We have known for over a century, that human skin drives ionic current out of regions where the integrity of the epidermis has been breached (DuBois-Reymond, 1843,Ann.Phys.U.Chem.58:1) DuBois-Reymond used one of the earliest galvanometers to measure 1 uA leaving wounds in his skin. This has been confirmed using modern techniques and we now know that this current is driven out of the wound by the transepithelial potential generated across the epidermis by the apical-basal transport of Na+. As this wound current traverses the epidermis it generates a local electric field that points towards the wound from all directions around it. While we know that wound currents exist, we do not know the local electric field strength that they generate as they move through the skin. It is this electric field that can influence wound healing by moving molecules by electrophoresis or attracting cells by galvanotaxis. Our goal is to measure this wound field in vivo. This field has been measured near guinea pig skin wounds but never in humans (Barker et al., 1982,Am.J.Physiol. 242:R358). Our company has been developing a new instrument called the Bioelectric Field Imager (BFI) that will be able to measure these lateral fields non-invasively. Just as the EKG can provide information about heart disease by measuring voltages between the limbs, the BFI technique provides information about skin disease. This will have many important applications to improving human health including the design of new electrical therapies for healing chronic wounds and possibly the early detection and diagnosis of skin diseases such as melanoma and psoriasis.
Our Specific Aim i s to adapt a prototype, BFI device to non-invasively measure the skin surface potential distribution in the region surrounding mammalian skin wounds. We will optimize vibration amplitude, distance between skin and probe, and signal averaging. We will introduce scanning capabilities that allow the two-dimensional mapping of the surface potential distribution around a skin wound. Finally we will determine the reproducibility of the device by laboratory bench testing on well-defined mammalian wounds. This instrument will allow us to compare the endogenous fields near normally healing wounds with those near chronic wounds in order to determine if there are differences that might be reduced by electrotherapy. This technique also has the potential for early detection and diagnosis of various skin diseases including melanoma and psoriasis.
| Nuccitelli, Richard; Nuccitelli, Pamela; Li, Changyi et al. (2011) The electric field near human skin wounds declines with age and provides a noninvasive indicator of wound healing. Wound Repair Regen 19:645-55 |
