Micro electrical impedance spectroscopy on a needle for ex vivo discrimination between human normal and cancer renal tissues

The ex-vivo discrimination between human normal and cancer renal tissues was confirmed using mu EoN (micro electrical impedance spectroscopy-on-a-needle) by measuring and comparing the electrical impedances in the frequency domain. To quantify the extent of discrimination between dissimilar tissues and to determine the optimal frequency at which the discrimination capability is at a maximum, discrimination index (DI) was employed for both magnitude and phase. The highest values of DI for the magnitude and phase were 5.15 at 1MHz and 3.57 at 1 kHz, respectively. The mean magnitude and phase measured at the optimal frequency for normal tissues were 5013.40 +/- 94.39 X and Omega 68.54 +/- 0.72 degrees, respectively; those for cancer tissues were 4165.19 +/- 70.32 X and Omega 64.10 +/- 0.52 degrees, respectively. A statistically significant difference (p<0.05) between the two tissues was observed at all the investigated frequencies. To extract the electrical properties (resistance and capacitance) of these bio-tissues through curve fitting with experimental results, an equivalent circuit was proposed based on the lEoN structure on the condition that the lEoN was immersed in the bio-tissues. The average and standard deviation of the extracted resistance and capacitance for the normal tissues were 6.22 +/- 0.24 kX and 280.21 +/- 32.25 pF, respectively, and those for the cancer tissues were 5.45 +/- 0.22 kX and 376.32 +/- 34.14 pF, respectively. The electrical impedance was higher in the normal tissues compared with the cancer tissues. The lEoN could clearly discriminate between normal and cancer tissues by comparing the results at the optimal frequency (magnitude and phase) and those of the curve fitting (extracted resistance and capacitance). Published by AIP Publishing.