Investigation into the antibacterial activity of silver, zinc oxide and copper oxide nanoparticles against poultry-relevant isolates of Salmonella and Campylobacter

Campylobacter control strategies at postharvest level

Campylobacter is highly associated with poultry and frequently causes foodborne illness worldwide. Thus, effective control measures are necessary to reduce or prevent human infections. In this review, Campylobacter control methods applicable at postharvest level for poultry meat during production, storage, and preparation are discussed. Drying and temperature are discussed as general strategies. Traditional strategies such as steaming, freezing, sanitizing, organic acid treatment, and ultraviolet light treatment are also discussed. Recent advances in nanotechnology using antibacterial nanoparticles and natural antimicrobial agents from plants and food byproducts are also discussed. Although advances have been made and there are various methods for preventing Campylobacter contamination, it is still challenging to prevent Campylobacter contamination in raw poultry meats with current methods. In addition, some studies have shown that large strain-to-strain variation in susceptibility to these methods exists. Therefore, more effective methods or approaches need to be developed to substantially reduce human infections caused by Campylobacter.

Antimicrobial Activity of Green Synthesized Silver and Copper Oxide Nanoparticles against the Foodborne Pathogen Campylobacter jejuni

Campylobacter jejuni is a major cause of global foodborne illnesses. To develop alternative antimicrobial strategies against C. jejuni, this study designed and optimized the green synthesis of metallic nanoparticles (NPs) with intracellular components of the medicinal fungus Ganoderma sessile to provide the needed reducing and stabilizing agents. NPs were characterized by transmission electron microscopy and dynamic light scattering, and the quasi-spherical NPs had sizes of 2.9 ± 0.9 nm for the copper oxide NPs and 14.7 ± 0.6 nm for the silver NPs. Surface charge assessment revealed zeta potentials of -21.0 ± 6.5 mV and -24.4 ± 7.9 mV for the copper oxide and silver NPs, respectively. The growth inhibition of C. jejuni by the NPs occurred through attachment to the outer cell membrane and subsequent intracellular internalization and resulted in minimum inhibitory concentrations of the silver NPs at 6 µg/mL and copper oxide NPs at 10 µg/mL. On the other hand, a differential ROS production caused by silver and copper NPs was observed. In summary, this research presents the first demonstration of using green synthesis with the medicinal fungus G. sessile to produce metallic NPs that effectively inhibit C. jejuni growth, providing a sustainable and effective approach to the traditional use of antimicrobials.

Surface Modifications of Silver Nanoparticles with Chitosan, Polyethylene Glycol, Polyvinyl Alcohol, and Polyvinylpyrrolidone as Antibacterial Agents against Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica

In medicine, the occurrence of antibiotic resistance was becoming a critical concern. At the same time, traditional synthesis methods of antibacterial agents often lead to environmental pollution due to the use of toxic chemicals. To address these problems, this study applies the green synthesis method to create a novel composite using a polymer blend (M8) consisting of chitosan (CS), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and silver nanoparticles. The results show that the highest ratio of AgNO3:M8 was 0.15 g/60 mL, which resulted in a 100% conversion of Ag+ to Ag0 after 10 h of reaction at 80 °C. Hence, using M8, Ag nanoparticles (AgNPs) were synthesized at the average size of 42.48 ± 10.77 nm. The AgNPs' composite (M8Ag) was used to inhibit the growth of Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and Salmonella enterica (SAL). At 6.25% dilution of M8Ag, the growth of these mentioned bacteria was inhibited. At the same dilution percentage of M8Ag, PA was killed.

Contribution of nanotechnology to greater efficiency in animal nutrition and production

Feed costs present a major burden in animal production for human consumption, representing a key opportunity for cost reduction and profit improvement. Nanotechnology offers potential to increase productivity by creating higher-quality and safer products. The feed sector has benefited from the use of nanosystems to improve the stability and bioavailability of feed ingredients. The development of nanotechnology products for feed must consider the challenges raised by biological barriers as well as regulatory requirements. While some nanotechnology-based products are already commercially available for animal production, the exponential growth and application of these products requires further research ensuring their safety and the establishment of comprehensive legislative frameworks and regulatory guidelines. Thus, this article provides an overview of the current state of the art regarding nanotechnology solutions applied in feed, as well as the risks and opportunities aimed to help researchers and livestock producers.

Antimicrobial potential of linear low-density polyethylene food packaging with Ag nanoparticles in different carriers (Silica and Hydroxyapatite)

Silver nanoparticles incorporation into polymeric packaging aims to prevent microbiological contamination in food products, thus ensuring superior food safety and preservation. In this context, this study aimed to verify the antimicrobial efficacy of linear low-density polyethylene (LLDPE) films incorporated with silver nanoparticles (AgNPs) dispersed in silica (SiO2) and hydroxyapatite (HAP) carriers at different concentrations. AgNPs + carriers polymer films were characterized at 0.2, 0.4, and 0.6% concentrations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission gun-scanning electron microscope (FEG-SEM), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and migration in acidic and non-acidic simulants. Antimicrobial action was investigated on Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and the Penicillium expansum and Fusarium solani fungi with antimicrobial activity by direct contact test and bacterial imaging by scanning electron microscopy. AgNPs addition to the LLDPE matrix did not interfere with the films' chemical and thermal properties and presented no significant migration to the external medium. For antimicrobial action, silver nanoparticles showed, in most concentrations, an inhibition percentage higher than 90% on all microorganisms studied, regardless of the carrier. However, a greater inhibitory action on S. aureus and between carriers was found, making hydroxyapatite more effective. The results indicated that nanostructured films with AgNPs + hydroxyapatite showed more promising antimicrobial action on microorganisms than AgNPs + silica, making hydroxyapatite with silver nanoparticle potentially useful in food packaging, improving safety and maintaining quality.

Green Synthesis of ZnO and V-Doped ZnO Nanoparticles Using Vinca rosea Plant Leaf for Biomedical Applications

The present work focused on the synthesis of Vinca rosea leaf extract derived ZnO and vanadium-doped ZnO nanoparticles (V-ZnO NPs). The chemical composition, structural, and morphology of ZnO and vanadium-doped ZnO NPs were examined by FTIR, XRD, and SEM-EDX. The FTIR confirmed the presence of functional groups corresponding to ZnO and vanadium-doped ZnO NPs. SEM-EDX clearly indicated the morphology of synthesised NPs; the hexagonal crystal of NPs was confirmed from XRD. In addition, the cytotoxic effect of ZnO and V-ZnO NPs was estimated against the breast cancer (MCF-7) cell line. From the assay, Vinca rosea (V. rosea) capped ZnO NPs have shown improved cytotoxic activity than that of Vinca rosea capped V-ZnO NPs. ZnO and vanadium-doped ZnO NPs showed the strongest antibacterial activity against Enterococcus, Escherichia coli, Candida albicans, and Aspergillus niger. The α-amylase inhibition assays demonstrated antidiabetic activity of synthesised NPs. From the assay test, results obtained Vinca rosea capped ZnO nanoparticles prepared using the green approach showed high effective antioxidant, antidiabetic activity, and anticancer activity than vanadium-doped ZnO NPs.

