Achieving Non-Interfacial Blocking Zinc Ion Transport Based on MOF Derived Manganese Oxides and Amorphous Carbon Hybrid Materials.

How to coordinate electron and ion transport behavior across scales and interfaces within ion battery electrodes? The exponential increase in surface area observed in nanoscale electrode materials results in an incomprehensibly vast spatial interval. Herein, to address the problems of volume expansion, dissolution of cathode material, and the charge accumulation problem existing in manganiferous materials for zinc ion batteries, metal organic framework is utilized to form the architecture of non-interfacial blocking ~10 nm Mn2O3 nanoparticles and amorphous carbon hybrid electrode materials, demonstrating a high specific capacity of 361 mAh g-1 (0.1 A g-1), and excellent cycle stability of 105 mAh g-1 after 2000 cycles under 1 A g-1. The uniform and non-separated disposition of Mn and C atoms constitutes an interconnected network with high electronic and ionic conductivity, minimizing issues like structural collapse and volume expansion of the electrode material during cycling. The cooperative insert mechanism of H+ and Zn2+ are analyzed via ex-situ XRD and in-situ Raman tests. The model battery is assembled to present practical possibilities. The results indicate that MOF-derived carbonization provides an effective strategy for exploring Mn-based electrode materials with high ion and electron transport capacity.

Unveiling childhood asthma: Exploring biomarkers, zinc, and beyond.

This editorial discusses a case-control study by Ibrahim et al, published in the recent issue of the World Journal of Clinical Pediatrics. Childhood bronchial asthma is a chronic inflammatory respiratory disease. It was found that an increase in oxidative stress leads to a decrease in antioxidants causing oxidative damage to mitochondrial respiratory chain complexes resulting in the inflammation of the airway, hypersecretion of mucus causing a cascade of clinical manifestations ranging from recurrent episodes of coughing, wheezing, and breathlessness to shortness of breath. Since oxidative stress mediates the inflammatory response in asthma, the supplementation of anti-oxidants can be one strategy to manage this disease. Zinc is one such antioxidant that has attracted much attention about asthma and airway inflammation. Zinc is a crucial trace element for human metabolism that helps to regulate gene expression, enzyme activity, and protein structure. Apart from zinc, free serum ferritin levels are also elevated in case of inflammation. Several previous studies found that ferritin levels may also help determine the pathology of disease and predict prognosis in addition to tracking disease activity. However, this study's results were different from the findings of the previous studies and the zinc levels did not show a significant difference between asthmatic children and non-asthmatic children but ferritin levels were significantly high in asthmatic children as compared to the controls. Hence, the possible role of the biochemical nutritional assessment including zinc and ferritin as biomarkers for asthma severity should be assessed in the future.

Compressively Strained Fe3O4 in Core-Shell Oxygen Reduction Electrocatalyst Boosts Zinc-Air Battery Performance.

Fe3O4 is barely taken into account as an electrocatalyst for oxygen reduction reaction (ORR), an important reaction for metal-air batteries and fuel cells, due to its sluggish catalytic kinetics and poor electron conductivity. Herein, how strain engineering can be employed to regulate the local electronic structure of Fe3O4 for high ORR activity is reported. Compressively strained Fe3O4 shells with 2.0% shortened Fe─O bond are gained on the Fe/Fe4N cores as a result of lattice mismatch at the interface. A downshift of the d-band center occurs for compressed Fe3O4, leading to weakened chemisorption energy of oxygenated intermediates, and lower reaction overpotential. The compressed Fe3O4 exhibits greatly enhanced electrocatalytic ORR activity with a kinetic current density of 27 times higher than that of pristine one at 0.80 V (vs reversible hydrogen electrode), as well as potential application in zinc-air batteries. The findings provide a new strategy for tuning electronic structures and improving the catalytic activity of other metal catalysts.

C2H2 proteins: Evolutionary aspects of domain architecture and diversification.

