Ag NP Research Articles

SERS Detection of Hydrophobic Molecules: Thio-β-Cyclodextrin-Driven Rapid Self-Assembly of Uniform Silver Nanoparticle Monolayers and Analyte Trapping.

High-sensitivity and repeatable detection of hydrophobic molecules through the surface-enhanced Raman scattering (SERS) technique is a tough challenge because of their weak adsorption and non-uniform distribution on SERS substrates. In this research, we present a simple self-assembly protocol for monolayer SERS mediated by 6-deoxy-6-thio-β-cyclodextrin (β-CD-SH). This protocol allows for the rapid assembly of a compact silver nanoparticle (Ag NP) monolayer at the oil/water interface within 40 s, while entrapping analyte molecules within hotspots. The proposed method shows general applicability for detecting hydrophobic molecules, exemplified as Nile blue, Nile red, fluconazole, carbendazim, benz[a]anthracene, and bisphenol A. The detection limits range from 10-6to 10-9 M, and the relative standard deviations (RSDs) of signal intensity are less than 10%. Moreover, this method was used to investigate the release behaviors of a hydrophobic pollutant (Nile blue) adsorbed on the nanoplastic surface in the water environment. The results suggest that elevated temperatures, increased salinities, and the coexistence of fulvic acid promote the release of Nile blue. This simple and fast protocol overcomes the difficulties related to hotspot accessibility and detection repeatability for hydrophobic analytes, holding out extensive application prospects in environmental monitoring and chemical analysis.

Enhancing optical properties and antimicrobial efficiency of polyamide-6 for medical applications

Abstract Polyamide-6 (PA-6) fibers are valued for their high mechanical strength and cost-effectiveness, but their inherent hydrophobicity restricts their applicability. To enhance functionality, a grafting process was applied at both low and high yields, enabling effective treatment of PA-6 fibers with silver nanoparticles (Ag NPs) to impart antimicrobial properties. An in-situ approach was employed to embed Ag NPs within the PA-6 fibers. The antimicrobial efficacy of the modified fibers was assessed against multidrug-resistant (MDR) pathogens, including methicillin-resistant, extended-spectrum beta-lactamase-producing, and quinolone- and carbapenem-resistant strains, using the shake flask method with optical density measurements. Fourier-transform infrared spectroscopy (FTIR) characterized the chemical changes associated with grafting and Ag NP incorporation. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) provided insights into fiber morphology and elemental composition, verifying the successful surface loading of Ag NPs. The Multiple Beam Fizeau fringes technique was used to evaluate optical properties, such as refractive index and birefringence, as indicators of structural changes. Although grafting reduced the optical properties initially, subsequent Ag NP treatment restored them. The PA-6-g-PAA 7%-t-Ag NPs fibers exhibited superior optical properties relative to PA-6-g-PAA 20.7%-t-Ag NPs fibers, though with lower antimicrobial impact on sensitive organisms. Conversely, PA-6-g-PAA 20.7%-t-Ag NPs showed significant antimicrobial activity against MDR pathogens. As a result, PA-6-g-PAA 20.7% is identified as the optimal choice, balancing effective antimicrobial properties with enhanced optical performance, suggesting its potential in antimicrobial fiber applications for medical use.

Design evaluation and performance analysis of silver nanoparticle ink-based printed heaters

Abstract Printed electronics provides a low-cost, sustainable and simple fabrication
route device fabrication. Silver nanoparticle (Ag NP) ink is commonly used to print
conductive lines, and optimizing the printed pattern design is critical for performance
improvement. This study compares three printed heater designs: serpentine, spiral,
and a combination spiral-serpentine pattern. The heaters are printed using direct
ink writing technique with commercial Ag NP ink on a quartz substrate, optimizing
key parameters such as the number of printed layers and ink volume per layer to
achieve good electrical conductivity. The conductivity values range from 3.42 × 107
Ω−1m−1 to 3.47 × 107 Ω−1m−1 for different printing passes, compared to the bulk
silver conductivity of 6.3 × 107 Ω−1m−1. Polydimethylsiloxane (PDMS) is used to
encapsulate the heater patterns, and their performance is tested at temperatures up
to 200 ◦C. This study also identifies potential applications for these heater designs,
such as wearable electronics and flexible heating elements for metal oxide-based gas
sensors. Future research will concentrate on optimizing material performance for
dynamic and flexible environments, improving long-term durability, and overcoming
technical barriers to large-scale production.

