Fabrication Of Silver Nanoparticles Research Articles

Mechanistic Investigation on the Antibacterial Activity of Biogenic Silver Nanoparticles Prepared Using Root Extract of Sarsaparilla and Demonstrated their In Vivo Efficacy in Zebrafish Model.

Antibiotic success rates are decreasing as drug-resistant bacteria become more prevalent, prompting the development of new therapeutic drugs. Herein, we demonstrated the antimicrobial activity of sarsaparilla root extract fabricated silver nanoparticles (sAgNPs). The UV-Visible spectra revealed that the surface Plasmon resonance maxima of sAgNPs were at 415nm. Transmission electron microscopy confirms that the particles are spherical with size of 12-35nm. The minimum inhibitory concentration (MIC) of sAgNPs against Escherichia coli, uropathogenic Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus was 62.5, 62.5, 62.5, 62.5, 125 and 125µM, respectively. At 1X MIC, sAgNPs induces excess reactive oxygen species (ROS) production and disturbs the bacteria membrane intergity, causing cytoplamic membrane depolarization. Interestingly, antibacterial activity of sAgNPs was considerably reduced in the presence of an antioxidant, N-acetyl cysteine, suggesting that ROS-induced membrane damage is a plausible cause of cell death. In contrast to many studies that only report the in vitro activity of NPs, we determined the in vivo antibacterial efficacy using the zebrafish model. It was found that sAgNPs protect fish from infection by inhibiting bacterial growth and eliminating them from the fish. In addition, the catalytic potential of sAgNPs for wastewater decontamination was demonstrated by degrading organic pollutants such as methyl orange, congo red, reactive black, and acid blue. The pollutants degraded in less than 10min, and the reaction follows pseudo-first-order kinetics. As a proof of concept, the catalytic potential of sAgNPs in degrading mixed dyes to satisfy industrial wastewater treatment needs was established. In summary, sAgNPs have the potential to act as nanocatalysts and nano-drugs, addressing key challenges in medical and environmental research.

Myco-fabricated silver nanoparticle by novel soil fungi from Saudi Arabian desert and antimicrobial mechanism

Biological agents are getting a noticeable concern as efficient eco-friendly method for nanoparticle fabrication, from which fungi considered promising agents in this field. In the current study, two fungal species (Embellisia spp. and Gymnoascus spp.) were isolated from the desert soil in Saudi Arabia and identified using 18S rRNA gene sequencing then used as bio-mediator for the fabrication of silver nanoparticles (AgNPs). Myco-synthesized AgNPs were characterized using UV–visible spectrometry, transmission electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering techniques. Their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae were investigated. In atrial to detect their possible antibacterial mechanism, Sodium dodecyl sulfate (SDS-PAGE) and TEM analysis were performed for Klebsiella pneumoniae treated by the myco-synthesized AgNPs. Detected properties of the fabricated materials indicated the ability of both tested fungal strains in successful fabrication of AgNPs having same range of mean size diameters and varied PDI. The efficiency of Embellisia spp. in providing AgNPs with higher antibacterial activity compared to Gymnoascus spp. was reported however, both indicated antibacterial efficacy. Variations in the protein profile of K. pneumoniae after treatments and ultrastructural changes were observed. Current outcomes suggested applying of fungi as direct, simple and sustainable approach in providing efficient AgNPs.

Fabrication of silver nanoparticles synthesize using Lantana camara leaves extract on biofilm of sodium alginate

