Concentrations Of AgNPs Research Articles

Highly transparent antibacterial hydrogel‐polymeric contact lenses doped with silver nanoparticles

AbstractBiocompatible polymers such as poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) are used to prepare hydrogels for biomedical applications, including optical applications such as the manufacture of sensing devices, cosmetic and smart, and medical contact lenses, among others. In this study, three contact lenses were prepared by doping PVP‐PVA supportive hydrogel with 0.1, 0.5, and 1 wt% of laboratory‐manufactured Ag NPs. The work demonstrates the evaluation of vision correction through each lens and the effect of changing the concentration of silver on its refractive index. The simulation involved the design and simulation of an aberrated human eye based on the Liou and Brennan model (LBM), and the insertion of the contact lenses for vision correction using the ZEMAX optical design program. This work also included a study of the antimicrobial properties of the resulting hydrogel contact lenses doped with Ag NPs. The resulting refractive index of one PVP‐PVA‐Ag lens was relatively high at 532 nm = 1.604, which made the lens provide the highest image contrast (the lowest MTF curve degradation) of 0.883 ± 0.027 at 20 cycles/mm and an RMS nearly the Airy disc diameter of 3.983 μm. PVA was used in combination with PVP for stabilizing Ag NPs to give the contact lenses an antibacterial property. Finally, the optimum contact lens with a 1 wt% Ag NPs concentration showed the highest inhibition activity.

Green preparation of electrically conductive solution blow spun nanofibers from recycled polyethylene terephthalate via plasma-assisted oxidation-reduction.

Simple and green strategy was described for the development of multifunctional polyester nanofibers (PNFs). Solution blow spinning (SBS) technology was applied to in situ immobilize nanocomposites of polyaniline (PANi) and silver nanoparticles (AgNPs) into plasma-treated polyester nanoscaled fibers prepared. The polyester nanofibers were prepared from recycled polyethylene terephthalate waste, which was exposed plasma-curing and a REDOX reaction in the presence of AgNO3, aniline, and CH3COONH4. Plasma-catalyzed oxidative polymerization of aniline to polyaniline together with a reductive process of Ag+ to silver nanoparticles led to their enduring insoluble dispersion into the surface of polyester nanofibers. By taking the advantage of the PANi oxidation, AgNPs were precipitated from an aqueous medium of AgNPs. The morphological properties were investigated by various analytical techniques. The polyester fiber diameter was determined in the range of 450-650nm. In addition, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were utilized to examine AgNPs, demonstrating diameters of 4-20nm. The plasma-uncured AgNPs/PANi immobilized nanofibrous film displayed weak absorption bands at 399nm and 403nm upon increasing the concentration of AgNPs. On the other hand, the plasma-cured AgNPs/PANi immobilized nanofibers displayed strong absorption bands at 526nm and 568nm upon increasing the concentration of AgNPs. The AgNP-induced antimicrobial performance and the PANi-induced electrically conductivity were explored. The prepared PNFs showed high UV protection.

Citrus limon phytocompounds decorated nanoparticles control poultry pathogens.

Antibiotic resistance poses a significant threat to the global health, food security, and environment. In poultry and livestock, antibiotics are beneficial since they improve poultry performance and are economically effective. Therefore, it is crucial to search for alternatives that can be environmentally safe and successful in treating these infections. In this study, we employed molecular docking to evaluate lemon peel phytochemical's protein binding capability against various poultry pathogens. The nanoparticles (LP AgNPs) obtained from the lemon peel were characterized and tested for their antibacterial activity against more poultry pathogens. LP AgNPs were characterized by using UV-Visible absorption spectra, which revealed an absorption peak at a wavelength of 420-440nm. The FT-IR analysis demonstrated that flavonoids and phenolic acids acted as capping, reducing, and stabilizing agents during the biosynthesis of AgNPs. EDAX showed a strong peak was observed at 3keV which revealed the absorption of metallic silver nanoparticles. The mean diameter was from 2 to 20nm through HRTEM. Zeta potential of the LP AgNps at - 17.2mV showed the high stability of the green synthesized AgNps. Maximum inhibitory concentrations of LP AgNps against the isolated poultry pathogens were 50μg/ml concentration. The toxicity tests were performed in the Vigna radiata seedlings and Artemia nauplii, which showed less toxic effects and eco-friendly nature of the LP AgNps. LP AgNps have the potential to treat antibiotic resistant poultry pathogens, thereby paving the way for the development of value-added novel products incorporated with nanoparticles for treating various infection caused by antibiotic-resistant poultry pathogens.

