Nanoparticles and Zeolites: Antibacterial Effects and their Mechanism against Pathogens

Zeolitic imidazolate frameworks (ZIFs): Advanced nanostructured materials to enhance the functional performance of food packaging materials

Zeolite imidazole framework (ZIF) materials are a class of metallic organic framework (MOF) materials that have several potential applications in the food and other industries. They consist of metal ions or clusters of metal ions coordinated with imidazole-based organic linkers, creating a three-dimensional solid structure with well-defined pores and channels. ZIFs possess several important features, including high porosity, tunable pore sizes, high surface areas, adjustable surface chemistries, and good stabilities. These characteristics make them highly versatile materials that can be used in a variety of applications, including smart and active food packaging. Based on their controllable compositions, dimensions, and pore sizes, the properties of ZIFs can be tailored for a diverse range of applications, including energy storage, sensing, separation, encapsulation, and catalysis. In this article, we focus on recent progress and potential applications of ZIFs in food packaging materials. Previous studies have shown that ZIFs can significantly improve the optical, mechanical, barrier, thermal, sustainability, and preservative properties of packaging materials. Moreover, ZIFs can be used as carriers to encapsulate, protect, and control the release of bioactive agents in packaging materials. ZIFs are capable of selectively adsorbing and releasing molecules based on their size, shape, and surface properties. These unique characteristics make them particularly suitable for smart or active food packaging applications. By selectively removing gases (such as oxygen, carbon dioxide, water, or ethylene) ZIFs can improve the shelf life and quality of packaged foods. In addition, they can be employed to control the growth of spoilage microorganisms and minimize oxidation reactions, thereby enhancing the freshness and extending the shelf life of foods. They may also be used to create sensors capable of detecting and indicating food spoilage. For instance, ZIFs that change color or release specific compounds when spoilage products are present can provide visual or chemical indications of food deterioration. This feature is especially valuable in ensuring the safety and quality of packaged food, as it enables consumers and retailers to easily identify spoiled products. ZIFs can be functionalized using various additives, including antioxidants, antimicrobials, pigments, and flavors, which can improve the preservative and sensory properties of packaged foods. Moreover, ZIF-based packaging materials offer sustainability benefits. Unlike traditional plastic packaging, ZIFs are biodegradable and can easily be disposed of without causing harm to the environment, thereby reducing the adverse effects of plastic waste materials. The application of ZIFs in smart/active food packaging offers exciting possibilities for enhancing the shelf life, quality, and safety of foods. With further research and development, ZIF-based packaging could become a sustainable alternative to plastic-based packaging in the food industry. An important aim of this review article is to stimulate further research on the development and application of ZIFs within food packaging materials.

Devitalization of Bacteria in Composted Cattle Manure with Natural Additives and Risk for Environment

Nowadays, there is an effort to improve the effectiveness of the composting process, supported by the addition of various supplements to reduce soil nutrition losses and increase soil remediation. The aim of this study was to examine the devitalization effect of natural additives like zeolite-clinoptilolite and its combination with hydrated lime in composted cattle manure on indicator and pathogen bacteria. The composting process was running in three static piles of cattle manure mixed with wheat straw (control, zeolite-lime, and zeolite) for 126 days. Composted manure substrates were determined for physicochemical (temperature, pH, nitrogen and phosphorus content, C/N, organic matter, and moisture) and microbiological analyses (Salmonella spp., indicator bacteria). The effects of additives were reflected in changes in physicochemical factors, e.g., an increase in temperature (<53 °C) or pH (<9.3). According to Pearson correlation, these changes (pH, Nt, Pt) resulted in a significant decrease (p < 0.001) of indicator bacteria (two or three orders) in zeolite pile or zeolite-lime pile. Die-off of Salmonella spp. in the zeolite-lime pile was indicated within 41 days; in other piles, this occurred on day 63. Our results can aid in further optimizing the composting of cattle manure in order to lower environmental pollution and the risk of human infection.