Silver nanoparticles (AgNPs) belong to the class of noble metal nanoparticles widely utilized across various sectors including biomedical applications, cosmetics, and everyday products like soaps, toothpaste, and detergents, thereby bringing individuals into direct contact with them. Extensive research has explored the antifungal properties of silver and silver nitrate. In this study, the synthesis of AgNPs was achieved effectively using a leaf extract from Lantana camara. Characterization of the synthesized AgNPs was performed employing transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Analysis via UV–vis spectroscopy, SEM and TEM proved reliable and sufficient, with the appearance of AgNPs resulting in a noticeable change in tonal form. SPR peaks for AgNPs were observed at 467–473 nm using UV–Vis spectroscopy, while FTIR studies delineated the stabilizing and peak properties of the AgNPs. Size of the synthesized silver nanoparticles increased with higher concentrations of AgNO3 solution, albeit averaging on the smaller side of the nanometer scale. Synthesized AgNPs have effective antibacterial properties of nanoparticles, their incorporation into food packaging materials could enhance food storage lifespan and ensure consumer safety. The burgeoning interest in developing biodegradable coatings, as alternatives to costly wax-based coatings lacking biodegradability, is on the rise. These coatings aim to preserve the qualities of harvested crops. These are flexible films derived from biological compounds like proteins and polysaccharides, act as barriers against external elements and exhibit bioflexibility. They hold potential applications in medicine, pharmacology, and the food industry. The integration of polysaccharides, proteins, and lipids to enhance the functionality of films represents a recent advancement in the manufacturing of biodegradable and biofilm-based films. The anticipated outcome of this study is to augment the beneficial properties of Lantana camara for the preparation of nanoparticles using its extract, thereby highlighting its biological activity against emerging pathogenic biofilm-forming species.

An Exploration of Chrysin Fabricated Silver Nanoparticles as Antibiofilm Agent against Pseudomonas aeruginosa

An Exploration of Chrysin Fabricated Silver Nanoparticles as Antibiofilm Agent against Pseudomonas aeruginosa

The potential toxicity of chemically fabricated silver nanomaterials based on accumulation and histological changes in fish (Cyprinus carpio).

The bio-reductive fabrication of nanomaterials is a developing arena of study that seeks to fabricate nanoparticles (NPs) using microorganisms, plants, and animal blood. However, the chemical approach of AgNPs fulfills the need of abundant need of NPs. In contrast, chemically fabricated AgNPs are more toxic than biological AgNPs. Therefore, the current study aimed to assess and evaluate the chemically fabricated silver nanoparticles (AgNPs) for their possible toxicity in Common carp fish (Cyprinus carpio). The chemically synthesized silver nanoparticles were purchased from the market and applied for their possible toxicity. The chemically fabricated AgNPs were used against the Cyprinus carpio for bioaccumulation in different organs and histological alterations in the intestine and muscles. The results revealed that the AgNPs were mostly accumulated in the intestines followed by the gills, liver, and muscles (p < .05). The accumulated AgNPs caused histological alterations in gills and intestines at the highest concentration (0.08 mg/L). However, no alterations were observed by the middle and lowest concentration of AgNPs, particularly, in the intestine. In conclusion, more extensive research is required to establish the hazards related to the use of nanoparticles to disclose their negative effects on fish and the aquatic environment. REASEARCH HIGHLIGHTS: The chemical method fabricates a large amount of AgNPs Additionally, considered more toxic than the bio-reductive method AgNPs have excellent and diverse applications AgNPs deposited in various organs and cause histological changes.

Design and Fabrication of Silver Nanoparticles Doped β-cyclodextrin-chitosan Functionalized Graphene Nanocomposite Modified Electrode for Determination of Cu(II)

Introduction: In this study, a nanocomposite film was prepared by doping silver nanoparticles onto β-cyclodextrin-chitosan functionalized Reduced Graphene Oxide (RGO), denoted as Ag/ β-CD/CS/G nanocomposite. The average diameter of the Ag NPs was found to be 62±17 nm. Methods: The fabricated composite was applied to monitor trace levels of copper ions in different industrial and environmental water samples. The morphology and microstructure of the fabricated sensor were extensively investigated using different techniques, including XRD, TGA, HR-TEM, FTIR, SEM, XPS, and EDX physicochemical techniques. For the electrochemical monitoring of Cu(II), the Ag/β-CD/CS/G nanocomposite electrode showed remarkable performance in terms of high sensitivity and a low limit of detection that was found to be 0.24 nmol L-1. Results: The developed sensors showed a linear dynamic range from 10-3 to 10-8 mol L-1 with an R2 of 0.99. The impacts of different electrochemical parameters, including medium pH, scanning rate, and interfering ions, were investigated. Conclusion: Furthermore, the fabricated modified electrode showed high efficiency for Cu(II) detection in groundwater samples.

