Disinfection Potential Research Articles

O‐Phthalaldehyde: A Versatile Chemical with its Roles and Future Perspectives

AbstractOrtho‐Phthaldehyde (OPA) is one of the isomers of benzenedicarbaldehydes. It exhibits distinctive chemical properties stemming from the closely attached dicarbaldehyde groups. Since its development, it has been widely employed as a potent disinfectant, owing to its inherent antimicrobial properties. OPA has the ability to form a fluorescent product with primary amines, making it useful for detecting and estimating various biogenic amines, peptides, and proteins in bodily fluids. Moreover, the combination of thiol and amine with OPA produces a more sensitive fluorogenic compound, significantly enhancing the sensitivity and specificity of OPA‐based analytical techniques. This review summarizes recent developments in biochemical analysis using OPA. It also discusses key achievements in the development of photoactive polymers. Additionally, it covers the use of OPA as a synthetic precursor to achieve small molecules with unique structures that have become increasingly important in various fields of scientific research from 2004.

Ag enhanced CuS nanoflower catalyst coupling dielectric barrier discharge plasma for disinfection performance and mechanism

In this study, the hydrothermal method was employed to grow submicron CuS on carbon cloth (CC), and the photoreduction method was used to grow Ag nanoparticles on the CuS submicron flowers, thus forming the Ag/CuS/CC catalytic electrode. The application of Ag/CuS/CC electrode-coupled dielectric barrier discharge (DBD) plasma in the disinfection of pathogenic bacteria in water was studied. The Ag/CuS/CC electrode exhibits strong antibacterial activity, and under an external voltage of 30 V, the degradation efficiency of Bacillus subtilis reaches 99.99% within 15 min without regeneration. After five cycles, the inactivation rate of Bacillus subtilis reached 99.99% within 25 min. The practical applicability of the Ag/CuS/CC-coupled DBD system for treating actual wastewater was evaluated, and the changes in biological toxicity were investigated. The results indicate that the prepared Ag/CuS/CC coupled DBD has great potential for safe disinfection of pathogenic bacteria in water through integrated processes.

In-vitro and in-vivo assessment of the bactericidal potential of peracetic acid and hydrogen peroxide disinfectants against A. hydrophila infection in Nile tilapia and their effect on water quality indices and fish stress biomarkers

This study aimed to assess the in vitro and in vivo disinfectant potential of peracetic acid (PAA) (1 mg/L) and hydrogen peroxide (H2O2) (20 mg/L) on the physicochemical and microbiological water quality parameters of fish aquaria, the microbial density of Nile tilapia muscular tissue, fish hepatic cortisol levels, and antioxidant biomarkers. In vitro, PAA and H2O2 reduced A. hydrophila colony viability by 5 log units after 30 and 5 min of contact time, respectively. PAA and H2O2 were added to aquaria water twice a week for the three-week experiment. Increased fish escape reflexes were observed only in the PAA group, which returned to normal within 10 min. No mortalities were reported in either the PAA or H2O2 groups. An in vivo experimental challenge with a pathogenic strain of A. hydrophila revealed a 20% reduction in mortality in the PAA group, with no mortalities in the H2O2 group. Cortisol levels and antioxidant markers were measured to assess the impact of PAA and H2O2 on fish health. Cortisol levels in the PAA and H2O2 groups were significantly higher than in the control group after disinfectant exposure, but they progressively returned to normal. A significant reduction in superoxide dismutase (SOD) and catalase (CAT) activity, along with considerably higher glutathione peroxidase (GPx) and malondialdehyde (MDA) enzymatic activity, was observed in the PAA and H2O2 groups compared to the control group. A substantial increase in total antioxidant capacity (TAC) was recorded in the PAA group. Physicochemical analyses revealed reduced pH and increased dissolved oxygen levels in the PAA and H2O2 groups. Microbiological analyses showed a significant reduction in bacterial density in water by 64% and 76% after 30 min of exposure to PAA and H2O2, respectively, with a non-significant increase in microbial count after bacterial challenge. Additionally, aerobic bacterial count, Aeromonas spp., and psychotropic bacterial count in fish muscle showed a significant reduction in the H2O2 group compared to the PAA and control groups before and after infection. The study concludes that regular application of PAA and H2O2 can temporarily reduce bacterial load in aquaria and fish muscle, regulate stress responses, and improve fish health by reducing A. hydrophila-induced infections and improving survival.