The largest group of transcription factors in higher eukaryotes are C2H2 proteins, which contain C2H2-type zinc finger domains that specifically bind to DNA. Few well-studied C2H2 proteins, however, demonstrate their key role in the control of gene expression and chromosome architecture. Here we review the features of the domain architecture of C2H2 proteins and the likely origin of C2H2 zinc fingers. A comprehensive investigation of proteomes for the presence of proteins with multiple clustered C2H2 domains has revealed a key difference between groups of organisms. Unlike plants, transcription factors in metazoans contain clusters of C2H2 domains typically separated by a linker with the TGEKP consensus sequence. The average size of C2H2 clusters varies substantially, even between genomes of higher metazoans, and with a tendency to increase in combination with SCAN, and especially KRAB domains, reflecting the increasing complexity of gene regulatory networks.

A novel missense variant located within the zinc finger domain of the GLI3 gene was identified in a Vietnamese pedigree with index finger polydactyly.

BACKGROUND: Polydactyly, particularly of the index finger, remains an intriguing anomaly for which no specific gene or locus has been definitively linked to this phenotype. In this study, we conducted an investigation of a three-generation family displaying index finger polydactyly. METHODS: Exome sequencing was conducted on the patient, with a filtration to identify potential causal variation. Validation of the obtained variant was conducted by Sanger sequencing, encompassing all family members. RESULTS: Exome analysis uncovered a novel heterozygous missense variant (c.1482A>T; p.Gln494His) at the zinc finger DNA-binding domain of the GLI3 protein within the proband and all affected family members. Remarkably, the variant was absent in unaffected individuals within the pedigree, underscoring its association with the polydactyly phenotype. Computational analyses revealed that GLI3 p.Gln494His impacts a residue that is highly conserved across species. CONCLUSION: The GLI3 zinc finger DNA-binding region is an essential part of the Sonic hedgehog signaling pathway, orchestrating crucial aspects of embryonic development through the regulation of target gene expression. This novel finding not only contributes valuable insights into the molecular pathways governing polydactyly during embryonic development but also has the potential to enhance diagnostic and screening capabilities for this condition in clinical settings.

Cytotoxicity of green synthesized zinc oxide nanoparticles using Musa acuminata on Vero cells.

Zinc oxide nanoparticles (ZnO NPs) have become a highly regarded substance in various industries especially biologically synthesized ZnO NPs due to their adherence to the principles of green chemistry. However, concerns have been raised regarding the potential cytotoxic effects of ZnO NPs on biological systems. This study aimed to investigate and compare the cytotoxicity of ZnO NPs that were synthesized through chemical (C-ZnO NPs) and green approach using Musa acuminata leaf aqueous extract (Ma-ZnO NPs) on Vero cells. Characterization of ZnO NPs through Uv-Vis, FESEM, EDX, XRD, FTIR and XPS confirmed the successful synthesis of C- and Ma-ZnO NPs. MTT and ROS assays revealed that C- and Ma-ZnO NPs induced a concentration- and time-dependent cytotoxic effect on Vero cells. Remarkably, Ma-ZnO NPs showed significantly higher cell viability compared to C-ZnO NPs. The corelation of ROS and vell viability suggest that elevated ROS levels can lead to cell damage and even cell death. Flow cytometry analysis indicated that Ma-ZnO NPs exposed cells had more viable cells and a smaller cell population in the late and early apoptotic stage. Furthermore, more cells were arrested in the G1 phase upon exposure to C-ZnO NPs, which is associated with oxidative stress and DNA damage caused by ROS generation, proving its higher cytotoxicity than Ma-ZnO NPs. Similarly, time-dependent cytotoxicity and morphological alterations were observed in C- and Ma-ZnO NPs treated cells, indicating cellular damage. Furthermore, fluorescence microscopy also demonstrated a time-dependent increase in ROS formation in cells exposed to C- and Ma-ZnO NPs. In conclusion, the findings suggest that green ZnO NPs possess a favourable biocompatibility profile, exhibiting reduced cytotoxicity compared to chemically synthesized ZnO NPs on Vero cells. These results emphasize the potential of green synthesis methods for the development of safer and environmentally friendly ZnO NPs.

Sunflower Pollen-Morphology Mimicked Spiky Zinc Nanomotors as a Photosensitizer for Killing Bacteria and Cancer Cells.

