Green synthesis of multifunctional ZnO/chitosan nanocomposite film using wild Mentha pulegium extract for packaging applications

Integrating hexagonal boron nitride-ZnO nanohybrids as multifunctional active fillers in PLA matrices to extend the shelf-life of fresh strawberries

PLA is a promising sustainable alternative to petroleum-based polymers. However, its suboptimal functional properties and lack of inherent bioactivity limit its applications in active food packaging. This study addresses these constraints and improves PLA's active functionalities through reinforcement with hexagonal boron nitride-ZnO (hBN-ZnO) binary inorganic nanofillers. PLA was fine-tuned with various ratios of hBN, and found that PLA-hBN1.5 film exhibits the optimum characteristics such as excellent film formation, highest tensile strength (62.14 MPa, 19.75 % increase), lowest water vapor permeability (1.23 ± 0.03 × 10-11 g.m-1.s-1.Pa-1, 32.04 % decrease), and improved UV-blocking and thermal resistance. Subsequently, a hydrothermally synthesized hBN-ZnO composite was incorporated into optimal PLA-hBN1.5 films, replacing pure hBN. The ZnO inclusion boosted the films antibacterial, antibiofilm, and antioxidant functionalities without significantly compromising mechanical or moisture barrier properties. Packaging studies on fresh strawberries demonstrated the superior potential of the PLA-hBN-ZnO film, making it a promising material for sustainable and active food packaging.

Chitosan/zinc oxide (ZnO) nanocomposites: A critical review of emerging multifunctional applications in food preservation and biomedical systems

The increasing uses of petroleum-based materials for food packaging and medical applications raised significant environmental concerns. Researchers and industry stakeholders are actively exploring sustainable alternatives to replace those materials. Chitosan/zinc oxide (ZnO) bio-nanocomposites have emerged as promising alternatives to replace conventional plastics. Chitosan, a biodegradable biopolymer, exhibits exceptional film-forming properties, biocompatibility, and antimicrobial activity for sustainable application. On contrary, it has also certain drawbacks that limit its industrial applications including poor mechanical properties and high sensitivity to humidity. The integration of ZnO nanoparticles addresses these limitations by enhancing their mechanical strength, UV-blocking ability, stability, and functional properties with superior antimicrobial and antioxidant capabilities. This study critically examines past and current research, innovations, and development in chitosan/ZnO nanocomposites, with a focus on their sources, latest synthesis methods, properties, limitations and potentials applications in the food preservation and biomedical fields. Findings indicate that these nanocomposites can not only extend the shelf life of food products and are used for effective wound treatment, drug delivery, and tissue engineering but also reduces environmental impact. By highlighting recent advancements and future research directions, this review aims to promote the development of sustainable and eco-friendly solutions to address global challenges in food waste and healthcare.

Fulvic acid-releasing chitosan nanoparticles promote the growth and salt stress tolerance of soybean plants

Nanotechnology offers several advantages over conventional inputs, with widespread application in agriculture. The current climate change crisis has accelerated the accumulation of salts in soils, which is a major challenge to global food security. Here, we synthesized fulvic acid-releasing chitosan nanoparticles (Ch-FANPs) for promoting soybean growth and salt stress tolerance. In a screening hydroponic experiment, 0.1 mM Ch-FANPs promoted plant growth and enhanced the growth parameters of pot-grown soybean plants significantly and modulated stomatal movement under control as well as salt stress conditions induced by 150 mM NaCl. Salt stress affected overall plant growth and reduced the chlorophyll content. However, plants treated with Ch-FANPs not only accumulated significantly higher chlorophyll under both control and salt conditions but also enhanced several above- and below-ground growth parameters by more than 50%. Interestingly, the Ch-FANP-treated salt-exposed plants accumulated ~30% less soluble proteins than untreated salt-stressed plants. Ch-FANPs-mediated protection against salt stress was related to the activation of antioxidant machinery as the highest ascorbate peroxidase (APX) activity was recorded in Ch-FANPs-treated salt-stressed plants along with significantly low MDA and H2O2 contents. ICP-MS analysis showed a tremendously higher accumulation of Na+ ions (~35 ppm) in the leaves of salt-stressed plants compared to 19 ppm Na+ ions when also treated with Ch-FANPs. Salt-exposed plants treated with Ch-FANPs had the highest K+ content (~76 ppm) and Ca2+ (62 ppm). Furthermore, Ch-FANPs-mediated protection against salt stress was associated with a significant increase in the expression of salt stress marker genes GmSOS1, GmSOS2, GmNHX1, and GmP5CS1.