Elucidating antibiofilm as well as photocatalytic disinfection potential of green synthesized nanosilver against multi-drug-resistant bacteria and its photodegradation ability of cationic dyes

BackgroundBioinspired nanomaterials have widely been employed as suitable alternatives for controlling biofilm and pathogens due to their distinctive physico-chemical properties.MethodologyThis study explored the antibiofilm as well as photocatalytic potential of silver (Ag) nanoparticles (NPs) synthesized using the cell-free supernatant of Lactobacillus acidophilus for the disinfection of multi-drug-resistant (MDR) strains of enteroaggregative E. coli (EAEC), Salmonella Typhimurium, S. Enteritidis and methicillin-resistant Staphylococcus aureus (MRSA) on exposure to LED light. In addition, the removal of toxic cationic dyes i.e., methylene blue (MB), rhodamine B (RhB) and crystal violet (CV) was explored on exposure to sunlight, LED and UV lights.ResultsInitially, the synthesis of AgNPs was verified using UV- Vis spectroscopy, X-ray diffraction and transmission electron microscopy. The synthesized AgNPs exhibited MIC and MBC values of 7.80 and 15.625 µg/mL, respectively. The AgNPs exhibited significant inhibition (P < 0.001) in the biofilm-forming ability of all the tested MDR isolates. On exposure to LED light, the AgNPs could effectively eliminate all the tested MDR isolates in a dose-dependent manner. While performing photocatalytic assays, the degradation of RhB was observed to be quite slower than MB and CV irrespective of the tested light sources. Moreover, the sunlight as well as UV light exhibited better photodegradation capacity than LED light. Notwithstanding the light sources, RhB followed zero-order kinetics; however, MB and CV followed primarily second-order kinetics.ConclusionThe green synthesized AgNPs were found to be an effective photocatalytic as well as antifouling candidate that could be applied in therapeutics and wastewater treatment.

Real-time water quality monitoring using AI-enabled sensors: Detection of contaminants and UV disinfection analysis in smart urban water systems

This study introduces a novel method for assessing water quality, employing a cutting-edge sensor system integrated with artificial intelligence (AI) technologies. Addressing the global challenge of water scarcity and pollution, the research focuses on the innovative use of spectroscopic analysis for real-time water quality monitoring. The study evaluates the effectiveness of this system in distinguishing between clean, contaminated, and UV-disinfected water samples, highlighting its precision in detecting variations in water quality. Central to the research is the deployment of advanced machine learning algorithms, including Random Forest, Support Vector Machines (SVM), and Neural Networks, to process and classify spectral data. These models demonstrate remarkable accuracy in real-time classification, underscoring the synergy between AI and environmental science in addressing critical public health issues. Significantly, the study showcases the potential of UV disinfection in water treatment, as evidenced by the spectral changes observed in disinfected water samples. This aspect of the research emphasizes the role of spectral analysis in verifying the efficacy of water treatment processes. Overall, this study paves the way for more sophisticated and accessible water quality monitoring systems, offering a promising solution to one of the most pressing environmental challenges. The integration of AI and spectral analysis in this research offers a breakthrough in ensuring a safe water supply and effective water resource management. This study utilizes advanced machine learning algorithms, including Random Forest, Support Vector Machines (SVM), and Neural Networks, for water quality assessment. These models process and classify spectral data with high precision, highlighting variations in water quality.

Artificial Bacteriophages for Treating Oral Infectious Disease via Localized Bacterial Capture and Enhanced Catalytic Sterilization.

With the rapid emergence of antibiotic-resistant pathogens, nanomaterial-assisted catalytic sterilization has been well developed to combat pathogenic bacteria by elevating the level of reactive oxygen species including hydroxyl radical (·OH). Although promising, the ultra-short lifetime and limited diffusion distance of ·OH severely limit their practical antibacterial usage. Herein, the rational design and preparation of novel virus-like copper silicate hollow spheres (CSHSs) are reported, as well as their applications as robust artificial bacteriophages for localized bacterial capture and enhanced catalytic sterilization in the treatment of oral infectious diseases. During the whole process of capture and killing, CSHSs can efficiently capture bacteria via shortening the distance between bacteria and CSHSs, produce massive ·OH around bacteria, and further iinducing the admirable effect of bacterial inhibition. By using mucosal infection and periodontitis as typical oral infectious diseases, it is easily found that the bacterial populations around lesions in animals after antibacterial treatment fall sharply, as well as the well-developed nanosystem can decrease the inflammatory reaction and promote the hard or soft tissue repair. Together, the high Fenton-like catalytic activity, strong bacterial affinity, excellent antibacterial activity, and overall safety of the nanoplatform promise its great therapeutic potential for further catalytic bacterial disinfection.

