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The Light Fantastic: Photobiology and Light Emitting Diodes
By: Erin Madigan-Fleck
Posted: January 31, 2014, from the February 2014 issue of Skin Inc. magazine.
Light therapy is one of the oldest modalities used to treat various health conditions and, throughout its illustrious existence, has claimed success under various applications. The early physician, Hippocrates, was an advocate of the sun’s abundant healing properties and, as testimony to the efficacy of light therapy, many time-honored protocols are still in practice today.
The inception of the electromagnetic spectrum fueled the exploration of photobiostimulation, light and laser devices, and other similar light research. The annals of photobiology have endorsed the therapeutic value of light for a myriad of health, beauty and wellness applications. According to the constitution of The American Society for Photobiology: “Photobiology includes all biological phenomena involving nonionizing radiation (natural light). It is recognized that photobiological responses are the result of chemical and/or physical changes induced in biological systems by nonionizing radiation.”1
Light receives its energy in the form of photons, which are propagated in the form of waves, or wavelength. The photon energy of each wavelength varies with the different energies and intensities emitted. (See Electromagnetic Spectrum.)
Perhaps one the most significant studies of cutaneous application of light-based therapy was the utilization of light-emitting diodes (LED) in NASA’s space program: “LEDs stimulated wound-healing at near-infrared wavelengths of 680, 730 and 880 nanometers (nm). Furthermore, near-infrared LED light has quintupled the growth of fibroblasts and muscle cells in tissue culture.”2 It is with this assertion that both the medical and wellness industries have supported continued research and the endorsement of LED applications.
What are LEDs?
LEDs are semiconductor bulbs that are used in a variety of instruments to convert energy from electricity into incoherent (photons in random phases) light with a very narrow spectrum. The energy that is obtained from LEDs has a substantially lower point of energy than lasers; therefore, they are not able to deliver enough peak power to damage tissue. From a photobiology perspective, LEDs may synchronize with biological tissue by becoming involved with intricate photo-biochemical reactions. These reactions include the absorption of light to enhance nutrient synthesis and to potentially activate the mitochondria respiration components.3