New Clinical Applications of Electrolyzed Water: A Review

Antimicrobial action and cytotoxicity of hypochlorous acid obtained from an innovative electrolytic device - An in vitro study

OBJECTIVE

This study evaluated the antimicrobial effect and cytotoxicity of hypochlorous acid(HClO) obtained from an innovative electrolytic device.

DESIGN

The root canals of fifty extracted human teeth were inoculated with Enterococcus faecalis and divided into 5 groups (n = 10): DW (control); 2% chlorhexidine gel(CHX); 2.5% sodium hypochlorite(NaOCl); 250 ppm HClO and 500 ppm HClO. The counting of colony forming units evaluated the decontamination potential of each group. Cytotoxicity was evaluated after inoculation of tested protocols in fibroblastic cells for 3 min, calculating the cell viability. Specific statistical analysis was performed (α = 5%).

RESULTS

The highest bacterial reduction was observed in experimental groups, with no statistical differences from each other (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences from each other (p < 0.05).

CONCLUSIONS

It could be concluded that HClO presented high antimicrobial activity and low cytotoxicity at both tested concentrations.

Evaluation of surface tensions and root-dentin surface contact angles of different endodontic irrigation solutions

BACKGROUND

Surface tension and contact angle properties, which play a crucial role in determining the effectiveness of irrigation solutions in penetrating dentin surfaces and dentin tubules, are highly important for the development of new irrigation solutions and their preferences. The aim of the current study was to compare the surface tension and contact angle properties of different irrigation solutions used in endodontics, both on the dentin surface and within dentin tubules.

METHODS

In this study, the contact angles and surface tensions of 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 5% boric acid (BA), 0.02% hypochlorous acid (HOCl), 0.2% chlorine dioxide (ClO2), Biopure MTAD, QMix solutions, and distilled water (control group) were measured. Measurements were conducted using a goniometer device (Attension Theta Lite Tensiometer, Biolin Scientific, USA), employing the sessile drop method for contact angle measurements on pre-prepared dentin surfaces, and the pendant drop method for surface tension.

RESULTS

Contact angle measurements revealed no statistically significant differences between the contact angle values of MTAD, ClO2, and CHX or between NaOCl, QMix, BA, and HOCl (p > 0.05). However, EDTA exhibited a significantly greater contact angle than did MTAD, ClO2, CHX, NaOCl, QMix, BA, and HOCl (p < 0.05). Furthermore, the contact angle of dentin with distilled water was greater than that with all other solutions tested (p < 0.05). Surface tension measurements revealed that the surface tension values of QMix and MTAD were statistically similar (p > 0.05). CHX exhibited lower surface tension than distilled water and HOCl (p < 0.05), and it also had lower surface tension than ClO2, NaOCl, and BA (p < 0.05). Additionally, the surface tension of the samples treated with EDTA was greater than that of all other solutions tested (p < 0.05).

CONCLUSION

The direct linear relationship between the surface tension of liquids and contact angles on different surfaces may not always hold true, and these values should be considered independently for each solution on various surfaces. Considering the contact angles and surface tension properties of irrigation solutions with root canal dentin, it can be suggested for clinical use that ClO2 could be recommended over NaOCl, and similarly, BA could be recommended over EDTA.

The HOCl dry fog-is it safe for human cells?

This study aims to investigate if high-concentration HOCl fogging disinfection causes cytotoxicity and genotoxicity to cultured primary human skin fibroblasts. The cells were exposed to a dry fog of HOCl produced from solutions with a concentration of 300 ppm (5.72 mM) or 500 ppm (9.53 mM). After four times when fibroblasts were exposed to aerosolized HOCl at a concentration of 500 ppm for 9 minutes, significant cytotoxicity and genotoxicity effects were observed. Significant changes in the morphology of fibroblasts and cell death due to membrane disruption were observed, independent of the number of exposures. Flow cytometry analyses performed under these experimental conditions indicated a decrease in the number of cells with an intact cell membrane in the exposed samples compared to the sham samples, dropping to 49.1% of the total cells. Additionally, under the same conditions, the neutral comet assay results demonstrated significant DNA damage in the exposed cells. However, no analogous damages were found when the cells were exposed to aerosolized HOCl generated from a 300-ppm solution for 3 minutes, whether once or four times. Therefore, we have concluded that aerosolized HOCl in dry fog, with a concentration exceeding 300 ppm, can cause cytotoxic and genotoxic effects on human skin fibroblasts.

Different electrolytic treatments for food sanitation and conservation simulating a wash process at the packinghouse

Microorganisms are predominantly responsible for food deterioration, necessitating the sanitization and removal of these entities from food surfaces. The packinghouse employs free chlorine in the sanitization process; however, free chlorine's propensity to react with organic matter, forming potentially toxic compounds, has led to its restriction or outright prohibition in several European countries. Therefore, this study aims to assess various washing methods, emulating packinghouse conditions, utilizing diverse forms of electrolyzed water to impede microbial proliferation and significantly enhance the food's shelf life. The subject of investigation was cherry tomatoes. The findings revealed that electrolyzed water containing NaCl exhibited superior efficacy compared to electrolysis with Na2SO4. Both forms of electrolyzed water demonstrated noteworthy effectiveness in inhibiting microorganisms, resulting in a reduction of 2.0 Log CFU mL-1 for bacteria and 1.5 Log CFU mL-1 for fungi. The electrolyzed water also exhibited a comparable capability to free chlorine in removing fecal coliforms from the tomato surfaces. Notably, both electrolyzed water treatments extended the shelf life of cherry tomatoes by at least three days, accompanied by minimal or negligible residues of free chlorine. Consequently, the electrolyzed water formulations proposed in this study present themselves as promising alternatives to traditional packinghouse sanitizers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05882-1.

