Ultrastructural changes in hepatocellular carcinoma cells induced by exponential pulses of nanosecond duration delivered via a transmission line.

Clinical applications of high-intensity pulsed electric fields have proven useful in ablating solid tumors. However, novel ideas for the development of an effective tumor ablation device are urgently needed. Here, we studied cellular effects of the nanosecond exponential pulse, which is generated by a capacitor-discharging circuit and delivered via a transmission line. Pulses of peak voltage boosted by transmission line oscillation possess high capability to induce swelling and to cause loss of viability in cells. The appropriate parameter of the pulse was selected to investigate the ultrastructural changes in swollen cells, which present smoothened plasma membrane, loss of microvilli, and lowered cytoplasm electron density. We propose the equivalent force field hypothesis to understand the mechanism underlying cell swelling induced by pulsing. Wrinkles on the plasma membrane might indicate recovery from cell swelling, and this was verified by co-culture of pulsed PKH26-Cells with sham-treated PKH67-Cells. We concluded that the ultrastructural changes, such as irregular pores formed on the plasma membrane, were mainly induced by the effect of electric pulse applied on the charged molecules in the membrane.

On the design and characterization of a new cold atmospheric pressure plasma jet and its applications on cancer cells treatment.

In this paper, a new configuration of a cold atmospheric pressure plasma jet has been designed and constructed. Poly-methyl-methacrylate was used as a new dielectric in this configuration which in comparison to other dielectrics is inexpensive, more resistant against break, and also more shapeable. Then, the plasma jet parameters such as plume temperature, rotational and vibrational temperatures, power, electrical behavior (voltage and current profile), electron density, and the produced reactive species were characterized. In order to determine the jet temperature and the amount of reactive species, effects of applied voltage, gas flow rate, and distance from the nozzle were studied. The power of the jet was specified using Lissajous curve approach. The plume temperature of the plasma jet was about the room temperature. Optical emission spectroscopy determined the type of reactive species, and also electron density and its corresponding plasma frequency (~6.4 × 10(13) cm(-3) and 4.52 × 10(11) Hz). Because of producing different reactive species, the device can be used in different applications, especially in plasma medicine. Thus, 4T1 cancer cells were treated using this plasma jet. The results showed that this plasma jet has a great potential to kill one of the most aggressive and resistant cancerous cell lines.