## 1 Introduction  
Transmissible spongiform encephalopathies (TSEs), also referred to as prion diseases, are responsible for deadly neurodegenerative disorders including human prion diseases such as Creutzfeldt-Jakob disease (CJD), fatal familial insomnia (FFI), and Gerstmann-Straussler-Scheinker syndrome (GSS) as well as animal prion diseases such as bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease (CWD) in cervids, and scrapie in goat and sheep [1]. Prion diseases are transmissible and can be caused by infection or inheritance, while most human prion diseases (85% to 90%) are sporadic and of unspecified origin [1, 2]. The prion agent is highly resistant to inactivation and therefore poses a risk to public health. Indeed, environmental and food contamination with prions may play a role in its transmission.  
Prion diseases are a type of proteopathy caused by an infectious particle (prion), whose main component comprises an abnormal isoform of prion protein (PrP\({}^{\text{Sc}}\)) [1]. Prion transmission can be achieved by the conformational change of the cellular isoform of prion protein (PrP\({}^{\text{C}}\)), which is mainly found in neurons, into PrP\({}^{\text{Sc}}\)[3]. The accumulation of PrP\({}^{\text{Sc}}\) in brain tissue causes neurological symptoms such as a type of dementia, which eventually results in death [3]. Because prions are infectious, the conversion of PrP\({}^{\text{C}}\) to PrP\({}^{\text{Sc}}\) is a crucial step in the transmission of prion diseases [4; 5]. Protein misfolding cyclic amplification (PMCA) is a laboratory based procedure that mimics the PrP\({}^{\text{C}}\)-PrP\({}^{\text{Sc}}\) conversion to amplify PrP\({}^{\text{Sc}}\) in vitro [6; 7]. As such, PMCA can be used to evaluate the efficiency of prion decontamination methods [8; 9; 10].  
Prions are notoriously difficult to inactivate using standard disinfection methods such as exposure to ultraviolet (UV) light, \(\gamma\)-rays, or autoclaving at 121 \({}^{\circ}\)C for 20 min [11; 12; 13]. There are some effective reagents against prions including treatment with 1 M NaOH, 2% NaOCl, or sodium dodecyl sulfate (SDS), as well as autoclaving at 134 \({}^{\circ}\)C for 18 min [14]. Unfortunately, these procedures can damage medical devices, especially heat-sensitive pieces of equipment. Thus, a safe and efficient inactivation method for prions is needed that is suitable for decontaminating medical instruments to protect public health.  
STERRAD(R) (Advanced Sterilization Products (ASP), Johnson & Johnson) is a hydrogen peroxide gas plasma sterilizer that is widely used for prion inactivation of heat-sensitive medical instruments [13]. AlthoughSTERRAD(R) generates gas plasma by radio frequency (RF) discharge, RF plasma is only used for the removal of hydrogen peroxide gas, and not for sterilization purposes [15; 16]. Indeed, the presence or absence of RF gas plasma did not affect the inactivation effect of the instrument [16; 17; 18].  
Hydrogen peroxide gas and/or plasma are known to be effective for the sterilization of heat-sensitive medical devices [19; 20; 21]. Studies using hydrogen peroxide gas sterilizers and gas plasma instruments have evaluated the inactivation effects against a range of pathogens [22; 23; 24; 25; 26; 27], including prions [28; 29; 30]. However, to date, no studies have investigated the effect of hydrogen peroxide gas plasma combined with dielectric barrier discharge (DBD) and corona discharge on the inactivation of prion agents.  
These considerations prompted us to study the effectiveness of hydrogen peroxide gas plasma combined with DBD and corona discharge as a novel inactivation method for prions. Here, we investigated whether mouse scrapie prion can be inactivated by using the hydrogen peroxide gas plasma instrument RENO-S130 (Renosem Co., Ltd., Gyeonggi-do, Korea). PMCA was used to analyze the proliferation activity of PrP\({}^{\text{Sc}}\) and a mouse bioassay was used to assess prion infectivity following treatment with the device.