Silver nanoparticles reinforced on silk fibroin/carboxymethylcellulose composite films for electrical applications

This study proposes the fabrication of silver nanoparticles (AgNPs) on silk fibroin-carboxymethylcellulose (SF-CMC) composite films for advancement in electronic device applications. Bombyx mori silk fibroin is a biopolymer that is used as a bio-template in the fabrication of AgNPs. Various silver nitrate (AgNO3) combinations are added to the prepared SF solution to synthesize AgNPs. To develop stand-alone biopolymer-nanocomposite (SF-CMC/AgNPs) films, SF-AgNPs colloidal solution is blended with CMC solution. Ultra Violet – Visible (UV–Vis), Photoluminescence (PL), Fourier Transform Infra-red Spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) have been employed to the prepared SF-CMC/AgNPs composites toevaluate the physical, chemical, structural, morphological, and topographical information of the composite films. Furthermore, the composites are subjected to LCR Hi-tester and electrochemical workstation CH instrument to analyze the AC, DC conductivity, dielectric characteristics, and electrochemical impedance analysis of SF-CMC/AgNPs composites. The UV–visible spectra reveals the formed nanoparticles in spherical shape with average particle size 35–40 nm. XRD reveals the formed AgNPs in face centred cubic (FCC) structure; TEM reveals the average particle size of 35 nm. AC conductivity of the SF-CMC/AgNPs composite found to be 4.0 × 10−4 to 8.04 × 10−4 S/cm. In spite of the presence of AgNPs, measurements of the dielectric behaviourof pure CMC and SF-CMC materials exhibit good dielectric performance. The obtained results demonstrated that the SF-CMCfilms exhibit significant conductivity following AgNPs incorporation and may therefore be used in biosensor and wearable electronic device applications.

Potential of a deep eutectic solvent in silver nanoparticle fabrication for antibiotic residue detection.

Deep eutectic solvents (DESs) have recently emerged as an alternative solvent for nanoparticle synthesis. There have been numerous advancements in the fabrication of silver nanoparticles (Ag NPs), but the potential of DESs in Ag NP synthesis was neither considered nor studied carefully. In this study, we present a novel strategy to fabricate Ag NPs in a DES (Ag NPs-DES). The DES composed of ᴅ-glucose, urea, and glycerol does not contain any anions to precipitate with Ag+ cations. Our Ag NPs-DES sample is used in a surface-enhanced Raman scattering (SERS) sensor. The two analytes for SERS quantitation are nitrofurantoin (NFT) and sulfadiazine (SDZ) whose residues can be traced down to 10-8 M. The highest enhancement factors (EFs) are competitive at 6.29 × 107 and 1.69 × 107 for NFT and SDZ, respectively. Besides, the linearity coefficients are extremely close to 1 in the range of 10-8 to 10-3 M of concentration, and the SERS substrate shows remarkable uniformity along with great selectivity. This powerful SERS performance indicates that DESs have tremendous potential in the synthesis of nanomaterials for biosensor substrate construction.

Green synthesis approach: Utilizing chrysanthemum extract as reducing and stabilizing agent for the fabrication of silver nanoparticles and their antimicrobial properties study

This research explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using Chrysanthemum extract, emphasizing its application in antimicrobial treatments. The study primarily focused on assessing the effect of extract concentration on nanoparticle characteristics. The synthesized AgNPs, at higher Chrysanthemum extract concentrations (up to 15%), exhibited a notable decrease in size, from 48.5 nm at 2% to 22.1 nm, and an increase in yield, achieving 2.24 mg/mL. The AgNPs showed a significant antibacterial effect, with the lowest IC50 value of 2.08 µg/mL against Vibrio cholerae, demonstrating a broad-spectrum efficacy. Advanced characterization techniques like SEM and FTIR spectroscopy confirmed the morphological integrity and phytochemical capping of the nanoparticles. The study successfully highlights the potential of Chrysanthemum extract not only as a sustainable source for nanoparticle synthesis but also in enhancing the biocompatibility and efficacy of AgNPs, paving the way for their application in medical and environmental fields.

