Inactivation of Biofilms Using a Low Power Atmospheric Pressure Argon Plasma Jet; the Role of Entrained Nitrogen

Abstract

The inactivation of microbial biofilms using a low temperature atmospheric pressure argon plasma jet is investigated. The treatment of Staphylococcus aureus biofilms was the most effective; 78% population reduction was reached within 3 min. Higher reduction rates were found for smaller plasma‐sample distances and for longer exposure time. Employing a pretreatment of the samples with ascorbic acid suggests that oxygen radicals might play a role in the inactivation process. A novel method for the quantitative analysis of spectra is introduced. It points towards an important role of entrained nitrogen and shows that excited nitrogen species are created in large abundances. These species can be important carriers of excitation energy to the biofilms or may function as important intermediate reactive species.

Determination of the Electron Density in an Argon Plasma Jet Using Absolute Measurements of Continuum Radiation

“…The Ar 4p lines situated in the interval are used to determine the electron temperature . The bands were studied in in relation with the ability of the plasma source to destroy biofilms. In this study, we are especially interested in the continuum as it delivers the electron density n e .…”

“…This paper is devoted to the determination of the electron density for plasmas created by a DBD plasma jet driven with sinusoidal voltages in the range of 7–20 kV pp and in the frequency range of 10–100 kHz. The plasmas which were described in Sarani et al and Taghizadeh et al are small in size and high in gas density, so that it is difficult to apply the H β and Thomson scattering method. Therefore, we will employ the continuum radiation method.…”

In vitro evaluation of the decontamination effect of cold argon plasma on selected bacteria frequently encountered in small animal bite injuries

“…The type of effluent is closely related to the carrier gas, the room air and the device used for generation of the plasma state [24, 26]. Furthermore, the distance between the plasma source and the wound surface influences the decontamination effect [32]. Longer treatment times have been found to result in greater ‘bacterial death’ however; this is influenced by bacteria species, growth form (biofilm) and substrate on which the bacteria grow [23,32–35].…”

Application of post-discharge region of atmospheric pressure argon and air plasma jet in the contamination control of Candida albicans biofilms

“…As an antimicrobial strategy, the advantages of non-thermal plasmas operated at atmospheric pressure are the simple design, low cost of construction/operation, usage of nontoxic gases, with operating conditions of gas at or near room temperature, and no harmful residues (Gaunt et al, 2006;Kong et al, 2009;Laroussi, 2002). In last years, much effort and progress have been done in order to elucidate the exact mechanisms leading to bacterial or fungal inactivation by the action of electric plasma (Alkawareek et al, 2012;Chen et al, 2014;Laroussi, 2002;Mai-Prochnow et al, 2014;Taghizadeh et al, 2015;Traba and Liang, 2015). It is considered that several plasma products play an important role in this process, namely reactive oxygen species (ROS), such as ozone, atomic oxygen, superoxide, hydrogen peroxide and hydroxyl radicals (Kong et al, 2009), and reactive nitrogen species (RNS), UV radiation, and charged particles (Gaunt et al, 2006;Laroussi and Leipold, 2004;Ma et al, 2008).…”