Recent advances in sterilization and disinfection technology: A review

Molybdenum disulfide nanosheets based non-oxygen-dependent and heat-initiated free radical nanogenerator with antimicrobial peptides for antimicrobial, biofilm ablation and wound healing

Chronic refractory wounds caused by multidrug-resistant (MDR) bacterial and biofilm infections are a substantial threat to human health, which presents a persistent challenge in managing clinical wound care. We here synthesized a composite nanosheet AIPH/AMP/MoS2, which can potentially be used for combined therapy because of the photothermal effect induced by MoS2, its ability to deliver antimicrobial peptides, and its ability to generate alkyl free radicals independent of oxygen. The synthesized nanosheets exhibited 61 % near-infrared (NIR) photothermal conversion efficiency, marked photothermal stability and free radical generating ability. The minimal inhibitory concentrations (MICs) of the composite nanosheets against MDR Escherichia coli (MDR E. coli) and MDR Staphylococcus aureus (MDR S. aureus) were approximately 38 μg/mL and 30 μg/mL, respectively. The composite nanosheets (150 μg/mL) effectively ablated >85 % of the bacterial biofilm under 808-nm NIR irradiation for 6 min. In the wound model experiment, approximately 90 % of the wound healed after the 4-day treatment with the composite nanosheets. The hemolysis experiment, mouse embryonic fibroblast (MEFs) cytotoxicity experiment, and mouse wound healing experiment all unveiled the excellent biocompatibility of the composite nanosheets. According to the transcriptome analysis, the composite nanosheets primarily exerted a synergistic therapeutic effect by disrupting the cellular membrane function of S. aureus and inhibiting quorum sensing mediated by the two-component system. Thus, the synthesized composite nanosheets exhibit remarkable antibacterial and biofilm ablation properties and therefore can be used to improve wound healing in chronic biofilm infections.

Sandwich-structured continuous ZIF-8/Ti3C2 MXene/ZIF-8 for efficient sterilization: Enhanced photocatalytic activity, photothermal effect, and environmental safety

The development of effective water purification systems is crucial for controlling and remediating environmental pollution, especially in terms of sterilization. Herein, we demonstrate elaborately designed composite nanosheets with a sandwich structure, composed of two-dimensional (2D) Ti3C2 MXene nanosheet core and conformal ZIF-8 ultrathin outer layers, and their potential applications in photocatalytic sterilization. The study results indicate that the conformal ZIF-8-MXene nanosheet exhibits an expanded light absorption range (826 nm), improved photothermal conversion efficiency (6.2 °C s-1), and photocurrent response, thus boosting photocatalytic sterilization efficiency (6.63 log10 CFU mL-1) against Escherichia coli under simulated sunlight within 90 min. Interestingly, 2D ZIF-8 layers exhibit positive zeta potential (19 mV), good hydrophilicity (40.6°), and local photogenerated-hole accumulation, possessing efficient bacteria-trapping efficiency. Membrane filters fabricated from optimized composite nanosheets exhibit an outstanding bacteria-trapping and sterilization efficiency (almost 100 %) against Escherichia coli under simulated sunlight within 30 min of the flow photocatalytic experiments. This work not only presents a rational structural design of the conformal and ultrathin anchoring of ZIF-8 onto a 2D conductive material for bacteria-trapping and sterilization, but also opens new opportunities for using metal-organic frameworks in photocatalytic disinfection of drinking water.

Acid etching post-treatment enhanced fungal sterilization performance of copper-manganese-cerium oxide in liquid and aerosol: Materials and molecular biological mechanisms

Bioaerosol is one of the main ways to spread respiratory infectious diseases. In order to further improve the sterilization efficiency of copper-manganese-cerium oxide (CuMnCeOx), the post-treatment method based on acid etching was adopted. The results showed that sterilization efficiency of the treated CuMnCeOx could reach 99% in aerosol with space velocity of 1400 h-1. L(+)-ascorbic acid successfully promoted the formation of Cu+, oxygen vacancies and the generation of reactive oxygen species (ROS) on the surface of the treated CuMnCeOx. During sterilization in liquid system, the transcriptome identified 316 differentially expressed genes, including 270 up-regulated genes and 46 down-regulated genes. Differentially expressed genes were significantly enriched in cell wall (GO:0005618) and external encapsulating structure (GO:0030312). Up-regulated genes were shown in regulation of reactive oxygen species biosynthetic processes (GO:1903409, GO:1903426, GO:1903428) and positive regulation all of reactive oxygen species metabolic process (GO:2000379), indicating that ROS induced cell death by destroying cell wall.