Biogenic synthesis, characterization and application of silver nanoparticles as biostimulator for growth and rebaudioside-A production in genetically stable stevia (Stevia rebaudiana Bert.) under in vitro conditions

In the present study, a simple, eco-friendly, biogenic protocol for synthesis of silver nanoparticles (AgNPs) using leaf extract of in vitro banana plantlets (Musa acuminata Colla cv. Grand Nain) was established. The synthesized AgNPs were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and fourier transform-infrared spectroscopy. Shoot tips of stevia (Stevia rebaudiana Bert.) were cultured on three forms of regeneration medium (Murashige and Skoog basal medium + 0.5 mg. L−1 6-benzyladenine) i.e. ‘semi-solid’, ‘liquid’, and ‘semi-solid followed by liquid’ supplemented with 100–400 µM of AgNPs to study the effect of different concentrations of AgNPs along with different forms of medium on plant growth and rebaudioside-A content in stevia under in vitro conditions. Among different concentrations, 400 µM AgNP showed the best growth response irrespective of different forms of medium. Nonetheless, the overall best growth response was recorded in ‘semi-solid followed by liquid’ medium. High performance liquid chromatography analysis of regenerants showed gradual incline in rebaudioside-A content with the increase in AgNP concentrations. Regenerants from medium containing 400 µM AgNPs produced the highest rebaudioside-A of 334.8 mg. g−1 dry weight (>2-fold) while control ones produced 154.3 mg. g−1 dry weight. Genetic fidelity of AgNP-treated and control regenerants was confirmed using 20 inter simple sequence repeats and start codon targeted primers. The present study can be useful for commercial-scale propagation of stevia ensuring higher fresh and dry biomass as well as ameliorated rebaudioside-A production.

Role of Ag nanoparticles embedded on optical, photoluminescence and elastic properties of samarium magnesium borotellurite glass system

This paper reports the effect of silver nanoparticle (Ag NPs) on the optical, photoluminescence and elastic properties of samarium magnesium borotellurite (TBMSm) glass system with nominal composition of (58-x) TeO2–30B2O3–10MgO-2Sm2O3-xAg NPs, where x = 0.0, 0.1, 0.3, 0.5, 1.0 and 2.0 mol% synthesized via melt quenching method. To achieve the goals, the glasses are analyzed using densitometer, X-Ray Diffraction, Transmission Electron Microscopy, UV–Visible Spectroscopy, Photoluminescence, CIE Chromaticity analysis and ultrasonic testing. The density is decreased from 4.162 to 4.310 g/cm3 with the incorporation of Ag NPs. The absence of a prominent peak in the XRD area demonstrated that the glasses were amorphous. TEM shows that the diameter size of Ag NPs is increasing from 40.94 nm to 367.70 nm with the rise of Ag NPs concentration. The indirect transitions have an optical band gap of 2.618–2.800 eV, while direct transitions have an optical band gap of 2.839–2.897 eV. The refractive index is ranging between 2.453 and 2.508 while the Urbach energy, ΔE, is in the range of 0.338–0.391 eV. Photoluminescence measurement shows the occurrence of four emission intensity at different wavelength, with the highest red emission intensity at 605 nm. The analysis of colour chromaticity indicated that the colour coordinates were situated in the red-orange region. When Ag NPs were incorporated into the glass sample, there was an inconsistent pattern observed in the values of the longitudinal, shear, Young's, and bulk moduli, which ranged from 59.17 to 70.84 GPa, 20.70–24.21 GPa, 50.97–60.02 GPa, and 31.57–41.77 GPa, respectively.

Blending Approach Preparation of PVA-g-PMA Films with Embedded "Green" Synthesized Silver Nanoparticles for Acetone Optical Detection.