Mechanistic insights of free radical scavenging-driven stabilization of edible oils and their shelf life extension using CeO2 nanoparticles

The rapid production of reactive oxygen species (ROS) due to lipid peroxidation of unsaturated bonds in wholesome vegetable oil during its storage and utilization happens to be the most alarming cause of concern in the edible oil industry. In researching for an ideal candidate to be used as an antioxidant, it has been identified that engineered CeO2 nanoparticle with curated surface chemistry (Ce3+/Ce4+ ratio) displays an enhanced ROS scavenging activity. Herein the CeO2 nanoparticles (∼100-110 nm) were manufactured though controlled synthesis protocol to achieve the desired outcome. The electronic structure of these nanoparticles were calculated accordingly to achieve clear understanding on electronic phenomenon which is responsible for this enhancement. It was determined that synthesized CeO2 are non-cytotoxic below 88 ppm and displays significant improvement of oxidative stability of oils at concentrations of 10-15 ppm. In addition, accelerated shelf-life study yields remarkable improvement of shelf life upto twice that of oils containing conventional antioxidants.

Influence of Nanoparticle Content and Cross-Linking Degree on Functional Attributes of Calcium Alginate-ZnO Nanocomposite Wound Dressings

Alginate-ZnO nanoparticles (ZnOnano) composite wound dressing membranes were prepared with two different ZnOnano concentrations (0.03 and 0.20 g ZnO/g sodium alginate) and cross-linked with two different calcium treatments (low and high Ca++concentration) to evaluate the influence of nanoparticle content and cross-linking degree on membrane attributes. ZnOnano addition did not significantly alter the mechanical properties, water vapor permeability, swelling degree in water and the alginate amorphous nature of the nanocomposite membranes. The increase in cross-linking degree, on the other hand, altered the microstructure of the membranes, increased the tensile strength and reduced the water vapor permeability of the nanocomposite membranes. The presence of ZnOnano in alginate membranes granted them antibacterial activity in vitro against Pseudomonas aeruginosa and Staphylococcus aureus and substantially increased the absorption capacity in phosphate buffer and fetal bovine serum solutions, validating their potential use as wound dressings.

Ultrasound-assisted green synthesized ZnO nanoparticles with different solution pH for water treatment

Metal oxide nanoparticles (NPs), particularly ZnO NPs, have garnered significant attention in addressing global water-related challenges. This study introduces NPs agents for acidic water treatment by synthesizing ZnO nanostructures via ultrasound-assisted green synthesis utilizing Ginger extract. The research investigates the influence of solution pH on the physical properties of NPs and their photocatalytic efficiencies in treating acidic (pH = 5) and neutral (pH = 7) water through the photodegradation of methylene blue (MB) under ultraviolet (UV) illumination. Results indicate that the solution pH, varying between 7 and 13, significantly controls the morphologies of ZnO NPs, yielding hexagonal plates, barley-like structures, and nanoflakes. The band gap energies of the synthesized NPs are quite independent of the solution pH, but their crystallite sizes decrease with increasing pH values. Notably, ZnO NPs synthesized at pH = 11 exhibit the highest BET-specific surface area of 26.74 m²/g, correlating with their superior photocatalytic activity. The optimal degradation efficiencies of MB in acidic conditions (pH = 5) reach 93.54% and 86.04% when utilizing 10 and 5 mg of the irradiated photocatalyst, respectively, after a reaction time of 160 min. These findings underscore the potential of ZnO NPs as a cost-effective and environmentally sustainable solution for efficient acidic wastewater treatment.