Unraveling the nuclear isotope tapestry: Applications, challenges, and future horizons in a dynamic landscape

Nuclear isotopes, distinct atoms characterized by varying neutron counts, have profoundly influenced a myriad of sectors, spanning from medical diagnostics and therapeutic interventions to energy production and defense strategies. Their multifaceted applications have been celebrated for catalyzing revolutionary breakthroughs, yet these advancements simultaneously introduce intricate challenges that warrant thorough investigation. These challenges encompass safety protocols, potential environmental detriments, and the complex geopolitical landscape surrounding nuclear proliferation and disarmament. This comprehensive review embarks on a deep exploration of nuclear isotopes, elucidating their nuanced classifications, wide-ranging applications, intricate governing policies, and the multifaceted impacts of their unintended emissions or leaks. Furthermore, the study meticulously examines the cutting-edge remediation techniques currently employed to counteract nuclear contamination while projecting future innovations in this domain. By weaving together historical context, current applications, and forward-looking perspectives, this review offers a panoramic view of the nuclear isotope landscape. In conclusion, the significance of nuclear isotopes cannot be understated. As we stand at the crossroads of technological advancement and ethical responsibility, this review underscores the paramount importance of harnessing nuclear isotopes' potential in a manner that prioritizes safety, sustainability, and the greater good of humanity.

Effect of silver vanadate on the antibiofilm, adhesion and biocompatibility properties of denture adhesive

Aim: To evaluate the biological and mechanical properties of an adhesive with nanostructured silver vanadate (AgVO3). Materials & methods: Specimens in poly(methyl methacrylate) (PMMA) were treated with Ultra Corega Cream (UCCA) denture adhesive with or without AgVO3. Biofilms of Candida albicans, Candida glabrata and Streptococcus mutans were grown and the viable cells counted. Fluorescence microscopy was used. The viability of the VERO cell and adhesive strength were evaluated. Results: All concentrations of AgVO3 reduced the biofilm formation and showed no cytotoxic effect. At 5 min and 24 h, UCCA with 5 and 10% AgVO3 showed better performance, respectively. Conclusion: AgVO3 promoted the antibiofilm activity of the adhesive, with a positive effect on the adhesive strength, and was biocompatible.

Quantifying sodium hypochlorite content in hypochlorite-based disinfectants via phase-conversion headspace technique

In this work, a novel and efficient approach for sodium hypochlorite analysis is proposed via phase-conversion headspace technique, which is based on the gas chromatography (GC) detection of generated carbon dioxide (CO2) from the redox reaction of sodium hypochlorite with sodium oxalate. The data obtained by the proposed method suggest the high detecting precision and accuracy. In addition, the method has low detection limits (limit of quantification (LOQ) = 0.24 μg/mL), and the recoveries of added standard ranged from 98.33 to 101.27 %. The proposed phase-conversion headspace technique is efficient and automated, thereby offering an efficient strategy for highly efficient analysis of sodium hypochlorite and related products.

Disinfection of wastewater by a complete equipment based on a novel ultraviolet light source of microwave discharge electrodeless lamp: Characteristics of bacteria inactivation, reactivation and full-scale studies

Ultraviolet (UV) light is widely used for wastewater disinfection. Traditional electrode-excited UV lamps, such as low-pressure mercy lamps (LPUV), encounter drawbacks like electrode aging and rapid light attenuation. A novel UV source of microwave discharge electrodeless lamp (MDEL) has aroused attention, yet its disinfection performance is unclear and still far from practical application. Here, we successfully developed a complete piece of equipment based on MDELs and achieved the application for disinfection in wastewater treatment plants (WWTPs). The light emitted by an MDEL (MWUV) shared a spectrum similar to that of LPUV, with the main emission wavelength at 254 nm. The inactivation rate of Gram-negative E. coli by MWUV reached 4.5 log at an intensity of 1.6 mW/cm2 and a dose of 20 mJ/cm2. For Gram-positive B. subtilis, an MWUV dose of 50 mJ/cm2 and a light intensity of 1.2 mW/cm2 reached an inactivation rate of 3.4 log. A higher MWUV intensity led to a better disinfection effect and a lower photoreactivation rate of E. coli. When inactivated by MWUV with an intensity of 1.2 mW/cm2 and a dose of 16 mJ/cm2, the maximum photoreactivation rate and reactivation rate constant Kmax of E. coli were 0.63 % and 0.11 % h-1 respectively. Compared with the photoreactivation, the dark repair of E. coli was insignificant. The full-scale application of the MDEL equipment was conducted in two WWTPs (10,000 m3/d and 15,000 m3/d). Generally 2-3 log inactivation rates of fecal coliforms in secondary effluent were achieved within 5-6 s contact time, and the disinfected effluent met the emission standard (1000 CFU/L). This study successfully applied MDEL for disinfection in WWTPs for the first time and demonstrated that MDEL has broad application prospects.