Biodegradable nano-reinforced packaging with improved functionality to extend the freshness and longevity of Plums Oemleria cerasiformis

Food packaging reinforced with Zn-doped TiO2 nanoparticles with enhanced prerequisite film-forming and biodegradable traits was prepared to augment fresh food storage. Pure and tailored metal (Zinc, Copper, and Selenium) doped TiO2 nanoparticles were synthesized and analyzed through multiple characterization techniques (optical spectra, XRD patterns (X-Ray Diffraction), Dynamic Light Scattering, and Scanning Electron Microscopy). The synthesized nanoparticles were tested for their Minimum Inhibitory Concentrations, antimicrobial potential against common lethal food pathogens, and cytotoxicity. Compared to Cu- and Se-doped nanoparticles, Zn-doped TiO2 nanoparticles displayed the most potent antimicrobial activity with insignificant cytotoxicity and were incorporated into the food packaging materials. The developed nano-reinforced food packaging efficaciously augmented the freshness of plums (Oemleria cerasiformis) for 16 days (42 ± 2 °C). The physicomechanical characterization of the nano-reinforced packaging establishes its utility in food packaging applications. The developed biodegradable packaging undergoes complete decomposition within 12 days of storage in natural soil.

Antimicrobial and antibiofilm activity of silver nanoparticles against Salmonella Enteritidis

Salmonella enterica serotype Enteritidis is one of the main pathogens associated with foodborne illnesses worldwide. Biofilm formation plays a significant role in the persistence of pathogens in food production environments. Owing to an increase in antimicrobial resistance, there is a growing need to identify alternative methods to control pathogenic microorganisms in poultry environments. Thus, this study aimed to synthesize silver nanoparticles (AgNPs) and evaluate their antibiofilm activity against poultry-origin Salmonella Enteritidis in comparison to a chemical disinfectant. AgNPs were synthesized, characterized, and tested for their minimum inhibitory concentration, minimum bactericidal concentration, and antibiofilm activity against S. Enteritidis strains on polyethylene surfaces. The synthesized AgNPs, dispersed in a liquid medium, were spherical in shape with a mean diameter of 6.2 nm. AgNPs exhibited concentration-dependent bactericidal action. The bacterial reduction was significantly higher with AgNPs (3.91 log10 CFU [Formula: see text] cm-2) than that with sanitizer (2.57 log10 CFU ∙ cm-2). Regarding the time of contact, the bacterial count after a contact time of 30 min was significantly lower than that after 10 min. The AgNPs exhibited antimicrobial and antibiofilm activity for the removal of biofilms produced by S. Enteritidis, demonstrating its potential as an alternative antimicrobial agent. The bactericidal mechanisms of AgNPs are complex; hence, the risk of bacterial resistance is minimal, making nanoparticles a potential alternative for microbial control in the poultry chain.

Antimicrobial Agents Based on Metal Complexes: Present Situation and Future Prospects

The rise in antimicrobial resistance is a cause of serious concern since the ages. Therefore, a dire need to explore new antimicrobial entities that can combat against the increasing threat of antibiotic resistance is realized. Studies have shown that the activity of the strongest antibiotics has reduced drastically against many microbes such as microfungi and bacteria (Gram-positive and Gram-negative). A ray of hope, however, was witnessed in early 1940s with the development of new drug discovery and use of metal complexes as antibiotics. Many new metal-based drugs were developed from the metal complexes which are potentially active against a number of ailments such as cancer, malaria, and neurodegenerative diseases. Therefore, this review is an attempt to describe the present scenario and future development of metal complexes as antibiotics against wide array of microbes.

Direct Bactericidal Comparison of Metal Nanoparticles and Their Salts against S. aureus Culture by TEM and FT-IR Spectroscopy

We report the bactericidal effect of Ag and Cu NPs with different concentrations on methicillin-resistant S. aureus strain in comparison to the effect of AgNO₃ and CuCl₂ solutions, characterized by microbiological tests, TEM and Fourier-transform infrared spectroscopy. NPs were produced by nanosecond laser ablation in distilled water and characterized by scanning electron microscopy, UV-vis, energy dispersive X-ray, FT-IR spectroscopy, as well as X-ray diffraction, dynamic light scattering size and zeta-potential measurements. Microbiological tests showed antibacterial activity of NPs and metal ion-containing salts. Comparative FT-IR spectroscopy of bacteria, treated with metal NPs and salts, showed the broadening of amide I and II bands, a CH₂-related peak and its frequency decrease, indicating the increase of membrane fluidity. The main mechanisms of the antibacterial effect were proposed: Ag and Cu NPs release ions and ROS, which result in lipid peroxidation; AgNO₃ forms precipitates on the cell surface, which lead to the mechanical rupture of the membrane and subsequent possible penetration of the precipitates in the emerged damaged spots, complete destruction of the membrane and bacterial death; Cu ions from the CuCl₂ solution cause damage to phosphorus- and sulfur-containing biomolecules, which leads to disruption of intracellular biochemical processes. The theories were confirmed by FT-IR spectroscopy and TEM.

Antimicrobial photodynamic inactivation of wastewater microorganisms by halogenated indole derivative capped zinc oxide

Novel 5-bromoindole (5B)-capped zinc oxide (ZnO) nanoparticles (5BZN) were synthesized to improve the antibacterial, antibiofilm, and disinfection processes for the control of microorganisms in wastewater treatment. When exposed to 5BZN, the biofilm density and cell attachment were reduced dramatically, as measured by scanning electron microscopy (SEM). The 5BZN were also investigated for photodynamic treatment of multidrug-resistant (MDR) bacteria and toxicity. The combination of 5B and ZnO exhibited strong antibacterial and antibiofilm activities against MDR bacteria even at low doses (20 μg/mL). After 12.5 mW/cm² blue LED irradiation, the composite 5BZN showed superior photodynamic inactivation of two wastewater MDR, Enterobacter tabaci E2 and Klebsiella quasipneumoniae SC3, with cell densities reduced by 3.9 log CFU/mL and 4.7 log CFU/mL, respectively, after 120 min. The mechanism of bacterial inactivation was studied using a scavenging investigation, and H₂O₂ was identified mainly as the reactive species for bacterial inactivation. The 5BZN exhibited higher photodynamic inactivation towards the total coliform bacteria in wastewater effluents under a blue LED light intensity of 12.5 mW/cm² with almost complete inactivation of the coliform bacteria cells within 40 min. Furthermore, when 5BZN (100 mg/L) was added to the reactor, the level of tetracycline antibiotic degradation was increased by 63.6% after 120 min. The toxicity test, animal model nematode studies and seed germination assays, showed that 5BZN is harmless, highlighting its tremendous potential as a self-healing agent in large-scale photodynamic disinfection processes.

