The Effect of Photobiomodulation with Red and Near-Infrared Wavelengths on Keratinocyte Cells

Photobiomodulation (PBM) is defined as the use of non-ionizing photonic energy to trigger photochemical changes, particularly in mitochondrial-sensitive cellular structures. Photobiomodulation is a form of treatment used in medicine in a practical and noninvasive way and it has a significant role in inflammation, ache, and pain reduction, wound healing, and tissue regeneration. It triggers proliferation and the activity of the cell, primarily by utilizing light from the near infrared-red to visible wavelength of the light (630-1000 nm). This in vitro study has analyzed comparatively the most appropriate energy doses with the wavelengths in the red and near-infrared spectrum to induce photobiomodulation on the keratinocyte cells. 1, 3, and $5\mathrm{J}/ \mathrm{m}^{2}$ energy densities of 655 nm and 808 nm diode lasers were used, which might affect wound healing mechanism and cell proliferation. The potential stimulating effect of photobiomodulation to promote wound healing and cell proliferation on human keratinocyte cells was analyzed via microscopic imaging of cell morphology, MTT analysis for cell proliferation and scratch assay for wound closure after light applications. The highest increase in cell viability was obtained with a rate of 112.6% after the triple treatment of 655-nm wavelength at 1 J/cm2. The best wound closure was achieved with a rate of 45% after the triple treatment of 655 nm wavelength at 3 J/cm2. This study revealed that PBM with 655-nm of wavelength was an effective tool to induce cell proliferation and speed up the wound healing process with specific energy doses.