One-step synthesis of silver nanoparticles embedded with polyethylene glycol as thin films

Silver nanoparticles (Ag NPs) embedded and stabilized with polyethylene glycol (PEG) were synthesized as colloids by heating and exposure to sunlight (direct and indirect) irradiation as green method. The deposition of Ag NP-PEGs onto Si-wafers was also made using the electrospray ionization deposition technique. The generating of Ag NP-PEGs as colloids was examined by UV–visible spectroscopy (UV–Vis) and transmission electron microscopy (TEM). The chemical composition of the resulted nanocomposites was evaluated by Fourier transform infrared (FTIR) and that of thin-film surfaces by X-ray photoelectron spectroscopy. Structure–property relationships of Ag-PEG nanocomposites prepared by heating were discussed in dependence on the time of heating. The UV–visible results confirmed the successful synthesis of spherical Ag NPs with absorption peaks at a wavelength of λ = 413 nm for the heating method and at λ = 418 as well as 449 nm for direct and indirect exposure to the sunlight. Ag-PEG nanocomposite thin films showed excellent antimicrobial activity. These results revealed that the Ag-PEG nanocomposites thin films can be used as potential materials in biomedical applications.     

Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag⁺ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO₃)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO₃/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO₃ and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO₃. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM).     

Green Chemical Synthesis of Silver Nanoparticles and its Catalytic Activity

Silver nanoparticles (Ag(0) NPs) were synthesized by the chemical reduction method, in which ceftriaxone (antibiotic) used as reducing (to convert Ag⁺ to Ag(0)) and capping agent. UV–Visible spectroscopy revealed the first indication of formation of Ag(0) NPs. FT-IR spectroscopy showed the interaction of formation of bonding between antibiotic standard and silver. X-ray powder diffraction powder pattern confirmed the crystalline nature of prepared Ag(0) NPs. These Ag(0) NPs were used as catalyst for three organic hazardous chemicals i.e., 4-nitro-1,3-Phenylene diamine, 6-methyl-2-nitroanilline, 4-methyle-2-nitroanilline. The prepared Ag(0) NPs showed good catalytic activity against these compounds.     

Synthesis of stable AuAg bimetallic nanoparticles encapsulated by diblock copolymer micelles

We present a facile method for the preparation of bimetallic AuAg nanoparticles (NPs) with controlled size and composition rendering them ideally suitable for optical and catalytic applications. In analogy to methods for the generation of monometallic Au and Ag NPs, AuAg NPs were prepared inside polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block-copolymer micelles formed in toluene, by loading the P4VP cores of the micelles first with AgNO(3) and then with HAuCl(4). In contrast to the reverse sequence of loading, homogenously bimetallic AuAg particle arrays were achieved after reduction carried out in solution with hydrazine monohydrate as the reducing agent. TEM reveals that stable and spherical NPs can be prepared well separated from one another and with a narrow size distribution with diameters of ～3 nm. The bimetallic NP composition was confirmed by energy-dispersive X-ray spectroscopy (EDX) of single NPs. The atomic ratio of Ag and Au contained in single particles is in good agreement with the relative concentrations of both metals used in the synthesis which was confirmed by atomic absorption spectroscopy. The atomic ratio Au?:?Ag was systematically varied between 3?:?1 and 1?:?3. For all ratios UV-vis spectra showed a single plasmon band. Its wavelength varied from 430 for Au?:?Ag = 1?:?3 to 515 nm for Au?:?Ag = 3?:?1, showing a linear dependence on the relative amount of gold within the range of plasmon wavelengths from monometallic gold (538 nm) to silver (415 nm).     