Recent advances in activated water systems for the postharvest management of quality and safety of fresh fruits and vegetables

Over the last three decades, decontamination management of fresh fruits and vegetables (FFVs) in the packhouses and along the supply chains has been heavily dependent on chemical-based wash. This has resulted in the emergence of resistant foodborne pathogens and often the deposition of disinfectant byproducts on FFVs, rendering them unacceptable to consumers. The management of foodborne pathogens, microbial contaminants, and quality of FFVs are a major concern for the horticultural industries and public health. Activated water systems (AWS), such as electrolyzed water, plasma-activated water, and micro-nano bubbles, have gained significant attention from researchers over the last decade due to their nonthermal and nontoxic mode of action for microbial inactivation and preservation of FFVs quality. The aim of this review is to provide a comprehensive summary of recent progress on the application of AWS and their effects on quality attributes and microbial safety of FFVs. An overview of the different types of AWS and their properties is provided. Furthermore, the review highlights the chemistry behind generation of reactive species and the impact of AWS on the quality attributes of FFVs and on the inactivation/reduction of spoilage and pathogenic microbes (in vivo or in vitro). The mechanisms of action of microorganism inactivation are discussed. Finally, this work highlights challenges and limitations for commercialization and safety and regulation issues of AWS. The synergistic prospect on combining AWS for maximum microorganism inactivation effectiveness is also considered. AWS offers a potential alternative as nonchemical interventions to maintain quality attributes, inactivate spoilage and pathogenic microorganisms, and extend the shelf-life for FFVs.

Kinetics of sterilization of atomized slightly acidic electrolyzed water on tableware

The aim of this study was to elucidate the kinetics of atomization of slightly acidic electrolyzed water (SAEW) for use in sterilization of secondary contaminated tableware surfaces. The sterilization efficacy of SAEW was assessed on the basis of the change in the total number of colonies with different contamination levels (101 CFU/mL and 102 CFU/mL), atomization time (10, 20, 30, 40, and 50 s), atomizing distance (5, 10, 15, 20, 25, and 30 cm), and available chlorine concentration (ACC; 25.2, 30.2, 34.9, 40.5, 44.8, and 53.3 mg/L) as the main influencing factors. According to the relationship among flux, atomization area, and time, a kinetic model of SAEW atomization for the sterilization of tableware surfaces was established. The results indicated that the sterilization efficacy of SAEW gradually improved with decreased contamination levels (12.69 %-15.74 %), extended atomization time (13.68 %-46.58 %), and increased ACC (36.89 %-95.14 %). Based on the kinetics analysis, the change law of the kinetic model of SAEW atomization and sterilization of tableware surfaces with secondary pollution was found to be consistent with the change law of sterilization (r2 > 0.8). The results of this study provide a theoretical basis for SAEW atomization for sterilization of secondary contaminated tableware surfaces and also contributes to the improvement of technological theory of SAEW sterilization.

Electrolyzed Hypochlorous Acid (HOCl) Aqueous Solution as Low-Impact and Eco-Friendly Agent for Floor Cleaning and Sanitation

Recently, the use of disinfectants has been becoming a diffused and sometimes indiscriminate practice of paramount importance to limit the spreading of infections. The control of microbial contamination has now been concentrated on the use of traditional agents (i.e., hypochlorite, ozone). However, their prolonged use can cause potential treats, for both human health and environment. Currently, low-impact but effective biocides that are prepared in a way that avoids waste, with a very low toxicity, and safe and easy to handle and store are strongly needed. In this study, produced electrochemically activated hypochlorous (HOCl) acid solutions are investigated and proposed, integrated in a scrubbing machine for floor cleaning treatment. Such an innovative machine has been used for floor cleaning and sanitation in order to evaluate the microbial charge and organic dirt removal capacity of HOCl in comparison with a machine charged with traditional Ecolabel standard detergent. The potential damage on floor materials has also been investigated by means of Scanning Electron Microscope (SEM). A comparative Life Cycle Assessment (LCA) analysis has been carried out for evaluating the sustainability of the use of the HOCl-based and detergent-based machine.

Effects of Hydrogen-rich Water on Cariogenic Bacteria

Context

Some kinds of electrolysed water have been reported to exhibit antioxidant and bactericidal activity. However, studies on the effect of electrolysed hydrogen-rich water (EHW) with a neutral pH on cariogenic bacteria are limited.

Aim

This study aimed to evaluate the feasibility of using EHW as a mouthwash by examining its various effects on cariogenic bacteria.

Materials and Methods

To test the bactericidal and anti-biofilm formation effects of EHW on Streptococcus mutans and Streptococcus sobrinus, bacterial growth curves, colony-forming unit (CFU) counts, and crystal violet staining of biofilms were examined after exposing the bacterial pellets to EHW or tap water as a control for one minute. In addition, the expressions of glucosyltransferase and glucan-binding proteins encoding genes were examined using real-time PCR.

Results

Bacterial growth and biofilm formation were inhibited, and the number of CFUs was significantly reduced in the EHW group compared to the control group. The expression of genes encoding glucosyltransferases (gtfB, gtfC, and gtfI) and glucan-binding proteins (gbpC and dblB) were also decreased in the EHW group compared to the control.

Conclusions

Exposing cariogenic bacteria to EHW at neutral pH for one minute can effectively inhibit bacterial growth and biofilm formation in vitro, suggesting that EHW is a promising mouthwash.

Hypochlorous Acid: A Novel Agent Against Echinococcus granulosus Protoscoleces

Objective

We aimed to determine the scolicidal effect of hypochlorous acid and its efficiency at different concentrations.

Materials and Methods

We tested the effectiveness of hypochlorous acid in-vitro on sterile gauze at different concentrations in test tubes. In addition, we compared its effectiveness with the scolicidal activity of other agents, povidone-iodine 10% and chlorhexidine-gluconate 0.04%.

