A Comparison of Floating-Electrode DBD and kINPen Jet: Plasma Parameters to Achieve Similar Growth Reduction in Colon Cancer Cells Under Standardized Conditions

Sander Bekeschus,Klaus-Dieter Weltmann,Kristian Wende,Alexander Fridman,Vandana Miller,Abraham Lin

doi:10.1007/s11090-017-9845-3

Abstract

A comparative study of two plasma sources (floating-electrode dielectric barrier discharge, DBD, Drexel University; atmospheric pressure argon plasma jet, kINPen, INP Greifswald) on cancer cell toxicity was performed. Cell culture protocols, cytotoxicity assays, and procedures for assessment of hydrogen peroxide (H2O2) were standardized between both labs. The inhibitory concentration 50 (IC50) and its corresponding H2O2 deposition was determined for both devices. For the DBD, IC50 and H2O2 generation were largely dependent on the total energy input but not pulsing frequency, treatment time, or total number of cells. DBD cytotoxicity could not be replicated by addition of H2O2 alone and was inhibited by larger amounts of liquid present during the treatment. Jet plasma toxicity depended on peroxide generation as well as total cell number and amount of liquid. Thus, the amount of liquid present during plasma treatment in vitro is key in attenuating short-lived species or other physical effects from plasmas. These in vitro results suggest a role of liquids in or on tissues during plasma treatment in a clinical setting. Additionally, we provide a platform for correlation between different plasma sources for a predefined cellular response.

Highlights

In the study of plasma medicine, partially ionized gases and their physico-chemical effectors are investigated for beneficial biological responses [1,2,3]
Two main types of plasma sources, a floating-electrode dielectric barriers discharge [10] and an atmospheric pressure argon plasma jet [11] were compared with regard to cell growth reduction and its dependence on main plasma active components
Our results demonstrate that H2O2 correlates with inhibition of CT26 metabolic activity

Summary

Introduction

In the study of plasma medicine, partially ionized gases and their physico-chemical effectors are investigated for beneficial biological responses [1,2,3]. There are technical and methodological challenges for direct plasma applications, especially with regard to different types of plasma sources and comparison of results. Major among them is the extent to which in vitro plasma effects depend on long-lived species or other effectors of the multicomponent system plasma, such as UV-radiation or electrical fields. Two main types of plasma sources, a floating-electrode dielectric barriers discharge [10] and an atmospheric pressure argon plasma jet [11] were compared with regard to cell growth reduction and its dependence on main plasma active components. To compare plasma effects across labs which is easy to perform, cheap and could be applicable for clinical device calibration, a simple biological read-out was chosen

Methods

Results

Conclusion