Iontophoresis instrumentation for the enhancement of gene therapy in wound healing

Iontophoresis and electroporation are two progressively expanding methods that are used to enhance drug delivery into the human body. They involve the exposure of cells to an external electric field, to drive genetic drugs (plasmid) to a desired location or permeabilize the cell's membranes for the drug to pass. While electroporation has been successful in enhancing plasmid gene therapy in the past, it requires very high local voltages and is less suitable for treating large wounds. Iontophoresis refers to the application of a controlled current at typically lower voltages and is of great interest for clinical wound healing involving naked plasmid transfection. We propose an electrical stimulation setup and instrumentation for meeting the demands of this advancing field. Extensive simulations of electrode placements on rat skin models are performed in COMSOL to determine the most promising setup for in vivo iontophoresis. Electrical circuits for iontophoresis, as well as for the measurement of resulting electrical parameters, are designed, simulated, built and tested. Finally, iontophoresis is performed in vivo (on rat dorsum) using intradermally injected DNA plasmids.