Results

Hypochlorous acid was 100% effective in 5 minutes at 1/1 (200 ppm/mL), 1/10 (20 ppm/ml), and 1/100 (2 ppm/mL) concentrations and in 10 minutes at 1/1000 (0.2 ppm/mL) concentration. Povidone-iodine 10%, and chlorhexidine-gluconate 0.04% were studied undiluted and were effective at all study times. Hypochlorous acid maintained the same scolicidal activity on gauze at all study times at the described dilutions.

Conclusion

Hypochlorous acid is an effective scolicidal agent in 5 minutes at even 1/100 concentrations. In addition, it maintains the same scolicidal activity on gauze used in surgery to wall the surgical site.

Effectiveness of Nitazoxanide and Electrolyzed Oxiding Water in Treating Chagas Disease in a Canine Model

Chagas disease (CD) is caused by the protozoan Trypanosoma cruzi, and affects seven million people in Latin America. Side effects and the limited efficacy of current treatment have led to new drug research. The objective of this work was to evaluate the effectiveness of nitazoxanide (NTZ) and electrolyzed oxidizing water (EOW) in a canine model of experimental CD. Náhuatl dogs were infected with the T. cruzi H8 strain and NTZ- or EOW-treated orally for 10 days. Seronegativity was shown at 12 months post-infection (mpi) in the NTZ-, EOW-, and benznidazole (BNZ)-treated groups. The NTZ and BNZ groups had high levels of IFN-γ, TNF-α, IL-6, IL-12B, and IL-1β at 1.5 mpi and low levels of IL-10. Electrocardiographic studies showed alterations from 3 mpi and worsening at 12 mpi; NTZ treatment produced fewer cardiac pathomorphological changes compared to EOW, similar to BNZ treatment. There was no cardiomegaly in any group. In conclusion, although NTZ and EOW did not prevent changes in cardiac conductivity, they were able to avoid the severity of heart damage in the chronic phase of CD. NTZ induced a favorable proinflammatory immune response after infection, being a better option than EOW as a possible treatment for CD after BNZ.

Disinfection, Sterilization, and Decontamination of Pathogens in Medicine

The ongoing coronavirus disease (COVID-19) pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is putting our public health services under enormous strain [...].

Hypochlorous acid inactivates oral pathogens and a SARS-CoV-2-surrogate

BACKGROUND

Droplets and aerosols produced during dental procedures are a risk factor for microbial and viral transmission. Unlike sodium hypochlorite, hypochlorous acid (HOCl) is nontoxic to tissues but still exhibits broad microbicidal effect. HOCl solution may be applicable as a supplement to water and/or mouthwash. This study aims to evaluate the effectiveness of HOCl solution on common human oral pathogens and a SARS-CoV-2 surrogate MHV A59 virus, considering the dental practice environment.

METHODS

HOCl was generated by electrolysis of 3% hydrochloric acid. The effect of HOCl on human oral pathogens, Fusobacterium nucleatum, Prevotella intermedia, Streptococcus intermedius, Parvimonas micra, and MHV A59 virus was studied from four perspectives: concentration; volume; presence of saliva; and storage. HOCl solution in different conditions was utilized in bactericidal and virucidal assays, and the minimum inhibitory volume ratio that is required to completely inhibit the pathogens was determined.

RESULTS

In the absence of saliva, the minimum inhibitory volume ratio of freshly prepared HOCl solution (45-60 ppm) was 4:1 for bacterial suspensions and 6:1 for viral suspensions. The presence of saliva increased the minimum inhibitory volume ratio to 8:1 and 7:1 for bacteria and viruses, respectively. Applying a higher concentration of HOCl solution (220 or 330 ppm) did not lead to a significant decrease in the minimum inhibitory volume ratio against S. intermedius and P. micra. The minimum inhibitory volume ratio increases in applications of HOCl solution via the dental unit water line. One week of storage of HOCl solution degraded HOCl and increased the minimum growth inhibition volume ratio.

CONCLUSIONS

HOCl solution (45-60 ppm) is still effective against oral pathogens and SAR-CoV-2 surrogate viruses even in the presence of saliva and after passing through the dental unit water line. This study indicates that the HOCl solution can be used as therapeutic water or mouthwash and may ultimately reduce the risk of airborne infection in dental practice.

Virucidal Activities of Acidic Electrolyzed Water Solutions with Different pH Values against Multiple Strains of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a threat to human health. Acidic electrolyzed water (AEW) has recently been suggested to demonstrate virucidal activity. Many types of AEW with different pH values, generated by the electrolysis of different chemicals, such as sodium chloride, potassium chloride, and hydrochloric acid, are commercially available. In this study, we compared the virucidal activities of these types of AEW against SARS-CoV-2, including the ancestral strain and variant Alpha, Beta, Gamma, Delta, and Omicron strains. Virus solution (viral titer, 6.9 log₁₀ 50% tissue culture infective dose [TCID₅₀]/mL) was mixed with AEW (free available chlorine concentration, 34.5 ppm) at mixing ratios of 1:9, 1:19, and 1:49. At mixing ratios of 1:9 and 1:19, AEW with a pH of 2.8 showed stronger virucidal activities than AEW with a pH of 4.1 to 6.5 against the SARS-CoV-2 ancestral strain in 20 s. From the strongest to the weakest virucidal activity, the AEW pH levels were as follows: pH 2.8, pH 4.1 to 5.4, pH 6.4 to 6.5. At a ratio of 1:49, the viral titers of viruses treated with all AEW solutions at pH 2.8 to 6.5 were almost below the detection limit, which was 1.25 log₁₀ TCID₅₀/mL. The virus inactivation efficiency of AEW was reduced in the presence of fetal bovine serum and other substances contained in the virus solution used in this study. AEW with pH values of 2.8 to 6.5 showed virucidal activity against all of the tested SARS-CoV-2 strains, including the ancestral and variant strains. These results provide useful knowledge for the effective application of AEW as a SARS-CoV-2 disinfectant. IMPORTANCE Acidic electrolyzed water (AEW) demonstrates virucidal activity against multiple viruses. Since AEW exhibits low toxicity, is inexpensive, and is environmentally friendly, it can be a useful disinfectant against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the pH values of currently available AEW products vary, the impact of different pH values on SARS-CoV-2 inactivation has not previously been evaluated in detail. In this study, we compared the virucidal activities of multiple AEW solutions with different pH values, under the same experimental conditions. We found that AEW solutions with lower pH values demonstrated more potent virucidal activity. Also, we showed that the extent of virus inactivation by the AEW was based on the balance of the abundance of free available chlorine, virus, and other organic substances in the mixture. AEW exhibited rapid virucidal activity against multiple SARS-CoV-2 strains. This study demonstrated the usefulness of AEW as a disinfectant which can be applied to the inactivation of SARS-CoV-2.

