Physicochemical and photocatalytic properties of Ag2CrO4/Fe2O3/CeO2 ternary nanocomposite.

The study presents Ag2CrO4/Fe2O3/CeO2 ternary nanocomposite, based on Fe2O3/CeO2 binary composites, which demonstrated excellent photocatalytic performance in the photodegradation of methylene blue under solar irradiation. The Ag2CrO4/Fe2O3/CeO2 nanocomposites was orthorhombic, ilmenite, and cubic-fluorite phases of Ag2CrO4, Fe2O3, and CeO2, respectively, according to the XRD examination. A strong bond between Ag2CrO4, Fe2O3, and CeO2 within the nanocomposite was demonstrated by the SEM and TEM investigations. Moreover, it was discovered that the coupling of Ag2CrO4 and Fe2O3 caused a red shift and moved CeO2 absorption edge from the UV to the visible spectrum. The reason behind this is that the band gap of CeO2 reduced 2.85 to 2.69 eV and the absorbance band intensity increased in visible region. Utilizing visible light, Ag2CrO4/Fe2O3/CeO2 ternary nanocomposites exhibit enhanced photocatalytic properties (98.90%) for the degradation of methylene blue (MB) within 100 min. The long-term reliability and recyclability of the photocatalyst were explored through 3 successive cycles. An active radical quenching test was conducted to elucidate the involvement of O2 - and OH which are the primary reactive species in the photocatalytic breakdown of MB. Ag2CrO4/Fe2O3/CeO2 ternary nanocomposites displayed notable improvements in photodegradation activity, making them well suited for the effective removal of hazardous dyes present in textile effluents.

Facile construction of efficient WO3/V2O5 coupled g-C3N4 ternary composite photocatalyst for environmental emergent aqueous pollutant degradation: Stability, degradation reaction pathway and effect of pH evaluation.

Currently, one of the primary challenges that human society must overcome is the task of decreasing the amount of energy used and the adverse effects that it has on the environment. The daily increase in liquid waste (comprising organic pollutants) is a direct result of the creation and expansion of new companies, causing significant environmental disruption. Water contamination is attributed to several industries such as textile, chemical, poultry, dairy, and pharmaceutical. In this study, we present the successful degradation of methylene blue dye using g-C3N4 (GCN) mixed with WO3 and V2O5 composites (GCN/WO3/V2O5 ternary composite) as a photocatalyst, prepared by a simple mechanochemistry method. The GCN/WO3/V2O5 ternary composite revealed a notable enhancement in photocatalytic performance, achieving around 97% degradation of aqueous methylene blue (MB). This performance surpasses that of the individual photocatalysts, namely pure GCN, GCN/WO3, and GCN/V2O5 composites. Furthermore, the GCN/WO3/V2O5 ternary composite exhibited exceptional stability even after undergoing five consecutive cycles. The exceptional photocatalytic activity of the GCN/WO3/V2O5 ternary composite can be ascribed to the synergistic effect of metal-free GCN and metal oxides, resulting in the alteration of the band gap and suppression of charge recombination in the ternary photocatalyst. This study offers a better platform for understanding the characteristics of materials and their photocatalytic performance under visible light conditions.

Carbon quantum dots from carbohydrate-rich residue of birch obtained following lignin-first strategy.

Carbon quantum dots (CQDs) were successfully synthesized from carbohydrate-rich residue of birch obtained following the lignin-first strategy. The optical and physicochemical properties of the CQDs were studied, along with their potential for photocatalytic pollutant degradation. By combining solvothermal and chemical oxidation methods, the product yield of CQDs from carbohydrate-rich residue reached 8.1 wt%. Doping nitrogen enhances the graphitization of CQDs and introduces abundant amino groups to the surface, thereby boosted the quantum yield significantly from 8.9 % to 18.7 %-19.3 %. Nitrogen-doped CQDs exhibited efficient photocatalytic degradation of methylene blue, reaching 37 % within 60 min, with a kinetic degradation rate of 0.00725 min-1. This study demonstrates that carbohydrate-rich residue obtained from lignin-first strategy are ideal precursors for synthesizing CQD with high mass yield and quantum yield by combining solvothermal treatment and chemical oxidation methods, offering a novel approach for the utilization of whole biomass components following the lignin-first strategy.

