Integrative Graduate Education and Research Training (IGERT)

Zhang et al. (2002) showed that non-invasive electroporation (EP) was successful for DNA delivery and gene therapy into skin cells with no adverse effects to the skin. The topical electrodes, a caliper electrode or a meander electrode, were designed based on two critical criteria; the electrical field strength and tissue damage. The system included a square wave pulse generator (ECM 830) and a topical electrode. According to the study, EP is defined as an application of short, controlled, electric pulses to the target tissue. It forms transient aqueous pathways across the cell membranes. The perforation of the stratum corneum and the transmembrane delivery of DNA into the skin cells were two distinct processes performed by this system.

The second study by Prausnitz (1996) characterized the effects of high-voltage pulses on the skin. It hypothesized that voltage pulses related to electroporation causes tissue changes. Transdermal transport was found to be voltage dependent. The voltage range was 50-100V. The third study by Ionescu-Tirgoviste et al. (1988) described the use of a Skin Electrical Relative Resistance Variation (SERV) system to detect the functional status of the autonomic nervous system (ANS) by evoked electrodermal responses. The fourth study by Ivanic et al. (2000) presented a non-symmetric thin film Interdigitated Array (IDA) electrode system used to characterize skin laminar structures. These micro-electrodes showed an increase in sensitivity measurements.

The fifth study by Riedel et al. (2001) compared two systems to induce different geometrical arrangements of eddy currents in conductive tissues. It was based on the assumption that a time varying magnetic field will induce eddy currents in conductive tissues. These systems were simulated using a conductivity gradient.  The sixth study by Nyren et al. (2003) compared nickel allergic contact reaction with induced sodium lauryl sulfate irritant contact reaction on the forearm.  Two methods (electrical impedance and Transepidermal Water Loss (TEWL)) were used and compared. Patients were chosen based on previous reaction on standard epicutaneous testing. A patch test is currently used to evaluate contact dermatitis.  To objectively assess the patch test, this study established an alternative test for classifying skin reactions. TEWL was tested by an Evaporimeter and the electrical impedance measurements were tested by an Electrical Impedance Spectrometer.