Exact Action Spectra for Cellular Responses Relevant to Phototherapy - https://pubmed.ncbi.nlm.nih.gov/16144476/
Objective: The aim of the present work is to analyze available action spectra for various biological responses of HeLa cells irradiated with monochromatic light of 580–860 nm. Background data: Phototherapy (low-level laser therapy or photobiomodulation) is characterized by its ability to induce photobiological processes in cells. Exact action spectra are needed for determination of photoacceptors as well as for further investigations into cellular mechanisms of phototherapy. Methods: Seven action spectra for the stimulation of DNA and RNA synthesis rate and cell adhesion to glass matrix are analyzed by curve fitting, followed by deconvolusion with Lorentzian fitting. Exact parameters of peak positions and bandwidths are presented. Results: The peak positions are between 613.5 and 623.5 nm (in one spectrum, at 606 nm), in the red maximum. The far-red maximum has exact peak positions between 667.5 and 683.7 nm in different spectra. Two near infrared max- ima have peak positions in the range 750.7–772.3 nm and 812.5–846.0 nm, respectively. Conclusions: In the wavelength range important for phototherapy (600–860 nm), there are four “active” regions, but peak positions are not exactly the same for all spectra.
From Results and Discusstion:
"In the wavelength range used in our experiments and impor- tant for phototherapy (600–860 nm), there are four “active” re- gions, but the peak positions are not exactly the same for all action spectra. The red band has peak position at 613.5–623.5 nm (in one spectrum, at 606 nm); the far-red band has peak po- sition at 667.5–683.7 nm, and two near IR bands in the range of 750.7–772.3 nm and 812.5–846.0 nm. The nature of the cy- tochrome c oxidase intermediates, whose absorption spectrum is mirrored in these action spectra, remains to be investigated."
Note: Pg. 357 Shows the light frequencies, in the range from 580–860 nm, that cause a response in cellular physiology. Two peaks are seen in Red, and Far Red. And Two peaks are seen in NIR.