Metal-Based Nanoparticles in Food Packaging and Coating Technologies: A Review

Food security has continued to be a topic of interest in our world due to the increasing demand for food. Many technologies have been adopted to enhance food supply and narrow the demand gap. Thus, the attempt to use nanotechnology to improve food security and increase supply has emerged due to the severe shortcomings of conventional technologies, which have made them insufficient to cater to the continuous demand for food products. Hence, nanoparticles have been identified to play a major role in areas involving food production, protection, and shelf-life extensions. Specifically, metal-based nanoparticles have been singled out to play an important role in manufacturing materials with outstanding properties, which can help increase the shelf-life of different food materials. The physicochemical and biological properties of metal-based nanoparticles, such as the large surface area and antimicrobial properties, have made them suitable and adequately useful, not just as a regular packaging material but as a functional material upon incorporation into biopolymer matrices. These, amongst many other reasons, have led to their wide synthesis and applications, even though their methods of preparation and risk evaluation remain a topic of concern. This review, therefore, briefly explores the available synthetic methods, physicochemical properties, roles, and biological properties of metal-based nanoparticles for food packaging. Furthermore, the associated limitations, alongside quality and safety considerations, of these materials were summarily explored. Although this area of research continues to garner attention, this review showed that metal-based nanoparticles possess great potential to be a leading material for food packaging if the problem of migration and toxicity can be effectively modulated.

Improving the functionality of biodegradable food packaging materials via porous nanomaterials

Non-biodegradability and disposal problems are the major challenges associated with synthetic plastic packaging. This review article discusses a new generation of biodegradable active and smart packaging based on porous nanomaterials (PNMs), which maintains the quality and freshness of food products while meeting biodegradability requirements. PNMs have recently gained significant attention in the field of food packaging due to their large surface area, peculiar structures, functional flexibility, and thermal stability. We present for the first time the recently published literature on the incorporation of various PNMs into renewable materials to develop advanced, environmentally friendly, and high-quality packaging technology. Various emerging packaging technologies are discussed in this review, along with their advantages and disadvantages. Moreover, it provides general information about PNMs, their characterization, and fabrication methods. It also briefly describes the effects of different PNMs on the functionality of biopolymeric films. Furthermore, we examined how smart packaging loaded with PNMs can improve food shelf life and reduce food waste. The results indicate that PNMs play a critical role in improving the antimicrobial, thermal, physicochemical, and mechanical properties of natural packaging materials. These tailor-made materials can simultaneously extend the shelf life of food while reducing plastic usage and food waste.

Nanobiotechnological approaches in anticoagulant therapy: The role of bioengineered silver and gold nanomaterials

Nanotechnology is a novel area that has exhibited various remarkable applications, mostly in medicine and industry, due to the unique properties coming with the nanoscale size. One of the notable medical uses of nanomaterials (NMs) that attracted enormous attention recently is their significant anticoagulant activity, preventing or reducing coagulation of blood, decreasing the risk of strokes, heart attacks, and other serious conditions. Despite successful in vitro experiments, in vivo analyses are yet to be confirmed and further research is required to fully prove the safety and efficacy of nanoparticles (NPs) and to introduce them as valid alternatives to conventional ineffective anticoagulants with various shortcomings and side-effects. NMs can be synthesized through two main routes, i.e., the bottom-up route as a more preferable method, and the top-down route. In numerous studies, biological fabrication of NPs, especially metal NPs, is highly suggested given its eco-friendly approach, in which different resources can be employed such as plants, fungi, bacteria, and algae. This review discusses the green synthesis and characterization of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) as two of the most useful metal NPs, and also their alloys in different studies focussing on their anticoagulant potential. Challenges and alternative approaches to the use of these NPs as anticoagulants have also been highlighted.

Application of antimicrobial, potential hazard and mitigation plans

The tremendous rise in the consumption of antimicrobial products had aroused global concerns, especially in the midst of pandemic COVID-19. Antimicrobial resistance has been accelerated by widespread usage of antimicrobial products in response to the COVID-19 pandemic. Furthermore, the widespread use of antimicrobial products releases biohazardous substances into the environment, endangering the ecology and ecosystem. Therefore, several strategies or measurements are needed to tackle this problem. In this review, types of antimicrobial available, emerging nanotechnology in antimicrobial production and their advanced application have been discussed. The problem of antimicrobial resistance (AMR) due to antibiotic-resistant bacteria (ARB)and antimicrobial resistance genes (AMG) had become the biggest threat to public health. To deal with this problem, an in-depth discussion of the challenges faced in antimicrobial mitigations and potential alternatives was reviewed.

