Inactivation of Microorganisms and Endotoxins by Low Temperature Nitrogen Gas Plasma Exposure

Abstract

The plasma of several different gases has shown a sporicidal activity. From these gases, nitrogen gas was most difficult to produce atomic nitrogen radicals. However, these radicals have a high energy, indicating that nitrogen gas plasma could be used to sterilize microorganisms and inactivate endotoxins. The sterilization mechanism of nitrogen gas plasma is the synergistic effect of a high rising-up voltage pulse, UV irradiation and atomic nitrogen radicals. Thus, the target cells were damaged by degradation, which resulted in death. The biological indicator (BI) used in this study was Geobacillus stearothermophilus ATCC 7953 at a population of 1 x 106 CFU/sheet. Sterility assurance was confirmed by using the Bl. Moreover, endotoxins were successfully inactivated. More than 5 log reduction of endotoxins could be attained with 30 minutes of nitrogen gas plasma exposure. Material functionality influenced by nitrogen gas plasma presented a satisfactory result. No deterioration of polymers could be observed by nitrogen gas plasma exposure.

Study of Sterilization and Disinfection in Room Air by Using Atmospheric Microplasma

“…In this case, the bacteria were the nutritive cell, and their physical shape and morphology were changed after microplasma treatment as shown in Figure 16 (b) to (d). These morphology changes by plasma process were already reported by other group, but not for Ar plasma [58,59]. These morphology changes could be considered by etching effect by Ar ions.…”

Investigation of a Sterilization System Using Active Oxygen Species Generated by Ultraviolet Irradiation

“…ated by a cold plasma apparatus has generated considerable interest Cvelbar et al, 2009Gans, et al 2005Hayashi et al, 2006Halfmann et al, 2007Moisan et al, 2001Mozetic and Vratnica, 2011Nagatsu et al, 2003Raballand et al, 2008Shintani et al, 2007Tanaka et al, 2005Von keudell et al, 2010 . The use of AOS has many advantages, such as low temperature processing, dry processing, lack of the residual effects of toxicants, and low initial and operational costs.…”

Inactivation of Bacterial Spore, Endotoxin, Lipid A, Normal Prion and Abnormal Prion by Exposures to Several Sorts of Gases Plasma

“…Alternative sterilization procedures are under investigation including the use of non-equilibrium gas plasma discharges we will see that plasma processes are able to sufficiently kill bacterial spores with more than a 6 log reduction without leaving residues of toxic gases Shintani, 2015 and when conducted at a relatively low temperature at 25-60 , endotoxin inactivation is achieved at more than a 5 log reduction Shintani et al, 2007, Figure 2 . Non-equilibrium gas plasma sterilization studies have been carried out to show that many types of pathogens can be inactivated Lerouge et al, 2001Moisan et al, 2001Rossi et al, 2006Shintani et al, 2007Shintani et al, 2010Shintani, 2012 and the mechanism and inactivation factors of gas plasma sterilization against microorganisms or biomolecules have been extensively studied.…”

“…Sterilization procedures must follow official rules such as ISO 14937 and 14161 and so on. This kind of subject will be discussed in a coming book Shintani, 2015, by nitrogen gas plasma exposure Shintani et al, 2007Shintani, 2012 . Moreover, the usual sterilization techniques have several drawbacks including the potential degradation of heat-sensitive healthcare products e.g., autoclave sterilization at 121.11 for 20 min is normal a relatively long operation time is required due to toxic gas degassing ethylene oxide gas or hydrogen peroxide gas sterilization .…”

“…Endotoxins are extremely resistant to temperature and are not removed by conventional sterilization procedures such as autoclave sterilization or -ray or e-beam sterilization. A few papers have been published on the effect of gas plasma exposure on endotoxins to cause more than a 5 log reduction during 30 min exposure to nitrogen gas plasma Shintani et al, 2007, Shintani et al 2010Shintani, 2012Sakudo et al, 2013 . In general a 3-log reduction is required by the authorities and GMP good manufacturing practice and, according published papers by Shintani et al in 2007 andShintani in 2012, dur-ing 10 min at 28-45 operation, a 3-log reduction was completed in Figure 2, which is a significant achievement.…”