Removal of Amoxicillin Using a New Adsorbent: Silver Nanoparticle Modified With Poly(ε‐Caprolactone)‐Block‐Poly(L‐Lactide) Copolymer

ABSTRACTThe aim of this study is to develop innovative hybrid materials with high adsorption capacity for removing amoxicillin from aqueous media. The study synthesized an AB‐type poly(ε‐caprolactone)‐block‐poly(L‐lactide) copolymer (PCL‐b‐PLLA) containing silver nanoparticles (Ag NP). A novel initiator, 2,4‐difluorobenzyl alcohol (1), was used to initiate the sequential ring‐opening polymerization (ROP) of ε‐CL and L‐LA, with tin octanoate Sn(Oct)2 as the catalyst. PCL (2) was synthesized by ROP of ε‐CL at 115°C, using (1) as an initiator and Sn(Oct)2 as the catalyst. Subsequently, PCL‐b‐PLLA (3) was obtained via ROP of L‐LA at 120°C in toluene, with (2) as a macroinitiator. The structures of the homo‐ and block copolymers were characterized using FT‐IR and 1H NMR. Ag NP was synthesized via a green method using Helichrysum arenarium extract. Polymer‐based composites containing Ag NPs possess functional surface properties that enhance selectivity and permeability, making them effective biocompatible adsorbents for removing contaminants from water. The nanoparticle content in the PCL‐b‐PLLA/Ag NP hybrid was analyzed by UV–Vis and TEM. For amoxicillin removal, both PCL‐b‐PLLA and PCL‐b‐PLLA/Ag NP were tested, achieving a maximum of 82% removal at pH 4.5 and 25°C. Adsorption studies were conducted in pure water and three wastewater samples to assess amoxicillin selectivity.

Flexible, stretchable multifunctional silver nanoparticles-decorated cotton textile based on amyloid-like protein aggregation for electrothermal and photothermal dual-driven wearable heater.

The design of multifunctional, high-performance wearable heaters utilizing textile substrates has garnered increasing attention, particularly in the development of body temperature and health monitoring devices. However, fabricating these multifunctional wearable heaters while simultaneously ensuring flexibility, air permeability, Joule heating performance, electromagnetic interference (EMI) shielding and antibacterial properties remains a significant challenge. This study utilizes phase transition lysozyme (PTL) film-mediated electroless deposition (ELD) technology to deposit silver nanoparticles (Ag NPs) on the cotton fabrics surface in a mild aqueous solution at room temperature, thereby constructing a wearable heater with long-term stability, high conductivity, and exceptional photothermal properties. The textiles enriched with Ag NPs exhibit remarkable electrothermal and photothermal dual-driven heating capabilities, achieving temperatures exceeding 110 °C within 50s under 2 V, or in merely a few seconds through photothermal conversion. Importantly, these textiles retain the intrinsic flexibility and breathability of the textile substrate. Furthermore, the amyloid-like protein Ag NP integrated textiles demonstrate excellent antibacterial properties, and exhibit a high EMI shielding efficiency of 50 dB within the frequency range of 8.2-12.4 GHz. Therefore, these multifunctional Ag NPs wearable heaters were expected to find applications in areas such as smart wearable clothing and future health management.

