Introduction: Duodenoscopes have been widely used for both diagnostic and therapeutic endoscopic retrograde cholangiopancreatography procedures. Numerous outbreaks of duodenoscope-associated infections involving multidrug-resistant bacteria have recently been reported. Plasma activated water (PAW) has been widely considered an effective agent for surface decontamination and is increasingly used for disinfection of medical equipment. The aim of this study was to evaluate whether the duodenoscopes currently on market are suited for the repeated use of PAW and to test the efficacy of PAW for their disinfection. Materials and methods: In order to evaluate the disinfection efficacy and the required time of contact, the duodenoscope samples were contaminated by immersing them in fasted-state simulated intestinal fluid containing Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, prior to PAW exposure. In order to test the duodenoscope polymer compatibility with PAW, a challenge test was conducted by immersing the samples in PAW for 30 minutes daily for 45 consecutive days. Results: Significant reductions in bacterial populations were achieved after 30 minutes of PAW treatment, indicating a high-level disinfection. Atomic force microscopy and scanning electron microscopy were used to demonstrate that repeated PAW treatment of duodenoscope coating polymer samples did not result in significant differences in morphological surface between the treated and untreated samples. Energy-dispersive X-ray spectroscopy analysis also showed no significant differences between the elemental composition of the duodenoscope coating polymer samples before and after repeated PAW treatment. Conclusion: Considering these preliminary results, PAW could be considered as a new alternative for duodenoscope reprocessing.

Non-thermal plasma activated water (PAW) has recently emerged as a powerful antimicrobial agent. Despite numerous potential bio-medical applications, studies concerning toxicity in live animals, especially after long-term exposure, are scarce. Our study aimed to assess the effects of long-term watering with PAW on the health of CD1 mice. PAW was prepared from distilled water with a GlidArc reactor according to a previously published protocol. The pH was 2.78. The mice received PAW (experimental group) or tap water (control group) daily for 90 days as the sole water source. After 90 days, the following investigations were performed on the euthanatized animals: gross necropsy, teeth mineral composition, histopathology, immunohistochemistry, hematology, blood biochemistry, methemoglobin level and cytokine profile. Mice tolerated PAW very well and no adverse effects were observed during the entire period of the experiment. Histopathological examination of the organs and tissues did not reveal any structural changes. Moreover, the expression of proliferation markers PCNA and Ki67 has not been identified in the epithelium of the upper digestive tract, indicating the absence of any pre- or neoplastic transformations. The results of our study demonstrated that long-term exposure to PAW caused no toxic effects and could be used as oral antiseptic solution in dental medicine.

Background. Cerium oxide nanoparticles present the mimetic activity of superoxide dismutase, being able to inactivate the excess of reactive oxygen species (ROS) correlated with a large number of pathologies, such as stents restenosis and the occurrence of genetic mutations that can cause cancer. This study presents the synthesis and biological characterisation of nanoconjugates based on nanoparticles of iron oxide interconnected with cerium oxide conjugates. Methods. The synthesis of magnetite-nanoceria nanoconjugates has been done in several stages, where the key to the process is the coating of nanoparticles with polyethyleneimine and its chemical activation-reticulation with glutaraldehyde. The nanoconjugates are characterised by several techniques, and the antioxidant activity was evaluated in vitro and in vivo. Results. Iron oxide nanoparticles interconnected with cerium oxide nanoparticles were obtained, having an average diameter of 8 nm. Nanoconjugates prove to possess superparamagnetic properties and the saturation magnetisation varies with the addition of diamagnetic components in the system, remaining within the limits of biomedical applications. In vitro free-radical scavenging properties of nanoceria are improved after the coating of nanoparticles with polyethylenimine and conjugation with magnetite nanoparticles. In vivo studies reveal increased antioxidant activity in all organs and fluids collected from mice, which demonstrates the ability of the nanoconjugates to reduce oxidative stress. Conclusion. Nanoconjugates possess magnetic properties, being able to scavenge free radicals, reducing the oxidative stress. The combination of the two properties mentioned above makes them excellent candidates for theranostic applications.