Free and bound sodium identification by skin dielectric properties separation algorithm of bioelectrical impedance spectroscopy (spa-BIS) in human skin model

Abstract

Free and bound sodium in human skin models have been identified by two proposals: skin’s phantom fabrication and skin’s dielectric properties separation algorithm of bioelectrical impedance spectroscopy (spa-BIS). The spa-BIS consist of conductivity-permittivity separation, contact impedance compensation, and a correlation score algorithm based on the vessel with a bipolar electrode. The skin phantom fabrication comprises a recipe combination with temperature-controlled protocol and sodium molarity calculation. In experiments, the human skin models are created to mimic the electrical properties of skin under 1 MHz with several different sodium molarities. Based on five types of human skin models with five samples of each group, the free sodium type conductivity and concentration results R 2 = 0.9903 − following a linear trendline of concentration change in skin tissues theorems with the fRequency range from 1 kHz to 1 MHz , while the bound sodium type results R 2 = 0.9061 − . The spa-BIS compensate 7 − 16 Ω of vessel contact impedance. The dielectric properties of each type have been extracted with less than 10% of the average standard deviation, which is considered an accurate identification method of dermis dielectric properties. The algorithm successfully identifies sodium type: free sodium has a negative, and bound sodium has a positive correlation score trend. As an additional discussion, the different time-dependent effects, the different water content, and different agar content analyses have been provided in this study. As a robust analysis method, the spa-BIS has a prominent performance to replace a 23Na-MRI in terms of free and bound sodium identification.