Photosensitizing agents have received increased attention from the medical community, owing to their higher photothermal efficiency, induction of hyperthermia, and sustained delivery of bioactive molecules to their targets. Micro/nanorobots can be used as ideal photosensitizing agents by utilizing various physical stimuli for the targeted killing of pathogens (e.g., bacteria) and cancer cells. Herein, we report sunflower-pollen-inspired spiky zinc oxide (s-ZnO)-based nanorobots that effectively kill bacteria and cancer cells under near-infrared (NIR) light irradiation. The as-fabricated s-ZnO was modified with a catechol-containing photothermal agent, polydopamine (PDA), to improve its NIR-responsive properties, followed by the addition of antimicrobial (e.g., tetracycline/TCN) and anticancer (e.g., doxorubicin/DOX) drugs. The fabricated s-ZnO/PDA@Drug nanobots exhibited unique locomotory behavior with an average speed ranging from 13 to 14 µm/s under 2.0 W/cm2 NIR light irradiation. Moreover, the s-ZnO/PDA@TCN nanobots exhibited superior antibacterial activity against E. coli and S. epidermidis under NIR irradiation. The s-ZnO/PDA@DOX nanobots also displayed sufficient reactive oxygen species (ROS) amplification in B16F10 melanoma cells and induced apoptosis under NIR light, indicating their therapeutic efficacy. We hope the sunflower pollen-inspired s-ZnO nanorobots have tremendous potential in biomedical engineering from the phototherapy perspective, with the hope to reduce pathogen infections.

Oriented Metal Stripping for Highly Reversible Zinc Anode.

Aqueous zinc metal batteries are a viable candidate for next-generation energy storage systems, but suffer from poor cycling efficiency of the Zn anode. Emerging approaches aim to regulate zinc plating behavior to suppress uncontrolled dendrites, while the stripping process is seldom considered. Herein, an oriented metal stripping strategy is demonstrated to stabilize the Zn anode by removing high-index facets for exposing the (002) plane through the addition of anionic additive sodium citrate (SC). Consequently, high-index facets that coordinate strongly with SC are preferentially stripped out due to a reduced stripping barrier, rendering stable (002) facet preponderant in epitaxial plating. After repeat stripping/plating, the ultra-high proportion of 93% for (002) and large-size grains of ≈100 µm (six times larger than before) can be obtained. Zn anode shows continuous 25 000 cycles with low overpotential at 100 mA cm-2 in symmetric cells and more than 70 h of stable operation even at an ultra-high depth of discharge of 92.3%. Moreover, an extremely long lifespan of 12 000 cycles at 10 A g-1 with a high capacity retention of 89% is achieved by the assembled Zn//I2 battery. This work provides a distinctive approach to improving the stripping process to design highly efficient zinc anodes for promising aqueous zinc metal batteries.

Development of a live cell assay for the zinc transporter ZnT8.

Zinc is an essential trace element that is involved in many biological processes and in cellular homeostasis. In pancreatic ß-cells, zinc is crucial for the synthesis, processing, and secretion of insulin, which plays a key role in glucose homeostasis and which deficiency is the cause of diabetes. The accumulation of zinc in pancreatic cells is regulated by the solute carrier transporter SLC30A8 (or Zinc Transporter 8, ZnT8), which transports zinc from cytoplasm in intracellular vesicles. Allelic variants of SLC30A8 gene have been linked to diabetes. Given the physiological intracellular localization of SLC30A8 in pancreatic ß-cells and the ubiquitous endogenous expression of other Zinc transporters in different cell lines that could be used as cellular model for SLC30A8 recombinant over-expression, it is challenging to develop a functional assay to measure SLC30A8 activity. To achieve this goal, we have firstly generated a HEK293 cell line stably overexpressing SLC30A8, where the over-expression favors the partial localization of SLC30A8 on the plasma membrane. Then, we used the combination of this cell model, commercial FluoZin-3 cell permeant zinc dye and live cell imaging approach to follow zinc flux across SLC30A8 over-expressed on plasma membrane, thus developing a novel functional imaging- based assay specific for SLC30A8. Our novel approach can be further explored and optimized, paving the way for future small molecule medium-throughput screening.