The blending approach (also known as the ex-situ approach) was used for the deposition of thin composite films comprising poly(vinyl alcohol-graft-methyl acrylate) (PVA-g-PMA) and silver nanoparticles (AgNPs). Firstly, the copolymer aqueous dispersion was synthesized through the redox polymerization of methyl acrylate (MA) on poly(vinyl alcohol) (PVA) using ammonium cerium (IV) nitrate as the initiator. Then, AgNPs were synthesized through a "green" method using the water extract of lavender based on by-products of the essential oil industry, and then they were blended with the polymer. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to determine nanoparticle size, along with their stability over time in suspension, during the 30-day period. Thin films of the PVA-g-PMA copolymer, with different AgNP volume fractions varying between 0.008 and 0.260%, were deposited via the spin-coating method on Si substrates, and their optical properties were explored. UV-VIS-NIR spectroscopy and non-linear curve fitting were used for the determination of the refractive index, extinction coefficient, and thickness of the films, while photoluminescence measurements at room temperature were conducted for studying the emission of the films. The concentration dependence of film thickness was observed and showed that thickness increased linearly from 31 nm to 75 nm when the nanoparticles' weight content increased from 0.3 wt% to 2.3 wt%. The sensing properties toward acetone vapors were tested in a controlled atmosphere by measuring reflectance spectra before and during exposure to the analyte molecules in the same film spot; the swelling degree of films was calculated and compared to the corresponding undoped samples. It was shown that the concentration of AgNPs of 1.2 wt% in the films is optimal for the enhancement of the sensing response toward acetone. The influence of AgNPs on the films' properties was revealed and discussed.

Efficiency of silver nano particles in removing Escherichia coli ATCC 25922 from drinking water distribution pipes

Many types of pathogenic microorganisms can live and transmitted in water, causing serious health problems upon consumption. So, the current study aimed to design a water distribution system (WDS), parts of it (polyvinyl chloride pipes) were coated with the biologically prepared silver nanoparticles (AgNPs) (green method) using leaves extract of Azadirachta indica (Meliaceae), silver nanoparticles (AgNPs) characterized by UV–Vis spectrum, FTIR spectrum, XRD, FESEM and TEM, also PVC coated with AgNPs pipes were characterized by XRD and FESEM, These techniques demonstrated the successful formation of AgNPs and highly efficient attachment of these nanoparticles to the inner surface of the pipes. To eradicate the viability cells of E. coli ATCC 25922 a laboratory scale water distribution system was built to serve this study, two concentrations of AgNPs (125 and 250) ppm and six exposure times were applied (0.0, 2, 5, 10, 15, and 20) min. to assess the viability rate of water transmitted E. coli ATCC 25922 by pour plate method. The results showed that, the inhibition rate reached 100% at 125 ppm of AgNPs through the period of time15 and 20 min, while with the concentration 250 ppm the inhibition rate reached 100% during period of time10, 15 and 20 min with significant differences between concentrations and exposure time.

Impact of ecofriendly synthesized silver nanoparticles on yield parameters and molecular traits of pea (Pisum sativum L.)

L. cv Master B) plants were grown under normal conditions and regularly irrigated or sprayed, once a week, with 20, 40, 80, and 160 mg/L of ecofriendly prepared AgNPs solutions and tap water, as control, after two weeks from sowing until harvesting. Yield parameters (number of mature pods per plant, length of pods, and number of seeds per pod and weight of 100 seeds) were recorded for the first and second generations (M1 & M2). Seed protein SDS-PAGE (Sodium dodecyl sulphate-polyacrylamide gel electrophoresis) profiling of M2 seeds and ISSR (Inter-simple sequence repeats) profile of the M2 seedlings have been analyzed. The results showed that most yield parameters of M1 were increased but decreased in M2. The weight of 100 seeds which is the major indicator of yield productivity was enhanced in both generations. Seed protein profiling showed slight variations among the applied treatments as compared to the control. The concentration of 20 mg/L AgNPs solution showed more variations in the ISSR profile than other treatments. This study suggested that the genotoxic effect of AgNPs on parent pea plants (plants irrigated or sprayed) transmitted to the next generations and genetic variation can be induced using low concentration of AgNPs that may be useful in plant pre-breeding. However, further studies are recommended to fully understand the toxicity of AgNPs to plants.