New formula of the green synthesised Au@Ag core@shell nanoparticles using propolis extract presented high antibacterial and anticancer activity

Antimicrobial alternatives such as nanoparticles are critically required to tackle bacterial infections, especially with the emerging threat of antibiotic resistance. Therefore, this study aimed to biosynthesize Au-Ag nanoparticles using propolis as a natural reducing agent and investigate their antibacterial activity against antibiotic-resistant Staphylococcus sciuri (S. sciuri), Pseudomonas aeruginosa (P. aeruginosa), and Salmonella enterica Typhimurium (S. enterica), besides demonstrating their anticancer activity in cancer cell lines. The biosynthesized Au@AgNPs were characterized using UV-Vis spectrophotometer, Transmission Electron Microscopy (TEM), Zeta potential, Dynamic Light Scattering (DLS), Fourier Transformation Infrared (FTIR), and Scanning Electron Microscopy (SEM). Moreover, the detection of antibacterial activity was assessed through disc diffusion, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), time-killing curve, and detection of cell membrane integrity via SEM. As a result, the UV-Vis spectrum revealed the formation of Au@AgNPs in a single peak between 533 and 555 nm. Furthermore, FTIR analysis confirmed nanoparticles' green synthesis due to the presence of carbon functional groups. The formulated Au@AgNPs showed antibacterial activity against both Gram-positive and Gram-negative bacteria. The MIC and the MBC of P. aeruginosa and S. sciuri were 31.25 µg/mL. However, nanoparticles were more effective on S. enterica with MIC of 7.5 µg/mL and MBC of 15.6 µg/mL. Furthermore, the time-killing curve of the three model bacteria with the treatment was effective at 50 µg/mL. Besides, SEM of the tested bacteria indicated unintegrated bacterial cell membranes and damage caused by Au@AgNPs. Regarding the anticancer activity, the results indicated that the biosynthesized Au@AgNPs have a cytotoxic effect on HEPG2 cell lines. In conclusion, this research revealed that the green synthesized Au@AgNPs could be effective antibacterial agents against S. sciuri, P. aeruginosa, and S. enterica and anticancer agents against HEPG2.

Latent Benefits and Toxicity Risks Transmission Chain of High Dietary Copper along the Livestock-Environment-Plant-Human Health Axis and Microbial Homeostasis: A Review

The extensive use of high-concentration copper (Cu) in feed additives, fertilizers, pesticides, and nanoparticles (NPs) inevitably causes significant pollution in the ecological environment. This type of chain pollution begins with animal husbandry: first, Cu accumulation in animals poisons them; second, high Cu enters the soil and water sources with the feces and urine to cause toxicity, which may further lead to crop and plant pollution; third, this process ultimately endangers human health through consumption of livestock products, aquatic foods, plants, and even drinking water. High Cu potentially alters the antibiotic resistance of soil and water sources and further aggravates human disease risks. Thus, it is necessary to formulate reasonable Cu emission regulations because the benefits of Cu for livestock and plants cannot be ignored. The present review evaluates the potential hazards and benefits of high Cu in livestock, the environment, the plant industry, and human health. We also discuss aspects related to bacterial and fungal resistance and homeostasis and perspectives on the application of Cu-NPs and microbial high-Cu removal technology to reduce the spread of toxicity risks to humans.

A Ternary Copper (II) Complex with 4-Fluorophenoxyacetic Acid Hydrazide in Combination with Antibiotics Exhibits Positive Synergistic Effect against Salmonella Typhimurium

Salmonella spp. continues to figure prominently in world epidemiological registries as one of the leading causes of bacterial foodborne disease. We characterised 43 Brazilian lineages of Salmonella Typhimurium (ST) strains, characterized drug resistance patterns, tested copper (II) complex as control options, and proposed effective antimicrobial measures. The minimum inhibitory concentration was evaluated for seven antimicrobials, isolated and combined with the copper (II) complex [Cu(4-FH)(phen)(ClO4)2] (4-FH = 4-fluorophenoxyacetic acid hydrazide and phen = 1,10-phenanthroline), known as DRI-12, in planktonic and sessile ST. In parallel, 42 resistance genes were screened (PCR/microarray). All strains were multidrug resistant (MDR). Resistance to carbapenems and polymyxins (86 and 88%, respectively) have drawn attention to the emergence of the problem in Brazil, and resistance is observed also to CIP and CFT (42 and 67%, respectively), the drugs of choice in treatment. Resistance to beta-lactams was associated with the genes blaTEM/blaCTX-M in 39% of the strains. Lower concentrations of DRI-12 (62.7 mg/L, or 100 μM) controlled planktonic and sessile ST in relation to AMP/SUL/TET and AMP/SUL/TET/COL, respectively. The synergistic effect provided by DRI-12 was significant for COL/CFT and COL/AMP in planktonic and sessile ST, respectively, and represents promising alternatives for the control of MDR ST.

Distinct response patterns of bacterial communities in Ag- and ZnO-rGO nanocomposite-amended silt loam soils

The widespread application of metal-based nanoparticle (MNPs)/reduced graphene oxide (rGO) composites inevitably leads to their release into soils. However, we lack a detailed understanding of the bacterial community response to MNPs-rGO exposure in farmland soils. Here, we conducted a soil microcosm experiment to analyze the potential impact of MNPs-rGO on bacterial communities in two field soils via high-throughput sequencing. The change in alpha diversity of bacterial communities was more susceptible to Ag-rGO and ZnO-rGO treatments than CuO-rGO. In both soils, MNPs-rGO significantly changed the bacterial community structure even at a low dose (1 mg kg^-1). The bacterial community structure was most strongly affected by Ag-rGO at 30 days, but the greatest changes occurred in ZnO-rGO at 60 days. The differences in soil properties could shape bacterial communities to MNPs-rGO exposure. Distance-based redundancy analysis and functional annotation of prokaryotic taxa showed that some bacterial species associated with nitrogen cycling were greatly influenced by Ag-rGO and ZnO-rGO exposure. In sum, Ag-rGO and ZnO-rGO may potentially affect bacterial communities and nitrogen turnover under long-term realistic field exposure. These findings present a perspective on the response of bacterial communities to MNPs-rGO and provide a fundamental basis for estimating the ecological behavior of MNPs-rGO.