Signal-On Detection of Caspase-3 with Methylene Blue-Loaded Metal-Organic Frameworks as Signal Reporters.

In this work, we report on an electrochemical method for the signal-on detection of caspase-3 and the evaluation of apoptosis based on the biotinylation reaction and the signal amplification of methylene blue (MB)-loaded metal-organic frameworks (MOFs). Zr-based UiO-66-NH2 MOFs were used as the nanocarriers to load electroactive MB molecules. Recombinant hexahistidine (His6)-tagged streptavidin (rSA) was attached to the MOFs through the coordination interaction between the His6 tag in rSA and the metal ions on the surface of the MOFs. The acetylated peptide substrate Ac-GDEVDGGGPPPPC was immobilized on the gold electrode. In the presence of caspase-3, the peptide was specifically cleaved, leading to the release of the Ac-GDEVD sequence. A N-terminal amine group was generated and then biotinylated in the presence of biotin-NHS. Based on the strong interaction between rSA and biotin, rSA@MOF@MB was captured by the biotinylated peptide-modified electrode, producing a significantly amplified electrochemical signal. Caspase-3 was sensitively determined with a linear range from 0.1 to 25 pg/mL and a limit of detection down to 0.04 pg/mL. Further, the active caspase-3 in apoptosis inducer-treated HeLa cells was further quantified by this method. The proposed signal-on biosensor is compatible with the complex biological samples and shows great potential for apoptosis-related diagnosis and the screening of caspase-targeting drugs.

Hydrogels comprising oxidized carboxymethyl cellulose and water-soluble chitosan at varied oxidation levels: Synthesis, characterization, and adsorptive toward methylene blue.

Chitosan, as a biomaterial, has increasingly garnered attention. However, its limited solubility in water-only dissolving in certain dilute acidic solutions-substantially restricts its broader application. In this investigation, chitosan underwent a solubilization modification to acquire water solubility, facilitating its dissolution in neutral aqueous mediums. Subsequently, this water-soluble chitosan (WSC) was interlinked with oxidized carboxymethyl cellulose (OCMC), characterized by varied oxidation extents, to synthesize hydrogels. Structural characterization verified the formation of imine bonds resulting from crosslinking interactions between the amino groups of water-soluble chitosan and the aldehyde groups of oxidized carboxymethyl cellulose. Employing performance characterization analysis, it was discerned that an increase in the oxidation level of the oxidized carboxymethyl cellulose corresponded to a denser hydrogel network architecture and the hardness increased from 3.01 N to 6.16 N. Moreover, the capacity of these hydrogels to adsorb methylene blue was meticulously examined. Notably, the hydrogel denoted as WSC/66%OCMC manifested an adsorption capability of 28.08 mg/g for methylene blue. Analytical findings from adsorption kinetics and isotherm studies indicate that the adsorption mechanism of the WSC/66%OCMC hydrogel follows the pseudo-second-order kinetic model and corresponds to the Freundlich isotherm model.

A handy way for forming N-doped TiO2/carbon from pectin and d,l-serine hydrazide hydrochloride.

N-doped TiO2/carbon composites (N-TiPC) have shown excellent photodegradation performances to the organic contaminants but are limited by the multistage preparation (i.e., preparation of porous carbon, preparation of N-doped TiO2, and loading of N-doped TiO2 on porous carbon). Here, we develop a handy way by combining the Pickering emulsion-gel template route and chelation reaction of polysaccharides. The N-TiPC is obtained by calcinating pectin/Dl-serine hydrazide hydrochloride (SHH)-Ti4+ chelate and is further described by modern characterization techniques. The results show that the N atom is successfully doped into the TiO2 lattice, and the bandgap value of N-TiPC is reduced to 2.3 eV. Moreover, the particle size of N-TiPC remains about 10 nm. The configurations of the composites are simulated using DFT calculation. The photocatalytic experiments show that N-TiPC has a high removal efficiency for methylene blue (MB) and oxytetracycline hydrochloride (OTC-HCL). The removal ratios of MB (20 mg/L, 50 mL) and OTC-HCL (30 mg/L, 50 mL) are 99.41 % and 78.29 %, respectively. The cyclic experiments show that the photocatalyst has good stability. Overall, this study provides a handy way to form N-TiPC with enhanced photodegradation performances. It can also be promoted to other macromolecules such as cellulose and its derivatives, sodium alginate, chitosan, lignin, etc.

