Integrated Diagnosis and Therapy Using Flexible Contact Electrodes: Low-Voltage Irreversible Electroporation and Quantitative Assessment of Therapeutic Efficacy.

Abstract

Irreversible electroporation (IRE) is a minimally invasive, non-thermal, and cell-selective technique. When combined with the noninvasive nature of contact electrodes, they hold great promise for the treatment of cardiac conditions, gastrointestinal tumors, and superficial lesions. However, its broader clinical application is hindered by its reliance on a kilovolt-level, high-voltage pulse characteristics power supply and the lack of real-time postoperative assessment methods for evaluating ablation efficacy. To address these challenges, a contact electrode system with integrated IRE and impedance monitoring functions was developed. Numerical simulations were performed to optimize the anode, gap, and cathode widths in the concentric electrode design. This ensured efficient electric-field focusing under low-voltage conditions. The ablation performance was verified using a potato model. A four-electrode impedance measurement technique was used to capture the spectral characteristics of biological tissues. The impedance changes were analyzed using a double-shell equivalent circuit model. The system achieved a 2 mm ablation depth at 125 V, which is suitable for the treatment of superficial lesions. This reduces the required voltage from the kilovolt level to the hundred-volt level. The four-electrode method reduced contact resistance interference, and the Nyquist plots showed a unique double-arc pattern. Changes in cell wall resistance correlated with ablation depth ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <msup><mrow><mtext>R</mtext></mrow> <mn>2</mn></msup> </math> = 0.86) with a prediction error of <10%. This study presents an innovative approach for IRE therapy that combines low-voltage operation with real-time feedback through impedance spectroscopy, thereby offering improved safety and treatment monitoring.