LC-ESI-QTOF/MS characterization of antimicrobial compounds with their action mode extracted from vine tea (Ampelopsis grossedentata) leaves

Vine tea (Ampelopsis grossedentata) is a tea plant cultivated south of the Chinese Yangtze River. It has anti-inflammatory properties and is used to normalize blood circulation and detoxification. The leaves of vine tea are the most abundant source of flavonoids, such as dihydromyricetin and myricetin. However, as the main bioactive flavonoid in vine tea, dihydromyricetin was the main focus of previous research. This study aimed to explore the antibacterial activities of vine tea against selected foodborne pathogens. The antimicrobial activity of vine tea extract was evaluated by the agar well diffusion method. Cell membrane integrity and bactericidal kinetics, along with physical damage to the cell membrane, were also observed. The extract was analyzed using a high-performance liquid chromatography-diode array detector (HPLC-DAD), and the results were confirmed using a modified version of a previously published method that combined liquid chromatography and electrospray-ionized quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF/MS). Cell membrane integrity and bactericidal kinetics were determined by releasing intracellular material in suspension and monitoring it at 260 nm using an ultraviolet (UV) spectrophotometer. A scanning electron microscope (SEM) was used to detect morphological alterations and physical damage to the cell membrane. Six compounds were isolated successfully: (1) myricetin (C15H10O8), (2) myricetin 3-O-rhamnoside (C21H20O12), (3) 5,7,8,3,4-pentahydroxyisoflavone (C15H10O7), (4) dihydroquercetin (C15H12O7), (5) 6,8-dihydroxykaempferol (C15H10O8), and (6) ellagic acid glucoside (C20H16O13). Among these bioactive compounds, C15H10O7 was found to have vigorous antimicrobial activity against Bacillus cereus (AS11846) and Staphylococcus aureus (CMCCB26003). A dose-dependent bactericidal kinetics with a higher degree of absorbance at optical density 260 (OD260) was observed when the bacterial suspension was incubated with C15H10O7 for 8 h. Furthermore, a scanning electron microscope study revealed physical damage to the cell membrane. In addition, the action mode of C15H10O7 was on the cell wall of the target microorganism. Together, these results suggest that C15H10O7 has vigorous antimicrobial activity and can be used as a potent antimicrobial agent in the food processing industry.

Development and Characterization of Antimicrobial Textiles from Chitosan-Based Compounds: Possible Biomaterials Against SARS-CoV-2 Viruses

Novel antiviral cotton fabrics impregnated with different formulations based on Chitosan (CH), citric acid (CA), and Copper (Cu) were developed. CA was selected as a CH crosslinker agent and Cu salts as enhancers of the polymer antimicrobial activity. The characterization of the polymeric-inorganic formulations was assessed by using atomic absorption spectroscopy, X-ray diffraction, Fourier transform infrared and UV–Vis spectroscopy, as well as thermogravimetric analysis. The achieved data revealed that CuO nanoparticles were formed by means of chitosan and citric acid in the reaction media. The antiviral activity of CH-based formulations against bovine alphaherpesvirus and bovine betacoronavirus was analyzed. Cotton fabrics were impregnated with the selected formulations and the antiviral properties of such textiles were examined before and after 5 to 10 washing cycles. Herpes simplex virus type 1 was selected to analyze the antiviral activities of the functionalized cotton fabrics. The resulting impregnated textiles exhibited integrated properties of good adhesion without substantially modifying their appearance and antiviral efficacy (~ 100%), which enabling to serve as a scalable biocidal layer in protective equipment’s by providing contact killing against pathogens. Thus, the results revealed a viable contribution to the design of functional-active materials based on a natural polymer such as chitosan. This proposal may be considered as a potential tool to inhibit the propagation and dissemination of enveloped viruses, including SARS-CoV-2.

The cellulose fibers functionalized with star-like zinc oxide nanoparticles with boosted antibacterial performance for hygienic products

Bacterial infectious diseases are serious health problem which extends to economic and social complications. Moreover, bacterial antibiotic resistance, lack of suitable vaccine or emergence of new mutations is forcing the development of novel antimicrobial agents. The objective of this study is to synthesize and characterize star-like zinc oxide nanoparticles for the application of antibacterial activities in cellulose based hygiene products. ZnO NPs were in situ synthesized via precipitation method on the surface of cellulose fibers. Since bactericidal activity of nanoparticles in part depends on the concentration in the growth medium, various amount of ZnO was incorporated into cellulose matrix ranging from 1 to 3 wt%. Microscopic (TEM, SEM) and spectroscopic (FT-IR, XRD) methods were utilized to investigate the final products. The infrared absorption spectra analysis supported by theoretical finding that during the reaction, ZnO nanoparticles could be bonded with cellulose fibers via hydrogen bonding. The yield of functionalization was determined through thermogravimetric analysis. Collected data proved the successful functionalization of the cellulose fibers with nanoparticles. Static contact angle measurements were carried out showing absorptive character of as prepared fabrics. All the samples were tested for the antibacterial properties and the results were compared to the samples prepared from the pristine cellulose fibers. Moreover, mechanical tests were performed revealing that the addition of only 2 wt% of the nanofiller boosted tensile, tearing and bursting strength by a factor of 1.6, 1.4 and 2.2 in comparison to unfunctionalized paper sample, respectively. Fabricated fabric presenting high hydrophilicity and antibacterial properties have gained increased applications in fabric industry, including hygiene product industry and hence the result of this study would be a welcomed option.

Cytotoxicity and Genotoxicity of Copper oxide Nanoparticles in chickens

Copper oxide nanoparticles (CuO-NPs) are consciously used to control the growth of bacteria, fungi, and algae. Several studies documented the beneficial and hazardous effects of CuO-NPs on human cells and different experimental animals but there are not many studies that report the effect of CuO-NPs in poultry. Therefore, the present study was performed to investigate the dose-dependent effects of copper oxide nanoparticles on the growth performance, immune status, oxidant/antioxidant capacity, DNA status, and histological structures of most edible parts of broiler chickens (muscle, heart, liver, spleen, and kidneys). The experiment was carried out on 90 1-day-old broiler chicks (Cobb 500) which were divided into three experimental groups (n = 30) in three replicates (n = 10). Group 1 was kept as a control group and did not receive copper oxide nanoparticles. Groups 2 and 3 received CuO-NPs by oral gavage at dose 5 mg/kg and 15 mg/kg bwt respectively at 1, 7, 14, 21, 28, and 35 days of the life of the chickens. An increase in the amount of feed intake and weight was recorded every week, and finally, the food conversion ratio (FCR) was calculated. Our results showed dose-dependent increases in malondialdehyde levels, copper contents, DNA fragmentation percent, and microscopic scoring in different examined organs of CuO-NPs-receiving groups associated with a remarkable reduction in weight gain, food conversion ratio, catalase activity, and antibody titer of both New Castle and Avian Influenza viruses. Histopathological alterations were observed in both groups receiving CuO-NPs with some variations in its severity. Our study concluded that CuO-NPs are considered cytotoxic and we recommend not adding them to poultry feed.

Review of Nanofluids and Their Biomedical Applications

Numerous researchers have reported significant improvements in nanofluid (NF) heat transfer (HT), suspension stability, thermal conductivity (TC), and rheological and mass transfer properties. As a result, nanofluids (NFs) play an important role in a variety of applications, including the health and biomedical engineering industries. The majority of the nanofluids (NFs) literature focuses on analyzing and comprehending the behavior of nanofluid models as heating or cooling mechanisms in various fields. This article represents a comprehensive study on nanofluids (NFs). It involves commonly used nanoparticles (NPs), magnetic nanofluids (MNFs), thermal conductivity (TC) enhancement, heat transfer (HT) enhancement, nanofluids (NFs) synthesis methods, stability evaluation methods, stability enhancement, nanofluids (NFs) applications in the biomedical field, and their impact on health and the environment. Nanofluids (NFs) play vital role in biomedical applications. It can be implemented in drug delivery systems, hyperthermia, sterilization processes, bioimaging, lubrication of orthopedic implants, and micro-pumping systems for drugs and hormones.

