Broadband coplanar system for in vitro experiments

A coplanar broadband and efficient system was developed for real-time exposure of in vitro neuronal samples to electromagnetic fields in the microwave range to test their effectiveness in nervous stimulation

Single Cell Microdosimetric Studies Comparing Ideal and Measured Nanosecond Pulsed Electric Fields

Recently, the promising effects induced by pulsed electric fields with high intensity and short duration have been highlighted. At the nanosecond time scale, electric pulse targets become both the plasmatic membrane and the sub-cellular structures (possibility of intracellular manipulation). In this paper, a circuit cell model with nucleus is presented, validated and used in order to assess the different cellular and sub-cellular (i.e. nucleus) effects, comparing ideal nanosecond pulsed electric fields (nsPEFs) waveforms with the ones measured from a planar, broadband matched microchamber

Evidences of plasma membrane-mediated ROS generation upon ELF exposure in neuroblastoma cells supported by a computational multiscale approach

Background: Molecular mechanisms of interaction between cells and extremely low frequency magnetic fields (ELF-MFs) still represent a matter of scientific debate. In this paper, to identify the possible primary source of oxidative stress induced by ELF-MF in SH-SY5Y human neuroblastoma cells, we estimated the induced electric field and current density at the cell level. Methods: We followed a computational multiscale approach, estimating the local electric field and current density from the whole sample down to the single cell level. The procedure takes into account morphological modeling of SH-SY5Y cells, arranged in different topologies. Experimental validation has been carried out: neuroblastoma cells have been treated with Diphenyleneiodonium (DPI) -an inhibitor of the plasma membrane enzyme NADPH oxidase (Nox)- administered 24 h before exposure to 50 Hz (1 mT) MF. Results: Macroscopic and microscopic dosimetric evaluations suggest that increased current densities are induced at the plasma membrane/extra-cellular medium interface; identifying the plasma membrane as the main site of the ELF-neuroblastoma cell interaction. The in vitro results provide an experimental proof that plasma membrane Nox exerts a key role in the redox imbalance elicited by ELF, as DPI treatment reverts the generation of reactive oxygen species induced by ELF exposure. General significance: Microscopic current densities induced at the plasma membrane are likely to play an active physical role in eliciting ELF effects related to redox imbalance. Multiscale computational dosimetry, supported by an in vitro approach for validation, is proposed as the innovative and rigorous paradigm to unveil mechanisms underlying the complex ELF-MF interactions

A microdosimetry study for a realistic shaped nucleus

n the last decades, the effects of ultrashort pulsed electric fields have been investigated demonstrating their capability to be involved in a great number of medical applications (e.g. cancer, gene electrotransfer, drug delivery, electrofusion). In particular, experiments in literature demonstrate that internal structures can be involved when pulse duration is reduced. Up to now, the mechanism that permits the electroporation phenomenon has not been completely understood and hence atomistic, microdosimetry and dosimetry models have been developed to help in this field

Confocal microscopy improves 3D microdosimetry applied to nanoporation experiments targeting endoplasmic reticulum

In the last years, microdosimetric numerical models of cells including intracellular compartments have been proposed, aiming to investigate the poration induced by the application of nanosecond pulsed electric fields (nsPEFs). A limitation of such models was the extremely approximate cell and organelle shapes, leading to an incorrect estimation of the electric field or transmembrane potential distribution in the studied domain. In order to obtain a reliable model of in vitro experiments and a one-to-one comparison between experimental and simulated results, here, a realistic model of 12 human mesenchymal stem cells was built starting from their optical microscopy images where different cell compartments were highlighted. The microdosimetric analysis of the cells group was quantified in terms of electric field and transmembrane potentials (TMPs) induced by an externally applied 10-ns trapezoidal pulse with rise and fall times of 2 ns, with amplitudes ranging from 2 to 30 MV/m. The obtained results showed that the plasma and endoplasmic reticulum (ER) membrane of each cell respond in a different way to the same electric field amplitude, depending on differences in shape, size, and position of the single cell with respect to the applied electric field direction. Therefore, also the threshold for an efficient electroporation is highly different from cell to cell. This difference was quantitatively estimated through the cumulative distribution function of the pore density for the plasma and ER membrane of each cell, representing the probability that a certain percentage of membrane has reached a specific value of pore density. By comparing the dose-response curves resulted from the simulations and those from the experimental study of De Menorval et al. (2016), we found a very good matching of results for plasma and ER membrane when 2% of the porated area is considered sufficient for permeabilizing the membrane. This result is worth of noting as it highlights the possibility to effectively predict the behavior of a cell (or of a population of cells) exposed to nsPEFs. Therefore, the microdosimetric realistic model described here could represent a valid tool in setting up more efficient and controlled electroporation protocols

