Tissue coefficient of bioimpedance spectrometry as an index to discriminate different tissues in vivo

Abstract

Bioimpedance indicating cell and tissue condition of the living things is of great importance in impedance spectrum analysis and other related researches, in which measurement of the skin impedance is a tricky problem due to the peculiarity of the stratum corneum. The aim of the study is to develop a method to elucidate the skin impedance in a large frequency range and to find out a biomarker to estimate it.In this article, we introduce a non-destructive method of using both surface and needle electrodes to investigate the electrical properties of the skin including stratum corneum of sixteen anesthetized C57BL/6 mice in vivo. A capacitance model was introduced to bridge the complex Debye’s model and the practical three-element model. A new biomarker (tissue coefficient) was introduced to compare the whole skin with the viable skin.The contribution of the viable skin to the impedance of the whole skin can be ignored unless the concerned frequency is much higher than 10 kHz. The CG plot show direct link with the ε-σ plot, and the tissue coefficient shows significant difference between the whole skin and viable skin and reflects the alpha and beta dispersions.The results suggest that the method of using both surface and needle electrodes to investigate the impedance the whole skin including stratum corneum is practical, and the tissue coefficient is especially suitable for in vivo study, and has great potentials in estimation and discrimination of living tissues, cancer detection, bioelectrical impedance analysis (BIA) and other related fields.