Synthesis of Rumex hastatus-based silver nanoparticles induced the inhibition of human pathogenic bacterial strains

The development of antibiotic resistance in pathogenic bacterial strains has drawn attention to the quest for new natural antibacterial drugs. Therefore, in the present study, extracts of Rumex hastatus leaves were obtained in methanol and water, and R. hastatus-based silver nanoparticles (AgNPs) were synthesized. Structural and functional properties of synthesized silver nanoparticles were determined by UV–vis spectroscopy, XRD, FTIR and SEM. The synthesized AgNPs and crude extracts were tested to check their antibacterial potential against human pathogenic bacterial strains of Staphylococcus aureus, Staphylococcus haemoliticus, Bacillus cereus, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa in well diffusion and broth dilution methods. The present investigation has revealed for the first time that the broth dilution method was found more reproducible than that of the well diffusion method even at lower concentrations of AgNPs and crude extracts. UV– Vis spectroscopic analysis of AgNPs revealed a peak at 367 nm. XRD pattern showed a face-centered cubical to the spherical structure of AgNP crystals. FTIR analysis revealed that flavonoids and terpenoids are responsible for the reduction of AgNO3 to Ag+. SEM analysis determined the spherical structure and 51 nm average diameter of nanoparticles. The antibacterial activity of R. hastatus-based (AgNPs) was found to be significantly higher than aqueous plant extract and silver nitrate alone. Bacterial growth was inhibited by R. hastatus-based AgNPs in a dose-dependent manner. To our knowledge, silver nanoparticles (AgNPs) of R. hastatus were synthesized and characterized for the first time in this study and, based on the findings of current research work R. hastatus extract-based silver nanoparticles are suggested to be used as an antibacterial drug instead of synthetic drugs for the treatment of various human diseases/infections caused by the tested bacterial strains.

Consumption and activity decline in Northern Pike (Esox lucius) during and after silver nanoparticle addition to a lake

Silver nanoparticles (AgNPs) are antimicrobial additives in many consumer products with high potential for release into aquatic ecosystems. Though AgNPs have been shown to have negative impacts on fish in laboratory experiments, these effects are rarely observed at ecologically relevant concentrations or in situ in field settings. To evaluate ecosystem-level effects of this contaminant, AgNPs were added to a lake at the IISD Experimental Lakes Area (IISD-ELA) during 2014 and 2015. Mean total silver (TAg) concentrations in the water column were 4 µg L−1 during additions. The growth of Northern Pike (Esox lucius) declined, and their primary prey, Yellow Perch (Perca flavescens) became less abundant after AgNP exposure. Here, we used a combined contaminant-bioenergetics modeling approach to show that individual activity and both individual and population-level consumption of Northern Pike declined significantly in the lake dosed with AgNPs, which, combined with other evidence, suggests that observed declines in body size were likely a result of indirect effects (i.e., reduced prey availability). Further, we found the contaminant-bioenergetics approach was sensitive to modelled elimination rates of mercury, overestimating consumption and activity by 43% and 55%, respectively, when using the mercury elimination rate commonly used in these models versus field-derived estimates for this species. This study contributes to the growing evidence of potentially long-term negative impacts on fish from chronic exposure to environmentally relevant concentrations of AgNPs in a natural setting.

Molecular identification and antiprotozoal activity of silver nanoparticles on viability of Cryptosporidium parvum isolated from pigeons, pigeon fanciers and water

Cryptosporidium is a protozoan that causes acute gastroenteritis, abdominal pain, and diarrhea in many vertebrate species, including humans, animals and birds. A number of studies have reported the occurrence of Cryptosporidium in domestic pigeons. Thus, this study aimed to identify Cryptosporidium spp. in samples collected from domestic pigeons, pigeon fanciers, and drinking water, as well as to investigate the antiprotozoal activity of biosynthesized silver nanoparticles (AgNPs) on the viability of isolated Cryptosporidium parvum (C. parvum). Samples were collected from domestic pigeons (n = 150), pigeon fanciers (n = 50), and drinking water (n = 50) and examined for the presence of Cryptosporidium spp. using microscopic and molecular techniques. The antiprotozoal activity of AgNPs was then assessed both in vitro and in vivo. Cryptosporidium spp. was identified in 16.4% of all examined samples, with C. parvum identified in 5.6%. The highest frequency of isolation was from domestic pigeon, rather than from pigeon fanciers or drinking water. In domestic pigeons, there was a significant association between Cryptosporidium spp. positivity and pigeon's age, droppings consistency, housing, hygienic and heath conditions. However, Cryptosporidium spp. positivity was only significantly associated with pigeon fanciers' gender and heath condition. The viability of C. parvum oocysts was reduced using AgNPs at various concentrations and storage times in a descending manner. In an in vitro study, the highest reduction in C. parvum count was observed at the AgNPs concentration of 1000 µg/mL after a 24 h contact time, followed by the AgNPs concentration of 500 µg/mL after a 24 h contact time. However, after a 48 h contact time, a complete reduction was observed at both 1000 and 500 µg/mL concentrations. Overall, the count and viability of C. parvum decreased with increasing the AgNPs concentration and contact times in both the in vitro and in vivo studies. Furthermore, the C. parvum oocyst destruction was time-dependent and increased with increasing the contact time at various AgNPs concentrations.