Synthesis and characterization of Ag nanoparticles embedded in PVA via UV-photoreduction technique for synthesis of Prussian blue pigment

Silver nanoparticles doped in polyvinyl alcohol (AgNps/PVA) were synthesized via polymer-promoted reductive reaction of AgNO₃ and PVA under time-dependent exposure to UV radiation. The AgNps/PVA composites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, UV–Vis spectroscopy, and transmission electron microscopy to describe the structure, nuclearity, and distribution of Ag Nps within the PVA matrix. The UV–Vis spectrum of AgNps/PVA exhibited a broad surface plasmon absorption around 425–443 nm which originated from the formation of Ag NPs. Surface analysis by XPS indicated that the Ag NPs were grown solely on the PVA surface at UV exposure time of 2 h (2.0AgNPs/PVA). Increasing the UV exposure time to 4 h will cause the transformation of metallic nanosilver to oxidized nanosilver. UV–Vis absorption spectra were in situ recorded to follow the synthesis of Prussian blue (PB) on 2.0AgNPs/PVA (PB@2.0AgNPs/PVA). The colloidal dispersion of 2.0AgNPs/PVA in an acidic medium containing free Fe(III) ions and potassium hexacyanoferrate(III) revealed an additional band centered at 720 nm due to the intermetal charge-transfer absorbance of the polymeric Fe(II)-C-N-Fe(III) of the PB@2.0AgNPs/PVA nanocomposite. Control experiments were shown to involve a spontaneous electron transfer reaction between 2.0AgNPs/PVA and Fe(III) ions, with a concomitant decomposition of hexacyanoferrate(III) and formation of PB was observed. Moreover, IR gave clear cut evidence for the synthesis of PB@2.0AgNPs/PVA from the appearance of a band for the cyano group at 2090 cm^?1.     

Effect of Laser Fluence on the Structural,Morphological and Optical Properties of 2H-PbI<Subscript>2</Subscript> Nanoparticles Prepared by Laser Ablation in Ethanol

The effect of laser fluence on the optical, structural and morphological properties of PbI₂ nanoparticles NPs synthesized by pulsed laser ablation in ethanol was studied. The direct optical energy gap of PbI₂ NPs prepared at various laser fluences was in the range of (3–3.3 eV) at room temperature. Three absorption peaks related to surface plasmon resonance at 337, 435 and 507 nm are observed. XRD results show that all the grown PbI₂ NPs are polycrystalline in nature and the formation of hexagonal structure 2H-polytype was observed at laser fluence of 3.6 J/cm². The surface morphology of PbI₂ NPs investigated by SEM revealed formation of hexagonal, platelet-like and spherical NPs morphologies. TEM images showed formation of spherical particles with size varied from 10 to 75 nm depending on the laser fluence. PL measurement shows emission of broad peak centered at 350 nm and increasing the laser fluence results in red shift. The Raman spectra of PbI₂ NPs revealed existence of five vibration modes situated at 74, 96,106, 169 and 213 per cm. FT-IR investigation showed a broad band at 3383 per cm indexed to symmetric stretching vibration of Pb–I clusters and band at 725 per cm related to bending mode of O–H.     

Radiation synthesis and characterization of polyvinyl alcohol/chitosan/silver nanocomposite membranes: antimicrobial and blood compatibility studies

Polyvinyl alcohol/chitosan/silver (PVA/CS/Ag) nanocomposite membranes were synthesized by γ-radiation with promising antimicrobial and biomedical applications. The nanocomposite membranes were prepared by mixing PVA and CS solutions with different copolymer compositions in the presence of silver nitrate (AgNO₃) and glutaraldehyde as cross-linker, followed by in situ reduction with γ-radiation at different doses. The nanocomposite membranes were characterized by ultraviolet spectroscopy (UV), Fourier transform infrared, X-ray diffraction (XRD) and transmission electron microscopy (TEM). UV studies showed a strong peak around λ _max at 430 nm due to surface plasmon resonance of silver nanoparticles formed during irradiation. As the irradiation dose increased from 25 to 75 kGy, the plasmon band is shifted from 430 to 418 nm with high intensity, indicating the formation of smaller particles. TEM investigation showed uniform distribution of silver nanoparticles (AgNPs) in the membranes with mean diameter of 32–19 nm. XRD results confirmed that the mean diameter of AgNPs estimated from the Debye–Scherrer formula was in the range of 27.5–12.8 nm which confirms the TEM results. The PVA/CS/Ag nanocomposite membranes exhibited good antibacterial activity and were found to cause significant reduction in microbial growth. The nanocomposite membranes showed non-thrombogenicity effect and slightly haemolytic potential, suggesting their promising use in biomedical applications.     

