Introduction: Skin electroporation is a promising treatment for transdermal drug delivery, gene electrotransfer, skin rejuvenation, electrochemotherapy, and wound disinfection. Although a considerable amount of in vitro and in vivo studies exists, the translation to clinics is not as fast as one would hope. We hypothesize the reason lies in the inadequate dosimetry, i.e. electrode configurations, pulse parameters and pulse generators used. We suggest adequate dosimetry can be determined by mathematical modeling and would allow comparison of protocols and facilitate translation into clinics. Areas covered: We introduce the mechanisms and applications of skin electroporation, present existing mathematical models and compare the influence of different model parameters. We review electrodes and pulse generators, prototypes as well as commercially available models. Expert opinion: The reasons for slow translation of skin electroporation treatments into clinics lie in uncontrolled and inadequate dosimetry, poor reporting rendering comparisons between studies difficult, and significant differences in animal and human skin morphology, often dismissed in reports. Mathematical models enable comparison of studies, however, when the parameters of the pulses and electrode configuration are not adequately reported, as is often the case, comparisons are difficult, if not impossible. For each skin electroporation treatment, systematic studies determining optimal parameters should be performed and treatment parameters standardized.

Nanosecond electroporation of cell organelles is being studied for more than a decade, but it is still not entirely understood. Unique prototype hardware equipment and challenging measuring methods may also be a contributing reason for this situation. In the scope of this paper we improve the performance of the high-voltage nanosecond pulse generator by introducing Silicon carbide (SiC) MOSFETs. We developed a new high-voltage Diode Opening Switch (DOS) - nanosecond pulse generator for laboratory use for “in vitro” experiments in electroporation cuvettes. Analysis and comparison of the most commonly used switching technologies in pulse generators were made. The device is designed by two parallel two-stage Marx-bank circuits with SiC MOSFETs which generates up to 200 A in the resonant network. A driving circuit for stable simultaneous switching of SiC MOSFETs was developed. The developed generator can deliver from 500 V to more than 6 kV, approximately 8 ns pulses to a 50 Ω load. Even though the amplitude of the output pulse is not as high as expected, the multiplication factor $V_{OUT} /V_{IN}$ is still approximately 9, which is an improvement compared to the previously published linear DOS generator. Measurement and evaluation process is described in detail. Additionally we emphasize on the size of an error which occurs during measurements.

Cell exposure to high-voltage, short-duration electric pulses can lead to temporary formation of hydrophilic pores in the plasma membrane and an increase in the membrane's permeability which consequently increases the transmembrane transport of molecules that are otherwise unable to cross the membrane. This phenomenon, termed membrane electroporation, is currently an applicable technique in different areas such as biomedicine, biotechnology, food technology and environmental applications. Electroporation pulses are generated by pulse power generators known as electroporators and delivered to the cells (in tissue) via electrodes. The objective of this paper is to review and compare characteristics of electroporation applications and equipment described in the literature and/or present on the market. Since there are no specific standards or regulations that specifically refer to the safety of medical devices with intended medical uses for electroporation, we propose guidelines for the design of clinical electroporators and define minimal requirements for their safe and efficient use which can be incorporated within the particular standards in the future. In order to facilitate the comparison of data obtained by different research groups and to enable reproduction of results under the same conditions, we want to stress the necessity of defining the electroporator's output parameters and tolerances of electroporation parameters for electroporation-based therapies.

The exact mechanisms of nucleic acid (NA) delivery with gene electrotransfer (GET) are still unknown, which represents a limitation for its broader use. Further, not knowing the effects that different experimental electrical and biological parameters have on GET additionally hinders GET optimization, resulting in the majority of research being performed using a trial-and-error approach. To explore the current state of knowledge, we conducted a systematic literature review of GET papers in in vitro conditions and performed meta-analyses of the reported GET efficiency. For now, there is no universal GET strategy that would be appropriate for all experimental aims. Apart from the availability of the required electroporation device and electrodes, the choice of an optimal GET approach depends on parameters such as the electroporation medium; type and origin of cells; and the size, concentration, promoter, and type of the NA to be transfected. Equally important are appropriate controls and the measurement or evaluation of the output pulses to allow a fair and unbiased evaluation of the experimental results. Since many experimental electrical and biological parameters can affect GET, it is important that all used parameters are adequately reported to enable the comparison of results, as well as potentially faster and more efficient experiment planning and optimization.

Currently, in high-frequency electroporation, much progress has been made but limited to research groups with custom-made laboratory prototype electroporators. According to the review of electroporators and economic evaluations, there is still an area of pulse parameters that needs to be investigated. The development of an asymmetric bipolar pulse generator with a maximum voltage of 4 kV and minimum duration time of a few hundred nanoseconds, would enable in vivo evaluation of biological effects of high-frequency electroporation pulses. Herein, from a series of most commonly used drivers and optical isolations in high-voltage pulse generators the one with optimal characteristics was used. In addition, the circuit topology of the developed device is described in detail. The developed device is able to generate 4 kV pulses, with theoretical 131 A maximal current and 200 ns minimal pulse duration, the maximal pulse repetition rate is 2 MHz and the burst maximal repetition rate is 1 MHz. The device was tested in vivo. The effectiveness of electrochemotherapy of high-frequency electroporation pulses is compared to “classical” electrochemotherapy pulses. In vivo electrochemotherapy with high-frequency electroporation pulses was at least as effective as with “classical” well-established electric pulses, resulting in 86% and 50% complete responses, respectively. In contrast to previous reports, however, muscle contractions were comparable between the two protocols.

Electroporation is an emerging technology, with great potential in many different medical and biotechnological applications, food engineering and biomass processing. Large variations of biological load characteristics, however, represent a great challenge in electroporator design, which results in different solutions. Because a clinical electroporator is a medical device, it must comply with medical device regulative and standards. However, none of the existing standards directly address the operation or electroporator’s performance requirements. In order to evaluate clinical, laboratory and prototype electroporation devices during the development process, or to evaluate their final performance considering at least from the perspective of output pulse parameters, we present a case study on the design of an electronic emulator of biological tissue as an electrical load during electroporation. The proposed electronic load emulator is a proof of concept, which enables constant and sustainable testing and unbiased comparison of different electroporators’ operations. We developed an analog electrical circuit that has equivalent impedance to the beef liver tissue in combination with needle electrodes, during high voltage pulse delivery and/or electroporation. Current and voltage measurements during electroporation of beef liver tissue ex vivo, were analyzed and parametrized to define the analog circuit equation. An equivalent circuit was simulated, built and validated. The proposed concept of an electronic load emulator can be used for “classical” electroporator (i.e., not nanosecond) performance evaluation and comparison of their operation. Additionally, it facilitates standard implementation regarding the testing protocol and enables quality assurance.