Screening of the global health priority BoxⓇ reveals potential new disinfectants against the emerging multidrug-resistant pathogen Candida auris

BackgroundCandida auris has been identified by the World Health Organization as a critical pathogen due to its invasive nature, resistance to multiple drugs, and high mortality rates in hospital outbreaks. This fungus can persist on surfaces and human skin for extended periods, complicating infection control efforts. The need for effective disinfection strategies is urgent, as current disinfectants are often ineffective against C. auris biofilms. ObjectiveThe study aimed to identify potential disinfectants from a collection of 240 compounds in the Global Health Priority Box® that are effective against C. auris, particularly strains resistant to existing options. MethodsThe research employed a screening protocol using a fluconazole-resistant strain of C. auris (149/23). Antifungal activity was assessed using the microdilution method to determine Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs). Additional assays were conducted to evaluate biofilm inhibition, biofilm eradication, cell membrane integrity, nucleotide leakage, sorbitol protection assay, efflux pump inhibition, and hemolysis assay. ResultsTwo compounds, Hydramethylnon (MMV1577471) and Flufenerim (MMV1794206), demonstrated significant inhibitory effects against C. auris. Hydramethylnon exhibited potent antifungal activity, inhibiting up to 93 % of fungal growth with an MFC of 16 μg/mL. Flufenerim inhibited up to 58 % of fungal growth, showing fungistatic action with an MFC greater than 4 μg/mL. Biofilm inhibition tests showed that both compounds significantly inhibited biofilm formation, with increased efficacy at higher concentrations. Both compounds showed eradication rates in both stages. Furthermore, Hydramethylnon and Flufenerim did not affect cell membrane integrity or nucleotide leakage, suggesting a mode of action not reliant on disrupting these cellular components. The sorbitol protection assay revealed that neither compound caused cell wall damage. In the efflux pump inhibition assay, Hydramethylnon did not activate efflux pumps, while Flufenerim activated efflux pumps, reducing its effectiveness. Hemocompatibility assay showed safety. ConclusionThe study highlights Hydramethylnon and Flufenerim as promising candidates for further development as disinfectants, offering potential solutions to the urgent need for effective disinfection agents against C. auris. The findings underscore the value of screening compound collections to identify novel antifungal agents and understand their mechanisms of action, thereby contributing to the advancement of new disinfection strategies in healthcare settings.

Experimental design of polymer synthesis applied to the removal of Cd2+ ions from water via adsorption

Cadmium is a highly toxic metal, and its presence can have adverse effects on both human health and aquatic ecosystems. The efficient removal of cadmium from wastewater is therefore of crucial importance, but traditional methods have proved to be inadequate. Thus, technologies for the treatment of wastewater containing cadmium, including adsorption, have been developed. The aim of this study was the preparation of a polymeric material by the grafting reaction of κ-carrageenan and its use as an adsorbent for cadmium removal. This was performed to study the removal capacity of cadmium ions in synthetic solutions, as well as the effects of pH and ions on adsorption capacity, adsorption kinetics, isotherms, and reusability. Additionally, the disinfectant potential of the solution was evaluated for the inactivation of total coliforms and E. coli in river water. The best adsorption capacity was 75.52 ± 1.325 mg g−1, with the kinetics described by the pseudo-second order model. Maximum adsorption capacity (127.6 ± 1.833 mg g−1) and RL (0.0113) were determined using the Langmuir model, the Freundlich model was the one that best fits the experimental data and indicated cooperative adsorption, and the Dubinin-Radushkevich isotherm was used to obtain the adsorption energy and identify that it is physical. The presence of ions K+, Na+, Mg2+, and Ca2+ in a concentration of 0.5% decreased the adsorption capacity, and that at pH 2.0, the adsorption capacity was drastically reduced. The study indicates that the polymer has potential as an adsorbent for removing cadmium from aqueous solutions and exhibits self-disinfecting properties.