An electrochemical biosensor for sensitive detection of live Salmonella in food via MXene amplified methylene blue signals and electrostatic immobilization of bacteriophages.

A novel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samples is presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs µm-2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5 CFU mL-1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria.

Wodyetia bifurcata (foxtail palm tree) leaves as a super-augmented instantaneous methylene blue remover from simulated water and wastewater.

Wodyetia bifurcata, also known as foxtail palm tree leaves, was tested for highly effective methylene blue (MB) removal from commercial and artificial effluent. BET surface area measurement, FESEM, FTIR, and pHzpc were used to get information on the shape and structure of the particles. Several important factors were used to determine its adsorption activity, including intake concentration, contact duration, and pH level. Accelerated adsorption is seen in the experimental results, with more than 94% adsorption occurring successfully in the initial 12 min and reaching equilibrium within 15 min (% removal = 97.45%) at neutral pH. It was discovered that the maximum adsorption capacity was 58.74 mg g-1 at 308 K. The adsorption procedure confirms an active adsorption process of linear and non-linear kinetics of pseudo-second order, and the adsorption path is well addressed by the Freundlich model both in linear and non-linear form, having an R2 value close to unity. Thermodynamic characteristics point to an exothermic, viable, spontaneous reaction with higher entropy. Utilizing a 1:1 MeOH/H2O ratio, spent adsorbent may be readily regenerated by as much as 75% with a possible three-cycle usage. The practical application of biosorbents was confirmed by real-time effectiveness testing using MB-carrying industrial wastewater, and up to 45.75% adsorption was shown. A relative standard deviation confirmed statistical dependability. All things considered, the current material provides a clean and environmentally friendly way to remove MB dye from various wastewater types.

Adsorption study of methylene blue dye using activated carbon prepared from waste palm fiber.

The study investigated the utilization of waste palm fiber as an adsorbent for methylene blue (MB) removal. The waste palm fiber was treated by a series of steps to prepare an activated charcoal adsorbent. The adsorption process of MB on the activated charcoal was modeled using the Box-Behnken design (BBD) in the response surface methodology (RSM). Adsorbent mass, solution pH, temperature, and time were selected as factors, while removal efficiency and adsorption capacity were chosen as responses. Both models were significant with correlation factors of 0.85 and 0.99 for removal efficiency and adsorption capacity, respectively. Optimal conditions for MB removal were achieved at an initial pH of 7, an adsorbent dose of 0.05 g/L, and a contact time of 30 min, resulting in a 99% removal efficiency. The adsorption of MB using the activated charcoal indicates the physical nature of the reaction.

[Protective effect and mechanism of methylene blue on myocardial injury in rats with sepsis].

