Finite-element modelling and preliminary validation of microneedle-based electrodes for enhanced tissue electroporation

This paper investigates the use of microneedle-based electrodes for enhanced testis electroporation, with specific application to the production of transgenic mice. During the design phase, finite-element software has been used to construct a tissue model and to compare the relative performance of electrodes employing a) conventional flat plates, b) microneedle arrays, and c) invasive needles. Results indicate that microneedle-based electrodes can achieve internal tissue field strengths which are an order of magnitude higher than those generated using conventional flat electrodes, and which are comparable to fields produced using invasive needles. Using a double-sided etching process, conductive microneedle arrays were then fabricated and used in prototype electrodes. In a series of mouse model experiments involving injection of a DNA vector expressing Green Fluorescent Protein (GFP), the performance of flat and microneedle electrodes was compared by measuring GFP expression after electroporation. The main finding, supported by experimental and simulated data, is that use of microneedle-based electrodes significantly enhanced electroporation of testis.