Research progress of electrochemical oxidation and self-action of electric field for medical wastewater treatment

A large number of pathogenic microorganisms exist in medical wastewater, which could invade the human body through the water and cause harm to human health. With the global pandemic coronavirus (COVID-19), public health safety become particularly important, and medical wastewater treatment is an important part of it. In particular, electrochemical disinfection technology has been widely studied in medical wastewater treatment due to its greenness, high efficiency, convenient operation, and other advantages. In this paper, the development status of electrochemical disinfection technology in the treatment of medical wastewater is reviewed, and an electrochemical three-stage disinfection system is proposed for the treatment of medical wastewater. Moreover, prospects for the electrochemical treatment of medical wastewater will be presented. It is hoped that this review could provide insight and guidance for the research and application of electrochemical disinfection technology to treat medical wastewater.GRAPHICAL ABSTRACT.

Antimicrobial efficacy, mode of action and in vivo use of hypochlorous acid (HOCl) for prevention or therapeutic support of infections

The objective is to provide a comprehensive overview of the rapidly developing field of the current state of research on in vivo use of hypochlorous acid (HOCl) to aid infection prevention and control, including naso-pharyngeal, alveolar, topical, and systemic HOCl applications. Also, examples are provided of dedicated applications in COVID-19. A brief background of HOCl's biological and chemical specifics and its physiological role in the innate immune system is provided to understand the effect of in vivo applications in the context of the body's own physiological defense mechanisms.

Electrolyzed water for the microbiologic control in the pandemic dental setting: a systematic review

BACKGROUND

Electrolyzed water has brought recent attention due to its antimicrobial properties. Indeed, electrolyzed water has been proposed to sterilize dental materials and instruments without compromising their structural integrity. In addition, electrolyzed water has been proposed as a mouthwash to control bacterial and viral oral infections without detrimental effects on the oral mucosa. However, no current consensus or evidence synthesis could indicate its potentially favorable use in the dental setting, particularly during the COVID-19 context. Therefore, this systematic review aimed to elucidate whether electrolyzed water could improve microbiologic control in the COVID-19 pandemic dental setting.

METHODS

MEDLINE via Pubmed, EMBASE, Cochrane's CENTRAL, Scopus, LILACS, and Web of Science databases were searched up to September 2021 to identify experimental studies utilizing electrolyzed water for eliminating microorganisms in a dental setting. Besides, a manual and a grey literature search were performed. The data selection and extraction were performed individually and in duplicate. The Risk of Bias (RoB) was assessed with the Nature Publication Quality Improvement Project (NPQIP) score sheet. The study protocol was registered at PROSPERO CRD42020206986.

RESULTS

From a total of 299 articles, 63 studies met the inclusion criteria. The included studies assessed several types of electrolyzed waters, which showed a high disinfection potential when used to deal with different oral conditions. Electrolyzed water demonstrated a broad antimicrobial spectrum and was highly efficient in the dental office disinfection against viruses, fungi, and bacteria, being compatible with most dental materials. In addition, electrolyzed water could protect against SARS-CoV-2 infection and contamination in the dental office. Regarding the RoB, only 35.18% of entries were answered as 'Yes', thus achieving less than half of the reporting sheet.

CONCLUSION

Electrolyzed water effectively disinfects contaminated surfaces, dental materials, and equipment. Therefore, their use is recommendable in the SARS-CoV-2 pandemic dental setting.

Electrolyzed-Reduced Water: Review I. Molecular Hydrogen Is the Exclusive Agent Responsible for the Therapeutic Effects

Numerous benefits have been attributed to alkaline-electrolyzed-reduced water (ERW). Sometimes these claims are associated with easily debunked concepts. The observed benefits have been conjectured to be due to the intrinsic properties of ERW (e.g., negative oxidation-reduction potential (ORP), alkaline pH, H₂ gas), as well enigmatic characteristics (e.g., altered water structure, microclusters, free electrons, active hydrogen, mineral hydrides). The associated pseudoscientific marketing has contributed to the reluctance of mainstream science to accept ERW as having biological effects. Finally, through many in vitro and in vivo studies, each one of these propositions was examined and refuted one-by-one until it was conclusively demonstrated that H₂ was the exclusive agent responsible for both the negative ORP and the observed therapeutic effects of ERW. This article briefly apprised the history of ERW and comprehensively reviewed the sequential research demonstrating the importance of H₂. We illustrated that the effects of ERW could be readily explained by the known biological effects of H₂ and by utilizing conventional chemistry without requiring any metaphysical conjecture (e.g., microclustering, free electrons, etc.) or reliance on implausible notions (e.g., alkaline water neutralizes acidic waste). The H₂ concentration of ERW should be measured to ensure it is comparable to those used in clinical studies.