Fabrication of silver nanoparticles decorated on sodium alginate microbeads enriched with keratin and investigation of its catalytic and antioxidant activity

In this study, an environmentally friendly, effective, easily synthesizable and recoverable nano-sized catalyst system (Ag@NaAlg-keratin) was designed by decorating Ag nanoparticles on microbeads containing sodium alginate (NaAlg) and keratin obtained from goose feathers. The structure, morphology and crystallinity of the Ag@NaAlg-keratin nanocatalyst were evaluated by XRD, FT-IR, FE-SEM, EDS/EDS mapping and TEM analyses. Catalytic ability of designed Ag@NaAlg-keratin nanocatalyst was then investigated against 4-nitrophenol (4-NP) and methyl orange (MO) reductions. Ag@NaAlg-keratin nanocatalyst effectively reduced 4-NP in 6 min and MO in 5 min, with rate constants of 0.17 min−1 and 0.16 min−1, respectively. Additionally, activation energies (Ea) were found as 39.8 kJ/mol for 4-NP and 37.9 kJ/mol for MO. Performed recyclability tests showed that the Ag@NaAlg-keratin nanocatalyst was easily recovered due to its microbead form and successfully reused five times, maintaining both its activity and structure. Furthermore, antioxidant activity of Ag@NaAlg-keratin nanocatalyst was the highest (73.16 %).

Synthesis, Characterization and Application of Biogenic Silver Nanoparticles as Antibacterial and Antifungal Agents

In order to provide a straightforward, affordable, and environmentally friendly process for the synthesis of metallic nanoparticles, scientists are turning to natural ways like employing plant extract in response to rising antimicrobial resistance and the desire for novel biocidal agents. In this study, we evaluated the efficacy of phyto-fabricated silver nanoparticles and antimicrobial agents against selected indoor bacterial and fungal strains isolated from the lecture and office rooms of Chukwuemeka Odimegwu Ojukwu University, Uli Nigeria. The indoor microorganisms were isolated, identified, and quantified using standard methods. To prepare and generate the aqueous extract employed in the biological synthesis of the silver nanoparticle, fresh soursop seeds were room dried, crushed, heated to boiling, and double filtered. The phyto-fabricated nanoparticles were centrifuged, dried and used for physicochemical characterization and antimicrobial assay. The synthesized silver nanoparticles were characterized using UV-Vis spectrophotometry, Fourier transformed Infra-Red Spectroscopy and scanning electron microscopy analyses. The antimicrobial assay was carried out using agar well diffusion method. The results revealed that Aeromonas, Pseudomonas, Staphylococcus, Vibrio, Rhizopus, Aspergillus, Penicillium and Microsporum were identified as the predominant potential indoor bacterial and fungal pathogenic strains. The characterized biogenic nanoparticles revealed the optical, spectral and morphological features unique to silver nanoparticles. Also, the antibacterial screening revealed that the highest zone of inhibition was observed against Vibrio sp. (27.50 ± 7.5 mm) at a concentration of 30 μg/mL while standard antifungal drug (ketoconazole) had the highest zone of inhibition of 21.0 ± 1.0 mm at 3.25 μg/mL against Microsporum gypseum while standard antifungal drug (ketoconazole) and Ag-NPs had the lowest zone of inhibition of 11.0 ± 1.0 mm at 15.0 μg/mL and 7.5 μg/mL against Rhizopus sp. and Aspergillus flavus, respectively. The negative control (DMSO) had no zone of inhibition on any of the potential indoor bacterial and fungal pathogenic strains. Statistically, there was significant (P &lt; 0.05) inhibition of bacterial and fungal pathogenic strains among the means of treatment doses of A. muricata AgNPs, ciprofloxacin and ketoconazole standard antibiotics. The excellent antimicrobial inhibition of the tested indoor bacterial and fungal strains by the A. muricata fabricated silver nanoparticles even at MIC of 3.25 μg/mL could be exploited as biostatic and biocidal agents where there is contamination or public health risk of pathogenic indoor bacteria and fungi.

Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria

Abstract In this study, the aqueous seed extract of Trachyspermum copticum was employed to fabricate silver nanoparticles (AgNPs) for their antibacterial performance. The structural characteristics of the phytofabricated AgNPs were investigated using ultraviolet–visible, energy dispersive X-ray, dynamic light scattering, zeta potential, field emission scanning electron microscope, and Fourier transform infrared spectroscopy. Further, the antibacterial effects of AgNPs were evaluated against two standard gram-positive strains of Staphylococcus aureus and Streptococcus pyogenes and two standard gram-negative strains of Escherichia coli and Klebsiella pneumoniae. The findings showed the phytofabrication of spherical-shaped AgNPs with a Z-average diameter of 119.7 nm and the polydispersity index of 0.56. The minimum inhibitory concentration of AgNPs against S. aureus, S. pyogenes, E. coli, and K. pneumoniae strains was 0.25, 1, 0.5, and 0.5 μg·mL−1, respectively. In addition, the minimum bactericidal concentration of these nanoparticles (NPs) against the mentioned strains was 8, 16, 4, and 4 μg·mL−1, respectively. Furthermore, the AgNPs enhanced the generation of reactive oxygen species significantly in all studied bacteria compared to the control (P &lt; 0.05) suggesting an oxidative-associated antibacterial mechanism of AgNPs. Moreover, a dose-dependent cell death was found in all bacterial samples based on flow cytometry analysis. Overall, this study showed a biological approach for the biosynthesis of AgNPs with significant antibacterial effects.

Assessment of Silver Nanoparticles Derived from Brown Algae Sargassum vulgare: Insight into Antioxidants, Anticancer, Antibacterial and Hepatoprotective Effect.

Algae are used as safe materials to fabricate novel nanoparticles to treat some diseases. Marine brown alga Sargassum vulgare are used to fabricate silver nanoparticles (Sv/Ag-NPs). The characterization of Sv/Ag-NPs was determined by TEM, EDX, Zeta potential, XRD, and UV spectroscopy. The Sv/Ag-NPs were investigated as antioxidant, anticancer, and antibacterial activities against Gram-positive bacteria Bacillus mojavensis PP400982, Staphylococcus caprae PP401704, Staphylococcus capitis PP402689, and Staphylococcus epidermidis PP403851. The activity of the Sv/Ag-NPs was evaluated as hepatoprotective in vitro in comparison with silymarin. The UV-visible spectrum of Sv/Ag-NPs appeared at 442 nm; the size of Sv/Ag-NPs is in range between 6.90 to 16.97 nm, and spherical in shape. Different concentrations of Sv/Ag-NPs possessed antioxidant, anticancer activities against (HepG-2), colon carcinoma (HCT-116), cervical carcinoma (HeLa), and prostate carcinoma (PC-3) with IC50 50.46, 45.84, 78.42, and 100.39 µg/mL, respectively. The Sv/Ag-NPs induced the cell viability of Hep G2 cells and hepatocytes treated with carbon tetrachloride. The Sv/Ag-NPs exhibited antibacterial activities against Staphylococcus caprae PP401704, Staphylococcus capitis PP402689, and Staphylococcus epidermidis PP403851. This study strongly suggests the silver nanoparticles derived from Sargassum vulgare showed potential hepato-protective effect against carbon tetrachloride-induced liver cells, and could be used as anticancer and antibacterial activities.

Investigation of Antimicrobial Activity and Cytotoxicity of Silver Nanoparticle Synthesized using Dopamine as a Reducing and Capping Agent

AbstractWe present a study focused on the controlled fabrication of silver nanoparticles (AgNPs) through colloidal synthesis, employing dopamine as a reducing and capping agent. By manipulating the concentration of silver nitrate, the production of spherical AgNPs with distinct particle diameters (16, 24, 48, and 74 nm) was achieved. The investigation extended to the evaluation of AgNPs′ impact on human embryonic kidney cells, revealing a concentration‐dependent response. At lower AgNPs concentrations, cell viability remained nearly 100 %, progressively declining with rising AgNPs concentrations. Importantly, the cytotoxic thresholds observed were notably elevated, underscoring the relatively mild to moderate toxicity profile of the nanoparticles. Furthermore, the antimicrobial efficacy of these synthesized AgNPs was probed against E. coli and S. aureus bacterial strains. Notably, the AgNPs exhibited robust antimicrobial activity, with superior performance exhibited by smaller‐sized particles compared to larger ones. Impressively, the minimum inhibitory concentration reached as low as 3.5 μg/mL, indicating their potent antimicrobial potential. The achieved distinct particle diameters, concentration‐dependent cytotoxic responses, and potent antimicrobial efficacy against bacterial strains underscore the multifaceted potential of these nanoparticles. These findings contribute valuable insights for their application in diverse fields, from biomedicine to antimicrobial solutions.