Zinc-exchanged montmorillonite clay: A promising slow-release nanofertilizer for rice (Oryza sativa L.).

This study is to examine zinc exchanged montmorillonite (Zn-MMT) as a potential slow release nanofertilizer for rice crop. The effective intercalation of zinc within the montmorillonite inter layers was firmly established via analytical techniques including Zeta potential, FE-SEM (Field Emission Scanning Electron Microscopy) with Energy Dispersive X-ray Analysis (EDAX), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The efficacy of Zn-MMT was examined by evaluating its ability to facilitate controlled zinc release, as confirmed through an incubation study. Subsequently, the kinetics of zinc release was analyzed by different mathematical models such as Zero-order kinetics, First-order kinetics, the Higuchi model, and the Korsmeyer-Peppas model. From the pot culture study spanning 90 days the results indicated that Zn-MMT had significantly high plant height, Leaf Area Index (LAI), Dry Matter Production (DMP), number of tillers per hill, panicles length, increased grain and straw yield, in comparison with conventional zinc sulphate (ZnSO4). Total phenol, total protein and total chlorophyll content were significantly at higher levels with Zn-MMT treated rice crops as compared to conventional fertilizers and control. A similar trend was seen with phytochemicals such as Indole Acetic Acid (IAA), Superoxide Dismutase (SOD) and Carbonic Anhydrase (CA). Notably, rice grains harvested from Zn-MMTtreated crops exhibited significantly higher zinc content than those using other treatments. This Zn-MMT can be confirmed as a better alternative to conventional zinc sulphate fertilizers owing to its slow-release of nutrient into the soil and thus increased zinc use efficiency.

Green synthesis of zinc oxide nanoparticles using Rhus coriaria extract and their anticancer activity against triple-negative breast cancer cells.

The growing interest in using plant extracts for the biogenic synthesis of zinc oxide nanoparticles (ZnO NPs) stems from their facile, eco-friendly, and biologically safe approach instead of chemical routes. For the first time, ZnO NPs were successfully biosynthesized using Rhus coriaria fruit aqueous extract as a reducing and capping agent. Characterization revealed that the biosynthesized ZnO NPs possessed a maximum absorbance of approximately 359 nm and closely resembled the hexagonal ZnO wurtzite crystalline structure, with an average crystalline size of 16.69 nm. The transmission electron microscope (TEM) showed the presence of spherical and hexagonal morphologies, with an average grain size of 20.51 ± 3.90 nm. Moreover, the elemental composition of the synthesized ZnO NPs was assessed via energy-dispersive X-ray spectrometry (EDX), and the presence of phytocompounds on their surface was subsequently verified through FT-IR analysis. The ζ-potential of ZnO NPs was recorded at - 19.9 ± 0.1663 mV. Regarding anti-cancer properties, ZnO NPs were found to possess potent anti-tumor effects on MCF-7 and MDA-MB-231 breast cancer cells. Their efficacy was dose-dependent, with IC50 values ranging from 35.04-44.86 µg/mL for MCF-7 and 55.54-63.71 µg/mL for MDA-MB-231 cells. Mechanistic studies in MDA-MB-231 cells revealed apoptosis induction, validated by DAPI staining, confocal microscopy, and Annexin V/PI staining, showing apoptosis by 12.59% and 81.57% at ½ IC50 and IC50 values, respectively. Additionally, ZnO NPs were observed to provoke S-phase arrest and inhibit colony-forming and metastatic potential by modulating apoptosis and metastasis-related genes. This study unravels new insights into how ZnO NPs provoke cancer cell death and inhibit metastasis, revealing new prospects in cancer nanotechnology.

Combined effect of zinc and cadmium ions on nitrification performance during the biological nitrogen removal of simulated livestock breeding wastewater.

