In vitro gene transfer by electrosonoporation.

Among the nonviral methods for gene delivery in vitro, electroporation is simple, inexpensive and safe. To upregulate the expression level of transfected gene, we investigated the applicability of electrosonoporation. This approach consists of a combination of electric pulses and ultrasound assisted with gas microbubbles. Cells were first electroporated with plasmid DNA encoding-enhanced green fluorescent protein and then sonoporated in presence of contrast microbubbles. Twenty-four hours later, cells that received electrosonoporation demonstrated a four-fold increase in transfection level and a six-fold increase in transfection efficiency compared with cells having undergone electroporation alone. Although electroporation induced the formation of DNA aggregates into the cell membrane, sonoporation induced its direct propulsion into the cytoplasm. Sonoporation can improve the transfer of electro-induced DNA aggregates by allowing its free and rapid entrance into the cells. These results demonstrated that in vitro gene transfer by electrosonoporation could provide a new potent method for gene transfer.

[Sonopermeabilization: therapeutic alternative with ultrasound and microbubbles]. / Sonoperméabilisation: alternative thérapeutique par ultrasons et microbulles.

Future applications of ultrasound and microbubbles extend to more than imaging applications. Over the last few years, it was reported that sonographic contrast agent effects under ultrasound, modulate transiently cell membrane permeability. This process, named sonoporation and classified as a new physical method to transfer genes or drugs, consists of using a physical energy source to modulate membrane integrity. The possibility to transfer therapeutic genes would be a new tool for gene therapy and could constitute an alternative method. After in vitro and in vivo studies presentation, the therapeutic potential of sonoporation will be investigated in this paper.