A Day in the Life of a Surgical Instrument: The Cycle of Sterilization

Surgeons must be confident that the instruments they use do not pose risk of infection to patients due to bioburden or contamination. Despite this importance, surgeons are not necessarily aware of the steps required to ensure that an instrument has been properly sterilized, processed, and prepared for the next operation. At the end of an operation, instruments must be transported to the sterile processing unit. There, instruments are decontaminated before being sterilized by heat, chemical, or radiation-based methods. Following this, they are stored before being brought back into use. This review highlights the intricacies of the processing of surgical instruments at the conclusion of an operation so that they are ready for the next one.

Progress of disinfection catalysts in advanced oxidation processes, mechanisms and synergistic antibiotic degradation

Human diseases caused by pathogenic microorganisms make people pay more attention to disinfection. Meanwhile, antibiotics can cause microbial resistance and increase the difficulty of disease treatment, resulting in risk of triggering a vicious circle. Advanced oxidation process (AOPs) has been widely studied in the field of synergistic treatment of the two contaminates. This paper reviews the application of catalytic materials and their modification strategies in the context of AOPs for disinfection and antibiotic degradation. It also delves into the mechanisms of disinfection such as the pathways for microbial inactivation and the related influencing factors, which are essential for understanding the pivotal role of catalytic materials in disinfection principles by AOPs. More importantly, the exploratory research on the combined use of AOPs for disinfection and antibiotic degradation is discussed, and the potential and prospects in this field is highlighted. Finally, the limitations and challenges associated with the application of AOPs in disinfection and antibiotic degradation are summarized. It aims to provide a starting point for future research efforts to facilitate the widespread use of advanced oxidation processes in the field of public health.

Fluorimetric determination of aqueous formaldehyde employing heating and ultrasound-assisted approach through its derivatization with a ß-diketone-nickel(2+) complex immobilized in a PMMA flow cell

Formaldehyde (FA) is a highly toxic substance present in many matrices, including freshwater as well as found in natural mechanisms such as rainfall and combustion of organic matter. Consumption of water contaminated with high levels of FA can cause severe short-term or long-term health problems. Due to these health risks, procedures are necessary to determine and quantify FA in aqua sources This paper reports on a study of fluorimetric determination of FA using a nickel(2 + )-diketonate coordination compound immobilized as a solid precursor. The compound was characterized by electronic absorption, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetry (TG), optical microscopy (OM), and scanner electron microscopy (SEM). The methodology was based on the reaction of the synthesized compound with an ammoniacal buffer generating a selective reagent for formaldehyde: fluoral-P. The product of the reaction generates 3,5-diacetyl-1,4-dihydrolutidine (DDL), which is responsible for the fluorescence of the system. Several parameters such as temperature, duration of heating time, and dilution effect with the best effects were studied to carry out FA determination. Under the optimum experimental conditions, a linear response ranging from 1.0 to 10.0 mg/L FA (R = 0.997 and n = 10), and a detection (3σ criterion) and quantification (10 σ criterion) limit estimated at 0.129 and 0.389 mg/L, respectively were achieved. The FA analysis was able to be conducted in 05 min with a relative standard deviation estimated at 1.10 %.

A review on sterilization methods of environmental decontamination to prevent the coronavirus SARS-CoV-2 (COVID-19 virus): A new challenge towards eco-friendly solutions

In recent years, the COVID-19 pandemic is currently wreaking havoc on the planet. SARS-CoV-2, the Severe Acute Respiratory Syndrome Coronavirus, is the current term for this outbreak. Reports about this novel coronavirus have been presented since the pandemic's breakout, and they have demonstrated that it transmits rapidly from person to person, primarily by droplets in the air. Findings have illustrated that SARS-CoV-2 can survive on surfaces from hours to days. Therefore, it is essential to find practical solutions to reduce the virus's impact on human health and the environment. This work evaluated common sterilization methods that can decontaminate the environment and items. The goal is that healthcare facilities, disease prevention organizations, and local communities can overcome the new challenge of finding eco-friendly solutions. Further, a foundation of information encompassing various sterilization procedures and highlighting their limits to choose the most appropriate method to stop disease-causing viruses in the new context has been presented. The findings of this crucial investigation contribute to gaining insight into the comprehensive sterilization approaches against the coronavirus for human health protection and sustainable environmental development.