Zinc and cadmium ions are usually found in livestock breeding wastewater, and the mixed ions will have an impact on the biological nitrogen removal. Nitrification performance plays an important role in biological nitrogen removal. In order to investigate the combined effect of zinc and cadmium ions on nitrification performance and to reveal the interactions between zinc and cadmium ions, three concentration ratios of zinc and cadmium ions, as well as 18 different concentration gradients were designed with the direct equipartition ray and the dilution factor method. The effect of pollutants on the nitrification performance of biological nitrogen removal was analyzed by the nonlinear regression equation, and the concentration-addition model was conducted to probe into the relationship between the mixed pollutants and the nitrification performance. The results showed that the effect on nitrification performance increased significantly with the increase of reaction duration and pollutant concentration, which indicated that the effects are concentration-dependent and time-dependent. The concentration-addition model suggested that the interactions between zinc and cadmium ions with different concentration ratios were mainly antagonistic, and as the percentage of cadmium ions in the mixtures increased, the antagonism between the mixtures became stronger. This study will provide a relevant theoretical basis for the regulation of the ratios and concentrations of heavy metal ions during the biological treatment of livestock breeding wastewater.

Technologies to Study Genetics and Molecular Pathways.

Over the last few decades, the study of congenital heart disease (CHD) has benefited from various model systems and the development of molecular biological techniques enabling the analysis of single gene as well as global effects. In this chapter, we first describe different models including CHD patients and their families, animal models ranging from invertebrates to mammals, and various cell culture systems. Moreover, techniques to experimentally manipulate these models are discussed. Second, we introduce cardiac phenotyping technologies comprising the analysis of mouse and cell culture models, live imaging of cardiogenesis, and histological methods for fixed hearts. Finally, the most important and latest molecular biotechniques are described. These include genotyping technologies, different applications of next-generation sequencing, and the analysis of transcriptome, epigenome, proteome, and metabolome. In summary, the models and technologies presented in this chapter are essential to study the function and development of the heart and to understand the molecular pathways underlying CHD.

Methyl Jasmonate and Zinc Sulfate Induce Secondary Metabolism and Phenolic Acid Biosynthesis in Barley Seedlings.

This study aimed to reveal the impact of MeJA and ZnSO4 treatments on the physiological metabolism of barley seedlings and the content of phenolic acid. The results showed that MeJA (100 µM) and ZnSO4 (4 mM) treatments effectively increased the phenolic acid content by increasing the activities of phenylalanine ammonia-lyase and cinnamate-4-hydroxylase (PAL) and cinnamic acid 4-hydroxylase (C4H) and by up-regulating the expression of genes involved in phenolic acid synthesis. As a result of the MeJA or ZnSO4 treatment, the phenolic acid content increased by 35.3% and 30.9% at four days and by 33.8% and 34.5% at six days, respectively, compared to the control. Furthermore, MeJA and ZnSO4 treatments significantly increased the malondialdehyde content, causing cell membrane damage and decreasing the fresh weight and seedling length. Barley seedlings responded to MeJA- and ZnSO4-induced stress by increasing the activities of antioxidant enzymes and controlling their gene expression levels. Meanwhile, MeJA and ZnSO4 treatments significantly upregulated calcium-adenosine triphosphate, calmodulin-dependent protein kinase-related kinase, and calmodulin-dependent protein genes in barley seedlings. This suggested that Ca2+ may be the signaling molecule that promotes phenolic acid synthesis under MeJA and ZnSO4 treatment. This study deepens the understanding of the phenolic acid enrichment process in barley seedlings under MeJA and ZnSO4 treatments.

Advancement of an Environmentally Friendly and Innovative Sustainable Rubber Wrap Film with Superior Sealing Properties.

