Anna E. Riordan

Objectives: There is a critical need for effective focal therapies for patients with inoperable or anatomically complex tumors where conventional ablation techniques pose high risk or are ineffective. Integrated Nanosecond Pulsed Irreversible Electroporation (INSPIRE) is a novel non-thermal ablation modality which uses real time temperature feedback during pulse delivery to safely treat tumors near critical structures. This study evaluated the impact of exposed electrode length on ablation zone size, reproducibility, and cardiac safety in a large animal model. Methods: INSPIRE treatments were performed in an in vivo healthy porcine liver model. All treatments administered 6000 V 1000 ns pulses with a 45 °C temperature set point. Treatments were administered percutaneously via an electrode and grounding pad approach using an internally cooled electrode applicator. The exposed electrode region at the distal end of the applicator was set to either 0.5, 1.0, 1.5, or 2.0 cm. Ablation zones were assessed via ultrasound, contrast-enhanced CT, and gross pathology one week post-treatment. Cardiac safety was evaluated by measuring pre- and post-treatment serum Troponin levels. Results: All treatments were completed without adverse events. Troponin levels remained stable (pre: 0.249 ng/mL; post: 0.224 ng/mL), indicating no measurable cardiac injury. The 1.5 cm exposure length produced the largest and most consistent ablation volumes, with a mean volume of 12.8 ± 2.6 cm³ and average dimensions of 3.7 × 2.7 cm in under 6 min. Increasing exposure length beyond 1.5 cm introduced greater variability and reduced treatment volumes. Conclusions: INSPIRE enables safe, large-volume, single-applicator ablation without a need for electrical pulse synchronization with R wave in cardiac rhythm. The 1.5 cm exposure length offers optimal balance between energy delivery and treatment consistency. These findings support further clinical investigation of INSPIRE for non-thermal ablation of inoperable tumors.

Electroporation is a promising technology utilizing electrical pulses for macromolecule delivery and soft-tissue ablation, with applications that include next-generation prophylactics and the treatment of genetic diseases such as cancer. This study demonstrates a high-throughput capable 3D tissue culture model for quantification of the reversible and irreversible electroporation thresholds for a given electroporation protocol. By using a non-uniform electric field and analyzing the spatial distribution of transfected cells, both reversible and irreversible thresholds can be identified within a single sample, increasing the efficiency at which electroporation protocols can be characterized, especially for in vivo translation. To show this capability, 3D tissue mimics containing HEK293 cells were transfected using a ring and pin electrode to deliver a GFP-encoding plasmid. Electroporation thresholds were then derived based on fluorescent microscopy images of the transfected samples. This model demonstrates potential for use as a means for high-throughput evaluation of electroporation protocols, a key advantage over current methods to evaluate these thresholds, which tend to be time-intensive and are less representative of in vivo conditions.

Electroporation is a promising technology utilizing electrical pulses for macromolecule delivery and soft-tissue ablation, with applications that include next-generation prophylactics and the treatment of genetic diseases such as cancer. This study demonstrates a high-throughput capable 3D tissue culture model for quantification of the reversible and irreversible electroporation thresholds for a given electroporation protocol. By using a non-uniform electric field and analyzing the spatial distribution of transfected cells, both reversible and irreversible thresholds can be identified within a single sample, increasing the efficiency at which electroporation protocols can be characterized, especially for in vivo translation. To show this capability, 3D tissue mimics containing HEK293 cells were transfected using a ring and pin electrode to deliver a GFP-encoding plasmid. Electroporation thresholds were then derived based on fluorescent microscopy images of the transfected samples. This model demonstrates potential for use as a means for high-throughput evaluation of electroporation protocols, a key advantage over current methods to evaluate these thresholds, which tend to be time-intensive and are less representative of in vivo conditions.