Electrolyzed-Reduced Water: Review II: Safety Concerns and Effectiveness as a Source of Hydrogen Water

Many studies demonstrate the safety of alkaline-electrolyzed-reduced water (ERW); however, several animal studies have reported significant tissue damage and hyperkalemia after drinking ERW. The mechanism responsible for these results remains unknown but may be due to electrode degradation associated with the production of higher pH, in which platinum nanoparticles and other metals that have harmful effects may leach into the water. Clinical studies have reported that, when ERW exceeds pH 9.8, some people develop dangerous hyperkalemia. Accordingly, regulations on ERW mandate that the pH of ERW should not exceed 9.8. It is recommended that those with impaired kidney function refrain from using ERW without medical supervision. Other potential safety concerns include impaired growth, reduced mineral, vitamin, and nutrient absorption, harmful bacterial overgrowth, and damage to the mucosal lining causing excessive thirst. Since the concentration of H₂ in ERW may be well below therapeutic levels, users are encouraged to frequently measure the H₂ concentration with accurate methods, avoiding ORP or ORP-based H₂ meters. Importantly, although, there have been many people that have used high-pH ERW without any issues, additional safety research on ERW is warranted, and ERW users should follow recommendations to not ingest ERW above 9.8 pH.

Effectiveness of neutral electrolyzed water in inactivating HCoV-OC43 and SARS-CoV-2 on the surfaces of plastic and the medicinal plant Centella asiatica (L.) urban

Concerns have been raised about viral contamination, including in crops due to the recent coronavirus disease 2019 pandemic. Limited evidence is available to support the use of sanitizing agents for human coronavirus-contaminated medicinal plants. Thus, we aimed to investigate the persistence of infectious human coronavirus OC43 (HCoV-OC43) as a SARS-CoV-2 surrogate in storage conditions and the capability of neutral electrolyzed water (NEW) to inactivate coronavirus, including in fresh plants such as C. asiatica. The levels of infectious HCoV-OC43 and the triterpenoid content of C. asiatica were quantified using a plaque assay and high-performance liquid chromatography, respectively. The results showed that the persistence of HCoV-OC43 on C. asiatica leaves is identical to that on inert polystyrene. When covered and kept at room temperature with high humidity (>90% RH), HCoV-OC43 can be stable on C. asiatica leaves for at least 24 h. NEW with 197 ppm of available chlorine concentration (ACC) was effective in inactivating both infectious HCoV-OC43 and SARS-CoV-2 in suspension (≥3.68 and ≥4.34 log reduction, respectively), and inactivated dried HCoV-OC43 on the surfaces of C. asiatica leaves (≥2.31 log reduction). Soaking C. asiatica leaves for 5 min in NEW with 205 ppm of ACC or water resulted in significantly higher asiaticoside levels (37.82 ± 0.29 and 35.32 ± 0.74 mg/g dry weight, respectively), compared to the unsoaked group (29.96 ± 0.78 mg/g dry weight). These findings suggest that although coronavirus-contaminated C. asiatica leaves can pose a risk of transmission, NEW could be an option for inactivation.

Cytotoxicity and Efficacy in Debris and Smear Layer Removal of HOCl-Based Irrigating Solution: An In Vitro Study

In the present study we evaluated the cytotoxicity of super-oxidized water on human gingival fibroblasts and its efficacy in debris and smear layer removal from root canal walls. Cultured gingival fibroblasts were exposed to super-oxidized water (Sterilox), which was diluted in Iscove’s modified Dulbecco’s medium (IMDM) at 30%, 40%, 50%, 60% and 70% concentrations. The control group was maintained in IMDM. The cell viability was evaluated by means of an MTT assay after incubation periods of 1 h, 2 h, 24 h and 48 h. Pathological cellular changes were also observed under fluorescence and phase contrast microscopes. The efficacy in debris and smear layer removal was evaluated in comparison to the conventional application of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). Forty maxillary premolars were randomly divided into two equal groups (n = 20) and shaped with ProTaper NEXT rotary instruments using Sterilox or NaOCl/EDTA for irrigation. Afterwards, roots were split longitudinally and examined under a scanning electron microscope. The results revealed that super-oxidized water and sterile distilled water have acceptable biological properties for endodontic applications at concentrations up to 50% (p > 0.05). Moreover, super-oxidized water is equally effective in debris and smear layer removal as compared to NaOCl/EDTA (p > 0.05).

Application of Electrolyzed Water in the Food Industry: A Review

Electrolyzed water is a novel disinfectant and cleaner that has been widely utilized in the food sector for several years to ensure that surfaces are sterilized, and that food is safe. It is produced by the electrolysis of a dilute salt solution, and the reaction products include sodium hydroxide (NaOH) and hypochlorous acid. In comparison to conventional cleaning agents, electrolyzed water is economical and eco-friendly, easy to use, and strongly effective. Electrolyzed water is also used in its acidic form, but it is non-corrosive to the human epithelium and other organic matter. The electrolyzed water can be utilized in a diverse range of foods; thus, it is an appropriate choice for synergistic microbial control in the food industry to ensure food safety and quality without damaging the organoleptic parameters of the food. The present review article highlights the latest information on the factors responsible for food spoilage and the antimicrobial potential of electrolyzed water in fresh or processed plant and animal products.

Stability and Antibiofilm Efficiency of Slightly Acidic Electrolyzed Water Against Mixed-Species of Listeria monocytogenes and Staphylococcus aureus

In the natural environment, most microorganisms live in mixed-species biofilms, in which the metabolism and growth of organisms are different from that in single-species biofilms. Adhesive bacteria and their biofilms on the surface of food processing equipment are the sources of cross-contamination, leading to the risk for humans. Slightly acidic electrolyzed water (SAEW) has been proposed as a novel sanitizer in the food and agriculture industry. In this study, we investigated the changes in the physical properties of SAEW under different conditions and the disinfection abilities of SAEW against spore-forming and non-spore-forming pathogens. Furthermore, we examined the disinfection abilities of SAEW after 12 months of shelf life on a mixed-species biofilm of Listeria monocytogenes Scott A and Staphylococcus aureus. The results showed that SAEW at 30 and 50 ppm achieved all-kill of the spore-forming pathogen Bacillus cereus within 30 s. Changes in the ACC and pH of the produced SAEW were generally affected by the storage conditions. Both spore-forming and non-spore-forming pathogens were not detected under treatment with 50 ppm SAEW for 5 min under HDPE-closed conditions throughout the whole storage period. Moreover, 25 mg/L SAEW can inactivate L. monocytogenes Scott A and S. aureus biofilm cells in ~2.45 and 2.57 log CFU/mL in biofilms within 5-min treatment. However, the decline of the two bacteria in the mixed-species biofilm was 1.95 and 1.43 log CFU/mL, respectively. The changes in the cell membrane permeability of the mixed-species biofilm under treatment with SAEW were observed by using atomic force microscopy and confocal laser scanning microscopy. L. monocytogenes Scott A was more sensitive to SAEW in the mixed-species biofilm cells. These findings exhibited strong antibiofilm activities of SAEW in impairing biofilm cell membranes, decreasing cell density, and eliminating biofilm, which suggest that SAEW is an excellent antibacterial agent in the food processing industries.