Bactericidal activity of preparations based on Juglans Regia against certified bacterial test cultures

Objective. To study the bactericidal activity of a number ofpreparations obtained by different technological processes from plant materials of individual parts of the Green walnuts on several certified model strains of bacteria that differ in biological diversity. To determine the disinfectant capabilities of these preparations in the absence of antagonistic and synergistic effects of the full range of mixtures of typical banal microflora of pig farms. Methods. The following methods were used: biological and botanical to determine the phase of vegetation of Juglans regia in the selection of raw materials from different parts of the plant; biochemical and chemical in the process of preparation and isolation of the active substance from these samples and their purification from ballast fiber by maceration and extraction, using a number of devices and equipment; microbiological for the preparation of standardized culture media with selective properties that correspond to the peculiarities of reproduction, development and distribution of selected model strains. Surface inoculation was performed on liquid and agar-based culture media in test tubes and Petri dishes using the standard streak plate method with a microbiological loop. Subsequently, standard incubation at 37°C for 24 hours was performed. Results. It was found that the greatest bactericidal and fungicidal activity, and therefore potential effectiveness as a possible disinfectant in organic pig production technology, was found in extracts of phytomaterials of Juglans regia L - potential disinfectants No. 2 (extractant - 5 % acetic acid, wax-ripening nut) and No. 4 (extractant - 20 % alcohol, wax ripening nut) - brought to 5 % alcohol after obtaining the primary extract. Conclusions. According to the results of studies on certified strains of microorganisms, it was found that the studied extracts have a significant effect on representatives of enterobacteria, a weak effect on spore forming bacilli. Keywords: organic pig production, bactericidal activity, phytodesinfectant, certified test cultures, Salmonella typhimurium, Bacillus subtilis, extract, walnut.

Assessing the effectiveness and mechanisms of Fe/PS, Fe/H2O2, and O3 treatment for water disinfection: Spotlight on VBNC bacteria

Advanced oxidation processes (AOPs) exhibit significant potential for water disinfection due to their generation of large quantities of highly oxidizing free radicals. However, the neglect of viable but nonculturable (VBNC) cells obscures their true disinfection efficacy and potential environmental health risks. Therefore, the study evaluated the disinfection effectiveness and mechanisms of typical AOPs, including Fe/H2O2, Fe/persulfate (PS), and O3, from the perspective of the production of VBNC bacteria. The results indicate that Fe/PS exhibits the strongest bacterial inactivation rate (99.94%), and the cells lose their ability to reactivate. Fe/H2O2 and O3 induce more cells to enter the VBNC state compared to Fe/PS. Moreover, different AOPs result in varying levels of free radical production and utilization efficiency, with SO4•− and O3 exhibiting greater selectivity in deactivating bacteria compared to HO•. The inhibition of VBNC bacteria production by Fe/PS treatment may be attributed to the combined action of HO• and SO4•− on microorganisms, leading to oxidative stress and metabolic disruption in bacteria through the inhibition of biofilm formation and aminoacyl-tRNA biosynthesis (p < 0.05), thereby causing direct bacterial death rather than entry into the VBNC state. In contrast, Fe/H2O2 and O3 result in the upregulation of the metabolism of alanine, aspartate, and glutamate, as well as styrene degradation capacity by the bacteria, leading to the production of more VBNC bacteria. Overall, the study offers insights into mitigating potential biological risks in water disinfection and developing environmentally friendly and efficient disinfection technologies.

Design strategies based on UV-C LED characterization to enhance Escherichia coli inactivation

This research is focused on the development of a UV-C LED lamp designed for effective water disinfection, tackling as a primary issue the low quantum efficiency and significant self-heating due to elevated operating currents which reduce the LED performance. By conducting thorough characterization and employing strategies including aluminum heat sinks and varied electrical biasing methods such as constant current, PWM, and high-current short-time pulses. The study assesses the disinfection potential against pathogenic bacteria such as Escherichia coli and Salmonella. Results indicate successful E. coli inactivation within agar mediums and notable growth suppression in Mueller-Hinton culture mediums, as confirmed through optical density measurements. Therefore, this investigation underlines the importance of optimized operational strategies to enhance UV-C LED lamps' disinfection capabilities.