Smart flexible planar electrodes for electrochemotherapy and biosensing

Electroporationis an effective method to deliver drugs into tumor cells to kill them, by applying a pulsed electric field to the cellular membrane [1, 2]. Existing electrodes consist of clamping claws or arrays of needles and can be effectively applied only to small areas. New electrodes that can treat large areas are sought; flexibility is needed to adapt to irregular tumor shape and, to be folded to enter from small surgical opening. In this work we present the design and test of a 16 cm2 flexible electrode for electroporation with biosensing capabilities, built with standard flexible circuit technologies enclosed in a biocompatible package. The electrode contains electronics to provide cryptography-based identification to the electroporation machine to avoid setup errors and protection against use of counterfeited electrodes. In-vitro tests of the electrode show that electroporation occurs up to a depth of 8 mm with 100% electroporation efficiency over the 30% of electrode area. Temperature rise on the electrode during treatment does not exceed 6 degrees celsius, a value that not causes damage to the cells

A Microdosimetric Realistic Model to Study Frequency-Dependent Electroporation in a Cell with Endoplasmic Reticulum

The study of the frequency-dependent response of a biological cell and its organelles to an intense electric field is of growing interest in the bioelectromagnetic area. The possibility offered by continuous waves to uncouple the effects of the electric field during electroporation is employed in this work using a numerical model including the realistic shape of cell and endoplasmic reticulum membranes. The higher efficiency of the microwave signals in electroporating the subcellular structures, in comparison with the radiofrequency signals, is highlighted

Feasibility of Drug Delivery Mediated by Ultra-Short and Intense Pulsed Electric Fields

The increasing interest towards biocompatible nanotechnologies in medicine, combined with electric fields stimulation, is leading to the development of electro-sensitive smart systems for drug delivery applications. Common examples of electro-sensitive materials include phospholipids that can be used to design nano-sized vesicles suitable for external electric actuation. To this regard, recently the use of pulsed electric fields to trigger release across phospholipid membranes has been numerically studied, for a deeper understanding of the phenomena at the molecular scale. Aim of this work is to give an experimental validation of the feasibility of controlling drug release from liposomes mediated by nanosecond pulsed electric fields

Smart flexible planar electrodes for electrochemotherapy and biosensing

Electroporationis an effective method to deliver drugs into tumor cells to kill them, by applying a pulsed electric field to the cellular membrane [1, 2]. Existing electrodes consist of clamping claws or arrays of needles and can be effectively applied only to small areas. New electrodes that can treat large areas are sought; flexibility is needed to adapt to irregular tumor shape and, to be folded to enter from small surgical opening. In this work we present the design and test of a 16 cm2 flexible electrode for electroporation with biosensing capabilities, built with standard flexible circuit technologies enclosed in a biocompatible package. The electrode contains electronics to provide cryptography-based identification to the electroporation machine to avoid setup errors and protection against use of counterfeited electrodes. In-vitro tests of the electrode show that electroporation occurs up to a depth of 8 mm with 100% electroporation efficiency over the 30% of electrode area. Temperature rise on the electrode during treatment does not exceed 6 degrees celsius, a value that not causes damage to the cells