OI Ljubljana

Non-invasive technique for Cell Membrane Permeabilization using pulsed electromagnetic fields

An exposure of a cell to an electric field of an adequate strength and duration leads to a transient increase of cell membrane permeability. This phenomenon, termed electroporation, allows various otherwise nonpermeant molecules to cross the membrane and enter the cell. Both in vitro and in vivo, electroporation allows for internalization of a wide range of substances, including chemotherapeutics and DNA. All electroporation applications require direct contact between the electrodes and the treated object, that is either via plate electrodes, which embrace the tissue, or using invasive needle electrodes, which are inserted into the tissue. The use of invasive electrodes, such as needle electrodes, which are most effective in electroporation treatment of a variety of tissues have a number of drawbacks common to all invasive procedures, e.g., assuring sterile incisions and causing trauma to tissues by incision. There are additional side effects due to application of electric pulses.

Recently, a new cell membrane permeabilization method by pulsed electromagnetic fields has been proposed. Pulsed electromagnetic fields induced increase of the cell membrane permeability is similar to conventional electroporation with the important difference of non-invasive establishment of electric field by exposing a treated tissue to a time-varying magnetic field. Currently, however, the electric field that is induced by the time-varying magnetic field is lower (by several orders of magnitude) than the electric field causing membrane permeabilization in conventional electroporation experiments, resulting in inferior efficacy of the pulsed electromagnetic fields treatment to conventional electroporation. Still, the proof of concept has been confirmed both in vitro and in vivo for the pulsed electromagnetic fields mediated transport of small molecules and large functional molecules.

The non-straightforward dependence of the pulsed electromagnetic fields induced permeabilization on the treatment parameters requires further research of different parameters of applied electromagnetic field. The proposed project is the first attempt to systematically explore the phenomenon of cell membrane permeabilization using magnetic pulses through in vitro and in vivo experimentation combined with theoretical and numerical analysis. In the project, we will explore a range of the magnetic pulse parameters, develop new magnetic pulse applicators and determine possibility of different molecules being loaded into cells by means of pulsed electromagnetic fields.

In the project, we will first determine both magnetic and electric field established during application of pulsed electromagnetic fields in cell suspensions and in tissues. Determination will be based on a numerical model which we will build from the geometry of the applicator and treated object, i.e. either cell suspensions or tissues. Then, we will focus on the development of new geometries of magnetic pulse applicators. We will evaluate different geometrical arrangement of coils for the applicators used in in vitro experiments as well for in vivo. New geometries will be developed through numerical modelling and most the appropriate coils will be built and used in experiments in the next stages of the project. We will start by performing experiments in vitro by evaluating the cell membrane permeabilization of cell suspensions treated with pulsed electromagnetic fields delivered by newly developed magnetic pulse applicator. Using magnetic pulse parameters, that will enable highest permeabilization of cells, we will perform the delivery of cytotoxic compound and nucleic acids into cells. In the last part of the project, we will analyze and improve antitumor effectiveness of pulsed electromagnetic fields as a drug delivery system for cytotoxic compounds to murine subcutaneous tumors and explore the feasibility of pulsed electromagnetic fields in gene electrotransfer for small and large molecules in tissues




© 2019 - Institute of Oncology Ljubljana
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