Bioelectrical Impedance Analysis for Post-Surgical Melanoma Excisions: Identifying the Ideal Frequency for Impedance Measurements

The human body comprises of four soft tissue types; muscle, nervous, connective and epithelial tissue. Skin, considered epithelial tissue, is the largest organ and has several functions. It consists of three major layers; the epidermis, dermis and hypodermis. The dermis is a dense fibrous tissue dictating the mechanical behaviour of skin at small stresses and strains. Furthermore, soft tissue possesses multiple direct current surface potentials. A wound causes a disruption to this charge altering its potential. This research proposes bioelectrical impedance analysis (BIA) as a simple method for measuring this change in cell potential enabling monitoring of soft biotissue during the wound healing process. By applying an alternating current at predefined frequencies, the charge penetrates the stratum corneum passing through the extracellular fluid (ECF) and intracellular fluid (ICF) of the biotissue under study (BUS) measuring its electrical activity through the biopotential difference in terms of impedance. This study adapts various frequencies of BIA to identify the relationship of this parameter to the skin impedance. To study this proof of concept, we adapted a model system using pork belly to emulate human skin due to their identical dielectric properties. To disrupt the skin, an excision based on the dimensions of melanoma excisions was created. This excision extracted the three layers of skin causing a disruption to the electrical properties of the biotissue. It is important to monitor skin impedance to identify healthy regeneration of this epithelial tissue.