Studies on the synthesis of electrospun PAN‐Ag composite nanofibers for antibacterial application

We have successfully synthesized polyacrylonitrile (PAN) nanofibers impregnated with Ag nanoparticles by electrospinning method at room temperature. Briefly, the PAN‐Ag composite nanofibers were prepared by electrospinning PAN (10% w/v) in dimethyl formamide (DMF) solvent containing silver nitrate (AgNO₃) in the amounts of 8% by weight of PAN. The silver ions were reduced into silver particles in three different methods i.e., by refluxing the solution before electrospinning, treating with sodium borohydride (NaBH₄), as reducing agent, and heating the prepared composite nanofibers at 160°C. The prepared PAN nanofibers functionalized with Ag nanoparticles were characterized by field emission scanning electron microscopy (FESEM), SEM elemental detection X‐ray analysis (SEM‐EDAX), transmission electron microscopy (TEM), and ultraviolet‐visible spectroscopy (UV‐VIS) analytical techniques. UV‐VIS spectra analysis showed distinct absorption band at 410 nm, suggesting the formation of Ag nanoparticles. TEM micrographs confirmed homogeneous dispersion of Ag nanoparticles on the surface of PAN nanofibers, and particle diameter was found to be 5–15 nm. It was found that all the three electrospun PAN‐Ag composite nanofibers showed strong antibacterial activity toward both gram positive and gram negative bacteria. However, the antibacterial activity of PAN‐Ag composite nanofibers membrane prepared by refluxed method was most prominent against S. aureus bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Development of pH-sensitive and antibacterial gelatin/citric acid/Ag nanocomposite hydrogels with potential for biomedical applications

This work aimed to prepare pH-sensitive and antibacterial drug releasing systems through a completely green route. To achieve this, the gelatin natural biopolymer was crosslinked with citric acid in the presence of Ag nanoparticles (NPs). Interestingly, Ag NPs formation and gelatin crosslinking were simultaneously occurred during annealing of samples without need for any toxic chemicals, which were confirmed by FTIR, UV-vis spectra, SEM and TEM observations. In addition, potential of the citric acid crosslinked-gelatin/Ag nanocomposite hydrogels was successfully explored for drug delivery applications using cefixime as a model drug. It was found that these hydrogels have pH-dependent swelling and drug release behavior with higher drug release at pH 7.4 compared to pH 1.2. Also, an antibacterial effect against the E. coli and S. aureus microorganisms was achieved by incorporation of Ag NPs into hydrogels. These hydrogels can be considered as stimuli responsive materials for oral drug delivery and wound dressing applications.     

Preparation and Characterization of Polypyrrole Silver Nanocomposites via Interfacial Polymerization

Conducting polypyrrole silver (Ppy-AgNC) nanocomposite was synthesized by an interfacial polymerization method. Ag⁺ ions from the AgNO₃ solution were taken in the formation of Ppy-AgNC. The incorporated silver was confirmed by X-ray diffraction (XRD). During the polymerization in a nitrate ion-containing solution, the impregnation leads to the formation of metallic silver. The size distribution of Ag into the polymer is confirmed by transmission electron microscopy (TEM), and proves the formation of a uniform species with spherical particles of Ag (mean diameter of 8-12 nm) branching at the border of Ppy. The thermal behavior of the material was studied by thermogravimetric measurements.     