Synthesis and antibacterial activity of silver doped zinc sulfide/chitosan bionanocomposites: A new frontier in biomedical applications

Numerous microbial species have caused infectious diseases worldwide, which have become a social burden and a menace to the community. So, there is a need to develop antimicrobial materials and specialized materials for biomedical applications. In the present investigation, we report the simple synthesis, the physicochemical, and antibacterial activity of Silver doped zinc sulfide (ZnS: Ag) capped with Chitosan (CS) to produce ZnS: Ag/CS bionanocomposites (BNCs). The prepared BNCs was evaluated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and UV-Vis spectroscopy. According to the XRD results, ZnS: Ag/CS particles with semicrystalline chitosan/hexagonal ZnS phase structures and an average crystallite size in the range of 30-40 nm was formed. According to FESEM images, a spherical/hexagonal shape of ZnS: Ag particles embedded in the polymeric chitosan matrix. The colony counting method was employed to investigate the antibacterial activity on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The results revealed that ZnS: Ag particles and ZnS: Ag/CS BNCs have stronger antibacterial activities than pure CS and ZnS. The reduction percentage of ZnS: Ag/CS BNCs against S. aureus and E. coli after 6 h of treatment was >99.9 % and 70 % respectively. These findings suggest that ZnS: Ag/CS BCs not only offer superior antimicrobial properties compared to individual ZnS and CS but also have great potential for advancing biomedical applications due to their enhanced antibacterial performance. The simplicity of the synthesis method and the use of non-toxic materials like chitosan make this a sustainable approach for developing antimicrobial agents, which is a key advantage of this study.

Green synthesized silver nanoparticles, a sustainable approach for fruit and vegetable preservation: An overview

Nanotechnology in which silver nanoparticles (AgNPs) have received more interest in fruits and vegetables (FaV) preservation due to their anti-microorganism properties. There are various approaches to synthesizing AgNPs, in which biological reduction, especially plant extraction containing bioactive compounds, is considered non-toxic, eco-friendly, and economically viable. AgNPs can be applied for FaV preservation by immersing or incorporating AgNPs into the edible coating or wrapper film. Depending on the type of coating and the kind of FaV, choosing the coating components is necessary to ensure the anti-microorganism ability and improve preservation efficiency. This review highlights green-synthesized AgNPs for preserving FaV. The study covered the materials employed in the green synthesis of AgNPs, their effectiveness against microorganisms, the influence of AgNPs on film structure, safety properties, and various preservation strategies. Using plant or bacterial-synthesized AgNPs in edible coatings offers a sustainable approach to enhance safety, edibility, environmental friendliness, and FaV quality during storage.

Au-H2Ti3O7 nanotubes for non-invasive anticancer treatment by simultaneous photothermal and photodynamic therapy

Treating lung and prostate cancer cells is a major health problem that may be solved through the interactions of laser beams with nanoparticles. In the paper, Au-H2Ti3O7 nanotubes (NTs) are proposed as a treatment agent and the interactions of different laser beams with the nanostructure are considered to solve the mentioned health problem. Also, the NTs are employed to treat the cancers in dark conditions. The results are motivating because Au-H2Ti3O7 NPs do not affect healthy cells, while they strongly affect cancer cells, and the viability percentage of LNCap cells reaches 16% for incubation times of 48 h. Furthermore, treating LNCap cells using the irradiated Au-H2Ti3O7 NTs by NIR beam at 808 nm has no cytotoxicity, while cytotoxicity of 92% is obtained using an irradiation laser beam at 532 nm. Also, applying the laser beam at 635 nm to the NTs leads to a cytotoxicity of ∼53% in lung cancer (A549 cells). In total, the Au-H2Ti3O7 NTs have a selective effect on cancer cells and greatly reduce the viability in the given dark and irradiation conditions, leading to the introduction of them as a promising agent for the non-invasive treatment of prostate cancer and a moderate candidate for lung cancer therapy.

Green synthesis and characterization of Fe2O3, ZnO and TiO2 nanoparticles and searching for their potential use as biofertilizer on sunflower