Copper Nanoparticles as Growth Promoter, Antioxidant and Anti-Bacterial Agents in Poultry Nutrition: Prospects and Future Implications

Copper (Cu) is a vital trace mineral involved in many physiological functions of the body. In the poultry industry, copper sulfate is being used as a major source of Cu. Copper in the bulk form is less available in the body, and much of its amount excreted out with feces causing environmental pollution and economic loss. The application of nanotechnology offers promise to address these issues by making nanoparticles. Copper nanoparticles (Cu-NP) are relatively more bioavailable due to their small size and high surface to volume ratio. Although, there is limited research on the use of Cu-NP in the poultry industry. Some researchers have pointed out the importance of Cu-NP as an effective alternative of chemical, anti-bacterial agents, and growth promoters. The effect of Cu-NP depends on their size, dose rate and the synthesis method. Apart from there, high bioavailability Cu-NP exhibited positive effects on the immunity of the birds. However, some toxic effects of Cu-NP have also been reported. Further investigations are essentially required to provide mechanistic insights into the role of Cu-NP in the avian physiology and their toxicological properties. This review aims to highlight the potential effects of Cu-NP on growth, immune system, antioxidant status, nutrient digestibility, and feed conversion ratio in poultry. Moreover, we have also discussed the future implications of Cu-NP as a growth promoter and alternative anti-bacterial agents in the poultry industry.

Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2-4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.

Antibacterial Potential of Biosynthesized Zinc Oxide Nanoparticles against Poultry-Associated Foodborne Pathogens: An In Vitro Study

Simple Summary

The overuse of antibiotics in the poultry industry has led to the emergence of multidrug-resistant microorganisms. Thus, there is a need to find an alternative to conventional antibiotics. Recently, zinc oxide nanoparticles (ZnO NPs) have gained much attention due to their excellent antibacterial activity. In addition, ZnO NPs is an essential trace mineral in poultry diets. In this sense, incorporating ZnO NPs into poultry can promote growth and performance while serving as an alternative antibacterial agent to control diseases. Therefore, this study aimed to assess the in vitro antibacterial activity and antibacterial mechanisms of ZnO NPs against poultry-associated foodborne pathogens (Salmonella spp., Escherichia coli, and Staphylococcus aureus). The obtained findings demonstrated effective antibacterial actions against the tested microorganisms. The nanotechnology approach could represent a new tool for combating pathogens in the poultry industry.

Abstract

Since the emergence of multidrug-resistant bacteria in the poultry industry is currently a serious threat, there is an urgent need to develop a more efficient and alternative antibacterial substance. Zinc oxide nanoparticles (ZnO NPs) have exhibited antibacterial efficacy against a wide range of microorganisms. Although the in vitro antibacterial activity of ZnO NPs has been studied, little is known about the antibacterial mechanisms of ZnO NPs against poultry-associated foodborne pathogens. In the present study, ZnO NPs were successfully synthesized using Lactobacillus plantarum TA4, characterized, and their antibacterial potential against common avian pathogens (Salmonella spp., Escherichia coli, and Staphylococcus aureus) was investigated. Confirmation of ZnO NPs by UV-Visual spectroscopy showed an absorption band center at 360 nm. Morphologically, the synthesized ZnO NPs were oval with an average particle size of 29.7 nm. Based on the dissolution study of Zn²⁺, ZnO NPs released more ions than their bulk counterparts. Results from the agar well diffusion assay indicated that ZnO NPs effectively inhibited the growth of the three poultry-associated foodborne pathogens. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were assessed using various concentrations of ZnO NPs, which resulted in excellent antibacterial activity as compared to their bulkier counterparts. S. aureus was more susceptible to ZnO NPs compared to the other tested bacteria. Furthermore, the ZnO NPs demonstrated substantial biofilm inhibition and eradication. The formation of reactive oxygen species (ROS) and cellular material leakage was quantified to determine the underlying antibacterial mechanisms, whereas a scanning electron microscope (SEM) was used to examine the morphological changes of tested bacteria treated with ZnO NPs. The findings suggested that ROS-induced oxidative stress caused membrane damage and bacterial cell death. Overall, the results demonstrated that ZnO NPs could be developed as an alternative antibiotic in poultry production and revealed new possibilities in combating pathogenic microorganisms.

Effects of Silver Nanoparticles on Proliferation and Apoptosis in Granulosa Cells of Chicken Preovulatory Follicles: An In Vitro Study

The continuous development of poultry production related to the growing demand for eggs and chicken meat makes it necessary to use modern technologies. An answer to this demand may be the use of nanotechnology in poultry farming. One of the promising nanomaterials in this field are silver nanoparticles (AgNPs), which are used as disinfectants, reducing microbial pollution and the amounts of greenhouse gases released. This study aimed to evaluate the effect of AgNPs on the proliferation and apoptosis process in the granulosa cells of chicken preovulatory follicles. The in vitro culture experiment revealed that both 13 nm and 50 nm AgNPs inhibited the proliferation of the granulosa cells. However, a faster action was observed in 50 nm AgNPs than in 13 nm ones. A size-dependent effect of AgNP was also demonstrated for the caspase-3 activity. AgNPs 13 nm in size increased the caspase-3 activity in granulosa cells, while 50 nm AgNPs did not exert an effect, which may indicate the induction of distinct cell death pathways by AgNPs. In conclusion, our study reveals that AgNPs in vitro inhibit granulosa cell proliferation and stimulate their apoptosis. These results suggest that AgNPs may disrupt the final stage of preovulatory follicle maturation and ovulation.

The Study on Molecular Profile Changes of Pathogens via Zinc Nanocomposites Immobilization Approach

The most critical group of all includes multidrug resistant bacteria that pose a particular threat in hospitals, as they can cause severe and often deadly infections. Modern medicine still faces the difficult task of developing new agents for the effective control of bacterial-based diseases. The targeted administration of nanoparticles can enhance the efficiency of conventional pharmaceutical agents. However, the interpretation of interfaces' interactions between nanoparticles and biological systems still remains a challenge for researchers. In fact, the current research presents a strategy for using ZnO NPs immobilization with ampicillin and tetracycline. Firstly, the study provides the mechanism of the ampicillin and tetracycline binding on the surface of ZnO NPs. Secondly, it examines the effect of non-immobilized ZnO NPs, immobilized with ampicillin (ZnONPs/AMP) and tetracycline (ZnONPs/TET), on the cells' metabolism and morphology, based on the protein and lipid profiles. A sorption kinetics study showed that the antibiotics binding on the surface of ZnONPs depend on their structure. The efficiency of the process was definitely higher in the case of ampicillin. In addition, flow cytometry results showed that immobilized nanoparticles present a different mechanism of action. Moreover, according to the MALDI approach, the antibacterial activity mechanism of the investigated ZnO complexes is mainly based on the destruction of cell membrane integrity by lipids and proteins, which is necessary for proper cell function. Additionally, it was noticed that some of the identified changes indicate the activation of defense mechanisms by cells, leading to a decrease in the permeability of a cell's external barriers or the synthesis of repair proteins.