Electrochemical Deposition of Highly Dispersed Palladium Nanoparticles on Nafion‐Graphene Film in Presence of Ferrous Ions for Ethanol Electrooxidation

An efficient method was developed to produce highly dispersed Pd nano particles (NPs), supported on Nafion‐graphene film by electrochemical deposition at constant potential in presence of ferrous ions. The Fe²⁺ ions govern the size, shape and morphology of Pd NPs. The as‐prepared catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). It was obeserved from TEM that the mean diameter of electrodeposited Pd NPs was 6.4 ± 1.3 nm with narrow diameter range from 4 to 10 nm. The electrocatalytic performance of the Pd NPs deposited on Nafion‐graphene (Nf‐G) catalyst was studied by cyclic voltametry (CV) and chronoamperometric measurements. The highly dispersed Pd NPs on Nf‐G film were obtained in presence of Fe²⁺ ions. This alters electrochemical active surface area and hence catalytic activity of Pd NPs. The prepared Pd/Nf‐G catalyst exhibit highest tolerance to the intermediate poisoning species (ratio I_f/I_b = 2.2). The as‐obtained catalyst shows an efficient electrocatalytic activity and good stability for ethanol oxidation in alkaline medium.     

Plasmonic-excitonic multi-hybrid glass-based nanocomposites incorporating Ag plus core-shell CdSe/CdS and alloyed CdSxSe1−x nanoparticles

Successful fabrication of glass-based hybrid nanocomposites (GHNCs) incorporating Ag, core-shell CdSe/CdS and CdS_xSe_1?x nanoparticles (NPs) is herein reported. Both metallic (Ag) and semiconductor (CdSe/CdS) NPs were pre-synthesized, suspended in colloids and added into the sol-gel reaction medium which was used to fabricate the GHNCs. During fabrication of the nanocomposites a fraction (20–60%) of core-shell CdSe/CdS NPs was alloyed into CdS_xSe_1?x (0.20 < x < 0.35) NPs without changing morphology. Modulation of in situ alloying is possible via the relative content of organics added into the sol-gel protocol. Within colloids Ag (core-shell CdSe/CdS) NPs presented average diameter and polydispersity index of 49.5 nm (4.2 nm) and 0.41 (0.21), respectively. On the other hand, the Ag (core-shell CdSe/CdS) NPs’ average diameter and polydispersity index assessed from the GHNCs were respectively 51.5 nm (4.1 nm) and 0.43 (0.25), revealing negligible aggregation of the nanophases within the glass template. The new GHNCs herein introduced presented two independent excitonic transitions associated to homogenously dispersed semiconductor NPs, peaking around 420 nm (core-shell CdSe/CdS) and 650 nm (CdS_xSe_1?x) and matching the plasmonic resonance (Ag NPs) in the 400–500 nm range. We envisage that the new GHNCs represent very promising candidates for superior light manipulation while illuminated with multiple laser beams in quantum interference-based devices.     

Photocrosslinkable acid urethane dimethacrylates from renewable natural oil and their use in the design of silver/gold polymeric nanocomposites

Castor oil-based acid urethane macromers were prepared and employed for obtaining Ag/Au/polymer nanocomposites. Structure and UV induced photopolymerization of the macromers were investigated by spectral methods. The polymerization rate and the degree of conversion decreased with about 10% in the presence of 2.5 wt.% silver nanoparticles (Ag NPs). For the diacid macromer, the surface plasmon intensity increased with irradiation time (the optical density of the absorption maximum (430 nm) attained 2.3 after 600 s), whereas a diminished efficiency was found for Ag NPs in situ generated. Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed uniform distribution of the spherical nanoparticles (0.6 nm (Ag NPs); 5 nm (Au NPs)) and the appearance of Ag 3d_3/2, Ag 3d_5/2, Au 4f_7/2 and Au 4f_5/2 peaks corresponding to Ag (0) or Au (0). Environmental scanning electron microscope with energy-dispersive X-ray detector, contact angle and mechanical parameters measurements complemented the above observations.     