Bionanocomposite Active Packaging Material Based on Soy Protein Isolate/Persian Gum/Silver Nanoparticles; Fabrication and Characteristics

In this study, nanocomposite active films were fabricated containing silver nanoparticles (SNPs) embedded within soy protein isolate (SPI)/Persian gum (PG) matrices. The physical, mechanical, and antibacterial properties of these composite films were then characterized. In addition, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to provide information about the microstructure, interactions, and crystallinity of the films. Pure SPI films had poor physicochemical attributes but the addition of PG (0.25, 0.5, or 1 wt%) improved their water vapor permeability, mechanical properties, and water solubility (WS). The moisture content (MC) of the films decreased after the introduction of PG, which was attributed to fewer free hydroxyl groups to bind to the water molecules. Our results suggest there was a strong interaction between the SPI and the PG and SNPs in the films, suggesting these additives behaved like active fillers. Optimum film properties were obtained at 0.25% PG in the SPI films. The addition of PG (0.25%) and SNPs (1%) led to a considerable increase in tensile strength (TS) and a decrease in elongation at break (EB). Furthermore, the incorporation of the SNPs into the SPI/PG composite films increased their antibacterial activity against pathogenic bacteria (Escherichia coli and Staphylococcus aureus), with the effects being more prominent for S. aureus. Spectroscopy analyses provided insights into the nature of the molecular interactions between the different components in the films. Overall, the biodegradable active films developed in this study may be suitable for utilization as eco-friendly packaging materials in the food industry.

New perspectives on electrospun nanofiber applications in smart and active food packaging materials

Packaging plays a critical role in determining the quality, safety, and shelf-life of many food products. There have been several innovations in the development of more effective food packaging materials recently. Polymer nanofibers are finding increasing attention as additives in packaging materials because of their ability to control their pore size, surface energy, barrier properties, antimicrobial activity, and mechanical strength. Electrospinning is a widely used processing method for fabricating nanofibers from food grade polymers. This review describes recent advances in the development of electrospun nanofibers for application in active and smart packaging materials. Moreover, it highlights the impact of these nanofibers on the physicochemical properties of packaging materials, as well as the application of nanofiber-loaded packaging materials to foods, such as dairy, meat, fruit, and vegetable products.

Decorative Multi-Walled Carbon Nanotubes by ZnO: Synthesis, Characterization, and Potent Anti-Toxoplasmosis Activity

Toxoplasmosis may become a fatal disease in immunodeficient, diabetic patients, pregnant women, and infants. Hence, the diligent search for new effective treatment is among the major concerns worldwide. The well-dispersed multi-walled carbon nanotubes lined with ZnO (ZnO-MWCNT), graphene oxide (GO-NPs), and zinc oxide (ZnO-NPs) were successfully synthesized through rapid and facile hydrothermal arc discharge technique (HTADT). The antiparasitic effects of ZnO-NPs, GO-NPs, and ZnO-MWCNT were investigated in mice infected with Toxoplasma gondii. The percent of tachyzoites reduction were detected. The observed results demonstrated that ZnO-MWCNT revealed a significant reduction in the parasite count reached 61% in brain tissues, followed by liver (52%), then spleen (45%). The assessments of antiparasitic, inflammatory, and anti-inflammatory cytokines confirmed the superior activity of ZnO-MWCNT as antiparasitic agent, which paves the way for the employment of ZnO-MWCNT as a treatment for the acute RH strain of T. gondii infection in vivo.

Titanium dioxide nanoparticles as multifunctional surface-active materials for smart/active nanocomposite packaging films

Environmental issues such as plastic packaging and high demand for fresh and safe food has increased the interest for developing smart/active food packaging films with colloidal nanoparticles (NPs). Titanium dioxide nanoparticles (TNPs) are cost effective and stable metal oxide NPs which could be used as a functional nano-filler for biodegradable food packaging due to their excellent biocompatibility, photo catalyzing, and antimicrobial properties. This article has comprehensively reviewed the functional properties and advantages of TNPs-containing smart/active films. The advantage of adding TNPs for ameliorating food packaging materials such as their physical, mechanical, moisture/light barrier, optical, thermal resistance, microstructure and chemical properties as well as, antibacterial, and photocatalytic properties are discussed. Also, the practical and migration properties of administrating TNPs in food packaging material are investigated. The ethylene decomposition activity of TNPs containing active films, could be used for increasing the shelf life of fruits/vegetables after harvesting. TNPs are safe with negligible migration rates which could be used for fabrication of multifunctional smart/active packaging films due to their antimicrobial properties and ethylene gas scavenging activities.

