Temperature Modulation of Electric Fields in Biological Matter

Abstract

Pulsed electric fields (PEF) have become an important minimally invasive surgical technology for various applications including genetic engineering, electrochemotherapy and tissue ablation. This study explores the hypothesis that temperature dependent electrical parameters of tissue can be used to modulate the outcome of PEF protocols, providing a new means for controlling and optimizing this minimally invasive surgical procedure. This study investigates two different applications of cooling temperatures applied during PEF. The first case utilizes an electrode which simultaneously delivers pulsed electric fields and cooling temperatures. The subsequent results demonstrate that changes in electrical properties due to temperature produced by this configuration can substantially magnify and confine the electric fields in the cooled regions while almost eliminating electric fields in surrounding regions. This method can be used to increase precision in the PEF procedure, and eliminate muscle contractions and damage to adjacent tissues. The second configuration considered introduces a third probe that is not electrically active and only applies cooling boundary conditions. This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions. This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF. Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments.

Effects of internal electrode cooling on irreversible electroporation using a perfused organ model

“…Due to the risks of thermal damage and thermally induced electric current rises increasing electric arching risk during therapy, thermal mitigation strategies may improve IRE therapies. Such mitigation strategies include: pre-cooling/heating the tissue prior to treatment, monitoring current and temperature rise, the use of phase change materials, and strategic pulsing paradigms [7,[23][24][25]. However, active internal cooling is a preeminent approach that could have major impact IRE therapy.…”

Tissue Damage, Temperature, and pH Induced by Different Electrode Arrays on Potato Pieces (Solanum tuberosum L.)

“…Nevertheless, it has not yet been established an optimal electrode array that allows obtaining the maximum effectiveness administrating EChT with minimal damage to the patient under treatment. Notwithstanding, two-dimensional (2D) ( 4 , 5 ) and three-dimensional (3D) ( 6 , 7 ) models have been proposed for their analysis. Such models help to determine how the electric potential, the electric field intensity, the electric current density, and/or the temperature, generated by several different types of electrodes array are distributed in the tumor and the surrounding healthy tissue.…”

Analytical solution of the bioheat equation for thermal response induced by any electrode array in anisotropic tissues with arbitrary shapes containing multiple-tumor nodules

“…Images of surface temperature and false-positive and false-negative constitute limitations of the infrared thermography method [6,7]. Therefore, several researchers have addressed their efforts to know how the temperature is distributed in a tissue (i.e., the tumor) [8][9][10]. Furthermore, mathematical modeling is used [8,[11][12][13].…”

“…Therefore, several researchers have addressed their efforts to know how the temperature is distributed in a tissue (i.e., the tumor) [8][9][10]. Furthermore, mathematical modeling is used [8,[11][12][13]. These studies evidence that thermal modeling is more complex than electrical ones because diffusion process depends on time.…”

“…Additionally, Pennes bioheat equation permits to describe the energy conservation equation for biological heat transfer on the basis of the classical Fourier's law of heat conduction [5]. Analytic modeling of temperature distribution is based on solving the linear bioheat transfer equation for tissue, which is the general heat equation for conduction, with added terms for heat sources [8][9][10]18].…”