OBJECTIVE: To explore the protective effect of methylene blue (MB) on myocardial injury in sepsis and its possible signaling pathway. METHODS: A total of 32 female Wistar rats were randomly divided into sham operation group, sepsis model group, MB prevention group, and MB treatment group, with 8 rats in each group. The MB prevention group was injected with 15 mg/kg MB in the peritoneal cavity 6 hours before modeling; the other 3 groups were injected with 4 mL/kg saline in the peritoneal cavity. The sepsis model was established by cecal ligation puncture (CLP); the sham operation group was only subjected to an exploratory incision without ligation or puncture of the caecum. The MB treatment group was injected with 15 mg/kg MB in the peritoneal cavity 0.5 hours after modeling; the other 3 groups were injected with 4 mL/kg saline in the peritoneal cavity. Peripheral blood and myocardial tissue were collected from each group at 6 hours and 12 hours after modeling. Histological changes in the myocardial tissue were observed under the microscope; the levels of serum cardiac troponin I (cTnI), MB isoenzyme of creatine kinase (CK-MB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were detected by enzyme-linked immunosorbent assay (ELISA); and the expressions of inducible nitric oxide synthase (iNOS), light chain 3 (LC3), and p62 in the myocardial tissue were detected by Western blotting. RESULTS: Under light microscopy, no obvious abnormalities were found in the myocardium of the sham operation group; the myocardium of the sepsis model group showed obvious inflammatory changes; the myocardium of the MB prevention group showed mild inflammatory changes at 6 hours after modeling, severe inflammatory changes at 12 hours but less severe than the sepsis model group; the myocardium of the MB treatment group showed more obvious inflammatory changes at 6 hours after modeling but less severe than the MB prevention group at 12 hours after modeling, and the inflammatory changes at 12 hours after modeling were alleviated but more severe than the 6 hours after modeling in MB prevention group. Compared with the sham operation group, the levels of cTnI, CK-MB, TNF-α and IL-6 in the MB prevention group at 6 hours and 12 hours after modeling were not significantly changed; compared with the sepsis model group, the cTnI, CK-MB, TNF-α and IL-6 levels in the MB treatment group at 6 hours and 12 hours after modeling were significantly lower [cTnI (ng/L): 175.03±12.26, 411.24±21.20 vs. 677.79±43.95 at 6 hours of modeling, 159.52±6.44, 412.46±32.94 vs. 687.61±55.09 at 12 hours of modeling; CK-MB (ng/L): 8.38±0.49, 16.87±1.41 vs. 24.87±1.74 at 6 hours of modeling, 7.94±0.30, 16.66±2.03 vs. 25.02±7.29 at 12 hours of modeling; TNF-α (ng/L): 26.98±3.31, 46.95±3.74 vs. 112.60±6.64 at 6 hours of modeling, 31.31±5.83, 90.97±5.14 vs. 149.30±4.67 at 12 hours of modeling; IL-6 (ng/L): 40.86±4.48, 128.90±3.14 vs. 248.90±12.76 at 6 hours of modeling, 80.13±7.94, 190.40±9.56 vs. 288.90±6.01 at 12 hours of modeling; all P < 0.05]. Western blotting showed that compared with the sham operation group, the protein expressions of iNOS, LC3, and p62 in the sepsis model group were significantly higher at 6 hours and 12 hours after modeling; compared with the sepsis model group, the protein expressions of iNOS, LC3, and p62 in the MB treatment group and MB prevention group were significantly lower at 6 hours and 12 hours after modeling (iNOS/GAPDH: 0.38±0.04, 0.60±0.04 vs. 0.77±0.04 at 6 hours of modeling; 0.38±0.02, 0.66±0.04 vs. 0.79±0.05 at 12 hours of modeling; LC3/GAPDH: 0.13±0.07, 0.42±0.07 vs. 1.05±0.16 at 6 hours of modeling; 0.08±0.02, 0.25±0.03 vs. 0.48±0.09 at 12 hours of modeling; p62/GAPDH: 0.17±0.05, 0.44±0.10 vs. 1.19±0.07 at 6 hours of modeling; 0.07±0.00, 0.28±0.08 vs. 0.69±0.02 at 12 hours of modeling; all P < 0.05). CONCLUSIONS: MB can reduce myocardial oxidative stress by inhibiting iNOS expression and mitochondrial autophagy in septic rats, thereby alleviating myocardial damage in sepsis, and has protective effect on myocardial damage in sepsis.

A smart hypochlorous acid fluorescent probe enabling Ibuprofen-release for osteoarthritis theranostics.

Background: Osteoarthritis (OA) standing as the most prevalent form of arthritis, closely associates with heightened levels of reactive oxygen species, particularly hypochlorous acid (HOCl). Although there are numerous probes available for detecting HOCl in the OA region, probes with dual functions of diagnostic and therapeutic capabilities are still significantly lacking. While this type of probe can reduce the time gap between diagnosis and treatment, which is clinically needed. Methods: We developed a fluorescent probe (DHU-CBA1) toward HOCl with theranostics functions through the release of methylene blue (MB) and ibuprofen (IBP) in this work. DHU-CBA1 can detect HOCl with high specificity and sensitivity, releasing MB and IBP with an impressive efficiency of ≥ 95% in vitro. Results: DHU-CBA1 exhibits good biosafety, enabling in vivo imaging of endogenous HOCl, along with reducing arthritis scores, improving synovitis and cartilage damage, and maintaining catabolic balance while alleviating senescence in cartilage. Conclusions: This study proposes a novel approach to enhance osteoarthritis therapy by releasing IBP via a smart HOCl-enabled fluorescent probe.