Green tea silver nanoparticles improve physiological motor and cognitive function in BALB/c mice during inflammation

Information on the basic changes associated with green tea small molecules in acute inflammation is deficient. The purpose of the study was to characterize and establish the effects of green tea silver nanoparticles (AgNPs) following inflammation in BALB/c male mice. In this study, green tea silver nitrate nanoparticles were characterized and the extract were made up to constitute high (100%), medium (10%), and low (1%) concentrations for administration. Acute inflammation was induced in groups I–V of the experimental rodents by injecting 0.5 ml/kg of fresh egg albumin on the subplantar surface of the right hind paw and animals were monitored for 36 h. Group I–III were administered 100%, 10%, 1% green tea nanoparticles extract while group IV was given diclofenac. Group V was the positive control while group VI was the negative control that received the vehicle. Paw edema was measured at a 2 h interval for 3 days, while the pain was assessed by measuring the locomotion activity using the voluntary wheel running and the anxiety-like behavior. Hypersensitivity was measured through the temperature sensation experiment and a non-linear regression analysis was done. Here, synthesized green tea AgNPs registered an absorbance band at 460 nm, phytochemicals due to presence of organic functional groups of OCO of oxycarbons, of CC of a conjugate alkene, CO of a stretching bond of a secondary alcohol. The silver green tea nanoparticles were spherical, covered by a slimy layer, capped and stable. Green tea AgNPs significantly decreased temperature hypersensitivity in BALB/c male mice and this demonstrated their protective effects. Low concentrations of green tea nanoparticles inhibited edema thus mimicking effects of diclofenac, however, the percentage of inhibition was highest in medium and high silver-tea nanoparticles concentrations demonstration the importance of concentration in therapeutics. Anxiety was lowest in BALB/c male mice treated with high concentrations of silver green tea nanoparticles, and this led to increased locomotory activity in mice. Green tea AgNPs have strong anti-inflammatory effects at high concentrations. Concentrations of green tea AgNPs modulated basic sensory and motor behaviors in BALB/c male mice demonstrating their importance in complementary and integrative medical practice.

Can Differently Stabilized Silver Nanoparticles Modify Calcium Phosphate Precipitation?

Calcium phosphates (CaPs) composites with silver nanoparticles (AgNPs) attract attention as a possible alternative to conventional approaches to combating orthopedic implant-associated infections. Although precipitation of calcium phosphates at room temperatures was pointed out as an advantageous method for the preparation of various CaP-based biomaterials, to the best of our knowledge, no such study exists for the preparation of CaPs/AgNP composites. Motivated by this lack of data in this study we investigated the influence of AgNPs stabilized with citrate (cit-AgNPs), poly(vinylpyrrolidone) (PVP-AgNPs), and sodium bis(2-ethylhexyl) sulfosuccinate (AOT-AgNPs) in the concentration range 5-25 mg dm-3 on the precipitation of CaPs. The first solid phase to precipitate in the investigated precipitation system was amorphous calcium phosphate (ACP). The effect of AgNPs on ACP stability was significant only in the presence of the highest concentration of AOT-AgNPs. However, in all precipitation systems containing AgNPs, the morphology of ACP was affected, as gel-like precipitates formed in addition to the typical chain-like aggregates of spherical particles. The exact effect depended on the type of AgNPs. After 60 min of reaction time, a mixture of calcium-deficient hydroxyapatite (CaDHA) and a smaller amount of octacalcium phosphate (OCP) formed. PXRD and EPR data point out that the amount of formed OCP decreases with increasing AgNPs concentration. The obtained results showed that AgNPs can modify the precipitation of CaPs and that CaPs properties can be fine-tuned by the choice of stabilizing agent. Furthermore, it was shown that precipitation can be used as a simple and fast method for CaP/AgNPs composites preparation which is of special interest for biomaterials preparation.

Biogenic nanosilver bearing antimicrobial and antibiofilm activities and its potential for application in agriculture and industry.