Calcium bicarbonate as an antimicrobial, antiviral, and prion‑inhibiting agent (Review)

Calcium bicarbonate does not act as a disinfectant at neutral pH; however, it exerts strong antimicrobial activity after it is placed in a high-voltage electric field, whereby it assumes an alkaline pH (12.4). Moreover, the microbicidal activity of the resulting solution (named CAC-717) is not influenced by the presence of organic material or resistance of the agent to inactivation. When sprayed on the skin surface, the pH of CAC-717 decreases rapidly to 8.84. CAC-717 comprises fine particles of 50-500 nm. When these mesoscopic crystals are dissolved in water, they destroy the genomes of bacteria or viruses and neutralize the infectious properties of abnormal prion proteins produced in ScN2a cells. The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic has resulted in unprecedented international demand for disinfectants. A small titer of SARS-CoV-2 remains infectious even after 30 sec in growth medium at pH 12.4. CAC-717 has exhibited a strong virucidal effect (3.6 to 4.4 log₁₀ decrease) against all examined SARS-CoV-2 isolates, including mutant forms. Similarly, human noroviruses also remain intact at pH 12.4; however, CAC-717 has been shown to cause a 3.25 log₁₀ reduction in norovirus genomic RNA compared to untreated samples. Existing evidence suggests that an unidentified mechanism controls the virucidal activity of CAC-717.

A Better Disinfectant for Low-Resourced Hospitals? A Multi-Period Cluster Randomised Trial Comparing Hypochlorous Acid with Sodium Hypochlorite in Nigerian Hospitals: The EWASH Trial

Environmental hygiene in hospitals is a major challenge worldwide. Low-resourced hospitals in African countries continue to rely on sodium hypochlorite (NaOCl) as major disinfectant. However, NaOCl has several limitations such as the need for daily dilution, irritation, and corrosion. Hypochlorous acid (HOCl) is an innovative surface disinfectant produced by saline electrolysis with a much higher safety profile. We assessed non-inferiority of HOCl against standard NaOCl for surface disinfection in two hospitals in Abuja, Nigeria using a double-blind multi-period randomised cross-over study. Microbiological cleanliness [Aerobic Colony Counts (ACC)] was measured using dipslides. We aggregated data at the cluster-period level and fitted a linear regression. Microbiological cleanliness was high for both disinfectant (84.8% HOCl; 87.3% NaOCl). No evidence of a significant difference between the two products was found (RD = 2%, 90%CI: -5.1%-+0.4%; p-value = 0.163). We cannot rule out the possibility of HOCl being inferior by up to 5.1 percentage points and hence we did not strictly meet the non-inferiority margin we set ourselves. However, even a maximum difference of 5.1% in favour of sodium hypochlorite would not suggest there is a clinically relevant difference between the two products. We demonstrated that HOCl and NaOCl have a similar efficacy in achieving microbiological cleanliness, with HOCl acting at a lower concentration. With a better safety profile, and potential applicability across many healthcare uses, HOCl provides an attractive and potentially cost-efficient alternative to sodium hypochlorite in low resource settings.

Antiseptic Effects and Biosafety of a Controlled-Flow Electrolyzed Acid Solution Involve Electrochemical Properties, Rather than Free Radical Presence

Electrolyzed acid solutions produced by different methods have antiseptic properties due to the presence of chlorine and reactive oxygen species. Our aim was to determine whether a controlled-flow electrolyzed acid solution (CFEAS) has the ability to improve wound healing due to its antiseptic and antibiofilm properties. First, we demonstrated in vitro that Gram-negative and Gram-positive bacteria were susceptible to CFEAS, and the effect was partially sustained for 24 h, evidencing antibiofilm activity (p < 0.05, CFEAS-treated vs. controls). The partial cytotoxicity of CFEAS was mainly observed in macrophages after 6 h of treatment; meanwhile, fibroblasts resisted short-lived free radicals (p < 0.05, CFEAS treated vs. controls), perhaps through redox-regulating mechanisms. In addition, we observed that a single 24 h CFEAS treatment of subacute and chronic human wounds diminished the CFU/g of tissue by ten times (p < 0.05, before vs. after) and removed the biofilm that was adhered to the wound, as we observed via histology from transversal sections of biopsies obtained before and after CFEAS treatment. In conclusion, the electrolyzed acid solution, produced by a novel method that involves a controlled flow, preserves the antiseptic and antibiofilm properties observed in other, similar formulas, with the advantage of being safe for eukaryotic cells; meanwhile, the antibiofilm activity is sustained for 24 h, both in vitro and in vivo.