Kinetics of antibacterial activities of cellulose nanocrystals and their silver-zinc oxide nanocomposites: Application as potential disinfectants

Cellulose nanocrystals (CNCs) were produced from corncob and used as reducing agent in the formation of ZnO/CNCs, Ag/CNCs, and ZnO-Ag/CNCs composites and applied as antibacterial agents for both grampositive and gram-negative bacteria and the kinetics of microbial growth inhibition studied. The CNCs and composites were characterized by UV-visible and Fourier transform-infrared (FTIR) spectroscopy. The characterization results revealed that the functional groups of CNCs were affected by their interactions with Ag+ and Zn2+ ions. The composites at 100 mg/mL displayed activities against Gram-positive bacteria - Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermis, Bacillus coagulans and Enterococcus faecalis and Gram-negative bacteria - Escherichia coli, Klebsiella pneumonia, Salmonella typhimurium, Pseudomonas aeruginosa, Enterococcus faecium and Acinetobacter baumanii) bacteria with inhibitory zones ranged between 9-46 mm. The kinetics of inhibition showed that the composites treated water had 4 to 28 times lower rate constants compared to the untreated water. This implied that the composites inhibit growth rates and have the potential of disinfecting for between 4 to 28 h depending on the bacteria. The materials showed better growth inhibition rate on gram-positive bacteria than on gram-negative. These composites may have potential applications as disinfectants in personal care products and serve as more eco-friendly alternative disinfectants to chlorophenols.

Organic-Inorganic Heterointerface-Expediting Electron Transfer Realizes Efficient Plasmonic Catalytic Sterilization via a Carbon-Dot Nanozyme.

Plasmonic nanozymes bring enticing prospects for catalytic sterilization by leveraging plasmon-engendered hot electrons. However, the interface between plasmons and nanozymes as the mandatory path of hot electrons receives little attention, and the mechanisms of plasmonic nanozymes still remain to be elucidated. Herein, a plasmonic carbon-dot nanozyme (FeCG) is developed by electrostatically assembling catalytic iron-doped carbon dots (Fe-CDs) with plasmonic gold nanorods. The energy harvesting and hot-electron migration are remarkably expedited by a spontaneous organic-inorganic heterointerface holding a Fermi level-induced interfacial electric field. The accumulated hot electrons are then fully utilized by conductive Fe-CDs to boost enzymatic catalysis toward overproduced reactive oxygen species. By synergizing with localized heating from hot-electron decay, FeCG achieves rapid and potent disinfection with an antibacterial efficiency of 99.6% on Escherichia coli within 5 min and is also effective (94.2%) against Staphylococcus aureus. Our work presents crucial insights into the organic-inorganic heterointerface in advanced plasmonic biocidal nanozymes.

High permeation, biodegradable hydrogel based flow-through reactor for water disinfection with controlled silver release

Innovative disinfection strategies for clean water access demand manufacturing and operational simplicity, offering benefits for technology adoption. A hydrogel reactor composed of chitosan/graphene oxide/nano-Ag (CS/GO/Ag) achieves complete disinfection of real water resources contaminated with natural and biomedical contaminants, present concomitantly at higher contamination levels (104-106 CFU mL−1). The hydrogel exhibits remarkable mechanical stability and maintains shape without permanent deformation through dynamic swelling behaviour. Its open-ended, porous network allows rapid water permeation with tuneable hydrophilicity to maximize hydrogel-water interactions for disinfection. Hydrogel is reusable while achieving complete disinfection and maintains a controlled silver release (87.4 ppb, 0.07 % rate) within safety limits through restricted oxidative-dissolution of immobilized AgNPs. A distinct species-specific disinfection potential was observed for completely eradicating four natural/biomedical pathogens within 120 min. The CS/GO/Ag hydrogel employs a multifaceted mechanism to combat bacteria and appears virtually non-toxic to humans along with desirable soil biodegradability, promising safer and sustainable use. In continuous-flow, the hydrogel disinfected over 30 L of contaminated water (initial count, 105 CFU mL−1) without regeneration. A consistent disinfection performance across various natural water resources, easy flow-through design, and the suitability of Weibull model highlights CS/GO/Ag hydrogel’s potential for large-scale disinfection, effectively addressing water purification challenges.

Amoebicidal effect of chlorine dioxide gas against pathogenic Naegleria fowleri and Acanthamoeba polyphaga.