Ag2O-Containing Biocidal Interpolyelectrolyte Complexes on Glass Surfaces-Adhesive Properties of the Coatings

Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial components was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a more than 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC, and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied with micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation in adhesion. On the other hand, use of the optical tweezers method makes it possible to analyze macromolecules at the submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

Well-designed protein amyloid nanofibrils composites as versatile and sustainable materials for aquatic environment remediation: A review

Amyloid nanofibrils (ANFs) are supramolecular polymers originally classified as pathological markers in various human degenerative diseases. However, in recent years, ANFs have garnered greater interest and are regarded as nature-based sustainable biomaterials in environmental science, material engineering, and nanotechnology. On a laboratory scale, ANFs can be produced from food proteins via protein unfolding, misfolding, and hydrolysis. Furthermore, ANFs have specific structural characteristics such as a high aspect ratio, good rigidity, chemical stability, and a controllable sequence. These properties make them a promising functional material in water decontamination research. As a result, the fabrication and application of ANFs and their composites in water purification have recently gained considerable attention. Despite the large amount of literature in this field, there is a lack of systematic review to assess the gap in using ANFs and their composites to remove contaminants from water. This review discusses significant advancements in design techniques as well as the physicochemical properties of ANFs-based composites. We also emphasize the current progress in using ANFs-based composites to remove inorganic, organic, and biological contaminants. The interaction mechanisms between ANFs-based composites and contaminants are also highlighted. Finally, we illustrate the challenges and opportunities associated with the future preparation and application of ANFs-based composites. We anticipate that this review will shed new light on the future design and use of ANFs-based composites.

Influence of cold atmospheric pressure plasma treatment of Spirulina platensis slurry over biomass characteristics

Cold atmospheric pressure plasma (CAPP) technique is an innovative non-thermal approach for food preservation and decontamination. This study aimed to evaluate the effect of CAPP power density on microorganism inactivation and quality of Spirulina platensis (S. platensis) slurry. 91.31 ± 1.61% of microorganism were inactivated within 2.02 ± 0.11 min by 26.67 W/g CAPP treatment under 50 ℃. Total phenolic, Chlorophyll-a (Chl-a), and carotenoids contents were increased by 20.51%, 63.55%, and 70.04% after 20.00 W/g CAPP treatment. Phycobiliproteins (PBPs), protein, intracellular polysaccharide, and moisture content of S. platensis was decreased, while vividness, lightness, color of yellow and green, antioxidant activity, Essential Amino Acid Index were enhanced after CAPP treatment. The nutrient release and filaments breakage of CAPP-treated S. platensis improved its bio-accessibility. The findings provided a deep understanding and insight into the influence of CAPP treatment on S. platensis, which were meaningful for optimizing its sterilization and drying processing condition.

Biosynthesis of silver nanoparticles using nitrate reductase from Aspergillus terreus N4 and their potential use as a non-alcoholic disinfectant

Green technology has been developed for the quick production of stabilized silver nanoparticles (AgNPs), with the assistance of nitrate reductase from an isolated culture of Aspergillus terreus N4. The organism's intracellular and periplasmic fractions contained nitrate reductase, with the former demonstrating the highest activity of 0.20 IU/g of mycelium. When the fungus was cultivated in a medium comprising 1.056% glucose, 1.836% peptone, 0.3386% yeast extract, and 0.025% KNO3, the greatest nitrate reductase productivity of 0.3268 IU/g was achieved. Statistical modeling via response surface methodology was used to optimize the enzyme production. The periplasmic and intracellular enzyme fractions were found to convert Ag+ to Ag0, initiating synthesis within 20 min, with predominant nanoparticle sizes between 25 and 30 nm. By normalizing the effects of temperature, pH, AgNO3 concentration, and mycelium age with a variable shaking period for enzyme release, the production of AgNPs with the periplasmic fraction was optimized. The synthesis of nanoparticles occurred at temperatures of 30, 40, and 50 °C, with the highest yield observed at 40 and 50 °C during shorter incubation periods. Similarly, the nanoparticles were synthesized at pH levels of 7.0, 8.0, and 9.0, with the greatest production observed at pH 8.0 and 9.0 at lower incubation periods. The antimicrobial activity of AgNPs was demonstrated against common foodborne pathogens, including Staphylococcus aureus and Salmonella typhimurium, indicating their potential as non-alcoholic disinfectants.