Valorization of pistachio (Pistacia vera L.) peel extract as an agricultural waste for green fabrication of bio-silver nanoparticles on cellulosic fabrics

The global trend toward producing multifunctional textiles using silver nanoparticles (Ag NPs) synthesized through phyto-synthesis, combined with natural dyes from plant extracts, reflects the appeal of eco-friendly, sustainable methods. This study leverages pistachio peel extract (PPE), a rich source of natural dyes, to dye cotton fabrics and enhance their antibacterial properties through microwave-assisted Ag NP synthesis. Ag NPs were synthesized using various ratios of PPE to Ag ions. Characterization of the synthesis process and particle size was carried out using UV–visible spectroscopy, atomic force microscopy (AFM), and dynamic light scattering (DLS), resulting in an average nanoparticle size of 73.5 nm. To optimize the biosynthesis process on cotton fabrics, the response surface method (RSM) was applied via central composite design (CCD). Surface morphology analysis through field emission scanning electron microscopy (FESEM) revealed nanoparticles of approximately 70 nm, and X-ray diffraction (XRD) patterns confirmed in-situ formation of Ag NPs on the cotton surface. Fourier-transform infrared spectroscopy (FTIR) offered insights into the chemical interactions involved in this in-situ synthesis. Colorimetric analysis of the dyed samples indicated a shift from yellow (from PPE) to dark brown after the successful incorporation of Ag NPs on the cotton, along with a significant increase in color strength (K/S) from 3.08 to 16.07. Furthermore, cotton fabrics treated with Ag NPs exhibited complete bacterial inhibition against E. coli and S. aureus, achieving 100 % antibacterial effectiveness with inhibition zone diameters of 4.1 mm for E. coli and S. aureus. Additionally, the treated fabrics showed excellent durability, with rub fastness at 4–5, washing fastness at 4–5, and light fastness at 7. Overall, this study presents a sustainable method for dyeing and enhancing the antibacterial properties of cotton textiles using PPE and Ag NPs.

One-step eco-friendly synthesis of Ag nanoparticles on bentonite-g-C₃N₄ for the reduction of hazardous organic pollutants in industrial wastewater.

Silver nanoparticles (Ag NPs) supported on natural materials have garnered significant attention due to their wide applicability across various research fields. This study presents an eco-friendly, scalable, and one-step approach to synthesizing high-purity Ag NPs supported by bentonite-graphitic carbon nitride (Bt-g-C3N4) nanocomposites via thermal reduction. The successful integration of Ag NPs into the Bt-g-C3N4 matrix was confirmed through several characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDX). XRF analysis identified the clay as beidellite-rich (Si/Al molar ratio less than 2), while EDX spectra and XRD patterns confirmed the presence of Ag NPs, with characteristic peaks at 38.04° and 44.24°. SEM and TEM images showed uniform Ag NP distribution with an average particle size of 4.75 nm and a spherical morphology. Acid-activated bentonite preserved its layered structure and exhibited a significant surface area increase, reaching 113.77 m²/g after hydrochloric acid treatment, thereby enhancing its capacity for supporting nanoparticle-based catalysts. The synthesized nanocomposites demonstrated exceptional catalytic performance, achieving reduction efficiencies of approximately 99 % for various organic pollutants, including nitrophenols (within 7 min for 4-nitrophenol), cationic dyes (within 12 min for Rhodamine B), and anionic dyes (within 5 min for methyl orange), using sodium borohydride (NaBH4) as the reducing agent. The reduction followed first-order kinetics, with activity factors (k′) calculated as 134 s−1.g−1, 260 s−1.g−1, and 92 s−1.g−1 for 4-NP, MO, and RhB, respectively. Furthermore, the Ag NPs/Bt-g-C3N4 nanocomposites exhibited remarkable recyclability, maintaining high catalytic efficiency across multiple cycles.

Tunable optical limiting in silver nanoparticle-naphthophenanthridine hybrids

Incorporation of functional nanoparticles into liquid crystals has emerged as a promising approach to create liquid crystal nanocomposites with superior opto-electronic properties. The properties of self-assembled supramolecular structures change remarkably upon the dispersion of a minute amount of metal nanoparticles in them. The effect of dispersing alkyl thiol-functionalized silver nanoparticles (Ag NP) in Naphthophenanthridine discotic liquid crystals on the nonlinear optical (NLO) properties is discussed in this work. Discotic liquid crystals (DLC) are synthesized via N-annulation of hexabutoxytriphenylene-1-amine with heptanaldehyde through the Pictet–Spengler reaction. A uniform dispersion of about 1–3 wt% Ag NPs in the columnar matrix enhances the nonlinear optical absorption, when measured under excitation by nanosecond laser pulses at 532 nm. By changing the amount of Ag NP loading, the nonlinear response of the hybrid can be tuned. These results indicate that the Ag-DLC hybrids are potential candidates for applications in NLO devices such as tunable optical limiters.

