Poster Presentation 2014 International Biophysics Congress

Recently, we reported effective penetration of macromolecules, such as functional nucleic acids and nanoparticles, into the skin by faint electricity (around 0.4 mA/cm²)^{1, 2}. Thus, siRNA and charged liposomes encapsulating insulin were delivered by the electric treatment into the deep region of skin. The mechanism of the electricity-mediated transdermal penetration of macromolecules was suggested that to be the change of intercellular interaction, such as tight junction and gap junction, by electric treatment of the skin. Moreover, since electric treatment induced decrease in F-actin and influx of Ca²⁺ion³, intracellular trafficking system, such as motor-proteins, would be accelerated by electricity. In addition, as in the previous report, specific gene expression was inhibited by the electricity-mediated delivery of siRNA, indicating that the naked functional nucleotides reached to cytoplasm via endosomal escape. Thus, it was suggested that electricity changed, not only intercellular interaction, but also intracellular trafficking. Based on these findings, we hypothesized that intracellular delivery of extraneous materials would be changed by the faint electric treatment via alteration of membrane potential. To prove this hypothesis, we analyzed the cellular entry and intracellular trafficking of nucleic acid and nanoparticles labeled with fluorescent dye under electric treatment by confocal laser scanning microscopic observation. As the results, cellular uptake and intracellular trafficking of extraneous materials were accelerated by electricity. The relationship between the electricity-mediated cellular phenomenon and membrane potential change is now studying. In the presentation, the mechanism of electricity-mediated alteration of cellular uptake and intracellular trafficking would be discussed.