Simultaneous enhancements on emissions from quantum dot and quantum well by Ag nanoparticles for color conversion

Quantum dots (QDs) have been paid much attention on the color conversion for light-emitting diode (LED) in micro-display recently. However, it is hard to achieve high color conversion efficiency in a thin QD layer. In this paper, we fabricated silver nanoparticles (Ag NPs) with radii ranging mostly from 25 to 35 nm on a blue LED with a peak wavelength of 450 nm, then spin-coated QDs with a peak wavelength of 565 nm. Scanning electron microscopy, cathodoluminescence, photoluminescence (PL), and time-resolved PL measurements were performed. The PL emissions from quantum wells (QWs) of blue LED and QDs were enhanced by 10% and 32%, respectively, when the Ag NPs were included. The PL lifetimes of QWs and QDs were reduced by 10 and 6 times, respectively, compared to their initial states. Finite difference time domain software and the perturbation method were used to simulate the PL measurements and variable separation. It was concluded that the coupling of QDs and QWs with localized surface plasmon improves the external quantum efficiency and enhances the spontaneous emission rate in both QWs and QDs. This paper provides a new idea for designing high-efficiency color conversion micro-LED.

Exploring the biological properties of Saccharomyces cerevisiae-derived silver nanoparticles: In vitro structural characteristics, antibacterial, biofilm inhibition and biofilm degradation, antioxidant, anticoagulant, thrombolytic, and antidiabetic performance

In the present study, Saccharomyces cerevisiae was employed to fabricate silver nanoparticles (AgNPs) as a sustainable and ecofriendly approach. The mycofabricated AgNPs were found to be spherical with a Z-average size of 29.07 nm and zeta potential of −16 mV. This study focused on the biological properties of fungus-mediated fabrication of AgNPs. The AgNPs ascertained significant antibacterial activity against Listeria monocytogenes and Serratia marcescens with minimum inhibitory concentration (MIC) of 4 and 2 µg mL−1 and minimum bactericidal concentration (MBC) of 16 and 16 µg mL−1, respectively. Besides, the AgNPs at the studied concentrations ascertained significantly higher biofilm inhibitory and degradation activity against S. marcescens compared to the reference antibiotic drug gentamicin (P < 0.05). In contrast, gentamicin at the studied concentrations exhibited significantly higher biofilm inhibitory and degradation activity against L. monocytogenes compared to AgNPs (P < 0.05). Moreover, Flow cytometry analysis exhibited dose-dependent antibacterial properties for both AgNPs and gentamicin against both S. marcescens and L. monocytogenes. Furthermore, the AgNPs ascertained a dose-dependent antioxidant activity with a maximum 65.75 ± 2.70 % at the concentration of 500 µg mL−1. Impressively, the AgNPs at the concentration of 500 µg mL−1 represented anticoagulant performance with PT and aPTT values of 21.80 ± 3.31 and 70.57 ± 2.25 s, respectively. Additionally, the AgNPs at the concentration of 500 µg mL−1 showed 19.48 ± 3.82 % thrombolysis and 64.74 ± 1.63 % alpha-amylase inhibition. The AgNPs also ascertained a maximum 38.26 ± 1.70 % glucose uptake inhibition by S. cerevisiae at a concentration of 1000 µg mL−1. Overall, the above-mentioned unique physicochemical and biological properties of AgNPs made them attractive for biomedicine.

Eco-Friendly Fabrication of Silver Nanoparticles for Sustainable Water Purification and Antibacterial Synergy

Eco-Friendly Fabrication of Silver Nanoparticles for Sustainable Water Purification and Antibacterial Synergy

Potent biological activity of newly fabricated silver nanoparticles coated by a carbon shell synthesized by electrical arc

Highly effective AgNPs@C was efficiently synthesized by electrical arc powered by single spark unit which was sufficient to ionize the dielectric media (deionized water) through applying strong electric field between the electrodes (silver and carbon). The AgNPs@C shell was characterized in terms of stability, morphology and phase structure. All characterizations showed that the prepared silver nanoparticles were spherical with average size reached 17 nm coated with carbon shell. The antibacterial effect of the synthesized nanoparticles was tested against Pseudomonas aeruginosa in comparison to Ceftazidime (commonly used antibiotic against P. aeruginosa infections). It was revealed that AgNPs@C shell has superior activity with inhibition zone diameter reached 15 mm and minimum inhibitory concentration reached 2 µg/mL. The observed activity was further confirmed by confocal microscope which showed an increased red region, representing the dead cells, correlated with the presence of AgNPs@C. Moreover, transmission electron microscope studies implied the possible AgNPs@C antibacterial mechanism of action was the nanoparticles adherence to the bacterial membrane causing cell lysis. The molecular studies against fimH (virulence adhesion gene), rmpA (mucoid factor encoding gene), and mrkA (biofilm forming gene) proved the inhibition of their genetic expression. The cytotoxic effect of the synthesized AgNPs@C showed CC50 reached 235.5 μg/mL against normal lung cells (L929 cell line).