Silver Nanoparticle‐Embedded Zirconium‐Based Metal‐Organic Framework for Photoreduction of Carbon Dioxide to Acetic Acid in Aqueous Medium

AbstractCatalytic conversion of CO2 into value‐added chemicals is necessary to mitigate the increasing global warming and energy‐related issues. The selective production of C2 or C2+ products by photoreduction of CO2 is a challenging task due to the sluggish kinetics of C─C coupling. Herein, the potential of a silver nanoparticle (Ag NP) incorporated metal‐organic framework (MOF), NU‐1000 is introduced, to harvest light and ease the uphill electron transfer. The growth of silver nanoparticles on thiol‐functionalized NU‐1000 is studied using the atomic pair distribution function (PDF) analysis. The C2 product formed using Ag@NU‐1000‐SH without any sacrificial agents is acetic acid, which is confirmed by 1H‐NMR and HRMS data. The catalyst displays a high acetate output of 293.58 µmolg−1h−1 with a selectivity of 79.4%. The XPS and DFT calculations evidence that the presence of the charge‐polarised states in the as‐synthesized catalyst act as asymmetric centers that favor the C─C coupling reaction. The combined experimental (in situ DRIFT spectroscopic studies) and theoretical calculations reveal that the C─C coupling takes place via the coupling of COOH*intermediates.

Effect of surface charge on laser-produced silver nanoparticles for dye reduction and surface-enhanced Raman spectroscopy

Silver nanoparticles (Ag NPs) are widely used in biological, chemical, and physical fields due to their distinct properties. However, the effect of surfactants with different polarities on the catalytic and surface-enhanced Raman spectroscopy (SERS) performance of Ag NPs has not been thoroughly studied. Here, we tailor the surface charge of laser-synthesized Ag NP without changing their morphology and investigate their catalytic and SERS capabilities. The surfactant-free silver nanoparticles (NPBare), synthesized via pulsed laser ablation in liquid (PLAL), are subsequently coated with ionic surfactants sodium dodecyl sulfate (NPSDS) and cetyltrimethylammonium bromide (NPCTAB). The synthesis and morphology of Ag NPs are confirmed using UV–Vis absorption spectroscopy and scanning electron microscopy. The surface charge of fabricated NPs is determined using zeta potential (ZP) measurements. The ZP values of NPBare, NPSDS, and NPCTAB are determined to be −17 mV, 28.7 mV, and 5.58 mV, respectively. The catalytic activity of bare and coated Ag NPs was tested against the cationic and anionic dyes, Methylene blue (MB) and Methyl orange (MO) respectively. The reduction rate of both dyes was highest when using NPBare. However, in the case of coated nanoparticles, the rate of MB and MO reduction depends on the difference between the ZP of the dye and nanoparticles: the rate of reduction increases with the difference between the zeta potentials of the dye and coated nanoparticles increases. The SERS capability of bare and coated NPs was evaluated for anionic (MO) and cationic (MB, Rhodamine B, and Crystal Violet) dyes. The SERS intensity of dyes strongly enhanced with the increase in ZP difference between the dye molecules and NPs. Surface charge modified NPs shown excellent SERS sensitivity with detection limit up to nanomolar for dye molecules as well as the homogeneity of NPs demonstrated in Raman mapping results with relative standard deviation of 17 %. The results suggest that the electrostatic interaction between the nanoparticles and dye molecules plays a dominant role in SERS enhancement. These findings highlight the significance of surface charge in improving the catalytic and sensing properties of noble metal nanoparticles.