Bionanomining: bioengineered CuO nanoparticles from mining and organic waste for photo-catalytic dye degradation.

The novel bioengineered CuO nanoparticles were successfully synthesized directly using green chemistry, the nontoxic and renewable aqueous extract of waste papaya peel (Carica papaya) as a precursor. The XRD analysis indicated a monoclinic phase of CuO nanoparticles and a size of 20 nm, and the optical absorption analysis showed a peak in the 264 nm range. In TEM, the morphology of the NPs was observed to be almost spherical with a particle size of 15 nm. The CuO nanoparticles showed good efficiency in the degradation of methylene, obtaining up to 50% in 40 min using 6 mg in 60 ml of MB at 10 mg/L. The novel presented in this work derives from using rock minerals, from which we have directly obtained copper salt and copper oxide nanoparticles. This process not only utilizes ecological green chemistry but also offers an economic advantage by directly producing nanoparticles from the mineral instead of purchasing costly pure chemical reagents and employing novel nanomaterials to purify wastewater.

Ultrasensitive Photoelectrochemical Biosensor for Dual-miRNAs Detection Based on Molecular Logic Gates and Methylene Blue Sensitized ZnO@CdS@Au Nanorods.

The occurrence of cancer is often closely related to multiple tumor markers, so it is important to develop multitarget detection methods. By the proper design of the input signals and logical operations of DNA logic gates, detection and diagnosis of cancer at different stages can be achieved. For example, in the early stages, specific input signals can be designed to correspond to early specific tumor markers, thereby achieving early cancer detection. In the late stage, logic gates for multitarget detection can be designed to simultaneously detect multiple biomarkers to improve diagnostic accuracy and comprehensiveness. In this work, we constructed a dual-target-triggered DNA logic gate for anchoring DNA tetrahedra, where methylene blue was embedded in the DNA tetrahedra to sensitize ZnO@CdS@Au, achieving ultrasensitive detection of the target substance. We tested the response of AND and OR logic gates to the platform. For AND logic gates, the sensing platform only responds when both miRNAs are present. In the concentration range of 10 aM to 10 nM, the photoelectric signal gradually increases with an increase of the target concentration. Subsequently, we used OR logic gates for miRNA detection. Even if only one target exists, the sensing platform exhibits excellent performance. Similarly, within the concentration range of 10 aM to 10 nM, the photoelectric signal gradually increases with an increase of the target concentration. The minimum detection limit is 1.10 aM. Whether it is the need to detect multiple targets simultaneously or only one of them, we can achieve it by selecting the appropriate logic gate. This strategy holds promising application prospects in fields such as biosensing, medical diagnosis, and environmental monitoring.

Management of isopropyl nitrate-induced methaemoglobinaemia in pregnancy.

A pregnant female in her early 30s presented with cyanosis and oxygen saturation of 78%. She ingested isopropyl nitrate mistaking it for cannabidiol. Her arterial blood gas showed a methaemoglobin of >30% (outside the measuring range). She was treated with 120 mg of methylthioninium chloride (2 mg/kg) and symptoms improved. Her pregnancy progressed but was induced at 36 weeks because her child was small for gestational age. Methaemoglobinaemia is a rare presentation in pregnancy. There have been no reported cases of isopropyl nitrate-induced methaemoglobinaemia in pregnancy. Historically, intra-amniotic methylthioninium chloride was used in amniocentesis but use stopped after links to fetal malformations and neonatal death were made. There is no evidence outlining the risks of isopropyl nitrate in pregnancy and limited data on fetal effects from maternal exposure to intravenous methylthioninium chloride. This case adds to the evidence that treating methaemoglobinaemia may outweigh the risks of maternal exposure to methylthioninium chloride.

