Tissue scaffolding is a key component for tissue engineering, and the extracellular matrix (ECM) is nature's ideal scaffold material. A conceptually different method is reported here for producing tissue scaffolds by decellularization of living tissues using nonthermal irreversible electroporation (NTIRE) pulsed electrical fields to cause nanoscale irreversible damage to the cell membrane in the targeted tissue while sparing the ECM and utilizing the body's host response for decellularization. This study demonstrates that the method preserves the native tissue ECM and produces a scaffold that is functional and facilitates recellularization. A two-dimensional transient finite element solution of the Laplace and heat conduction equations was used to ensure that the electrical parameters used would not cause any thermal damage to the tissue scaffold. By performing NTIRE in vivo on the carotid artery, it is shown that in 3 days post NTIRE the immune system decellularizes the irreversible electroporated tissue and leaves behind a functional scaffold. In 7 days, there is evidence of endothelial regrowth, indicating that the artery scaffold maintained its function throughout the procedure and normal recellularization is taking place.

Background:Non-thermal irreversible electroporation (NTIRE) has recently been conceived as a new minimally invasive ablation method, using microsecond electric fields to produce nanoscale defects in the cell membrane bilayer and induce cell death while keeping all other molecules, including the extracellular matrix, intact. Here, we present the first in vivo study that examines the effects of NTIRE on the small intestine, an organ whose collateral damage is of particular concern in the anticipated use of NTIRE for treatment of abdominal cancers.Methods:A typical NTIRE electrical protocol was applied directly to the rat small intestine and histological analysis was used to examine the effect of NTIRE over time.Results:The application of NTIRE led to complete cell ablation in the targeted tissue, but the animal did not show any physiological effects of the procedure and the intestine showed signs of recovery, developing an epithelial layer 3 days post treatment and regenerating its distinct layers within a week.Conclusion:Our results indicate that this novel procedure can be used for abdominal cancer treatment while minimising collateral damage to adjacent tissues because of the unique ability of the NTIRE ablation method to target the cell membrane.

Electrolytic ablation is a method that operates by delivering low magnitude direct current to the target region over long periods of time, generating electrolytic products that destroy cells. This study was designed to explore the hypothesis stating that electrolytic ablation can be made more effective when the electrolysis-producing electric charges are delivered using electric pulses with field strength typical in reversible electroporation protocols. (For brevity we will refer to tissue ablation protocols that combine electroporation and electrolysis as E 2 .) The mechanistic explanation of this hypothesis is related to the idea that products of electrolysis generated by E 2 protocols can gain access to the interior of the cell through the electroporation permeabilized cell membrane and therefore cause more effective cell death than from the exterior of an intact cell. The goal of this study is to provide a first-order examination of this hypothesis by comparing the charge dosage required to cause a comparable level of damage to a rat liver, in vivo, when using either conventional electrolysis or E 2 approaches. Our results show that E 2 protocols produce tissue damage that is consistent with electrolytic ablation. Furthermore, E 2 protocols cause damage comparable to that produced by conventional electrolytic protocols while delivering orders of magnitude less charge to the target tissue over much shorter periods of time.

A synergistic combination of electroporation and electrolysis (SEE) has been found with distinct advantages over tissue ablation by electrolysis or electroporation alone. Minimally invasive tissue ablation by electrolysis uses a low magnitude direct electric current to produce a lesion due to the creation of chemical products that result in cell death. Electroporation creates permeabilizations in the cell membrane which may lead to loss of cell homeostasis and cell death. When these two modes of tissue ablation are combined, a more effective method of cell death is achieved, likely due to the ability of electrolytic products to access the cell interior through the permeabilized cell membrane. Here, a new method of achieving SEE tissue ablation is obtained through the application of a single exponential decay pulse. This parametric study explores the mechanisms of damage as a function of the initial electric field and amount of delivered charge. It is seen that treatment parameters can dictate the mode of tissue ablation, either by SEE or by irreversible electroporation alone.

Electrolytic ablation is a minimally invasive tissue ablation technique that operates by delivering low magnitude direct current to the target region over long periods of time, generating electrolytic products that destroy cells. Our study seeks to examine the hypothesis that permeabilizing the cell membrane with reversible electroporation will reduce the electrolytic dose required for tissue ablation, by exposing the interior of the cell to the electrolytic products. The hypothesis is examined by evaluating the extent of tissue damage when electrolytic and reversible electroporation sequences are delivered separately and in combination, in vivo, to rat liver tissue. The study shows that combining reversible electroporation with electrolysis produces a substantial increase in the extent of tissue ablation compared to that achieved by electrolysis alone. INNOVATIONTh is study shows that when reversible electroporation is used to modulate electrolytic ablation, the combination of electrolytic products generated at the electrodes and the permeabilization of the cell membrane greatly increases the extent of tissue ablation. Th us, the electrical parameters typical to reversible electroporation protocols can be harnessed to facilitate cell death. Th is suggests a new technology for tissue ablation. Th e advantage of this technology is that it uses much lower electric fi elds than conventional irreversible electroporation and requires a much lower dose of electrolytic products than typically seen with electrolytic ablation.