Combined bactericidal process of lignin and silver in a hybrid nanoparticle on E. coli

Among multiple engineered nanoparticles that have been used in the bactericidal application, silver nanoparticles (Ag NPs) are the most explored bactericidal functional materials with their high efficiency and broad-spectrum bactericidal properties. However, environmental toxicology and lack of modifiability restrict their further development. In this study, a simple and economic method was established to fabricate lignin and silver hybrid nanoparticles (Lig-Ag NPs) with bactericidal ability. Afterwards, material characterization, bactericidal evaluation, and mechanism exploration were implemented to explore the properties of Lig-Ag NPs. The results indicated that Lig-Ag NPs not only demonstrated remarkable dispersity, uniformity, and encapsulation efficiency but also possessed approximated bactericidal ability on Escherichia coli and better durability compared with the same concentration of Ag NPs on E. coli. On the other hand, flow cytometry and transcriptomic analysis were used to further explore the bactericidal mechanism of Lig-Ag NPs. The results showed that oxidative stress was the possible leading bactericidal mechanism of Lig-Ag NPs. The formation approaches of reactive oxygen species production were various including the slow release of silver ion and generation of quinone/semi-quinone radicals on account of the combined effect of lignin and silver.

GRAPHICAL ABSTRACT

Lig-Ag NPs exhibited remarkable dispersity, uniformity, encapsulation efficiency, and possessed approximated bactericidal ability and better durability compared with Ag NPs.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42114-022-00460-z.

Incorporation of silver nanoparticles into active antimicrobial nanocomposites: Release behavior, analyzing techniques, applications and safety issues

Employing new strategies to develop novel composite systems has become a popular area of interest among researchers. Raising people's awareness and their attention to the health and safety issues are key parameters to achieve this purpose. One of the recommended strategies is the utilization of nanoparticles within the matrix of composite materials to improve their physical, mechanical, structural and antimicrobial characteristics. Silver nanoparticles (Ag NPs) have attracted much attention for nanocomposite applications mainly due to their antimicrobial characteristics. Herein, the current review will focus on the different methods for preparing antimicrobial nanocomposites loaded with Ag NPs, the release of Ag NPs from these nanostructures in different media, analyzing techniques for the evaluation of Ag release from nanocomposites, potential applications, and safety issues of nanocomposites containing Ag NPs. The applications of Ag NPs-loaded nanocomposites have been extensively established in food, biomedical, textile, environmental and pharmacological areas mainly due to their antibacterial attributes. Several precautions should be addressed before implementation of Ag NPs in nanocomposites due to the health and safety issues.

Preparation and characterization of antibacterial nano cerium oxide/chitosan/hydroxyethylcellulose/polyethylene glycol composite films

Due to the rapidly increasing biological applications and antibacterial properties of versatile nano cerium oxide particles, the effects of these particles on chitosan-based films were investigated. Chitosan-based composite films with and without cerium oxide nanoparticles (NPs) were prepared by a casting method. Hydroxyethylcellulose (HEC) was used for the flexibility of films, and polyethylene glycol (PEG) was used as a plasticizer in the blending stage of film preparation. Characterizations of films were done by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), and dynamic mechanical analyzer (DMA). Cerium oxide nanoparticle incorporation enhanced the antibacterial activity of chitosan-based films against Escherichia coli and Staphylococcus aureus. This composite film is proposed as packaging or coating material because of its flexibility, antibacterial efficacy, and good mechanical strength.

Functional biocompatible nanocomposite films consisting of selenium and zinc oxide nanoparticles embedded in gelatin/cellulose nanofiber matrices