Green synthesis and evaluation of dual herb-extracted DHM-AgNPs: Antimicrobial efficacy and low ecotoxicity in agricultural and aquatic systems

Uncontrolled applications of weedicide and fertilizer can harm the soil ecology, and most significantly, earthworms are hazardous soil engineers. Thus, we aimed at the toxicity and histopathological alterations in the earthworm Eudrilus euginae following exposure to glyphosate (weedicide), urea (fertilizer), and environmentally friendly dual herb-mixed silver nanoparticles (DHM-AgNPs). The DHM-AgNPs were synthesized using a blend of Alfinia officinarum and Curcuma longa aqueous leaf extracts with 1 mM silver nitrate. The color change from yellow to brown after an hour of incubation was a significant indicator of successful DHM-AgNP synthesis. Characterization of the DHM-AgNPs using UV–Vis spectra indicated a surface plasmon resonance (SPR) peak at 430 nm. In addition to FT-IR spectroscopy and XRD analysis, SEM, TEM, and SEM investigations were performed to identify the DHM-AgNPs. The XPS analysis revealed the oxidation state and surface chemical composition, and Ag NP's specific surface area and degree of porosity were measured using BET. Furthermore, different concentrations of urea and glyphosate were administered to Artemia nauplii and E. euginae to assess their toxicity. The mortality rate for E. euginae exposed to a higher urea concentration (10 g/kg of soil) was 100%. In contrast, a % mortality rate of 83% was noted at 0.5 g/kg of soil. The maximum mortality (90 ± 0.64%) was observed at a 10 mL/kg/L concentration for glyphosate. In contrast, low mortality was noted in E. euginae and A. nauplii exposed with gradient concentrations of DHM-AgNPs compared to glyphosate and urea. As aquaculture and foodborne diseases are widespread, DHM-AgNPs showed significant anti-Vibrio activity against pathogenic Vibrio-related bacteria, inhibiting 80% at 100,100 μg/L, which is of great concern. This study suggests the potential use of DHM-AgNPs in field aqua and crops culture for eco-friendly pest control and anti-Vibrio activity without causing soil and environmental pollution. Further research is warranted to determine the efficacy, safety, and cost-effectiveness of DHM-AgNPs in aqua and agricultural practices.

Exosomal therapy mitigates silver nanoparticles-induced neurotoxicity in rats

Introduction Our investigation aims to appraise the neuroprotective impact of Bone Marrow-Mesenchymal Stem Cells (BM-MSCs) derived exosomes against Ag NPs-inducing neurotoxicity in rats. Materials and Methods Twenty-four albino rats were divided into 3 groups. Group I (control negative), Group II (intraperitoneally injected with Ag NPs for 28 days, whereas Group III (intraperitoneally injected with Ag NP and BM-MSCs derived exosomes. Results There was a marked elevation of Malondialdehyde (MDA) along with a reduction of brain antioxidants, Gamma-aminobutyric acid (GABA) and Monoamine Oxidase (MAO) in the Ag NPs receiving group. Ag NPs upregulated c-Jun N-terminal Kinases (JNK) genes and c-Myc and downregulated the tissue inhibitors of metalloproteinases (TIMP-1) and Histone deacetylase 1 (HDAC1) genes. Otherwise, the co-treatment of BM-MSCs derived exosomes with Ag NPs could markedly increase the rat’s body weight, activity and learning while, decreasing anxiety, restoring all the toxicological parameters and improving the microscopic appearance of different brain areas. Conclusion BM-MSCs-derived exosomes downregulated both apoptotic and inflammatory mediators and upregulated the antiapoptotic genes. BM-MSCs-derived exosomes exhibit a great therapeutic effect against the neurotoxic effects of Ag NPs.