Due to the increasing resistance of bacteria and fungi to antimicrobials, it is necessary to search for effective alternatives to prevent and treat pathogens causing diseases in humans, animals, and plants. In this context, the mycosynthesized silver nanoparticles (AgNPs) are considered as a potential tool to combat such pathogenic microorganisms. AgNPs were synthesized from Fusarium culmorum strain JTW1 and characterized by Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Nanoparticle Tracking Analysis (NTA), Dynamic Light Scattering (DLS) and Zeta potential measurement. The minimum inhibitory (MIC) and biocidal concentrations (MBC) were determined against 13 bacterial strains. Moreover, the combined effect of AgNPs with antibiotics (streptomycin, kanamycin, ampicillin, tetracycline) was also studied by determining the Fractional Inhibitory Concentration (FIC) index. The anti-biofilm activity was examined by crystal violet and fluorescein diacetate (FDA) assays. Furthermore, antifungal activity of AgNPs was evaluated against a panel of phytopathogenic fungi viz., Botrytis, Colletotrichum, Fusarium, Phoma, Sclerotinia, and an oomycete pathogen Phytophthora by agar well-diffusion and micro-broth dilution method to evaluate the minimal AgNPs concentrations that inhibit fungal spore germination. Fungi-mediated synthesis resulted in the formation of small (15.56 ± 9.22 nm), spherical and stable (zeta potential of - 38.43 mV) AgNPs with good crystallinity. The results of FTIR spectroscopy indicated the presence of various functional groups, namely hydroxyl, amino, and carboxyl ones, from the biomolecules on the surface of AgNPs. The AgNPs showed antimicrobial and antibiofilm formation activities against Gram-positive and Gram-negative bacteria. The values of MIC and MBC ranged between 16-64 and 32-512 μg mL-1, respectively. The enhanced effect of AgNPs in combination with antibiotics was confirmed against human pathogens. The highest synergistic effect (FIC = 0.0625) was demonstrated by the combination of AgNPs with streptomycin against two strains of Escherichia coli (ATCC 25922 and ATCC 8739), followed by Klebsiella pneumoniae and Pseudomonas aeruginosa (FIC = 0.125). Enhanced effects of AgNPs with ampicillin were also shown against Staphylococcus aureus ATCC 25923 (FIC = 0.125) and P. aeruginosa (FIC = 0.25), as well as kanamycin against S. aureus ATCC 6538 (FIC = 0.25). The crystal violet assay revealed that the lowest concentration of AgNPs (0.125 μg mL-1) reduced the development of biofilms of Listeria monocytogenes and Salmonella enterica, while the maximum resistance was shown by Salmonella infantis, its biofilm was reduced after exposure to a concentration of 512 μg mL-1. A high inhibitory effect on the activity of bacterial hydrolases was observed by the FDA assay. AgNPs at a concentration of 0.125 μg mL-1 reduced the hydrolytic activity of all biofilms formed by the tested pathogens, except E. coli ATCC 25922, P. aeruginosa, and Pectobacterium carotovorum (efficient concentration was 2-fold higher, at 0.25 μg mL-1), while the hydrolytic activity of E. coli ATCC 8739, Salmonella infantis and S. aureus ATCC 6538 was suppressed after treatment with AgNPs at concentrations of 0.5, 2 and 8 μg mL-1, respectively. Moreover, AgNPs inhibited fungal growth and spore germination of Botrytis cinerea, Phoma lingam, and Sclerotinia sclerotiorum. MIC and MFC values of AgNPs against spores of these fungal strains were determined at 64, 256, and 32 μg mL-1, and zones of growth inhibition were 4.93, 9.54, and 3.41 mm, respectively. Fusarium culmorum strain JTW1 was found to be an eco-friendly biological system for an easy, efficient and inexpensive synthesis of AgNPs. In our study, the mycosynthesised AgNPs demonstrated remarkable antimicrobial (antibacterial and antifungal) and antibiofilm activities against a wide range of human and plant pathogenic bacteria and fungi singly and in combination with antibiotics. These AgNPs could be applied in medicine, agriculture, and food industry to control such pathogens that cause numerous human diseases and crop losses. However, before using them extensive animal studies are required to evaluate the toxicity, if any.