Optimization and Effect of Water Hardness for the Production of Slightly Acidic Electrolyzed Water on Sanitization Efficacy

Slightly acidic electrolyzed water (SAEW) has been recently proposed as a novel promising sanitizer and cleaner in the agricultural and food industries. However, several factors, including water hardness, were considered to strongly affect the physical properties and sanitization efficacy of SAEW. To study the effect of water hardness on the SAEW production, we evaluated the production properties and sanitization effect of SAEW, which was generated from water sources in 16 representatively geographical locations of South Korea. The results showed that the hardness of water sources from Kangwon-do, Jeollanam-do, and Daegu was 22-41 ppm; that from Busan, Gyeongnam-do, Gwangju Bukgu was 80-443 ppm, and that from seven other locations was 41-79 ppm. SAEW is produced from water hardness less than 50 ppm and greater than 80 ppm was beyond the accepted pH range (5.0-6.5). Notably, high-hardness water (>80 ppm) containing 5% HCl could be used to produce SAEW with accepted pH. The SAEW generated from low-hardness water with additions of 2% HCl and 2 M NaCl at 7 A showed accepted pH and higher germicidal effect. Furthermore, SAEW with the available chlorine concentration of 27-41 mg/L for 1 min was sufficient to completely inactivate non-spore-forming foodborne pathogens. Sanitization efficacy was not markedly affected by storage conditions for SAEW at 40 ppm. Our results demonstrated that the degree of water hardness is an important factor in the production of SAEW, which would provide a foundation for commercial application of SAEW.

Applicability of neutral electrolyzed water for cleaning contaminated fixed orthodontic appliances

INTRODUCTION

We investigated whether water jet washing with neutral electrolyzed water (NW) can be an easy and safe self-performed cleaning method for oral environments of fixed orthodontic appliance-wearing patients. In line with this, we examined the bactericidal effects and dissolution behaviors of metal elements released from appliances.

METHODS

A metal or resin bracket ligated with a metal wire and metal bracket adhered to an apatite-pellet were used as specimens. The bacteria and plaque removal effects of the 30 seconds of NW (30, 100 ppm) jet washing for contaminated specimens were examined via an agar-plate method and the observation of the residual plaque, comparing with other treatments (brushing and flow washing), those treatments with tap water (TW), and flow washings with commercial mouthwashes, Listerine Total Care + (LS) and ConCool F (CC). The amounts of metal released from metal specimens during the 1-week immersion in NW were analyzed and compared with those in TW, LS, and CC.

RESULTS

NW jet washing produced larger decreases of surviving bacteria than the treatments with TW and CC (P <0.05) and equal or larger decreases than the treatment with LS (P <0.05). NW jet washing yielded the highest plaque removal level. The amounts of nickel and chromium released from metal specimens after the 1-week immersion in NW (30 ppm) were less than or equal to those with LS.

CONCLUSIONS

NW jet washing could be applicable for cleaning fixed orthodontic appliances because of its higher bactericidal effects than the treatments with commercial mouthwashes, inducing no or a slight metal release in actual usage time.

Properties of serum albumin in electrolyzed water

Introduction. Electrochemical activation of water controls the physicochemical parameters of aquatic food environment without any reagents. Electrolyzed water affects the properties of macronutrient solutions. The present research studied the effect of anodic and cathodic fractions of electrochemically activated water on protein molecules and their interaction patterns. Study objects and methods. The study featured bovine serum albumin and its properties in electrochemically activated water with nonstandard redox and acidity values. The aqueous solution of bovine serum albumin was studied by viscometry, UV spectrometry, time-of-flight secondary ion mass spectrometry, and electrophoresis. Results and discussion. By knowing the interaction patterns of electrochemically activated water and protein molecules, food producers can control the properties of biological raw materials. Bovine serum albumin was studied in metastable fractions of electrochemically activated water obtained in the anode or cathode chamber of an electrochemical reactor. Both fractions of electrochemically activated water appeared to modify the properties of bovine serum albumin. The oxidized fraction of electrochemically activated water (anolyte) converted the protein solution into a more homogeneous molecular composition. The solution of bovine serum albumin in the reduced fraction of electrochemically activated water (catholyte) had an abnormally negative redox potential (–800 mV). The aqueous solution of bovine serum albumin in catholyte retained its initial viscosity for a long time, and its level was lower than in the control sample. This effect was consistent with other physicochemical characteristics of the solution. Conclusion. The research revealed some patterns that make it possible to apply reagent-free viscosity regulation to protein media in the food industry.

Nasopharyngeal and oropharyngeal rinses with neutral electrolyzed water prevents COVID-19 in front-line health professionals: A randomized, open-label, controlled trial in a general hospital in Mexico City

The worldwide efforts that healthcare professionals are making in the COVID-19 pandemic is well known, and the high risk of illness and death that front-line staff experience on a daily basis is a reality, despite well-defined protocols for the use of personal protective equipment. In addition, it is well known that vaccination is still faraway to be achieved worldwide and that new variants are emerging, thus additional protective measures must be explored. A prospective open-label randomized controlled clinical trial was performed on front-line medical staff from the Dr. Enrique Cabrera General Hospital in México City to evaluate the effectiveness of nasopharyngeal and oropharyngeal rinses with a neutral electrolyzed water, known as SES, to reduce the risk of COVID-19 disease among front-line, not vaccinated medical staff. A total of 170 volunteers were enrolled and equally divided in a control group and SES group. All members of the trial wore the adequate personal protection equipment at all times while performing their duties, as required by standard COVID-19 safety protocols. Additionally, the SES group participants followed a prophylactic protocol with SES (oral and nasal rinses, three times a day for 4 weeks). All participants were monitored for COVID-19 symptoms and disease in a time-frame of 4 weeks and the incidence of illness per group was registered. The relative risk of disease, associated with each treatment was calculated. The presence of COVID-19-positive cases, in the group that received the nasal and oral rinses with SES was 1.2%, while in the group that did not do the SES rinses (control group), it was 12.7% (P=0.0039 and RR=0.09405; 95% CI of 0.01231-0.7183). The prophylactic protocol was demonstrated as a protective factor, in more than 90%, for developing the disease, and without adverse effects. Nasal and oral rinses with SES may be an efficient alternative to reinforce the protective measures against COVID-19 disease and should be further investigated. The present clinical trial was retrospectively registered in the Cuban public registry of clinical trials (RPCEC) database (March 16, 2021; PREVECOVID-19: RPCEC00000357).

