The human body possesses an endogenous bio-electric system that constantly produces natural electrochemical signals in different areas, such as the brain, skin, muscles, heart, and bones.
The electrical potentials are generated by an asymmetric ionic flow across the tissue. One such example is the transepithelial electric potential, which is generated by the movement of ions through Na+/K+ ATPase pumps of the epidermis, leading to a negative potential of the epidermis while the dermis is electropositive. An injury to the skin short-circuits the normal transepithelial electric potential at the wound site. As a result, an electrical potential directed towards the wound centre can be measured around the wound edges (see Figure). This in turn initiates the so called ‘current of injury’, which is essential for normal wound healing as it signals to the epithelial cells to migrate into the wound area, consequently activating the body’s own natural healing process.
Bioelectrical current before (A) and after (B) skin injury (Source: PMID: 28461755)
The current of injury is maintained as long as the wound area is moist, since moisture is essential for the bio-electric system to function. It is also known that in cases of nutritional and metabolic disorders, electrical properties of wound tissue may become abnormal, thus delaying wound healing.