The interaction of Ag2O nanoparticles with Escherichia coli: inhibition-sterilization process

Silver-based antibacterial agents have obtained wide attention due to the fact that bacteria in the environment is ubiquitous, which has become one of the most difficult problems for human health. However, the antibacterial mechanism and process are still inconclusive. Here, Ag₂O nanoparticles (NPs) with uniform spherical morphology and small size (around 30 nm) were prepared. The as-prepared Ag₂O NPs induced high antibacterial activity (100% inhibition ratio) against E. coli. A two-step antibacterial process was proposed and confirmed, which divided into inhibition and sterilization steps. The optical density measurement, malondialdehyde concentration detection, morphologic imaging with electronic microscopy and Fourier transform infrared spectroscopic analysis unveiled the interaction of Ag₂O NPs with E. coli, which verified the inhibition–sterilization process we proposed.

Application of nanostructures as antimicrobials in the control of foodborne pathogen

Foodborne pathogens are the main cause of human foodborne diseases and pose a serious threat to food safety. The control of them has always been a significant issue in food industry. With good biocompatibility and stability, nanomaterials display excellent bactericidal properties against many kinds of bacteria. In this review, the generation and application of nanostructures as antibacterial in the control of foodborne pathogens was summarized. The antibacterial effects of photocatalytic and contact bacteriostatic nanomaterials agents were mainly introduced. The influence factors and mechanisms of nanomaterials on the inactivation of foodborne pathogens were displayed. The photocatalytic nanostructured bacteriostatic agents can produce reactive oxygen species (ROS) and lead to charge transfer, which result in damaging of cell wall and leakage of small molecules under light irradiation. In addition, metals and metal oxide nanoparticles can kill bacterial cells by releasing metal ions, forming ROS and electrostatic interaction with cell membrane. Besides, the synergistic action of nanoparticles with natural antibacterial agents can improve the stability of these agents and their bactericidal performance. These current researches provided a broader idea for the control of microorganisms in food.

Self-healing functionalization of sulfonated hafnium oxide and copper oxide nanocomposite for effective biocidal control of multidrug-resistant bacteria

The combination of copper and sulfonated hafnium oxide nanoparticles could be used as an alternative antimicrobial agent to combat multidrug resistant bacteria and membrane biofouling.

Microfiltration Membranes Modified with Composition of Titanium Oxide and Silver Oxide by Magnetron Sputtering

In this work, the authors present the possibility of modification of polymer membranes by TiO₂ + AgO coating created by the magnetron sputtering method. The two-component TiO₂ + AgO coating can improve and shape new functional properties such as bactericidal and photocatalytic properties. The influence of magnetron power changes on the structure of the membrane was investigated as well. The structure and elemental composition of TiO₂ + AgO coatings were analyzed using SEM and EDS technique. All deposited coatings caused a total inhibition of the growth of two investigated colonies of Escherichia coli and Bacillus subtilis on the surface. The photocatalytic properties for membranes covered with oxide coatings were tested under UV irradiation and visible light. The filtration result show that polymer membranes covered with two-component TiO₂ + AgO coatings have a permeate flux similar to the non-coated membranes.

The Bio-Synthesis of Three Metal Oxide Nanoparticles (ZnO, MnO2, and MgO) and Their Antibacterial Activity Against the Bacterial Leaf Blight Pathogen

Xanthomonas oryzae pv. oryzae (Xoo) is the most infectious pathogen of rice, which causes bacterial leaf blight (BLB) disease. However, the accumulation of chemical or antibiotic resistance of Xoo necessitate the development of its alternative control. In this study, we biologically synthesize three metal oxide nanoparticles (ZnO, MnO2, and MgO) using rhizophytic bacteria Paenibacillus polymyxa strain Sx3 as reducing agent. The biosynthesis of nanoparticles was confirmed and characterized by using UV-vis spectroscopy, XRD, FTIR, EDS, SEM, and TEM analysis. The UV Vis reflectance of the nanoparticle had peaks at 385, 230, and 230 nm with an average crystallite particle size 62.8, 18.8, and 10.9 nm for ZnO, MnO2, and MgO, respectively. Biogenic ZnO, MnO2, and MgO nanoparticles showed substantial significant inhibition effects against Xoo strain GZ 0006 at a concentration of 16.0 μg/ml, for which the antagonized area was 17, 13, and 13 mm and the biofilm formation was decreased by 74.5, 74.4, and 80.2%, respectively. Moreover, the underlining mechanism of nanoparticles was inferred to be in relation to the reactive oxygen species based on their antibacterial efficiency and the deformity in the cell wall phenomenon. Overall, an attractive and eco-friendly biogenic ZnO, MnO2, and MgO nanoparticles were successfully produced. Altogether, the results suggest that the nanoparticles had an excellent antibacterial efficacy against BLB disease in rice plants, together with the increase in growth parameter and rice biomass. In conclusion, the synthesized nanoparticles could serve as an alternative safe measure in combatting the antibiotic-resistant of Xoo.

Antimicrobial photodynamic activity of gallium-substituted haemoglobin on silver nanoparticles

Methicillin-resistant Staphylococcus aureus (MRSA), a major scourge in skin and soft-tissue infections, expresses surface-bound haemoprotein receptors that can be exploited for the targeted delivery of photosensitizers. We have developed a nanosized agent for targeted antimicrobial photodynamic therapy (aPDT), comprised of GaPpIX (a hemin analog with potent photosensitizer activity) encapsulated in haemoglobin (GaHb), mounted on 10 nm Ag nanoparticles (AgNPs). The average GaHb-AgNP contains 28 GaPpIX units stabilized by Hb αβ-dimer units. Eradication (>6-log reduction) of S. aureus and MRSA can be achieved by a 10-second exposure to 405 nm irradiation from a light-emitting diode (LED) array (140 mW cm-2), with GaHb-AgNP loadings as low as 5.6 μg mL-1 for S. aureus and 16.6 μg mL-1 for MRSA, corresponding to nanomolar levels of GaPpIX. This reduction in bacterial count is several orders of magnitude greater than that of GaHb or free GaPpIX on a per mole basis. The GaHb-AgNP platform is also effective against persister MRSA and intracellular MRSA, and can provide comparable levels of aPDT with a 15-minute irradiation by an inexpensive compact fluorescent lightbulb. Collateral phototoxicity to keratinocytes (HaCaT cells) is low at the GaHb-AgNP concentrations and fluences used for aPDT. GaHb adsorbed on 10 nm AgNPs is much more potent than that on 40 nm AgNPs or 10 nm AuNPs, indicating that both size and plasmon-resonant coupling are important factors for enhanced aPDT. Electron microscopy analysis reveals that GaHb-AgNPs are not readily internalized by S. aureus but remain attached to the bacterial cell wall, the likely target of photo-oxidative damage.