Exploring the Antimicrobial, Antioxidant, and Antiviral Potential of Eco-Friendly Synthesized Silver Nanoparticles Using Leaf Aqueous Extract of Portulaca oleracea L.

Herein, the prospective applications of green fabricated silver nanoparticles (Ag-NPs) within the biomedical field were investigated. The leaf aqueous extract of Portulaca oleracea L., a safe, cheap, and green method, was used to fabricate Ag-NPs. The maximum plasmon resonance of synthesized NPs has appeared at 420 nm. The various biomolecules present in the plant extract to assemble spherical Ag-NPs with sizes of 5-40 nm were analyzed using Fourier transform infrared and transmission electron microscopy. The Ag was the major content of the formed Ag-NPs with an atomic percent of 54.95% and weight percent of 65.86%, as indicated by EDX. The crystallographic structure of synthesized NPs was confirmed by the diffraction of the X-ray. The dynamic light scattering exhibits the homogeneity and mono-dispersity nature with a polydispersity index of 0.37 in the colloidal fluid and a zeta potential value of -36 mV. The synthesized Ag-NPs exhibited promising antimicrobial efficacy toward various prokaryotic and eukaryotic pathogenic microorganisms with low MIC values of 12.5 µg mL-1 and 6.25 µg mL-1, respectively. Additionally, the P. oleracea-formed Ag-NPs showed optimistic antioxidant activity assessed by DPPH and H2O2 assay methods with the highest scavenging percentages of 88.5 ± 2.3% and 76.5 ± 1.7%, respectively, at a concentration of 200 µg mL-1. Finally, the biosynthesized Ag-NPs showed high antiviral properties toward the hepatitis A virus and Cox-B4 with inhibition percentages of 79.16 ± 0.5% and 73.59 ± 0.8%, respectively. Overall, additional research is essential to explore the Ag-NP-based aqueous extract of P. oleracea for human health. In the current investigation the use of synthesized Ag-NPs as antimicrobial, antioxidant, and antiviral agents to protect against pathogenic microbes, degenerative diseases caused by various oxidative stresses, and deadly viruses is recommended.

Fabrication of Silver Nanoparticle Loaded into Nanocellulose Derived from Hemp and Poly(vinyl alcohol)-Based Composite as an Electrode for Electrochemical Sensors for Lactate Determination.

Nanocellulose derived from hemp (HNC) with the addition of silver nanoparticles (AgNPs) is utilized for improving the electrochemical sensing performances for lactate detection. Initially, HNC is chemically extracted and purified by using alkali treatment and acid hydrolysis. Then, AgNPs are nucleated in situ by the self-reduction process prior to forming a composite with poly(vinyl alcohol) (PVA). This nanocomposite significantly improves the electrochemical properties of the electrode, including electrochemical conductivity and electrocatalysis. The morphologies and chemical alterations of the HNC/AgNPs-PVA nanocomposite are investigated by field emission scanning electron microscopy. It demonstrates a three-dimensional network with random orientation of the nanocellulose fiber. The AgNPs are well-dispersed in the nanocomposite. Moreover, the nanocomposite provides high thermal stability up to 450 °C. Then, it is remarkably noted that 10 wt % HNC/AgNPs-PVA modified on the electrode provides the highest current responses, with a standard redox couple [(Fe(CN)6]3-/4-]. For lactate detection, this modified screen-printed graphene electrode with nonimmobilized lactate oxidase exhibits an increase in the current signal with the increment of lactate concentration and offered a linear range of 0-25 mM, covering a cutoff value (12.5 mM) for muscle fatigue indication. Eventually, this sensor is successfully applied for lactate detection with high potential for a wearable lactate sensor.