Theory and in Vivo Application of Electroporative Gene Delivery

Abstract

Efficient and safe methods for delivering exogenous genetic material into tissues must be developed before the clinical potential of gene therapy will be realized. Recently, in vivo electroporation has emerged as a leading technology for developing nonviral gene therapies and nucleic acid vaccines (NAV). Electroporation (EP) involves the application of pulsed electric fields to cells to enhance cell permeability, resulting in exogenous polynucleotide transit across the cytoplasmic membrane. Similar pulsed electrical field treatments are employed in a wide range of biotechnological processes including in vitro EP, hybridoma production, development of transgenic animals, and clinical electrochemotherapy. Electroporative gene delivery studies benefit from well-developed literature that may be used to guide experimental design and interpretation. Both theory and experimental analysis predict that the critical parameters governing EP efficacy include cell size and field strength, duration, frequency, and total number of applied pulses. These parameters must be optimized for each tissue in order to maximize gene delivery while minimizing irreversible cell damage. By providing an overview of the theory and practice of electroporative gene transfer, this review intends to aid researchers that wish to employ the method for preclinical and translational gene therapy, NAV, and functional genomic research.

Effective gene transfer to solid tumors using different nonviral gene delivery techniques: Electroporation, liposomes, and integrin-targeted vector

“…It was already proposed that this observation could be due to the specific properties of the tumor tissue, such as differences in tissue organisation, in extracellular matrix, presence or absence of necrosis, overall tissue conductivity, the ability of cells to express transfected genes, cell density, and cell size. 13,19,33 A correlation between cell density and transfection efficiency by electroporation demonstrated that lower cell density yielded better transfection (Fig 7 ), which is in agreement with in vitro data obtained on adherent cells. 36 The correlation was not very high, as only four tumor types were included and should be expanded in a further study to prove the hypothesis.…”

“…13 In the case of tumors, many different electrical parameters for electroporation were employed for delivering plasmid DNA encoding either reporter (luciferase, -galactosidase, GFP ) or therapeutic genes (IL -12, Stat3, GM -CSF, IL -2). 25 -35 Our study focused on optimisation of plasmid DNA delivery to tumors by using different electrical parameters and DNA concentrations in the SaF tumor model.…”

“…11,12 In addition, some recent studies have examined the use of electroporation to deliver plasmid DNA to various types of tissues in vivo, such as skin, liver, testis, brain, skeletal muscle, and tumors. 13 Various settings of electroporation were used, with no general conclusion on the optimal electrical, DNA, and environmental parameters for effective DNA transfer, especially when delivering DNA to tumors. High -voltage microsecond pulses, which were used in electrochemotherapy, and low-voltage milliseconds pulses, which were found to be the most suitable for skeletal muscle transfection, were both used in gene delivery protocols for transfecting tumors.…”

Synergistic antitumor effect of antiangiogenic factor genes on colon 26 produced by low-voltage electroporation

“…12 In addition, efficacy is also dependent on the concentration gradient of the molecules that are to be delivered. 21 The longer the loading period, the longer the cell surface is open. Hence, it is likely that more of the agent would be transferred from the extracellular to the intracellular space.…”

Monitoring intracellular degradation of exogenous DNA using diffusion properties

“…Then a sequential process progresses spontaneously with escape from endosomes, dissociation of complexes, and diffusion of naked DNAs in the cytoplasm to reach the nucleus [4][5][6]. On the other hand, physical approaches such as microinjection [7,8] and electroporation [9] are performed to incorporate naked DNAs directly into cytoplasm across the plasma membrane. Some naked DNAs diffuse in the cytoplasm to the nucleus [10].…”