Studies on the effect of long-chain and head groups of nonionic surfactants synthesized from palm and coconut oil on the formation of silver nanoparticles

Four fatty amides were synthesized using coconut and palm oil sources. The chemical structure of the as-prepared fatty acids was confirmed using Fourier Transform Infrared (FT-IR) and ¹H, ¹³C NMR spectroscopy. The effect of different chain lengths and head groups of these compounds on Ag nanoparticles (NPs) synthesis was investigated. Ultraviolet–visible spectroscopic studies showed characteristic absorbance peaks (λ_max ≈ 410 nm). FT-IR results indicated that the surfactant functionalities are responsible for the Ag NPs stability. The effect of fatty amides on the morphology and size distribution of the Ag NPs was investigated using transmission electron microscope (TEM). The TEM micrographs showed the formation of fine spherical morphology due to surfactant-mediated self-assembly with an average particle size of 1–3 nm. Dynamic light scattering (DLS) analysis showed the micellar self-assembly of Ag NPs-fatty amides. The effect of surfactant on the solution behavior was analyzed using surface tension measurements. Cocamide and palm DEA showed relatively low free energy (∆G_mic) values, resulting in smaller particles with good distribution. Finally, the Ag NPs showed outstanding antimicrobial activity against Pseudomonas putida bacteria.     

Gamma Irradiation Assisted the Sol–Gel Method for Silver Modified-Nickel Molybdate Nanoparticles Synthesis: Unveiling the Antimicrobial,and Antibiofilm Activities Against Some Pathogenic Microbes

Herein, this work aims to reveal the gamma irradiation-assisted the sol–gel method for the synthesis of silver (Ag) modified-nickel molybdate nanoparticles (NiMoO₄; NMO NPs) and tested for their antimicrobial and antibiofilm activities against some pathogenic bacteria and unicellular fungi. The prepared samples were characterized via XRD, HR-TEM, SEM, EDX, and elemental mapping analysis. The antimicrobial potential was tested as ZOI and MIC, while antibiofilm was estimated by tube method. The detected diffraction peaks of bare NMO NPs affirmed the successful synthesis of NMO NPs without any foreign phases. Also, three diffraction peaks were detected affirming the formation of Ag NPs on the surface of NMO NPs. The average crystallite size for the bare NMO NPs and Ag@NMO NPs was found to be 71.8 nm and 48.28 nm, respectively. Also, the SEM images have illustrated the decoration of Ag NPs on the NMO surface. Further, the TEM image illustrated that the particles of NMO possess a hexagonal shape in the nanoscale regime. Also, the elemental mapping images confirm the uniform distribution of these elements over the Ag@NMO sample. Antimicrobial results revealed that the synthesized Ag@NMO NPs recorded the most significant inhibition zone more than NMO NPs against Enterococcus columbae (33.3?±?0.115 mm), and Candida albicans (30.8?±?0.572 mm), and the lowest MIC (0.048 µg/ml) against E. columbae. Antibiofilm activity of Ag@NMO NPs recording 94.32% for E. columbae, 91.99% for S. vitulinus, and 90.98% for C. albicans. SEM imaging in the lack of Ag@NMO NPs exhibited normally grown bacterial cells with standard typical semi-formed biofilm. After Ag@NMO NPs treatment, remarkable morphological changes; including the total lysis of the outer surface attended by deformations with the reduction in the whole viable number.

     

Development of alginate-gum acacia-Ag0 nanocomposites via green process for inactivation of foodborne bacteria and impact on shelf life of black grapes (Vitis vinifera)

The main objective of this investigation is to develop sodium alginate-gum acacia-silver nanocomposite films (AGA-Ag⁰ NC) to inhibit the growth of foodborne and to extend the shelf life of food. The Ag nanoparticles were generated in sodium alginate-gum acacia (AGA) blend matrix through reduction by basil leaves (Tulasi). The formation of Ag⁰ was monitored by UV–vis spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), thermogravimetrical analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The absorption band at 420 nm in UV–vis spectrum and change in the band positions in FTIR spectrum of AGA-Ag⁰ NC compared to that of AGA corresponds to the formation of Ag nanoparticles. The XRD profile of AGA-Ag⁰ NC exhibits characteristic d-lines of Ag nanoparticles. The spherical shape of Ag nanoparticles uniformly formed throughout the films was recognized in SEM image with a size of ~ 4 ± 1 nm as observed by TEM. The water uptake and mechanical properties of the films were also studied. The AGA-Ag⁰NC films offered excellent antimicrobial activity against various foodborne bacteria and shelf life of food enhanced efficiency of the AGA-Ag⁰NC films is also tested on grape fruit (Vitus vinifera). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47331.     