The pathogenic free-living amoebae, Naegleria fowleri and Acanthamoeba polyphaga, are found in freshwater, soil, and unchlorinated or minimally chlorinated swimming pools. N. fowleri and A. polyphaga are becoming problematic as water leisure activities and drinking water are sources of infection. Chlorine dioxide (ClO2) gas is a potent disinfectant that is relatively harmless to humans at the concentration used for disinfection. In this study, we examined the amoebicidal effects of ClO2 gas on N. fowleri and A. polyphaga. These amoebae were exposed to ClO2 gas from a ready-to-use product (0.36 ppmv/h) for 12, 24, 36, and 48h. Microscopic examination showed that the viability of N. fowleri and A. polyphaga was effectively inhibited by treatment with ClO2 gas in a time-dependent manner. The growth of N. fowleri and A. polyphaga exposed to ClO2 gas for 36h was completely inhibited. In both cases, the mRNA levels of their respective actin genes were significantly reduced following treatment with ClO2 gas. ClO2 gas has an amoebicidal effect on N. fowleri and A. polyphaga. Therefore, ClO2 gas has been proposed as an effective agent for the prevention and control of pathogenic free-living amoeba contamination.

Rapid inactivation of antibiotic resistance genes and virulence genes in the building ventilation duct by UV185+254 irradiation

The energy-efficient inactivation of airborne antibiotic resistance genes (ARGs) and virulence genes was seldom investigated in full-scale ventilation systems. This study examined the potential of UV disinfection to inactivate two types of chromosome- or plasmid-encoded ARGs (mecA and amp) and one chromosomal virulence gene (tst1) within two host bacterial species: Staphylococcus aureus and Escherichia coli. UV185+254 disinfection exhibited dual damages (i.e., physical by 254 nm UV and oxidative by the produced ozone) on those target genes, resulting in relatively strong adaptability to temperature and low electrical energy per order in specific gene removal (down to 1 kJ m−3). It was found that the disinfection efficiency of target genes was up to 2 orders of magnitude lower than that of the host bacteria. The target genes with more bases and higher weighted bipyrimidine content were more susceptible to UV185+254 treatment. Thicker cell walls and plasmid carriers prominently hindered UV185+254 deactivation, requiring larger radiation power to enhance the gene removal efficiency in bioaerosols.

Pathogens inactivation and preservation of Pacific white shrimp by atmospheric cold plasma treatment

Atmospheric cold plasma (ACP) efficacy in inactivating Listeria monocytogenes and Vibrio parahaemolyticus was investigated on fresh and frozen shrimp. ACP inactivation efficacy increased with treatment time (5–20 min) and treatment voltages (60–80 kV) due to increased reactive gas species. ACP yielded stronger pathogen inactivation on frozen versus fresh shrimp. ACP treatment at 80 kV for 30 min maximally reduced L. monocytogenes and V. parahaemolyticus by 0.94 and 1.26 log CFU/g on fresh shrimp and by 1.68 and 2.0 log CFU/g on frozen shrimp. During storage at 4 °C, ACP-treated shrimp exhibited slightly higher thiobarbituric acid reactive substances (TBARS) levels but overall improved quality attributes, including lower total viable count, total volatile basic nitrogen, and pH, as well as higher sensory scores compared to the controls. ACP also extended shrimp shelf-life by 2 days. Therefore, ACP holds significant potential for seafood disinfection and preservation. Industrial relevanceACP effectively reduced levels of Listeria monocytogenes and Vibrio parahaemolyticus on both fresh and frozen shrimp with greater inactivation effects on frozen shrimp. In addition to enhancing microbial safety, ACP also improved shrimp quality and extended shelf-life. ACP could readily be coupled with packaging technology and bio preservatives to enhance its efficacy. This research provides a foundation for the eventual industrial adoption of ACP technology to benefit both consumers through reduced pathogen risks, and seafood processors through improved product safety, quality, and shelf-life.

Optimization of green silver nanoparticles as nanofungicides for management of rice bakanae disease

