nih.gov/15362946/
- “Irradiating HeLa cell suspension with monochromatic visible-to-near infrared radiation before plating increases the number of cells attached to glass substratum. The action spectrum exhibits maxima at 619, 657, 675, 700, 740, 760, 800, 820, 840, and 860 nm.”
Photobiological Modulation of Cell Attachment via Cytochrome C Oxidase
https://pubmed.ncbi.nlm.nih.gov/14872239/
- “The well-structured relationship between this biological response and the radiation wavelength (action spectrum with maxima at 620, 680, 760, and 820 nm) suggests the existence of a photoacceptor responsible for the enhancement of attachment (presumably cytochrome c oxidase, the terminal enzyme of the respiratory chain) and, secondly, the existence of signaling pathways between the mitochondria, the plasma membrane, and the nucleus of the cell.”
Gene Expression Under Laser and Light-emitting Diodes Radiation for Modulation of Cell Adhesion: Possible Applications for Biotechnology
https://pubmed.ncbi.nlm.nih.gov/21796755/
- “Irradiating cells with specific wavelengths of light (maxima at 619, 675, 740, 760, and 820 nm) can enhance cell adhesion and proliferation. Conversely, inhibiting the activity of the photoacceptor (cytochrome c oxidase in the mitochondrial respiratory chain) with chemicals before irradiation reduces cell adhesion and proliferation.”
Use alone or in Combination of Red and Infrared Laser in Skin Wounds
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4291816/
- Combination of red and infrared light is superior to both of them individually
- This article, functioning as a case study, aggregates data from various papers, thereby mitigating potential systematic errors present in individual studies.
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Other Tiina Karu Articles- not as important for wavelength purposes:
Is It Time to Consider Photobiomodulation As a Drug Equivalent?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3643261/
- “The peak at 620 nm belongs to reduced CuA, and that at 680 nm, to oxidized CuB atoms in cytochrome c oxidase molecule.”
- What is CuA and CuB? In “classical” CcO, CuA accepts electrons from cytochrome c which are then transferred via heme a to the coupled heme a 3-CuB dioxygen-reducing site.
Absorption Measurements of Cell Monolayers Relevant to Mechanisms of Laser Phototherapy: Reduction or Oxidation of Cytochrome C Oxidase Under Laser Radiation at 632.8 Nm
https://pubmed.ncbi.nlm.nih.gov/19099388/?from_term=tiina+karu&from_page=2&from_pos=2
- “Our experimental results show that irradiation at 632.8 nm transiently reduces or oxidizes the photoacceptor, likely cytochrome c oxidase, depending on its initial redox status.”
Elementary Processes in Cells After Light Absorption Do Not Depend on the Degree of Polarization: Implications for the Mechanisms of Laser Phototherapy
https://pubmed.ncbi.nlm.nih.gov/18307393/?from_term=tiina+karu&from_pos=9
- “The biological effect (stimulation of cell attachment) of light with lambda = 637 nm on cells in our model system was pronounced, but did not depend on the degree of light polarization.”
https://www.jstage.jst.go.jp/article/islsm/10/2/10_2_55/_article/-char/en
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Misc.
Red (660 Nm) or Near-Infrared (810 Nm) Photobiomodulation Stimulates, While Blue (415 Nm), Green (540 Nm) Light Inhibits Proliferation in Human Adipose-Derived Stem Cells
https://pubmed.ncbi.nlm.nih.gov/28798481/
ATP superiority of red over blue green 2017
Summary of above:
Examining these papers for the best red light wavelengths, Tiina Karu consistently highlighted the following effective nm values, frequently cited in her research:
~620, ~680, ~760, ~820; frequently ~680 as well.
This correlates similarly, but not exactly with general consensus in other papers, which use ~635 nm and ~800 nm.
620-630, 670-680, 825-835
