Measurement of Electrical Properties of Tissues with and without Gold Nanoparticles (GNPs) At Different Temperatures

Electrical impedance tomography (EIT) is a real-time imaging modality for detecting lesions based on the electrical impedance of the tissues. Its use could be limited by the low current intensity and/or low-temperature differences between the tissues. The purpose of this study is to measure the electrical properties of tissues with and without gold nanoparticles (GNPs) at different temperatures. In this study, GNPs (20-25 nm) were successfully synthesized by the reduction of chloroauric acid (HAuCl4) with sodium citrate (C6H7NaO7). The 4-electrode method was established using two sets of phantoms made of chicken muscle and fat tissues.  An increase in the tissue temperature or applied current frequency decreases the impedance amplitude (|Z|), phase angle (θ), resistive impedance (ZR=R), capacitive impedance (ZC=X), and specific resistance (ρ), while increasing the specific conductance (δ). The loading of tissues with GNPs amplified these changes, especially at low temperatures and at low frequencies. Loading tissues with GNPs has the potential to increase the signal intensity and/or improve temperature resolution in temporal mapping in EIT.