Passion fruit peel pectin/chitosan based antibacterial films incorporated with biosynthesized silver nanoparticles for wound healing application

Antimicrobial pectin/chitosan composite films have potential as wound dressing and food packaging. However, almost biofilms were synthesized through chemical routes, causing eco-unfriendliness, and negative impacts on the environment and human health. Green synthesis of composite films incorporating with biosynthesized AgNPs is therefore necessary to enhance mechanical and antimicrobial activities. This study focused on the influence of biosynthesized AgNPs on characteristics of passion fruit peel pectin/chitosan (P/CH) biofilms. Characterization, mechanical, antimicrobial activities of P/CH/AgNPs biofilms were evaluated. Incorporating AgNPs into P/CH-based films significantly exerted apparent color and optical properties of biofilms. As AgNPs concentration increased, P/CH/AgNPs biofilms had higher water content (20.1%), better water vapor permeability (1.28 × 10–9 g/mm h Pa), but lower mechanical, water solubility (43.98%), swelling (630.29 ± 11.79%) indexes. P/CH/AgNPs biofilms exhibited outstanding antibacterial properties against S. aureus, B. cereus, P. aeruginosa, K. pneumonia. As expected, in vivo results consolidated the evidence of excellent wound closure (100%) of P/CH/AgNPs biofilms after 15 days. Our findings recommend P/CH/AgNPs antibacterial biofilms have promising biomedical applications.

In Vitro Acaricidal Activity of Silver Nanoparticles (AgNPs) against the Poultry Red Mite (Dermanyssus gallinae)

Dermanyssus gallinae (PRM) is the most common blood-sucking ectoparasite in laying hens and is resistant against numerous acaricides. Silver nanoparticles (AgNPs) represent an innovative solution against PRM. The current study aimed to assess the in vitro acaricidal activity of AgNPs against PRM and describe their potential mechanism of action. Nanoparticles were produced using a wet chemistry approach. Mites were collected using AviVet traps from 18 poultry farms in Greece. Contact toxicity bioassays were carried out for 24 h with negative controls, 20, 40, 60, or 80 ppm AgNPs. Analysis of variance was used to compare the mortality rates of PRM between the control and treatment groups, while LC50, LC90, and LC99 values were estimated using probit regression analysis for the total farms jointly and separately. Nanoparticles displayed strong acaricidal activity, and mortality rates were significantly different between groups and increased by AgNPs concentration. Overall mean LC50, LC90, and LC99 values were 26.5, 58.8, and 112.3 ppm, respectively. Scanning electron microscopy on mites treated with 80 ppm AgNPs revealed cracks in their exoskeleton and limb detachments, presumably resulting from the interaction between AgNPs and the mites' chitin. Future studies should focus on assessing AgNPs residues in chicken tissues before moving into field trials.

An Investigation of Antimicrobial Activity for Plant Pathogens by Green-Synthesized Silver Nanoparticles Using Azadirachta indica and Mangifera indica

Photo-microbes are well known to demolish rice and fruits, as farmers use chemical pesticides to overcome agricultural problems and economic damage. The use of pesticides in agriculture fails to protect crops in lower concentrations and increases the intake of chemicals that cause many human ailments. The sophisticated nanotechnology approach used in agriculture for antimicrobial activities offers several advantages for growth and improves nutrient absorption in plants. We report the green synthesis of silver nanoparticles (AgNPs) using Azadirachta indica (A. indica) and Mangifera indica (M. indica) tree leaf extract that contains antioxidants to treat numerous diseases. AgNPs tested against three plant pathogens, fungi Alternaria alternata (A. alternata), Sclerotium rolfsii (A. rolfsii), and bacteria Xanthomonas oryzae (X. oryzae), which leads to agricultural problems. The experiment was performed with different concentrations of AgNPs in μL/mL prepared using two other plants extract against fungi and bacteria during summer. The results expose the importance of plant extract in synthesizing silver nanoparticles (AgNPs) and their efficacy for microbes. A comparison among different concentrations of AgNPs (4 μL/mL, 6 μL/mL, and 10 μL/mL) was performed for two fungi (tomato disease) and bacteria (rice leaf blight disease). A-AgNPs (A. indica-AgNPs) demonstrate a greater zone of inhibition than M-AgNPs (M. indica-AgNPs), further highlighting the dependence of plants. Under in vitro conditions, the results of the antifungal activity showed zones of inhibition of 21 mm against A. alternata and 17 mm against A. rolfsii, while antibacterial activity against X. oryzae bacteria showed a 15 mm zone of inhibition at 10 mg/mL for A-AgNPs, and less for M-AgNPs. For AgNPs, the antifungal activity was characterized bya more significant area of inhibition than antibacterial activity was. The current study indicates that AgNPs with lower concentrations exhibitsuperior toxicity to microbes and may be able to manage diseases in rice and tomato, and increase plant growth.

