Non invasive contact electrodes for in vivo localized cutaneous electropulsation and associated drug and nucleic acid delivery.

For an effective tissue controlled electropermeabilization as requested for electrochemotherapy and electrogenotherapy, it is very important to have informations about the electric field distribution provided by a defined set of electrodes. Computer simulations using the finite element models approach predicted the associated field distributions and currents. Phantoms made of gels with well-defined electrical conductance were used to measure the current responses of a new electrode geometry (wires), A good agreement between the measured and predicted currents was observed supporting the validity of the prediction for the field distribution. Field distribution was observed to be very localized and highly homogeneous with the new concept of contact wire electrodes. They allowed to focus the field effect along the surface of the tissue to induce a controlled release of drugs or plasmids. Non invasive (contact) electrodes can be moved rapidly on the body and avoid puncturing the skin and the tissue. They can be used for large surface effects, to treat the skin and subcutaneous tumors. The use of contact electrodes after drug or DNA intradermal injection were validated by clinical treatment of large surface skin tumors and by in vivo imaging of permeabilization or of gene expression.