Rice bakanae, a devastating seed-borne disease caused by Fusarium species requires a more attractive and eco-friendly management strategy. The optimization of plant-mediated silver nanoparticles (AgNPs) as nanofungicides by targeting Fusarium species may be a rational approach. In this study, Azadirachta indica leaf aqueous extract-based AgNPs (AiLAE-AgNPs) were synthesized through the optimization of three reaction parameters: A. indica leaf amount, plant extract-to-AgNO3 ratio (reactant ratio), and incubation time. The optimized green AgNPs were characterized using ultraviolet–visible light (UV–Vis) spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and powder X-ray diffraction (XRD) techniques. The optimal conditions for producing spherical, unique, and diminutive-sized AgNPs ranging from 4 to 27 nm, with an average size of 15 nm, were 2 g AiLAE at a 1:19 ratio (extract-to-AgNO3) and incubated for 4 h. Fusarium isolates collected from infected soils and identified as F. fujikuroi (40) and F. proliferatum (58 and 65) by PCR were used for seed infestation. The AgNPs exhibited concentration-dependent mycelial growth inhibition with EC50 values ranging from 2.95 to 5.50 μg/mL. The AgNPs displayed exposure time-dependent seed disinfectant potential (complete CFU reduction in F. fujikuroi (40) and F. proliferatum (58) was observed at a concentration of 17.24 μg/mL). The optimized green AgNPs were non-toxic to germinating seeds, and completely cured bakanae under net-house conditions, suggesting their great nano-fungicidal potency for food security and sustainable agriculture.

Remediation of multifarious metal ions and molecular docking assessment for pathogenic microbe disinfection in aqueous solution by waste-derived Ca-MOF.

The present study demonstrates an eco-friendly and cost-effective synthesis of calcium terephthalate metal-organic frameworks (Ca-MOF). The Ca-MOF were composed of metal ions (Ca2+) and organic ligands (terephthalic acid; TPA); the former was obtained from egg shells, and the latter was obtained from processing waste plastic bottles. Detailed characterization using standard techniques confirmed the synthesis of Ca-MOF with an average particle size of 461.9 ± 15nm. The synthesized Ca-MOF was screened for its ability to remove multiple metal ions from an aqueous solution. Based on the maximum sorption capacity, Pb2+, Cd2+, and Cu2+ ions were selected for individual parametric batch studies. The obtained results were interpreted using standard isotherms and kinetic models. The maximum sorption capacity (qm) obtained from the Langmuir model was found to be 644.07 ± 47, 391.4 ± 26, and 260.5 ± 14mgg-1 for Pb2+, Cd2+, and Cu2+, respectively. Moreover, Ca-MOF also showed an excellent ability to remove all three metal ions simultaneously from a mixed solution. The metal nodes and bonded TPA from Ca-MOF were dissociated by the acid dissolution method, which protonated and isolated TPA for reuse. Further, the crystal structure of Ca-MOF was prepared and docked with protein targets of selected pathogenic water-borne microbes, which showed its disinfection potential. Overall, multiple metal sorption capability, regeneration studies, and broad-spectrum antimicrobial activity confirmed the versatility of synthesized Ca-MOF for industrial wastewater treatment.

Engineering Atomic Ag1-N6 Sites with Enhanced Performance of Eradication Drug-Resistant Bacteria over Visible-Light-Driven Antibacterial Membrane.

Utilizing visible light for water disinfection is a more convenient, safe, and practical alternative to ultraviolet-light sterilization. Herein, we developed silver (Ag) single-atom anchored g-C3N4 (P-CN) nanosheets (Ag1/CN) and then utilized a spin-coating method to fabricate the Ag1/CN-based-membrane for effective antibacterial performance in natural water and domestic wastewater. The incorporated Ag single atom formed a Ag1-N6 motif, which increased the charge density around the N atoms, resulting in a built-in electric field ∼17.2 times stronger than that of pure P-CN and optimizing the dynamics of reactive oxygen species (ROS) production. Additionally, the Ag1-N6 motif inhibited the release of Ag ions, ensuring good biocompatibility. Based on the first-principles calculation, the adsorption energy of O2 on the Ag1/CN (-0.32 eV) was lower than that of P-CN (-0.07 eV), indicating that loaded Ag single atom can lower the energy barrier for O2 activation, generating extra *OH radicals that cooperated with *O2- to effectively neutralize bacteria. As a result, the Ag1/CN powder-catalyst with the concentration of 30 ppm demonstrated a 99.9% antibacterial efficiency against drug-resistant bacteria (Escherichia coli, Staphylococcus aureus, kanamycin-resistant Escherichia coli, and methicillin-resistant Staphylococcus aureus) under visible-light irradiation for 4 h. This efficacy was 24.8 times higher than that of the P-CN powder catalyst. Moreover, the Ag1/CN-based-membrane can maintain a 99.9% bactericidal efficiency for natural water and domestic wastewater treatment using a homemade flow device, demonstrating its potential for water disinfection. Notably, the visible-light-driven antibacterial efficiency of the Ag1/CN catalyst outperformed the majority of the reported g-C3N4-based catalysts/membranes.