In recent decades, environmental concerns and increasing consumer demand for healthy and nutritious food products with prolonged shelf life have made the food packaging industry pay more attention to the preparation of multifunctional biodegradable packaging films based on biopolymers containing active components such as antioxidant and antimicrobial agents. In this study, bio-nanocomposite films were fabricated from gelatin (G) and cellulose nanofibers (CNFs), and different concentrations of zinc oxide (ZnO) and/or Selenium (Se) nanoparticles (NPs) by the casting method. The mechanical, barrier, optical, and structural (FTIR, XRD, and SEM) properties of the films were investigated along with their antibacterial and antioxidant features. The incorporation of ZnO and Se NPs improved the physicomechanical and water resistance of G/CNF films. In this regard, the maximum tensile strength value was obtained for the G/CNF containing 5% w/w ZnO NPs (G/CNF/ZnO3) and G/CNF containing 0.1% w/w Se NPs (G/CNF/Se2) films (~2.20-fold and ~2.13-fold higher than the G/CNF film, respectively). Also, G/CNF with 3% w/w ZnO NPs (G/CNF/ZnO₂) film had the lowest water vapor permeability and water solubility among all films. Results of the disc diffusion assay showed a stronger antibacterial effect of ZnO NPs compared with Se NPs. The bacterial susceptibility to the antibacterial films was as follows: Listeria monocytogenes > Escherichia coli > Staphylococcus aureus > Pseudomonas fluorescens. The G/CNF films incorporated with Se nanoparticles possessed the higher property of scavenging free radicals in comparison films containing ZnO nanoparticles. Also, the combination of Se NPs and ZnO NPs enhanced the antioxidant effect of the films. In conclusion, gelatin-based edible films containing CNFs, ZnO NPs, and Se NPs can be used in the development of active food packaging products.

Carbon nanomaterials against pathogens; the antimicrobial activity of carbon nanotubes, graphene/graphene oxide, fullerenes, and their nanocomposites

Recently, antibiotic resistance of pathogens has grown given the excessive and inappropriate usage of common antimicrobial agents. Hence, producing novel antimicrobial compounds is a necessity. Carbon nanomaterials (CNMs) such as carbon nanotubes, graphene/graphene oxide, and fullerenes, as an emerging class of novel materials, can exhibit a considerable antimicrobial activity, especially in the nanocomposite forms suitable for different fields including biomedical and food applications. These nanomaterials have attracted a great deal of interest due to their broad efficiency and novel features. The most important factor affecting the antimicrobial activity of CNMs is their size. Smaller particles with a higher surface to volume ratio can easily attach onto the microbial cells and affect their cell membrane integrity, metabolic procedures, and structural components. As these unique characteristics are found in CNMs, a wide range of possibilities have raised in terms of antimicrobial applications. This study aims to cover the antimicrobial activities of CNMs (both as individual forms and in nanocomposites) and comprehensively explain their mechanisms of action. The results of this review will present a broad perspective, summarizes the most remarkable findings, and provides an outlook regarding the antimicrobial properties of CNMs and their potential applications.

Nanocomposite films consisting of functional nanoparticles (TiO2 and ZnO) embedded in 4A-Zeolite and mixed polymer matrices (gelatin and polyvinyl alcohol)

In this study, nanocomposite films with enhanced functional properties were prepared by loading titanium dioxide (TiO₂) and/or zinc oxide (ZnO) nanoparticles within 4A zeolite (4AZ) particles, and then incorporating these nanocomposites into a poly (vinyl alcohol) (PVA) and gelatin matrix. The composition and morphology of the films were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). The thermal behavior of the films was established using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). SEM showed the nanoparticles were dispersed throughout the films when used at these levels. FTIR indicated that the inorganic nanoparticles interacted with the PVA/gelatin polymer network through hydrogen bonding. XRD confirmed that the nanoparticles were in a crystalline state within the films. DSC and TGA showed that introduction of the nanoparticles modified the nanocomposite's thermal behavior. Nanoparticle addition had a number of effects: (i) it decreased film transparency from 78.7% to 69.4% 72.0% and 69.7%; (ii) it decreased film water vapor permeability (WVP) from 8.20 × 10^-9 to 5.13 × 10^-9, 5.71 × 10^-9 and 5.24 × 10^-9 g/Pa.h.m; (iii) it reduced film oxygen permeability from 4.57 to 3.29, 3.10 and 3.00 mEq/g; and (i) it increased film tensile strength (TS) from 14.6 to 22.0, 20.3 and 18.0 MPa, for PVA/gelatin films containing 0%, 1.5% ZnO, 1.5% TiO₂ and 1% (ZnO + TiO₂) nanoparticles, respectively (with the nanoparticles being trapped within 4AZ). Moreover, active nanocomposite films exhibited significant antimicrobial effects especially against gram-negative bacteria. Overall, our results show that nanoparticle-loaded PVA/gelatin nanocomposites may be useful as active biodegradable nanocomposite films for application in the packaging industry and that their properties can be modulated by controlling the nature and level of nanoparticles incorporated.