Antimicrobial activity of copper surfaces against biofilm formation by Salmonella Enteritidis and its potential application in the poultry industry

As a consequence of developing antimicrobial resistance to disinfectants, copper, which exhibits antimicrobial activity, has been studied as a possible alternative to the use of stainless steel surfaces. The aim was to evaluate the antimicrobial activity of copper surfaces in preventing biofilm formation by Salmonella Enteritidis and to determine their corrosive capacity. Strains of S. Enteritidis were incubated at 4 °C, 12 °C, and 25 °C with 1 cm² coupons of electrolytic copper (99.9% Cu), brass (70% Cu), copper coated with tin, and stainless steel (control). A planktonic cell-suspension assay was used, followed by serial dilutions and bacterial counts. The corrosion test was performed with two disinfectants: benzalkonium chloride and sodium hypochlorite (100, 200, and 400 ppm). There was a significant reduction in biofilm production (log₁₀ CFU cm^-2) on the copper (2.64 at 4 °C, 4.20 at 12 °C, 4.56 at 25 °C) and brass (2.79 at 4 °C, 3.49 at 12 °C, 4.55 at 25 °C) surfaces compared to the control (5.68 at 4 °C, 5.89 at 12 °C, 6.01 at 25 °C). The antimicrobial surfaces showed uniform corrosion similar to that of surfaces generally used. These results demonstrated the effectiveness of copper surfaces in reducing S. Enteritidis and suggest they can be used as a complementary antimicrobial to control for this pathogen.

Development and Characterization of Clay-Nanocomposites for Water Purification

In this work we propose a facile method of preparing cost-effective clay-metaloxide/metal (CuO/Ag and ZnO/Ag) composite pellets for an efficient water purification technique. Clay, with intrinsic antibacterial activity, served as a membrane support for different metaloxide/Ag nanoparticles (NPs) concentrations (2.5, 5 and 10 wt.%), as the active fillers. The effect of time (24 and 48 h) on the bactericidal activity of these pellets was also monitored. The clay-nanocomposite pellets were characterized using: X-ray diffraction, X-ray fluorescence, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible (UV-Vis) spectrophotometry and nitrogen desorption analysis. The antibacterial activity performance was tested using E. coli and S. aureus strains of ATCC25922 and ATCC25923, respectively, in two aqueous media (nutrient broth and nutrient-free) by the colony-forming unit method. The results showed that the clay-CuO/Ag composite with a bandgap (1.24 eV) exhibited overall best performance under all conditions and time factors of ~100% efficiency in nutrient-free medium for all concentrations and times and 20-40% efficiency in nutrient broth for 24 h. The clay-ZnO/Ag with a bandgap of 2.88 eV showed no bactericidal activity in both media, except for that with 10 wt.% ZnO/Ag which showed 100% efficiency in nutrient-free medium after 24 h. All the synthesized composites showed 100% bactericidal efficiency in nutrient free medium after 48 h. These results indicate that, the clay/metaloxide/Ag could serve as efficient water purification technique, with a potential for large-scale commercialization.

Synthesis of Ag@CuO nanohybrids and their photo-enhanced bactericidal effect through concerted Ag ion release and reactive oxygen species generation

Ag and CuO in the form of nanoparticles have been widely used in our daily life as antibacterial agents, through releasing Ag ions and generating reactive oxygen species (ROS). In this work, we demonstrate that by synthesizing Ag@CuO nanohybrids with core-shell configurations, their bactericidal activity can be synergistically enhanced compared to the respective constituents. Upon AM 1.5G light illumination for short durations, the measured minimum inhibitory concentrations of the Ag@CuO nanohybrids show a significant decrease against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacterial strains, requiring only 7% and 34% of those when conducted in the dark. The spread plate results demonstrate that with nanohybrid concentrations of 11.0 and 21.9 mg L^-1, at least 7 orders of magnitude decrease in Escherichia coli and Staphylococcus aureus colony forming units is achieved, when the Ag@CuO nanohybrids are exposed to light illumination for 10 min. The effect of illumination is found to induce Ag⁺ release and enhance ¹O₂ generation, which act concertedly to facilitate the remarkable photo-enhanced bactericidal effect.

Nano-particles of Trace Minerals in Poultry Nutrition: Potential Applications and Future Prospects

Nano-technology is an emerging technology with tremendous potential and diverse applications in human health, agriculture, and animal nutrition. It also offers potential advantages in supporting research in many areas of life sciences. Nano-technology has many vital biological applications as living systems depend on many nano-scale objects like proteins, DNA, and enzymes. Trace minerals are normally used in very minute quantity in animal nutrition but issues like lower bioavailability, antagonism, and higher excretion rates from body limit their efficiency. Nano-technology offers opportunity to mediate these issues as nano-particles possess different physical and chemical properties than other forms of minerals. Nano-particles possess higher physical activity and chemical neutrality. Bioavailability can be enhanced by increasing the surface area of respective minerals by making their nano-particles. Owing to potential advantages of nano-particles, interest in exploring their potential use and efficacy in animal production has increased significantly in this decade. Although limited literature is available regarding potential effects of nano-particles in poultry nutrition, still some convincing evidences have suggested the feeding of trace minerals (zinc, copper, silver, selenium, iron, chromium, and manganese) in the diets of broilers, layers, turkeys, quails, etc. Excellent antimicrobial activities of nano-particles of Ag, Cu, and Zn, against key poultry pathogens like Salmonella and Campylobacter, indicate their potential for effective use in poultry production. Recent studies have also demonstrated modulation of gut health by nano-particle through increasing abundance of beneficial microbes (Lactobacillus and Faecalibacterium) and production of short-chain fatty acids. This review aims to provide insights on absorption, metabolism, and distribution of nano-minerals in the body. Moreover, potential applications and various aspects of using nano-trace minerals in different poultry species with potential effects on performance and health of birds are discussed.

Comparing the Bacteriostatic Effects of Different Metal Nanoparticles Against Proteus vulgaris

For many years, researchers were looking for new antibacterial substances to deal with hospital infections and especially resistant infections. Nanoparticles attracted much attentions because of their very small size that increases the surface to capacity ratio and consequently increase chemical activity. In this study, the antibacterial effects of silver, copper oxide, nickel oxide, and titanium dioxide nanoparticles were studied on Proteus vulgaris, as a bacterium involved in the resistant hospital infections. The capability of nanoparticles to inhibit the growth of bacteria was assessed via 9 different methods including cylinder, disk, and well-diffusion, spot test, MBC, MIC, liquid inhibitory action test, diffusion, and assessing the effects of nanoparticles on a 24-h culture. Based on the results, copper oxide and silver nanoparticles had high antibacterial effects on P. vulgaris in both liquid and solid cultures, respectively. However, nickel oxide and titanium dioxide nanoparticles only had a weak effect on the inhibition of bacterial growth in the liquid culture. CuO and Ag NPs could release ions and consequently produce free radicals, disturb the equilibrium of electrons between electron donor groups and inactivate enzymes and DNA of the organisms. Moreover, they triggered holes in the bacterial membrane to disturb cellular ion equilibrium. So, they can be used to inhibit the growth of pathogens. Besides, further studies have shown that they could be used as a supplementary treatment and/or in combination with other drugs to cure infections caused by P. vulgaris.

