Electro-gene transfer to skin using a noninvasive multielectrode array

Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
Journal of Controlled Release (Impact Factor: 7.71). 05/2011; 151(3):256-62. DOI: 10.1016/j.jconrel.2011.01.014
Source: PubMed


Because of its large surface area and easy access for both delivery and monitoring, the skin is an attractive target for gene therapy for cutaneous diseases, vaccinations and several metabolic disorders. The critical factors for DNA delivery to the skin by electroporation (EP) are effective expression levels and minimal or no tissue damage. Here, we evaluated the non-invasive multielectrode array (MEA) for gene electrotransfer. For these studies we utilized a guinea pig model, which has been shown to have a similar thickness and structure to human skin. Our results demonstrate significantly increased gene expression 2 to 3 logs above injection of plasmid DNA alone over 15 days. Furthermore, gene expression could be enhanced by increasing the size of the treatment area. Transgene-expressing cells were observed exclusively in the epidermal layer of the skin. In contrast to caliper or plate electrodes, skin EP with the MEA greatly reduced muscle twitching and resulted in minimal and completely recoverable skin damage. These results suggest that EP with MEA can be an efficient and non-invasive skin delivery method with less adverse side effects than other EP delivery systems and promising clinical applications.

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    • "The protective nature of the SC is attributed to its multilayered wall-like structure, in which terminally differentiated keratinocytes are embedded in an intercellular lipid-rich matrix. Various approaches have been developed in recent decades to overcome the skin barrier properties including physical approaches using iontophoresis, sonophoresis and microneedles [3,4], chemical approaches using penetration enhancers, and biochemical approaches using liposomal vesicles and enzyme inhibition [5,6,7,8]. "
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    ABSTRACT: In the present study, we designed and developed novel lipids that include (Z)-1-(Octadec-9-en-1-yl)-pyrrolidine (Cy5T), 1, 1-Di-((Z)-octadec-9-en-1-yl)pyrrolidin-1-ium iodide (Cy5), (Z)-1-(Octadec-9-en-1-yl)-piperidine (Cy6T), and 1, 1-Di-((Z)-octadec-9-en-1-yl) piperidin-1-ium iodide (Cy6) to enhance the transdermal permeation of some selected drugs. Firstly, we evaluated the transdermal permeation efficacies of these lipids as chemical permeation enhancers in vehicle formulations for melatonin, ß-estradiol, caffeine, α-MSH, and spantide using franz diffusion cells. Among them Cy5 lipid was determined to be the most efficient by increasing the transdermal permeation of melatonin, ß-estradiol, caffeine, α-MSH, and spantide by 1.5 to 3.26-fold more at the epidermal layer and 1.3 to 2.5-fold more at the dermal layer, in comparison to either NMP or OA. Hence we developed a nanoparticle system (cy5 lipid ethanol drug nanoparticles) to evaluate any further improvement in the drug penetration. Cy5 lipid formed uniformly sized nanoparticles ranging from 150-200 nm depending on the type of drug. Further, Cy5 based nanoparticle system significantly (p<0.05) increased the permeation of all the drugs in comparison to the lipid solution and standard permeation enhancers. There were about 1.54 to 22-fold more of drug retained in the dermis for the Cy5 based nanoparticles compared to OA/NMP standard enhancers and 3.87 to 66.67-fold more than lipid solution. In addition, epifluorescent microscopic analysis in rhodamine-PE permeation studies confirmed the superior permeation enhancement of LEDs (detection of fluorescence up to skin depth of 340 μm) more than lipid solution, which revealed fluorescence up to skin depth of only 260 μm. In summary the present findings demonstrate that i) cationic lipid with 5 membered amine heterocyclic ring has higher permeating efficacy than the 6 membered amine hertocyclic ring. ii) The nanoparticle system prepared with Cy5 showed significant (p<0.05) increase in the permeation of the drugs than the control penetration enhancers, oleic acid and NMP.
    Full-text · Article · Dec 2013 · PLoS ONE
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    • "A second option is hairless guinea pig (HLGP) skin, whose skin is very similar to human skin anatomically and histologically as opposed to the skin of normal rodents [20]. Previously, we [12], [16] demonstrated that GET to the skin resulted in efficient expression in rat and the Hartley guinea pig (haired). In this study, we further characterize several important aspects associated with potential clinical applications, such as the level and duration of gene expression, distribution of gene expression within the tissue and side effects in this model. "
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    ABSTRACT: Topical gene delivery to the epidermis has the potential to be an effective therapy for skin disorders, cutaneous cancers, vaccinations and systemic metabolic diseases. Previously, we reported on a non-invasive multielectrode array (MEA) that efficiently delivered plasmid DNA and enhanced expression to the skin of several animal models by in vivo gene electrotransfer. Here, we characterized plasmid DNA delivery with the MEA in a hairless guinea pig model, which has a similar histology and structure to human skin. Significant elevation of gene expression up to 4 logs was achieved with intradermal DNA administration followed by topical non-invasive skin gene electrotransfer. This delivery produced gene expression in the skin of hairless guinea pig up to 12 to 15 days. Gene expression was observed exclusively in the epidermis. Skin gene electrotransfer with the MEA resulted in only minimal and mild skin changes. A low level of human Factor IX was detected in the plasma of hairless guinea pig after gene electrotransfer with the MEA, although a significant increase of Factor IX was obtained in the skin of animals. These results suggest gene electrotransfer with the MEA can be a safe, efficient, non-invasive skin delivery method for skin disorders, vaccinations and potential systemic diseases where low levels of gene products are sufficient.
    Full-text · Article · Aug 2013 · PLoS ONE
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    ABSTRACT: Current progress in the development of vaccines has decreased the incidence of fatal and non-fatal infections and increased longevity. However, new technologies need to be developed to combat an emerging generation of infectious diseases. DNA vaccination has been demonstrated to have great potential for use against a wide variety of diseases. Alone, this vaccine technology does not generate a significant immune response for vaccination, but combined with delivery by electroporation (EP), can enhance plasmid expression and immunity against the expressed antigen. Most EP systems, while effective, can be invasive and painful making them less desirable for use in vaccination. Our lab recently developed a non-invasive electrode known as the multi-electrode array (MEA), which lies flat on the surface of the skin without penetrating the tissue. This study evaluated the use of the MEA for the development of DNA vaccines. We assessed the appropriate delivery conditions for gene expression and the development of humoral immunity. We used both B. anthracis and HBV as infectious models for our experiments. Our results indicated that the MEA can enhance gene expression in a mouse model with minimal to no tissue damage. Optimal delivery conditions, based on generation of antibodies, were determined to be 125-175V/cm and 150ms with 200ug and a prime boost protocol administered on Day 0 and 14. Under these conditions, end-point titers of 20,000-25,000 were generated. Neutralizing antibodies were noted in 40-60% of animals. Additionally, we utilized a guinea pig model to assess the translation potential of this electrode. The plasmid encoding HBsAg, pHBsAg, was delivered intradermally with the MEA to guinea pig skin. The results show increased protein expression resulting from plasmid delivery using the MEA as compared to injection alone. Within 48 hours of treatment, there was an influx of cellular infiltrate in the experimental groups. Humoral responses were also increased significantly in both duration and intensity as compared to the injection only groups. Results from both experimental models demonstrate that protective levels of humoral immunity can be generated and that this electrode should translate well to the clinic.
    Full-text · Article · Jan 2011
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