Abstract

While cold atmospheric pressure plasmas (CAPPs) 1 and electric pulses (EPs) 2 have demonstrated excellent potential for sterilization, wound healing, and cancer treatment, synergistic combinations have only rarely been considered. 3 While EPs induce biological effects predominantly by membrane charging 2, CAPPs induce effects by creating reactive species that change cellular function 1. To explore the parameter space for these synergistic effects, we assess the impact of combining a helium plasma jet 4 with an electric pulse in various combinations beyond those considered previously with an argon jet 3. Understanding and optimizing the biological effects of these treatments requires measuring the reactive species and comparing those to the resulting biological effects, such as cell death or membrane permeabilization. We spatially characterize the cold helium plasma by optical emission spectroscopy (OES) using an optical fiber/convex lens pair. We project an approximately 4 cm plasma plume, generated by a 2 kV high voltage system with a helium flow rate of 1.0 lpm, onto the OES system. This permits the spatial characterization of the molecular species as they vary along the plume length by using key molecular emission lines. Potential implications for biophysical experiments are discussed.