Nanoparticles, thanks to their superior properties such as large surface area and high reactivity, can be an alternative to traditional fertilizers for improving nutrient uptake. Furthermore, considering that chemical and physical synthesis methods require high energy consumption and cause environmental pollution, plant-mediated green synthesis of NPs has attracted great attention since it provides eco-friendly, biocompatible, and inexpensive solutions. In this present study, plant mediated green synthesis of Iron Oxide (Fe2O3), Zinc Oxide (ZnO) and Titanium Dioxide (TiO2) nanoparticles by using Laurus nobilis leaves (bay leaves) were carried out and their structural properties were characterized by UV visible spectra, Dynamic Light Scattering (DLS), Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). UV spectrum and FTIR analysis exhibited characteristic peaks indicating the presence of the desired NPs, while DLS analysis and TEM images confirmed that synthesized particles are in nano-scale. The potential of nanoparticles as biofertilizer in agricultural uses were assessed by investigating their effects on sunflower growth in hydroponic system. TEM images of the NP applied plant tissues proved the uptake and translocation of NPs from root to leaf. Furthermore, Fe2O3, ZnO and TiO2 NP applications on sunflower up to 5 ppm generally improved physiological growth parameters such as root length, fresh weight and leaf surface area while 20 ppm of Fe2O3 and ZnO NPs application cause a significant decrease.

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Mechanical properties, sustained release, and oxygen scavenging properties of nanocomposite films loaded with bimetallic nanoparticles (Fe2O3/TiO2) in extra virgin olive oil

The aim of this study was the synthesis of bimetallic nanoparticles based on Fe2O3/TiO2 and its use in the poly(lactic acid) (PLA) films as an oxygen scavenger in extra virgin olive oil (EVOO) packaging. Bimetallic nanocomposites were prepared by two different precipitation methods (precipitation with ammonia and sodium hydroxide). The characteristics of bimetallic nanoparticles precipitated with sodium hydroxide (Na-Ti0.01Fe0.048O0.08) and bimetallic nanoparticles precipitated with ammonia (NH-Ti0.01Fe0.022O0.09) were compared. Relative amounts of elements in bimetallic nanocomposites and their morphological characteristics were determined using field emission scanning electron microscopy coupled with energy-dispersive X-ray spectrometer. Porosity volume and surface area of bimetallic nanoparticles were calculated using adsorption-desorption isotherms and the Brunauer-Emmett-Teller method. The formation/characterization of bimetallic nanoparticles and their location in the matrix of PLA-based nanocomposite film was studied using X-ray diffraction and Fourier transform infrared. In nanocomposite films based on PLA, bimetallic nanoparticles lead to better oxidative stability (peroxide value, p-anisidine index, K232, and K270) of the EVOO and oxygen scavenging during storage compared to free nanoparticles. Mechanical properties of nanocomposite films were improved due to bimetallic nanoparticles, which were better for Na-Ti0.01Fe0.048O0.08. In vitro release modeling of the bimetallic nanoparticles in EVOO proved that Fickian diffusion is the dominant mechanism, and the Peleg model was the best description of the release behavior of nanoparticles.

The Fate of Microplastics, Derived from Disposable Masks, in Natural Aquatic Environments

This paper mainly reviews the fate of microplastics, released from used face masks, in the water environment. Through previous experiments, the amount of fiber microplastics released from used face masks into aqueous environments was not negligible, with the maximum microplastics releasing amount reaching 10,000 piece·day-1 for each mask. Microplastic derived from these masks often occurred in the shape of polymeric fibers that resulted from the breakage of the chemical bonds in the plastic fibers by the force of water flow. The potential contact forces between microplastics (originating from face masks) with other pollutants, primarily encompass hydrophobic and electrostatic interactions. This critical review paper briefly illustrates the fate of microplastics derived from disposable face masks, further devising effective strategies to mitigate the environmental impact of plastic particle release from the used personal protective equipment.

Developing Sustainable Agriculture Systems in Medicinal and Aromatic Plant Production by Using Chitosan and Chitin-Based Biostimulants

Chitosan is illustrated in research as a stimulant of plant tolerance and resistance that promotes natural defense mechanisms against biotic and abiotic stressors, and its use may lessen the amount of agrochemicals utilized in agriculture. Recent literature reports indicate the high efficacy of soil or foliar usage of chitin and chitosan in the promotion of plant growth and the induction of secondary metabolites biosynthesis in various species, such as Artemisia annua, Curcuma longa, Dracocephalum kotschyi, Catharanthus roseus, Fragaria × ananassa, Ginkgo biloba, Iberis amara, Isatis tinctoria, Melissa officinalis, Mentha piperita, Ocimum basilicum, Origanum vulgare ssp. Hirtum, Psammosilene tunicoides, Salvia officinalis, Satureja isophylla, Stevia rebaudiana, and Sylibum marianum, among others. This work focuses on the outstanding scientific contributions to the field of the production and quality of aromatic and medicinal plants, based on the different functions of chitosan and chitin in sustainable crop production. The application of chitosan can lead to increased medicinal plant production and protects plants against harmful microorganisms. The effectiveness of chitin and chitosan is also due to the low concentration required, low cost, and environmental safety. On the basis of showing such considerable characteristics, there is increasing attention on the application of chitin and chitosan biopolymers in horticulture and agriculture productions.