Common kitchen wraps like plastic and aluminum foil create significant environmental burdens. Plastic wrap, typically made from non-renewable fossil fuels, often ends up in landfills for centuries, breaking down into harmful microplastics. Aluminum foil, while effective, requires a large amount of energy to produce, and recycling it at home can be impractical due to food residue. A promising new alternative, low-nitrosamine rubber wrap film, aims to reduce waste by offering a reusable option compared to traditional single-use plastic wrap. The film is environmentally friendly, durable, and effective in sealing containers and keeping food fresh or crispy. The raw materials used to make the product were studied, namely fresh and concentrated natural rubber latex. No nitrosamines were found in either the fresh or concentrated latex, which is important as nitrosamines are known to be carcinogenic. The absence of nitrosamines in the raw materials suggests that the universal rubber wrap film is safe for use. In this study, the rubber formulation and properties of rubber used to make rubber wrap film were studied. The content of additives affecting the rubber properties was varied to find the optimum rubber formulation for making rubber wrap films. The rubber formulation with the least amount of chemicals that met the following criteria was selected: tensile strength of at least 15 MPa, elongation at break of at least 600%, and nitrosamine content below 6 ppm. It was found experimentally that the optimum rubber formulation for making a translucent rubber film had 0.7 phr zinc oxide and 1.0 phr sulfur. Performance tests revealed the rubber wrap film's superior sealing capabilities. Its elasticity allows for a tighter fit on containers, effectively conforming to various shapes and creating an optimal seal compared to plastic wrap and aluminum foil. The results of this study provide valuable information for developing a universal rubber wrap film that is safe with low nitrosamines.

Zinc Supplementation Improves Texture, Oxidative Stability of Caciotta Cheese and Reduces Biogenic Amines Production.

Zinc is essential for animals, playing a vital role in enzyme systems and various biochemical reactions. It is crucial to ensure a sufficient intake of zinc through the diet to maintain efficient homeostasis. Only few studies on zinc effect in cow lactating diet evaluated the effects on milk and cheese quality, with conflicting findings. 24 cows of the Friesian breed were divided into two groups (CTR: control and TRT: treated group). Cows were selected for age, body weight, parity and phase of lactations (mid lactation, 140-160 days). CTR diet contained 38 mg/kg of Zn and TRT diet was supplied with 120 mg/kg of complete feed for 60 days. The objective of current investigation was to evaluate the impact of a dietary Zinc Oxide (ZnO) integration of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, aw, texture, and sensory profile of cheese and to improve the chemical-nutritional quality of milk and cheese. The results showed that ZnO supplementation reduced mesophilic aerobic bacteria and Presumptive Pseudomonas spp. growth, proteolysis, biogenic amines content, lipid oxidation, odour intensity and sour and increased hardness, gumminess, chewiness, elasticity of cheese. Biogenic amines are considered an important aspect of food safety. ZnO integration in cow diet could represent a promising strategy for improving the quality, the safety and shelf-life of caciotta cheese.

Mechanism Analysis of OsZF8-Mediated Regulation of Rice Resistance to Sheath Blight.

Transcription factors are key molecules involved in transcriptional and post-transcriptional regulation in plants and play an important regulatory role in resisting biological stress. In this study, we identified a regulatory factor, OsZF8, mediating rice response to Rhizoctonia solani (R. solani) AG1-IA infection. The expression of OsZF8 affects R. solani rice infection. OsZF8 knockout and overexpressed rice plants were constructed, and the phenotypes of mutant and wild-type (WT) plants showed that OsZF8 negatively regulated rice resistance to rice sheath blight. However, it was speculated that OsZF8 plays a regulatory role at the protein level. The interacting protein PRB1 of OsZF8 was screened using the yeast two-hybrid and bimolecular fluorescence complementation test. The results showed that OsZF8 effectively inhibited PRB1-induced cell death in tobacco cells, and molecular docking results showed that PRB1 had a strong binding effect with OsZF8. Further, the binding ability of OsZF8-PRB1 to ergosterol was significantly reduced when compared with the PRB1 protein. These findings provide new insights into elucidating the mechanism of rice resistance to rice sheath blight.

Oral Exposure to Titanium Dioxide E171 and Zinc Oxide Nanoparticles Induces Multi-Organ Damage in Rats: Role of Ceramide.

