Limits...
Temperature modulation of electric fields in biological matter.

Daniels CS, Rubinsky B - PLoS ONE (2011)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of California, Berkeley, California, United States of America. daniels.charlotte@gmail.com

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.

Show MeSH

Related in: MedlinePlus

Comparison of cooling and control models for a supplemental one-dimensional study.Graphs illustrate: a) Temperature and b) electric field. Control models are held at constant body temperature.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3113852&req=5

pone-0020877-g005: Comparison of cooling and control models for a supplemental one-dimensional study.Graphs illustrate: a) Temperature and b) electric field. Control models are held at constant body temperature.

Mentions: This effect is seen best in a supplemental analysis, shown in Figure 5. It consists of a simple one-dimensional Cartesian study of a 6 cm slab of tissue between two parallel plates. The leftmost plate applies a voltage of 2500 V and the rightmost plate applies ground. Figure 5 compares the electric field at constant temperature with the case in which cooling at 0°C is applied on the leftmost plate and body temperature, 37°C, is applied to the rightmost plate for 90 seconds. The effect of temperature induced tissue property heterogeneities is evident. At a constant temperature, the electric field is constant across the slab. For the case of cooling at one plate, the field is substantially higher near the cold surface and it decays to low values away from the cold surface. The difference between the electric field in cold regions and the electric field at body temperature is an order of magnitude. These results, as well as those demonstrated in Figures 2 and 3, suggest that inducing heterogeneity in tissue electrical properties through local cooling, with an analogue circuit of two resistors in series, has the effect of confining and enhancing the electric fields in the colder regions and reducing the field in the higher temperature regions.


Temperature modulation of electric fields in biological matter.

Daniels CS, Rubinsky B - PLoS ONE (2011)

Comparison of cooling and control models for a supplemental one-dimensional study.Graphs illustrate: a) Temperature and b) electric field. Control models are held at constant body temperature.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113852&req=5

pone-0020877-g005: Comparison of cooling and control models for a supplemental one-dimensional study.Graphs illustrate: a) Temperature and b) electric field. Control models are held at constant body temperature.
Mentions: This effect is seen best in a supplemental analysis, shown in Figure 5. It consists of a simple one-dimensional Cartesian study of a 6 cm slab of tissue between two parallel plates. The leftmost plate applies a voltage of 2500 V and the rightmost plate applies ground. Figure 5 compares the electric field at constant temperature with the case in which cooling at 0°C is applied on the leftmost plate and body temperature, 37°C, is applied to the rightmost plate for 90 seconds. The effect of temperature induced tissue property heterogeneities is evident. At a constant temperature, the electric field is constant across the slab. For the case of cooling at one plate, the field is substantially higher near the cold surface and it decays to low values away from the cold surface. The difference between the electric field in cold regions and the electric field at body temperature is an order of magnitude. These results, as well as those demonstrated in Figures 2 and 3, suggest that inducing heterogeneity in tissue electrical properties through local cooling, with an analogue circuit of two resistors in series, has the effect of confining and enhancing the electric fields in the colder regions and reducing the field in the higher temperature regions.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of California, Berkeley, California, United States of America. daniels.charlotte@gmail.com

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.

Show MeSH
Related in: MedlinePlus