Simultaneous Irradiation with UV-A, -B, and -C Lights Promotes Effective Decontamination of Planktonic and Sessile Bacteria: A Pilot Study

Surfaces in highly anthropized environments are frequently contaminated by both harmless and pathogenic bacteria. Accidental contact between these contaminated surfaces and people could contribute to uncontrolled or even dangerous microbial diffusion. Among all possible solutions useful to achieve effective disinfection, ultraviolet irradiations (UV) emerge as one of the most "Green" technologies since they can inactivate microorganisms via the formation of DNA/RNA dimers, avoiding the environmental pollution associated with the use of chemical sanitizers. To date, mainly UV-C irradiation has been used for decontamination purposes, but in this study, we investigated the cytotoxic potential on contaminated surfaces of combined UV radiations spanning the UV-A, UV-B, and UV-C spectrums, obtained with an innovative UV lamp never conceived so far by analyzing its effect on a large panel of collection and environmental strains, further examining any possible adverse effects on eukaryotic cells. We found that this novel device shows a significant efficacy on different planktonic and sessile bacteria, and, in addition, it is compatible with eukaryotic skin cells for short exposure times. The collected data strongly suggest this new lamp as a useful device for fast and routine decontamination of different environments to ensure appropriate sterilization procedures.

Antioxidant and Antiaging Activity of Fermented Coix Seed Polysaccharides on Caenorhabditis elegans

Aging is closely related to many diseases and is a long-term challenge that humans face. The oxidative damage caused by the imbalance of free radicals is an important factor in aging. In this study, we investigate the antioxidant and antiaging activities of fermented coix seed polysaccharides (FCSPs) via in vitro and in vivo experiments. The FCSPs were extracted by fermenting coix seed with Saccharomyces cerevisiae for 48 h and utilizing water-extracted coix seed polysaccharides (WCSPs) as a control. Their antiaging activity and mechanism were evaluated based on the antiaging model organism Caenorhabditis elegans (C. elegans). The results showed that the molecular weight of the FCSPs extracted by fermentation was smaller than that of the WCSPs, making them more easily absorbed and utilized. At a concentration of 5 g/L, the FCSPs' capacity to scavenge the DPPH·, ABTS⁺·, OH·, and O₂^-· radicals was greater than the WCSPs' capacity by 10.09%, 14.40%, 49.93%, and 12.86%, respectively. Moreover, C. elegans treated with FCSPs exhibited higher antioxidant enzyme activities and a lower accumulation of malonaldehyde. By inhibiting the expression of the pro-aging genes daf-2 and age-1, and upregulating the expression of the antiaging genes daf-16, sod-3, skn-1, and gcs-1 in the insulin/insulin-like growth factor-1 (IIS) signaling pathway, the FCSPs could effectively enhance stress tolerance and delay C. elegans aging. The lifespan of C. elegans in the FCSPs group was 5.91% higher than that of the WCSPs group. In conclusion, FCSPs exert better antioxidant and antiaging effects than WCSPs, which can act as a potential functional ingredient or supplement in food.

Modelling of Nonthermal Dielectric Barrier Discharge Plasma at Atmospheric Pressure and Role of Produced Reactive Species in Surface Polymer Microbial Purification

A nonthermal atmospheric plasma reactor was used to sterilize polymer surfaces and satisfy safety constraints in a biological medium. A 1D fluid model was developed using COMSOL Multiphysics software^® 5.4 with a helium-oxygen mixture at low temperature for the decontamination of bacteria on polymer surfaces. An analysis of the evolution of the homogeneous dielectric barrier discharge (DBD) was carried out through studying the dynamic behavior of the discharge parameters including the discharge current, the consumed power, the gas gap voltage, and transport charges. In addition, the electrical characteristics of a homogeneous DBD under different operating conditions were studied. The results shown that increasing voltage or frequency caused higher ionization levels and maximum increase of metastable species' density and expanded the sterilization area. On the other hand, it was possible to operate plasma discharges at a low voltage and a high density of plasma using higher values of the secondary emission coefficient or permittivity of the dielectric barrier materials. When the discharge gas pressure increased, the current discharges declined, which indicated a lower sterilization efficiency under high pressure. A short gap width and the admixture of oxygen were needed for sufficient bio-decontamination. Plasma-based pollutant degradation devices could therefore benefit from these results.