In photobiomodulation (PBM), where is light primarily absorbed within the cell?

In photobiomodulation (PBM), light is primarily absorbed in the mitochondria of cells. Mitochondria are known as the powerhouses of the cell, where adenosine triphosphate (ATP) is produced through cellular respiration. The absorption of specific wavelengths of light, particularly in the red and near-infrared spectrum, leads to a series of biochemical responses that enhance mitochondrial function.

When light photons are absorbed by the cytochrome c oxidase enzyme complex within the mitochondria, it stimulates a cascade of events that increase ATP production, promote cell proliferation, and reduce inflammation. This process plays a pivotal role in tissue repair and regeneration, making it the focus of PBM applications in various therapeutic settings.

While other cellular components such as the plasma membrane, nucleus, and cytoplasm can interact with light, the mitochondria are the primary sites where the therapeutic effects of PBM are realized, particularly in enhancing energy metabolism and cellular health.