Nanomaterials in Dentistry: State of the Art and Future Challenges

Nanomaterials are commonly considered as those materials in which the shape and molecular composition at a nanometer scale can be controlled. Subsequently, they present extraordinary properties that are being useful for the development of new and improved applications in many fields, including medicine. In dentistry, several research efforts are being conducted, especially during the last decade, for the improvement of the properties of materials used in dentistry. The objective of the present article is to offer the audience a complete and comprehensive review of the main applications that have been developed in dentistry, by the use of these materials, during the last two decades. It was shown how these materials are improving the treatments in mainly all the important areas of dentistry, such as endodontics, periodontics, implants, tissue engineering and restorative dentistry. The scope of the present review is, subsequently, to revise the main applications regarding nano-shaped materials in dentistry, including nanorods, nanofibers, nanotubes, nanospheres/nanoparticles, and zeolites and other orders porous materials. The results of the bibliographic analysis show that the most explored nanomaterials in dentistry are graphene and carbon nanotubes, and their derivatives. A detailed analysis and a comparative study of their applications show that, although they are quite similar, graphene-based materials seem to be more promising for most of the applications of interest in dentistry. The bibliographic study also demonstrated the potential of zeolite-based materials, although the low number of studies on their applications shows that they have not been totally explored, as well as other porous nanomaterials that have found important applications in medicine, such as metal organic frameworks, have not been explored. Subsequently, it is expected that the research effort will concentrate on graphene and zeolite-based materials in the coming years. Thus, the present review paper presents a detailed bibliographic study, with more than 200 references, in order to briefly describe the main achievements that have been described in dentistry using nanomaterials, compare and analyze them in a critical way, with the aim of predicting the future challenges.

Kinetics Analysis and Susceptibility Coefficient of the Pathogenic Bacteria by Titanium Dioxide and Zinc Oxide Nanoparticles

Purpose: The increase of bacterial resistance to common antibacterial agents is one of the major problems of health care systems and hospital infection control programs. In this study, antimicrobial activity of titanium dioxide (TiO₂ ) and zinc oxide (ZnO) nanoparticles (NPs) was investigated against E. coli, Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus pathogenic bacteria by determining sensitivity coefficient and kinetics of bacterial death. Methods: Antimicrobial tests were performed with ~10⁶ CFU/mL of each bacterium at baseline. At first, minimum inhibitory concentration (MIC) was concluded by the dilution method and then, death kinetic and susceptibility coefficient of NPs suspensions was determined at 0 to 360 min. treatment time. Results: The results of this study revealed that, the highest susceptibility was observed for L. monocytogenes (Z=0.025 mL/μg) to TiO₂ NPs, whereas the lowest susceptibility was obtained in the reaction of ZnO NPs with S. enteritidis (Z=0.0033 mL/μg). The process of bacterial death in NPs suspension was assumed to follow first-degree kinetic and the survival ratio of bacteria decreased by the increase in treatment time. An increase in the concentration of NPs was seen to enhance the bactericidal action. Conclusion: Results showed that L. monocytogenes had higher sensitivity compared to S. enteritidis. The results of this study also demonstrated that TiO₂ NPs have a strong antimicrobial effect in comparison with ZnO NPs and it could be employed to aid the control of pathogenic bacteria.

Antimicrobial activity of Titanium dioxide and Zinc oxide nanoparticles supported in 4A zeolite and evaluation the morphological characteristic

In this study, the antimicrobial activity of titanium dioxide (TiO₂), zinc oxide (ZnO), and TiO₂/ZnO nanoparticles supported into 4A zeolite (4A z) was assessed. Based on antimicrobial experiments, minimum inhibitory concentration (MIC₉₀), minimum bactericidal concentration (MBC), fractional inhibitory concentration (FIC) and disc diffusion test were determined after 24 h of contact with the prepared nanocomposites. These results are in agreements with the results of disc diffusion test. During the experiments, the numbers of viable bacterial cells of Staphylococcus aureus, Pseudomonas fluorescens, Listeria monocytogenes and Escherichia coli O₁₅₇:H₇ decreased significantly. The crystallinity and morphology of nanoparticles were investigated by X-ray diffraction patterns (XRD), elemental mapping at the microstructural level by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), and transmission electron microscopy (TEM). As a result, it was demonstrated that TiO₂/ZnO nanoparticles supported in 4A zeolite could lead to an optimum activity as antimicrobial agents.