J4-4324 — Annual report 2012
1.
A numerical analysis of multicellular environment for modeling tissue electroporation

We have developed a first multiscale three-dimensional model of tissue electroporation consisting of random ternary core-shell (CS) spheres representing cells with given size distribution. So far different models existed, either describing single cell electroporation or 3D models of "bulk " tissue electroporation, whill eou rmodel couples single-cell solution and multicellular enviroment. We investigate the temporal evolution of the electric conductivity of such cell system during application of an applied electric field. We compute the volume fraction of electroporated cells, showing a hyperbolic tangent dependence of electric field. The collective physical processes causing the transient permeability of the cell membranes can be understood by analogy with the physics of a two-state system with an external field.

COBISS.SI-ID: 9058388
2.
The role of electrically stimulated endocytosis in gene electrotransfer

The mechanisms of DNA entry into cytoplasm during gene electrotransfer are so far not clear. One of hypothesis is electro-stimulated endocytotic uptake. We have developed a protocol which enables us visualization of endocytosis during gene electrotransfer. We have shown that we can observe temperature dependent endocytosis and increased vesiculation after exposure to stress. However, our results do not show increased endocytosis after pulse delivery suggesting that the hypothesis of DNA translocation through hydrophilic pores in the lipid bilayer is more plausible.

COBISS.SI-ID: 8747092
3.
Gene electrotransfer : from understanding the mechanisms to optimization of parameters in tissues

Gene electrotransfer is one of the promising non-viral methods for introducing genes into the cell by using high voltage electric pulses which transiently permeabilize cell membrane. We focused on the importance of electric pulse parameters for efficient gene electrotransfer, analyze the relation between cell membrane electropermeabilization and gene electrotransfer and present state of the art of different steps involved in electric pulse mediated pDNA delivery. Furthermore we present theoretical analysis of gene electrotransfer, calculation of pDNA mobility during electric pulse application with special emphasis on electrophoresis of highly charged pDNA. We discuss the importance of DNA availability at cell membrane level and estimate the number of DNA molecules in contact with the membrane for different concentrations of pDNA used in experiments. A novel study of DNA mobility and gene electrotransfer efficiency in cells embedded in 3-D collagens is also presented. Finally optimization of parameters for gene electrotransfer in muscle tissue using 3D numerical modeling is shown.

COBISS.SI-ID: 9632596