Electrocatalytic Degradation of Rhodamine B Using Li-Doped ZnO Nanoparticles: Novel Approach

In this paper, we discuss the preparation of Li-doped ZnO nanostructures through combustion and report on their structural, morphological, optical, and electrocatalysis properties. X-ray diffraction analyses show that the samples have a structure crystallized into the usual hexagonal wurtzite ZnO structure according to the P63mc space group. The scanning electron microscope images conceal all samples' nanosphere bundles and aggregates. The reflectance spectra analysis showed that the direct bandgap values varied from 3.273 eV (for pure ZnO, i.e., ZnL1) to 3.256 eV (for high Li-doped ZnO). The measured capacitance concerning frequency has estimated the variation of dielectric constant, dielectric loss, and AC conductivity against AC electric field frequency. The dielectric constant variations and AC conductivity are analyzed and discussed by well-known models such as Koop's phenomenological theory and Jonscher's law. The Raman spectra have been recorded and examined for the prepared samples. Rhodamine B was electro-catalytically degraded in all prepared samples, with the fastest time for ZnL5 being 3 min.

Green Synthesized Zinc Oxide Nanoparticles Based on Cestrum diurnum L. of Potential Antiviral Activity against Human Corona 229-E Virus

SARS-CoV-2 has caused more than 596 million infections and 6 million fatalities globally. Looking for urgent medication for prevention, treatment, and rehabilitation is obligatory. Plant extracts and green synthesized nanoparticles have numerous biological activities, including antiviral activity. HPLC analysis of C. dirnum L. leaf extract showed that catechin, ferulic acid, chlorogenic acid, and syringic acid were the most major compounds, with concentrations of 1425.16, 1004.68, 207.46, and 158.95 µg/g, respectively. Zinc nanoparticles were biosynthesized using zinc acetate and C. dirnum extract. TEM analysis revealed that the particle size of ZnO-NPs varied between 3.406 and 4.857 nm. An XRD study showed the existence of hexagonal crystals of ZnO-NPs with an average size of 12.11 nm. Both ZnO-NPs (IC₅₀ = 7.01 and CC₅₀ = 145.77) and C. dirnum L. extract (IC₅₀ = 61.15 and CC₅₀ = 145.87 µg/mL) showed antiviral activity against HCOV-229E, but their combination (IC₅₀ = 2.41 and CC₅₀ = 179.23) showed higher activity than both. Molecular docking was used to investigate the affinity of some metabolites against the HCOV-229E main protease. Chlorogenic acid, solanidine, and catchin showed high affinity (-7.13, -6.95, and -6.52), compared to the ligand MDP (-5.66 Kcal/mol). Cestrum dinurum extract and ZnO-NPs combination should be subjected to further studies to be used as an antiviral drug.

Antibacterial and Photodegradation of Organic Dyes Using Lamiaceae-Mediated ZnO Nanoparticles: A Review

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using plant extracts has been receiving tremendous attention as an alternative to conventional physical and chemical methods. The Lamiaceae plant family is one of the largest herbal families in the world and is famous for its aromatic and polyphenolic biomolecules that can be utilised as reducing and stabilising agents during the synthesis of ZnO NPs. This review will go over the synthesis and how synthesis parameters affect the Lamiaceae-derived ZnO NPs. The Lamiaceae-mediated ZnO NPs have been utilised in a variety of applications, including photocatalysis, antimicrobial, anticancer, antioxidant, solar cells, and so on. Owing to their optical properties, ZnO NPs have emerged as potential catalysts for the photodegradation of organic dyes from wastewater. Furthermore, the low toxicity, biocompatibility, and antibacterial activity of ZnO against various bacteria have led to the application of ZnO NPs as antibacterial agents. Thus, this review will focus on the application of Lamiaceae-mediated ZnO NPs for the photodegradation of organic dyes and antibacterial applications.