Ratiometric electrochemical biosensor based on hybridization chain reaction signal amplification for sensitive microRNA-155 detection.

In this work, a sensitive ratiometric electrochemical biosensor for microRNA-155 (miRNA-155) detection is reported based on a hybridization chain reaction amplifying the electrochemical signal. The biosensor was fabricated using Au NPs as a modified material to assemble capture DNA labeled with ferrocene (Fc) molecules, and a DNA probe labeled with methylene blue (MB) was employed for the signal probe. In the presence of target miRNA-155, it can be dual hybridized with capture and signal probe, especially with signal probe to continuously produce long concatemers containing lots of MB molecules. The electrochemical signal of Fc was used for the internal signal, and the signal from MB was used as an indicator signal. As the concentration of miRNA-155 was altered, the internal reference signal of Fc remained constant, and only the indicator signal changed in a sensitive way. The change in the ratio (IMB/IFc) between the indicator signal of MB and internal reference signal of Fc can be used to monitor the concentration of miRNA-155. Under optimal conditions, the prepared ratiometric biosensor could detect miRNA-155 within a wide linear range from 100 fM to 100 nM with low detection limit of 33 fM (at S/N = 3). Moreover, the biosensor was evaluated with human serum samples, and satisfactory recoveries were obtained, indicating that the ratiometric biosensor can be applied to clinical sample analysis.

Poly-vinyl-pyrrolidone capped luminescent zinc oxide nanocomposites as excellent tools for germicidal and photo-catalytic performances.

Alternate antibiotics developed through the involvement of nanomaterials are gaining interest due to their economical and lower toxicity concerns. A newly developed biopolymer-based polyvinylpyrrolidone/zinc oxide (PVP/ZnO) nanocomposite (NCs) was efficiently synthesized by an environment-friendly approach, utilizing onion and garlic peel extract as a bio-surfactant, zinc acetate as the source, PVP as the stabilizing agent, and sodium hydroxide as the precipitant. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) investigations verified the crystalline properties of ZnO, PVP, and PVP/ZnO-based NCs. The structure of the biopolymer-linked ZnO particles interpolated inside the PVP array was seen to have a layered and flaky structure, as validated by field emission scanning electron microscopy (FE-SEM) analysis, which revealed its occurrence in the nanometer range. The XRD examination verified that the surface topographical image of PVP/ZnO NCs had an average thickness of 21 nm. The PVP/ZnO nanocrystals demonstrated exceptional photocatalytic efficacy, with a breakdown rate of 88% and almost 92% for the methylene blue dye. Therefore, the PVP/ZnO matrix exhibits superior antibacterial activity compared to other extracts, resulting in greater microbial suppression. The results above indicate that the ZnO-intercalated PVP array has a stronger reinforcing effect than other components. Hence, PVP/ZnO nanocrystals exhibit enormous potential as a favorable substance for environmental and biomedical intentions.

Carica Papaya leaf-infused metal oxide nanocomposite: a green approach towards water treatment and antibacterial applications.

This study successfully synthesized ZnO-CuO nanocomposite using the hydrothermal method with Carica papaya leaf extract. The incorporation of the leaf extract significantly enhanced the nanocomposite properties, a novel approach in scientific research. Characterization techniques, including X-ray diffraction, Fourier Transmission Infrared spectroscopy, and Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis, confirmed a cubic crystal structure with an average size of 22.37 nm. The Fourier Transmission Infrared spectrum revealed distinctive vibrations at 627, 661, and 751 cm-1 corresponding to ZnO-CuO nanocomposite corresponding to stretching and vibration modes. SEM images confirmed a cubic-like and irregular structure. The nanocomposite exhibited outstanding photocatalytic activity, degrading methylene blue dye by 96.73% within 120 min under visible light. Additionally, they showed significant antimicrobial activity, inhibiting Staphylococcus aureus (20 mm) and Klebsiella pneumonia (17 mm). The results highlight the efficiency of Carica papaya leaf-derived ZnO-CuO nanocomposite for environmental and health challenges.