Eco-Friendly Photocatalytic Treatment of Dyes with Ag Nanoparticles Obtained through Sustainable Process Involving Spirulina platensis

The development of efficient photocatalysts is crucial in addressing water pollution concerns, specifically in the removal of organic dyes from wastewater. In this context, the use of silver nanoparticles (Ag NPs) might represent a method to achieve high dye degradation efficiencies. On the other hand, the classical Ag NP production process involves several reactants and operating conditions, which make it poorly sustainable. In the present work, Ag NPs were synthesized according to a new sustainable process involving the use of natural extracts of Spirulina platensis and milder operating conditions. The material was also calcined to determine the influence of organic content on the properties of Ag NPs. The X-ray diffraction (XRD) analysis displayed the AgCl and Ag phases with a crystalline size of 11.79 nm before calcination. After calcination, only the Ag phase was present with an increased crystalline size of 24.60 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the capping role of the metabolites from the extract. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the spherical or quasi-spherical morphologies with agglomeration due to the calcination. Energy-dispersive X-ray spectroscopy (EDX) and Thermogravimetric (TGA) analyses further confirmed the involvement of metabolites in the synthesis of Ag NPs. The optical changes in the products were observed in a UV-Vis analysis. The Ag NPs were tested for their photocatalytic activity against the laboratory dye brilliant blue r in visible light in various conditions. The highest degradation efficiency of 81.9%, with a kapp value of 0.00595 min−1, was observed in alkaline medium after 90 min of light irradiation.

Cyanobacterial Silver Nanoparticles and Their Potential Utility-Recent Progress and Prospects: A Review.

The current situation involves an increase in interest in nanotechnology, in particular the ways in which it can be applied in the commercial and medical fields. However, traditional methods of synthesizing nanoparticles have some drawbacks, including the generation of harmful byproducts, high energy consumption, and cost. As a result, researchers have shifted their focus to "green" nanoparticle synthesis to circumvent these drawbacks. Because of their exceptional physiochemical properties, silver nanoparticles (Ag Nps) are the noble metal nanoparticles that are used most frequently. The green approach to Ag NP synthesis is environmentally friendly, non-toxic, and cost-effective, and it makes use of a variety of biological entities. Cyanobacteria, in particular, have garnered the most attention because of the abundance of bioactive substances that they contain, which serve both as reducing agents and as stabilizing agents during the process of biosynthesis. This review article discusses the current state of cyanobacteria-mediated Ag NP synthesis, the potential mechanisms that are involved, nanoparticle characterization, the various applications of Ag NP in different fields, and their prospects.

Conductive Coatings on PDMS, PMMA, and Glass: Comparative Study of Graphene, Graphene Oxide, and Silver Nanoparticle Composites

The development of conductive coatings has significant implications for microelectronics and electrochemistry. However, conductive coatings may exhibit different electrochemical properties when prepared on different substrate materials. This research explores the comparative performance of graphene, graphene oxide (GO), and silver nanoparticle (Ag NP) composites as conductive coatings on diverse substrate materials, including polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and glass. The study employed various preparation methods, such as mixing conductive materials with substrate materials and preparing copolymer composite materials. The conductive coating approach was found to be the most straightforward and convenient, with broader development prospects and fewer restrictive conditions. The results indicate that the distinct surface characteristics of the substrate materials influence the conductive properties of coating materials. Consequently, results show that graphene exhibits the highest conductivity on all three substrates, while GO is more conductive than Ag NPs on PMMA and PDMS but less conductive than Ag NPs on glass. That offers valuable insights into the selection of substrate materials and coating materials for the preparation of conductive materials.

Aspergillus fumigatus-induced biogenic silver nanoparticles' efficacy as antimicrobial and antibiofilm agents with potential anticancer activity: An in vitro investigation

