Regulated Heat Combined with Impedance Spectroscopy to Improve and Control Electroporative DNA Delivery to the Skin in Vivo

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PROJECT SUMMARY / ABSTRACT: Gene therapy is not yet a reality. One obstacle and generalization is that methods for delivering genes in vivo have not yet achieved a desired level of reliability and control. In vivo electroporation is a method for delivering DNA that has been successful in preclinical studies. These have been performed using the technology for a variety of applications. Collectively, they prove that the physical basis of the method makes it adaptable to any tissue. These studies paved the way for over 100 clinical trials that use the technology in vivo. Thus, there are clear research and clinical applications for this DNA delivery method. But, the method could be improved because it still suffers from lack of control/reliability. One reason for this is that the characteristics of the electric pulses used to induce DNA uptake are normally fixed for a particular tissue type based upon optimization in animal models. These may have little translatability to analogous tissues in clinical settings as models may not be identical to human tissues. In addition, there is variation from individual to individual. Thus, using the same electric pulses (or dose of electricity) to deliver DNA to a particular type of tissue is not likely to be optimal each time the method is used in that tissue type. Unfortunately, this is the current state of the art. A means of customizing/adapting electrical treatment in real-time could circumvent this issue and add to the efficiency/reliability of the method. Another issue with the state of the art is that in vivo electroporation affects cell membranes and has traditionally been performed at ambient temperature. Moderately increased temperatures could affect the results as they influence membrane fluidity. This proposed R01 has been designed to address these two aspects in combination to improve delivery in skin. The basis for this study is preliminary data that indicate approximately 10-fold increases in delivery when customized pulses or moderate temperature increases are used alone The research plan includes implementing electroporation pulse delivery that is dynamic rather than fixed while controlling the temperature at the skin treatment site. The system will utilize real-time measurements of tissue electrical impedance changes that result from electroporation pulses. The system will be capable of applying multiple electric pulses, measure impedance between pulses, and make adjustments to the electrical treatment to control the delivery procedure while maintaining a user set moderately elevated temperature. It is expected that reliability and control will be increased by achieving higher delivery/expression of the DNA and reduced variation.