Ex vivo and in vivo mapping of electric fields in tumor tissues
Electric field-mediated gene delivery is a promising therapeutic modality that uses an externally applied voltage source to introduce exogenous genetic materials to target cells by field-dependent phenomena, such as electrophoresis and electroporation. In previous studies, the genes and cells inside a tumor are assumed to encounter the applied field. However, several factors, such as ionic polarization at the electrode interface, the skin barrier (for in vivo transfection), and the presence of cells, may affect both the magnitude and direction of the intra-tumoral field. Herein, we described a novel method for measuring the electric field in tumors in response to an applied voltage stimulus in both ex vivo and in vivo mouse models. For comparison, we also measured the electric field in tissue phantoms, which consisted of 1% agarose gels, with or without cells. Our results showed that the electric field in tumor tissues could be as low as 69% and 24% of the applied field magnitude in ex vivo and in vivo situations, respectively.