Bio-Mediated Synthesis and Characterization of Zinc Phosphate Nanoparticles Using <i>Enterobacter aerogenes</i> Cells for Antibacterial and Anticorrosion Applications

BACKGROUND

The promising properties of Zinc Phosphate (ZnP) Nanoparticles (NPs) have made them come into prominence as one of the most favorable catalysts in various industries with ever- increasing applications. Among several proposed synthetic methods, biological methods have mostly been desired for their sheer person-environment compatibility in comparison with those of chemical and physical ones.

OBJECTIVE

Therefore, the synthesis of ZnP NPs via biological route was developed in this study.

METHOD

Herein proposed a facile, applicable procedure for ZnP NPs via biosynthesis route, which included precipitation of Zinc Nitrate (Zn(NO3)2.6H2O) and diammonium hydrogen phosphate ((NH4)2HPO4) in the presence of Enterobacter aerogenes as the synthetic intermediate. Investigation of the anti-corrosion behavior of the synthesized NPs was explored on carbon steel in the hydrochloric acid corrosive environment to provide deeper insight into their unique anti-corrosion properties. Additionally, their antibacterial activities were also examined against Escherichia coli, Staphylococcus aureus and Streptococcus mutans.

RESULTS

The results of X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and the Energy Dispersive X-Ray Spectroscopy (EDS) analyses confirmed the successful synthesis of ZnP NPs. Moreover, the examinations of both anti-corrosion and antibacterial properties, revealed that the synthesized NPs could be a promising anti-corrosion/antibacterial agent.

CONCLUSION

ZnP NPs with an average size of 30-35 nm were successfully synthesized via the simple, suitable biological method. Results implied that these particles could be used as a non-toxic, environmentally friendly, corrosion-resistant and antibacterial agent instead of toxic and uneco-friendly ones.

Growth, serum biochemical, and histopathological responses of broilers administered with silver nanoparticles as a drinking water disinfectant

The supplementation of 50 ppm dosed silver nanoparticles (AgNPs) as a disinfectant in broilers drinking water was investigated to examine their growth performance, blood serum biochemistry, and organ histology in the case group, compared to the control. The growth performance parameters, such as water intake, feed intake, and body weight were recorded 6 times, each in an interval of 7 days, over a period of 42 days. At the end of each 42 days, the blood and major organs of the 1 case boiler out of 75 and 1 control broiler out of 75 were collected in random. The procedure was repeated 3 sets one after another, each consisting 42 day intervening period. The liver enzyme, lipid profile, glucose level, organ histology, and concentration of AgNPs in liver, spleen, heart, and small intestine were determined. The obtained results show that the growth performance of the case broilers was significantly higher than the control section (p < 0.05). However, in all the three sets the changes in lipid profile, liver enzyme, and glucose level of the case broilers were not statistically significantly different compared to the control (p > 0.05). The histology of liver, kidney, heart, spleen, and small intestine of broilers has not shown any damages to the cells as compared to the control samples. In the case samples, the highest concentration of AgNPs was observed in the small intestine (5.44 µg/g) followed by liver (4.32 µg/g), kidney (3.94 µg/g), heart (3.82 µg/g), and spleen (3.49 µg/g). The present study concludes that the administering 50 ppm AgNPs of average 15 nm size in the poultry drinking water was found safe for consumption as well as for growth enhancing, due to better bird comfort.

Antibacterial and photocatalytic activities of 5-nitroindole capped bimetal nanoparticles against multidrug resistant bacteria

The emergence of antibiotic resistance to commercially- available antibiotics is becoming a major health crisis worldwide. Non-antibiotic strategies are needed to combat biofilm-associated infectious diseases caused by multidrug resistant (MDR) bacterial pathogens. In this study, MBR1 was isolated from a membrane bioreactor used in wastewater treatment plants, and the resistance profile was explored. 5-Nitroindole (5 N)-capped CuO/ZnO bimetal nanoparticles (5 NNP) were synthesized using a one pot method to improve the antibacterial and antibiofilm activities of 5 N against Gram-negative (Escherichia coli ATCC700376 and Pseudomonas aeruginosa PA01) and positive (Staphylococcus aureus ATCC6538) human pathogens. 5 NNP containing 1 mM of 5 N exhibited strong antibacterial and antibiofilm properties to most MDR bacteria. In addition, the photocatalytic activity of CuO/ZnO reduced bacterial cell growth by 1.8 log CFU/mL maximum when exposed to visible light. Scanning electron microscopy showed that 5 NNP reduced the cell density and biofilm attachment of MBR1 by >90% under static conditions. In addition to the antimicrobial and antibiofilm activities, 5 NNP inhibited the persister cell formation of MDR bacterial strains P. aeruginosa, MBR1, E. coli and S. aureus. Therefore, it is speculated that 5 NNP potentially inhibits biofilm and persister cells; hence, 5 NNP could be an alternative agent to combat MDR infectious diseases using a non-antibiotic therapeutic approach.

Synthesis, characterization, and comparison of antibacterial effects and elucidating the mechanism of ZnO, CuO and CuZnO nanoparticles supported on mesoporous silica SBA-3

Silanized iminodiacetic acid (GLYMO–IDA) modified mesoporous silica (G-SBA) was prepared following a co-condensation method. G-SBA/Cu²⁺, G–SBA/Zn²⁺ and G-SBA/Cu²⁺–Zn²⁺ were obtained through the impregnation method with coordination by GLYMO–IDA. SBA/CuO, SBA/ZnO, and SBA/CuZnO were generated after calcination of G-SBA/Cu²⁺, G-SBA/Zn²⁺ and G-SBA/Cu²⁺–Zn²⁺. After modification, the amount of metal ion was 6 to 70 times higher than that of the blank mesoporous silica. The diameter of nano-copper oxide particles in mesoporous silica was 4.8 nm. The bacteriostatic rates of SBA/CuO at a copper oxide concentration of 250 ppm against E. coli and S. aureus were 85.87% and 100%, respectively. SBA/CuO and SBA/CuZnO with {111} lattice planes exhibited better antibacterial effects compared to the commercial-grade nano-zinc oxide and nano-copper oxide. When exposed to ultraviolet light, SBA/CuZnO displayed the highest photocatalytic activity and optimal antimicrobial effect. Therefore, SBA/CuZnO can be an alternative to antibiotics because of its non-toxic nature and good antibacterial properties.

Silanized iminodiacetic acid (GLYMO–IDA) modified mesoporous silica (G-SBA) was prepared following a co-condensation method.