Co-Application of Silver Nanoparticles and Symbiotic Fungus Piriformospora indica Improves Secondary Metabolite Production in Black Rice

In the current research, unique Nano-Embedded Fungus (NEF), made by the synergic association of silver nanoparticles (AgNPs) and endophytic fungus (Piriformospora indica), is studied, and the impact of NEF on black rice secondary metabolites is reported. AgNPs were synthesized by chemical reduction process using the temperature-dependent method and characterized for morphological and structural features through UV visible absorption spectroscopy, zeta potential, XRD, SEM-EDX, and FTIR spectroscopy. The NEF, prepared by optimizing the AgNPs concentration (300 ppm) in agar and broth media, showed better fungal biomass, colony diameter, spore count, and spore size than the control P. indica. Treatment with AgNPs, P. indica, and NEF resulted in growth enhancement in black rice. NEF and AgNPs stimulated the production of secondary metabolites in its leaves. The concentrations of chlorophyll, carotenoids, flavonoids, and terpenoids were increased in plants inoculated with P. indica and AgNPs. The findings of the study highlight the synergistic effect of AgNPs and the fungal symbionts in augmenting the secondary metabolites in leaves of black rice.

Physicochemical characteristics of Pangasius sp. skin-gelatin-based-edible film enriched with silver nanoparticles

Background: Edible films intended for food packaging have been produced from hydrocolloids, lipids, resins, and composites, including gelatin. Gelatin is known to have a good filming ability and has been suggested as an alternative to non-biodegradable plastics. Naturally active compounds incorporated into film packaging may not only protect the food product from oxidation and microbial contamination, but they may also alter the physicochemical properties of the film. Silver nanoparticles have been used in food packaging as active agents due to their antibacterial and antifungal properties. The addition may affect the characteristics of the packaging. Therefore, this study aims to determine the effect of the addition of silver nanoparticles on the physicochemical characteristics of edible film from Pangasius sp. skin gelatin Methods: Mangrove extract of Bruguiera gymnorrhiza was used to synthesize silver into nanoparticle size. In this study, silver nanoparticles (AgNPs) with different concentrations (0, 2, 4 and 8%) were added into gelatin-based edible film. The edible films produced were observed for their physicochemical characteristics, including thickness, tensile strength, elongation, water vapour transmission, moisture content, pH, and colour. Results: AgNPs affected the colour of the fish-gelatin-based edible film, as an increased concentration of AgNPs resulted in a darker film. Nevertheless, the addition of AgNPs showed no significant effect on the thickness (145–216 µm), tensile strength (14.58–19.72 MPa), elongation (21.86–54.19%), water vapour transmission (30. 91–42.55 g/m2/day), moisture content (9.57–11.16%) or pH (5.92–6.01) of the fish-gelatin-based edible film. Conclusions: The addition of AgNPs has no significant effect on gelatin-based edible film physicochemical properties except colour. Therefore, the incorporated edible film has the potential to be developed further.

Sustainable and energy-efficient photocatalytic degradation of textile dye assisted by ecofriendly synthesized silver nanoparticles

In this study, we have touched on two goals of sustainable development, namely, the provision of clean water and sanitation and clean energy at acceptable prices, hoping for good health for all ages. A green economical method was used to prepare silver nanoparticles from chitosan biopolymer. AgNPs were fully characterized using UV–Vis, FTIR, XRD, HR-TEM, and EDX analysis. Different concentrations (0.02–0.18 g/L) of the nanoparticles were integrated into a mixture of heterogeneous nano photocatalysts TiO2 and ZnO (1:1 weight ratio) under UV irradiation for the photocatalytic degradation of Acid Red 37 textile dye to obtain clean water. The kinetic description of the performed photocatalytic process was presented assuming a pseudo-first-order reaction. The data revealed that increasing the concentration of AgNPs in the catalytic mixture showed a high apparent rate constant (kapp) accompanied by an increase in the apparent quantum yield (%Qapp), followed by dye destruction after a very short time (t0.5 = 3 min). Since the photocatalytic degradation process consumes electrical energy, the electrical energy per order (EE/O) was calculated, showing a low value of 20 kWh/m3/order, using 0.18 g/L AgNPs, indicating that the elicited photocatalytic degradation method is a sustainable one for the mineralization of the targeted dye.