Food-grade titanium dioxide (E171) and zinc oxide nanoparticles (ZnO NPs) are common food additives for human consumption. We examined multi-organ toxicity of both compounds on Wistar rats orally exposed for 90 days. Rats were divided into three groups: (1) control (saline solution), (2) E171-exposed, and (3) ZnO NPs-exposed. Histological examination was performed with hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM). Ceramide (Cer), 3-nitrotyrosine (NT), and lysosome-associated membrane protein 2 (LAMP-2) were detected by immunofluorescence. Relevant histological changes were observed: disorganization, inflammatory cell infiltration, and mitochondrial damage. Increased levels of Cer, NT, and LAMP-2 were observed in the liver, kidney, and brain of E171- and ZnO NPs-exposed rats, and in rat hearts exposed to ZnO NPs. E171 up-regulated Cer and NT levels in the aorta and heart, while ZnO NPs up-regulated them in the aorta. Both NPs increased LAMP-2 expression in the intestine. In conclusion, chronic oral exposure to metallic NPs causes multi-organ injury, reflecting how these food additives pose a threat to human health. Our results suggest how complex interplay between ROS, Cer, LAMP-2, and NT may modulate organ function during NP damage.

Antimicrobial Packaging for Plum Tomatoes Based on ZnO Modified Low-Density Polyethylene.

Food safety and quality are major concerns in the food industry. Despite numerous studies, polyethylene remains one of the most used materials for packaging due to industry reluctance to invest in new technologies and equipment. Therefore, modifications to the current materials are easier to implement than adopting whole new solutions. Antibacterial activity can be induced in low-density polyethylene films only by adding antimicrobial agents. ZnO nanoparticles are well known for their strong antimicrobial activity, coupled with low toxicity and UV shielding capability. These characteristics recommend ZnO for the food industry. By incorporating such safe and dependable antimicrobial agents in the polyethylene matrix, we have obtained composite films able to inhibit microorganisms' growth that can be used as packaging materials. Here we report the obtaining of highly homogenous composite films with up to 5% ZnO by a melt mixing process at 150 °C for 10 min. The composite films present good transparency in the visible domain, permitting consumers to visualize the food, but have good UV barrier properties. The composite films exhibit good antimicrobial and antibiofilm activity from the lowest ZnO composition (1%), against both Gram-positive and Gram-negative bacterial strains. The homogenous dispersion of ZnO nanoparticles into the polyethylene matrix was assessed by Fourier transform infrared microscopy and scanning electron microscopy. The optimal mechanical barrier properties were obtained for composition with 3% ZnO. The thermal analysis indicates that the addition of ZnO nanoparticles has increased thermal stability by more than 100 °C. The UV-Vis spectra indicate a low transmittance in the UV domain, lower than 5%, making the films suitable for blocking photo-oxidation processes. The obtained films proved to be efficient packaging films, successfully preserving plum (Rome) tomatoes for up to 14 days.

Efficient Immobilization of heavy metals using newly synthesized magnetic nanoparticles and some bacteria in a multi-metal contaminated soil.

Simultaneous application of modified Fe3O4 with biological treatments in remediating multi-metal polluted soils, has rarely been investigated. Thus, a pioneering approach towards sustainable environmental remediation strategies is crucial. In this study, we aimed to improve the efficiency of Fe3O4 as adsorbents for heavy metals (HMs) by applying protective coatings. We synthesized core-shell magnetite nanoparticles coated with modified nanocellulose, nanohydrochar, and nanobiochar, and investigated their effectiveness in conjunction with bacteria (Pseudomonas putida and Bacillus megaterium) for remediating a multi-metal contamination soil. The results showed that the coatings significantly enhanced the immobilization of heavy metals in the soil, even at low doses (0.5%). The coating of nanocellulose had the highest efficiency in stabilizing metals due to the greater variety of surface functional groups and higher specific surface area (63.86 m2 g-1) than the other two coatings. Interestingly, uncoated Fe3O4 had lower performance (113.6 m2 g-1) due to their susceptibility to deformation and oxidation. The use of bacteria as a biological treatment led to an increase in the stabilization of metals in soil. In fact, Pseudomonas putida and Bacillus megaterium increased immobilization of HMs in soil successfully because of extracellular polymeric substances and intensive negative charges. Analysis of metal concentrations in plants revealed that Ni and Zn accumulated in the roots, while Pb and Cd were transferred from the roots to the shoots. Treatment Fe3O4 coated with modified nanocellulose at rates of 0.5 and 1% along with Pseudomonas putida showed the highest effect in stabilizing metals. Application of coated Fe3O4 for in-situ immobilization of HMs in contamination soils is recommendable due to their high metal stabilization efficiency and suitability to apply in large quantities.