Blue Light

While sunlight has been used since ancient times to treat certain diseases, modern phototherapy came about following the work of the Danish dermatologist Finsen who was awarded the Nobel Prize in Medicine in 1903, following the publication of the results of lupus vulgaris treatment with concentrated and UV-rich light generated by an arc lamp.

Following the development of lasers in the 60s and then LEDs (Light Emitting Diodes), light sources that emit “monochromatic” light, it has been possible to investigate the interaction between biological tissues and specific wavelengths. This was the birth of Biophotonics, the branch of physics studying such interactions, and that has led to the development of various medical devices for therapeutic and diagnostic treatments.

The therapeutic effect of light occurs thanks to the presence of endogenous molecules in an organism’s tissues that are capable of absorbing light. The energy conveyed by the light spectrum is absorbed by these naturally existing elements, known as “chromophores”, and is used to promote chemical reactions or produce conformational changes in certain biomolecules.

This process translates into beneficial therapeutic effects such as reduction of pain and inflammation. The immunomodulation and induction of wound healing and tissue regeneration was defined as “Photobiomodulation” in 2014 by the North American Association for Laser Therapy and by the World Association for Laser Therapy at a joint conference.
Each chromophore has a different absorption spectrum and therefore a different sensitivity to various wavelengths which, once absorbed by tissues, can produce varying photophysical and photochemical effects.

EmoLED has developed a photobiomodulation-based therapy for skin lesions that uses specific wavelengths of visible light spectrum in the blue range. Blue light is absorbed by electron transport chain enzymes and by flavoproteins.

Its therapeutic effects include resolving inflammation, reducing pain and stimulating tissue regeneration, as observed in preclinical and clinical studies.

Inflammation is a necessary phase in the wound repair process that should last no more than four weeks in total. Due to diseases or specific physical conditions (such as old age, nutritional deficits and mobility restrictions), the inflammatory phase can stall, causing the wound to become chronic. The most widespread and impacting aetiologies of chronic wounds are lower leg ulcers, deriving predominantly from venous insufficiency; these affect 1% of the adult population and 3.6% of the population over age 65. Diabetic foot, which affects one diabetes mellitus patient out of three is the most frequent cause of lower limb amputation in the world. Pressure or “decubitus” ulcers caused by the pressure of a bone prominence in people with limited mobility, such as patients in intensive care, have an average prevalence of 13.7% in the European population.

A poorly regulated inflammatory response can also give rise to complications in wounds with major tissue loss, caused by a trauma or a burn, and to surgical wound dehiscence. 

Photobiomodulation with blue light, a therapy that can stimulate inflammatory phase transition, can contribute to the resolution of wounds with a delayed or not-completed healing process. Such wounds represent a major healthcare problem given the high costs of management and the low quality of life of patients affected by them.

Fibroblasts are the most numerous cells in the connective tissue of the skin and play a fundamental role in its reconstruction following damage. Preclinical studies have demonstrated that blue light can modulate the activity of fibroblasts. The metabolism and proliferation of these cells are increased or, alternatively, inhibited, depending on the dose of light used for irradiating them.

In addition, better outcomes in terms of organisation and morphology of collagen in wounds treated with blue light have been found compared to control. Based on this evidence, photobiomodulation with blue light can contribute to a good scarring outcome and could be used in the treatment and prevention of keloids, abnormal scar tissue that can develop following abrasions and wounds, where the cause lies in the hyperactivity of fibroblasts.