Electrical impedance decreases in annulus fibrosus cartilage exposed to microsecond pulsed electric fields ex vivo

Abstract

Electropermeabilization of biomembranes often is measured by microscopic imaging of a membrane-impermeable fluorophore that penetrates the cells following pulsed electric field (PEF) exposure. PEF exposure subsequently changes physiological properties of tissue. One way to probe these changes in tissue is measuring electrical properties by way of electrochemical impedance spectroscopy (EIS). In this study, we analyse impedance and conductivity of bovine annulus fibrosus (AF) cartilage before and after exposures to PEF of 100 μs duration. Two PEF parameters-electric field amplitude and number of pulses-are varied, and total specific dose of PEF is calculated. AF tissue conductivity increases with both amplitude and number of pulses, indicating electropermeabilization of the AF cells. A Live/Dead cell imaging assay validates the EIS measurements, indicating intratissue cell permeabilization by μsPEF exposure. These results support the extension of EIS to monitor extent of electropermeabilization of cells within cartilage tissue.