A worldwide hazard to human health is posed by the growth of pathogenic bacteria that have contaminated fresh, processed, cereal, and seed products in storage facilities. As the number of multidrug-resistant (MDR) pathogenic microorganisms rises, we must find safe, and effective antimicrobials. The use of green synthesis of nanoparticles to combat microbial pathogens has gained a rising interest. The current study showed that Aspergillus fumigatus was applied as a promising biomass for the green synthesis of biogenic silver nanoparticles (Ag NPs). The UV–visible spectra of biosynthesized Ag NPs appeared characteristic surface plasmon absorption at 475 nm, round-shaped with sizes ranging from 17.11 to 75.54 nm and an average size of 50.37 ± 2.3 nm. In vitro tests were conducted to evaluate the antibacterial, antioxidant, and anticancer effects of various treatment procedures for Ag NP applications. The synthesized Ag NPs was revealed antimicrobial activity against Aspergillus flauvas, A. niger, Bacillus cereus, Candida albicans, Esherichia coli, Pseudomonas aerugonosa, and Staphylococcus aureus under optimum conditions. The tested bacteria were sensitive to low Ag NPs concentrations (5, 10, 11, 8, 7, 10, and 7 mg/mL) which was observed for the mentioned-before tested microorganisms, respectively. The tested bacterial pathogens experienced their biofilm formation effectively suppressed by Ag NPs at sub-inhibitory doses. Antibacterial reaction mechanism of Ag NPs were tested using scanning electron microscopy (SEM) to verify their antibacterial efficacy towards S. aureus and P. aeruginosa. These findings clearly show how harmful Ag NPs are to pathogenic bacteria. The synthesized Ag NPs showed antitumor activity with IC50 at 5 μg/mL against human HepG-2 and MCF-7 cellular carcinoma cells, while 50 mg/mL was required to induce 70 % of normal Vero cell mortality. These findings imply that green synthetic Ag NPs can be used on cancer cell lines in vitro for anticancer effect beside their potential as a lethal factor against some tested pathogenic microbes.

Integration of Silver Nanoparticles into Carbon-Encapsulated Tungsten Oxide Promoting Visible-Light-Driven Photocatalytic Degradation Efficiency

WO3-based photocatalysts have garnered popularity due to their low cost and high stability. However, the strong photogenerated electron-hole recombination limits their practical applicability. Herein, we developed an innovative heterostructure that integrates silver nanoparticles (Ag NPs) into carbon-encapsulated WO3 (C-WO3) through a combination of solvothermal synthesis and photoreduction methods. Under visible light irradiation, the Ag/C-WO3 photocatalyst demonstrated significant photocatalytic activity for rhodamine B (RhB) degradation, and the fine-tuned Ag/C-WO3 photocatalyst possesses excellent RhB degradation performance, achieving a removal rate of 98.2 % with excellent photostability. The photocatalytic process follows first-order kinetics, with adsorbent diffusion identified as the rate-limiting step. The optimized Ag/C-WO3 had an apparent rate constant of 0.039 min−1, 9.75 times higher than that of the unmodified C-WO3 (0.004 min−1). The enhanced photocatalytic activity is primarily owing to the surface plasmon resonance effect of Ag NP, which increases the absorption of visible light and boosts electron generation. Additionally, the carbon layer that encapsulates WO3 serves as a bridge for electron transfer from Ag to WO3, thereby accelerating the separation of photogenerated electron-hole pairs and elevating the overall photocatalytic degradation efficiency. The Ag NP-decorated C-WO3 with superior degradation properties is expected to be a potential candidate in practical and industrial applications.

Facile synthesis, morphological, optical, catalytic and photocatalytic properties of Ag nanoparticles decorated Ce doped ZnO hybrid plasmonic nanorods

Designing plasmonic metal–semiconductor hybrid nanostructures for photodecomposition of industrial textile effluent has been considered as a great way to boost the catalytic and photocatalytic capability by promoting effective separation of photoexcited charge carriers. Herein, fabrication of Ag nanoparticles decorated Ce doped ZnO nanostructures were demonstrated via facile wet chemical method. The morphology and structure of the fabricated photocatalysts were analysed using FESEM, XRD and Raman spectroscopy whereas PL, TRPL and UV–vis absorption spectroscopy were employed to examine their optical behaviour. Catalytic response of the synthesized catalysts was studied for 4-NP to 4-AP reduction and the results are more favourable for Ag loaded Ce doped ZnO catalysts and achieved 96.4 % reduction of 4-NP in only 4 min. Photocatalytic measurements showed that higher Ag NP loading onto Ce doped ZnO nanostructures led to superior photodegradation ability over other photocatalysts for the degradation of synthetic dyes and levofloxacin antibiotic. The sunlight driven photodecolorization of harmful synthetic dyes and levofloxacin were studied and efficacy of 97.5, 97.1, 85.1, and 70.9 % were achieved for MG, MB, RhB and MO dyes, respectively in 12 min and 97.2 % efficiency for degradation of levofloxacin was achieved in 20 min of sunlight exposure. Furthermore, the key reactive species was identified and tentative photodegradation process was explained. This work provides an excellent plasmonic-semiconductor catalyst and photocatalyst with good photostability and practical applicability indicating its enormous potential for application in environmental remediation.