Acute inhalation toxicity of aerosolized electrochemically generated solution of sodium hypochlorite

OBJECTIVE

The objective was to determine the inhalation toxicity of the electrochemically generated sodium hypochlorite solution after its single administration to laboratory animals in the form of a highly dispersed aerosol.

MATERIALS AND METHODS

The study has been conducted according to the OECD Test Guideline №403 'Acute Inhalation Toxicity.' Laboratory animals were exposed to inhalation of an aerosol containing 1.7 ± 0.13 mg/m³ of active chlorine. The hematological and biochemical parameters of the blood of experimental animals have been determined, as well as specific parameters: the activity of cathepsins B and L, catalase, and α1-antitrypsin. Histological study of the lungs of animals has been carried out.

RESULTS

During inhalation and 14 days after it, no death of the animals was observed; the behavior, appearance, and weight gain did not differ from the control group. There were no significant deviations in hematological parameters, except the decrease in the level of platelets. The biochemical study showed slight changes in the activity of alkaline phosphatase and aspartate aminotransferase on the 1st day after inhalation; these parameters returned to normal within 14 days of observation. Specific biochemical parameters did not show the development of oxidative stress. No specific histological pathologies of lung tissue have been found.

CONCLUSIONS

Thus, the studied electrochemically generated sodium hypochlorite solution under single inhalation exposure in aerosol form practically does not cause a toxic effect. The data obtained allow classifying such solution to the 4th (or even 5th - after additional studies) class of toxicity in accordance with Globally Harmonized System of Classification and Labeling of Chemicals.

Research Trends on the Application of Electrolyzed Water in Food Preservation and Sanitation

Electrolyzed water (EW) has been proposed as a novel promising sanitizer and cleaner in recent years. It is an effective antimicrobial and antibiofilm agent that has several advantages of being on the spot, environmentally friendly, cheap, and safe for human beings. Therefore, EW has been applied widely in various fields, including agriculture, food sanitation, livestock management, medical disinfection, clinical, and other fields using antibacterial technology. Currently, EW has potential significance for high-risk settings in hospitals and other clinical facilities. The research focus has been shifted toward the application of slightly acidic EW as more effective with some supplemental chemical and physical treatment methods such as ultraviolet radiations and ultrasound. This review article summarizes the possible mechanism of action and highlights the latest research studies in antimicrobial applications.

Antimicrobial Effect of Calcium Hydroxide Combined with Electrolyzed Superoxidized Solution at Neutral pH on Enterococcus faecalis Growth

Objective

To evaluate the effect of the combination of calcium hydroxide (Ca(OH)₂) and a novel electrolyzed superoxidized solution at neutral pH, known as OxOral® on Enterococcus faecalis growth in root canals.

Methods

Sixty human teeth were used, from which root canals were infected and randomly divided into the following treatment groups: saline solution, saline solution plus Ca(OH)₂, OxOral®, and OxOral® plus Ca(OH)₂.

Results

A permanent reduction in bacterial growth was observed at days 1, 6, 12, and 18 after OxOral® plus Ca(OH)₂ treatment from 4.4 ± 0.074 log₁₀ CFU/mL to 0.0 ± 0.001 log₁₀ CFU/mL. In addition, alkaline conditions maintenance was observed from application time (pH = 12.2 ± 0.033) to 18 d posttreatment (pH = 12.6 ± 0.083).

Conclusion

The combination of OxOral® and Ca(OH)₂ provides an alkaline pH and inhibits E. faecalis growth into the root canals. Our study opens the possibility for further research on the use of OxOral® in endodontic therapy.

Development of Alkaline Reduced Water Using High-Temperature-Roasted Mineral Salt and Its Antioxidative Effect in RAW 264.7 Murine Macrophage Cell Line

Oxidative stress (OS) plays an important role in many diseases, and its excessive increase affects human health. Although the antioxidant effect of sea salt can be strengthened through special processing, it is scarcely studied. This study confirmed the antioxidative effect of high-temperature roasted mineral salt (HtRMS) produced through repeated roasting of sea salt at high temperature in a ceramic vessel. The dissolved HtRMS exhibited properties such as high alkalinity, rich mineral content, and a high concentration of hydrogen (H2). To detect the antioxidative effect of HtRMS, OS was induced in RAW 264.7 murine macrophage cells with hydrogen peroxide (H2O2) and lipopolysaccharide (LPS), and then treated with HtRMS solution at different concentrations (0.1, 1, and 10%). Cell viability, reactive oxygen species (ROS), nitric oxide (NO), and antioxidant enzymes such as catalase (CAT) and glutathione peroxidase (GPx), Ca2+, and mitogen-activated protein kinase (MAPK) pathway-related proteins (p-p38, p-JNK, and p-ERK) were measured. OS was significantly induced by treatment with H2O2 and LPS (p < 0.001). After treatment with HtRMS, cell viability and GPx activities significantly increased and ROS, NO, Ca2+, and CAT significantly decreased in a concentration-dependent manner compared to H2O2 and LPS-only groups, which was not observed in tap water (TW)-treated groups. Similarly, p-p38, p-JNK, and p-ERK levels significantly decreased in a concentration-dependent manner in HtRMS groups compared to both H2O2 and LPS-only groups; however, those in TW groups did not exhibit significant differences compared to H2O2 and LPS-only groups. In conclusion, our results suggest that HtRMS may have antioxidant potential by regulating the MAPK signaling pathway.

Electrolyzed Water Generated On-Site as a Promising Disinfectant in the Dental Office During the COVID-19 Pandemic

Electrolyzed water is a safe, broad-spectrum bactericidal and viricidal agent, which can be used as a potent and effective alternative disinfectant in case of supply shortages. This report describes the on-site production of slightly acidic electrolyzed water (EW) from diluted salt solution and vinegar at a dental office using a portable EW generator unit. Such measures can ensure the safe continuity of important dental service provision for our patients during the coronavirus disease 2019 (CoVID-19) pandemic.