RESUMEN
Nanosecond electric pulses are an effective power source in plasma medicine and biological stimulation, in which biophysical responses are governed by peak power and not energy. While uniphasic nanosecond pulse generators are widely available, the recent discovery that biological effects can be uniquely modulated by reversing the polarity of nanosecond duration pulses calls for the development of a multimodal pulse generator. This paper describes a method to generate nanosecond multiphasic pulses for biomedical use, and specifically demonstrates its ability to cancel or enhance cell swelling and blebbing. The generator consists of a series of the fundamental module, which includes a capacitor and a MOSFET switch. A positive or a negative phase pulse module can be produced based on how the switch is connected. Stacking the modules in series can increase the voltage up to 5 kV. Multiple stacks in parallel can create multiphase outputs. As each stack is independently controlled and charged, multiphasic pulses can be created to produce flexible and versatile pulse waveforms. The circuit topology can be used for high-frequency uniphasic or biphasic nanosecond burst pulse production, creating numerous opportunities for the generator in electroporation applications, tissue ablation, wound healing, and nonthermal plasma generation.
Asunto(s)
Fenómenos Fisiológicos Celulares/fisiología , Electrofisiología/instrumentación , Electrofisiología/métodos , Modelos Biológicos , Nanotecnología/métodos , Animales , Células CHO , Cricetinae , CricetulusRESUMEN
Non-thermal atmospheric pressure plasma has been demonstrated to inactivate a wide range of surface-dwelling pathogenic microorganisms including airborne viral particles, vegetative bacteria and bacterial spores. This shows the promise of plasma-based decontamination procedures for broad-spectrum sterilization and disinfection and promotes the in-depth and systematic study of how plasma treatment conditions relate to pathogen inactivation efficiency. A wide knowledge gap nonetheless exists regarding whether certain plasma parameters and exposure conditions can alter the resistance of virus-linked cancer cells to treatment. The current work reveals the effects of a non-thermal needle-shaped atmospheric-pressure plasma on the viability of an adherent human cervical carcinoma cell line containing a human papillomavirus type 16 (HPV-16) provirus. Using a helium plasma device driven by 8 kV, 2 kHz, 150 ns pulses, CaSki cells moistened with culture medium were exposed to plasma for different treatment durations, gap distances and gas flow rates. Open-well exposure to helium flow alone for 120 s did not produce significant changes in CaSki cell viability. By comparison, cells exposed to plasma showed a dose-dependent reduction in viability from at least 15% to 60% compared to the control. These findings reveal possibilities for NTP treatment of HPV-16 infected cervical cancers and indicate the importance of NTP parameters to treatment outcome.