Using Femtosecond Laser Pulses to Explore the Nonlinear Optical Properties of Ag/Au Alloy Nanoparticles Synthesized by Pulsed Laser Ablation in a Liquid.

Metallic nanoparticles have gained attention in technological fields, particularly photonics. The creation of silver/gold (Ag/Au) alloy NPs upon laser exposure of an assembly of these NPs was described. First, using the Nd: YAG pulsed laser ablation's second harmonic at the same average power and exposure time, Ag and Au NPs in distilled water were created individually. Next, the assembly of Ag and Au NP colloids was exposed again to the pulsed laser, and the effects were examined at different average powers and exposure times. Furthermore, Ag/Au alloy nanoparticles were synthesized with by raising the average power and exposure time. The absorption spectrum, average size, and shape of alloy NPs were obtained by using an ultraviolet-visible (UV-Vis) spectrophotometer and transmission electron microscope instrument. Ag/Au alloy NPs have been obtained in the limit of quantum dots (<10 nm). The optical band gap energies of the Ag/Au alloy colloidal solutions were assessed for different Ag/Au alloy NP concentrations and NP sizes as a function of the exposure time and average power. The experimental data showed a trend toward an increasing bandgap with decreasing nanoparticle size. The nonlinear optical characteristics of Ag/Au NPs were evaluated and measured by the Z-scan technique using high repetition rate (80 MHz), femtosecond (100 fs), and near-infrared (NIR) (750-850 nm) laser pulses. In open aperture (OA) Z-scan measurements, Ag, Au, and Ag/AuNPs present reverse saturation absorption (RSA) behavior, indicating a positive nonlinear absorption (NLA) coefficient. In the close-aperture (CA) measurements, the nonlinear refractive (NLR) indices (n2) of the Ag, Au, and Ag/Au NP samples were ascribed to the self-defocusing effect, indicating an effective negative nonlinearity for the nanoparticles. The NLA and NLR characteristics of the Ag/Au NPs colloids were found to be influenced by the incident power and excitation wavelength. The optical limiting (OL) effects of the Ag/Au alloy solution at various excitation wavelengths were studied. The OL effect of alloy NPs is greater than that of monometallic NPs. The Ag/Au bimetallic nanoparticles were found to be more suitable for optical-limiting applications.

Enhanced Catalytic, Antioxidant, and Electrochemical Properties of Green‐Synthesized Graphene‐Silver Nanocomposite Utilizing Moringa Oleifera Leaf Extract

AbstractGraphene, a remarkable material known for its exceptional properties, can be efficiently produced through environmentally friendly methods using renewable resources and eco‐friendly solvents. Recent studies have highlighted the potential of leaf extracts as effective reducing and stabilizing agents in converting graphene oxide (GO) to graphene. This paper presents a green and cost‐effective approach for the effective deposition of silver nanoparticles (Ag NPs) onto the reduced graphene oxide (RGO) nanosheets. The process involves the co‐reduction of GO and AgNO3 in water using Moringa olifera leaf extract, resulting in the formation of a nanocomposite termed reduced graphene oxide‐silver (Ag‐RGO). The formation of RGO and Ag NP is confirmed through UV‐visible spectroscopy, XRD, and Raman spectroscopy techniques. TEM images revealed the morphology of the nanocomposite, depicting 2‐dimensional graphene sheets adorned with Ag NPs. FT‐IR analysis confirmed the removal of oxygenated functional groups from GO, indicating graphene formation. The synthesized Ag‐RGO nanocomposite exhibited significant catalytic, antioxidant, and electrochemical properties. This study underscores the utilization of natural ingredients as sustainable alternatives for producing multifunctional graphene‐silver nanocomposites.