Preliminary Study on the Effect of a Single High-Energy Electromagnetic Pulse on Morphology and Free Radical Generation in Human Mesenchymal Stem Cells

Abstract

The effect of nanosecond electromagnetic pulses on human health, and especially on forming free radicals in human cells, is the subject of continuous research and ongoing discussion. This work presents a preliminary study on the effect of a single high-energy electromagnetic pulse on morphology, viability, and free radical generation in human mesenchymal stem cells (hMSC). The cells were exposed to a single electromagnetic pulse with an electric field magnitude of ~1 MV/m and a pulse duration of ~120 ns generated from a 600 kV Marx generator. The cell viability and morphology at 2 h and 24 h after exposure were examined using confocal fluorescent microscopy and scanning electron microscopy (SEM), respectively. The number of free radicals was investigated with electron paramagnetic resonance (EPR). The microscopic observations and EPR measurements showed that the exposure to the high-energy electromagnetic pulse influenced neither the number of free radicals generated nor the morphology of hMSC in vitro compared to control samples.

New approaches for low phototoxicity imaging of living cells and tissues

“…[10,22] Additional techniques, like electron paramagnetic resonance, offer precise determination of free radicals in the sample. [23] Notably, this method can be executed on microscope slides, distinguishing it as the technique capable of quantitatively measuring the concentration of oxygen species in the biological sample under microscopic observation. [24,25]…”

Advancing the Design of Artificial Nano-organelles for Targeted Cellular Detoxification of Reactive Oxygen Species

“…The specific nitroxide ESR spectrum appeared (with a gyromagnetic factor g = 2.0064 and a N hyperfine coupling constant a = 45.08 MHz) (Figure 3B). 26 The low level of the nitroxide radical associated-ESR spectra obtained from cells without AnOs reflects basal ROS levels in K562 cells (Figure 3D). When control cells were stressed by 40 and 300 μM H 2 O 2 , the ROS levels increased 2-fold and 3-fold, respectively (Figure 3D).…”

“…CMH serves to detect the presence of ROS by formation of the electron paramagnetic resonance (EPR) detectable 3-methoxycarbonyl-proxyl radical, CM • (Figure A). , Then, cells were incubated with 40 or 300 μM H 2 O 2 and incubated at 37 °C for another 4 h before the measurement. The specific nitroxide ESR spectrum appeared (with a gyromagnetic factor g = 2.0064 and a N hyperfine coupling constant a = 45.08 MHz) (Figure B) . The low level of the nitroxide radical associated-ESR spectra obtained from cells without AnOs reflects basal ROS levels in K562 cells (Figure D).…”

“…The surface-exposed dendritic cell-penetrating peptides were crucial for a more efficient delivery of AnOs to cells, while the insertion of the transmembrane pores formed by melittin in the first place, allowed H 2 O 2 to cross the membrane barrier and to get degraded inside the AnOs. Furthermore, the AnOs were designed with a hydrophilic PMOXA domain, which renders surfaces nonadhesive along with decreasing immunogenicity and thus improving the systemic circulation time. , The mixture of diblock copolymers provided the necessary fluidity and stability of the AnOs, while supporting melittin insertion and their further functionalization with dendritic cell-penetrating peptides for cell targeting. As a first step toward biomedical application, these AnOs should prove a useful tool for studying how artificial organelles integrate into existing cellular signaling networks, in particular those involved in the cell’s endogenous response to redox imbalance, as for example the Nrf2 pathway.…”