Photoluminescence of Ag Nanoparticles and Tm3+ Ions in the Bismuth Germanate Glasses for the Blue Light‐Excited W‐LED

Materials containing rare‐earth ions and Ag nanoparticles (NPs) have been widely applied due to prior demonstration of increase in their luminescence properties. Here, Tm³⁺ ions‐doped bismuth germanate glasses were synthesized by a chemical reduction method based on the conventional melting‐quenching technique. The Ag NPs were facilely precipitated in the glass matrix by the chemical reduction method during the annealing process. TEM image shows that the Ag NPs are closely dispersed in the glass matrix. The luminescence properties and energy‐transfer mechanism were systematically investigated by means of absorption, emission, and excitation spectra. Significant enhancements of Tm³⁺ ions emission and a broad emission band centered at 568 nm caused by Ag NPs are observed upon 474‐nm excitation. Our research may illustrate the interactions between Tm³⁺ ions and Ag NPs and provide a simplified way to synthesize the high‐efficiency luminescent materials for the blue light‐excited W‐LEDs.     

Silver nanoparticles enhanced photoluminescence and the spectroscopic performances of Nd3+ ions in sodium lanthanum borate glass host: Effect of heat treatment

Silver nanoparticles (NPs) impact on the emission attributes of Nd³⁺ activated Na₂O–La₂O₃–B₂O₃ vitreous host matrix has been studied and discussed in detail. The effect of nucleation and growth of Ag NPs occurred due to the different heat–treatment durations at the temperature of 450 °C has been discussed. Transmission electron microscopy measurement revealed the formation of spherically shaped Ag NPs in the studied samples. The median Ag NPs size was increased from 2 to 9 nm with heat–treatment durations. Utilizing the absorption spectra of Nd³⁺ ions, the phenomenological Judd–Ofelt (J–O) parameters (Ω_{λ= 2, 4, 6}) were estimated. The optimized luminescence intensity at 1056 and 875 nm have realized for 10 h of annealing at 450 °C, with an enhancement factor of 160%. Moreover, the quantum efficiency for 1056 nm increased steadily with the heat–treatment duration. The stimulated emission cross–section and gain bandwidth for 1056 nm laser transition has shown to be 2.92 × 10^?20 cm² and 9.19 × 10^?26 cm³ for the Ag NPs embedded glass–composite. The results exemplifies the suitability of Ag NPs embedded glass–composites for the fabrication of compact solid–state infrared lasers.     

A straightforward preparation and characterization of novel poly(vinyl alcohol)/organoclay/silver tricomponent nanocomposite films

In the present investigation, novel poly(vinyl alcohol)/organoclay/silver (PVA/OMMT/Ag) tricomponent nanocomposite (NC) films with different compositions were prepared by solution intercalation method under ultrasonic irradiation process. The NC films were obtained by mixing a colloidal solution consisting of Ag nanoparticles (NPs) (3, 5, 7 and 9 wt%) with a water solution of PVA and OMMT (10 wt%) via solution casting method. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA) were utilized to characterize the morphology and properties of the PVA/OMMT/Ag NC films. TGA confirmed that the heat stability of the nanocomposite was improved. The enhancement in the thermal properties of the hybrid materials was due to strong hydrogen bonding between OH groups of PVA, free acid functionalized groups of OMMT, and the Ag NPs. SEM and TEM results also showed that the OMMT and Ag NPs were dispersed homogeneously in the PVA matrix on nanoscale.     

Synthesis of Bimetallic Nanoparticles (Au–Ag Alloy) Using <Emphasis Type="Italic">Commelina nudiflora L.</Emphasis> Plant Extract and Study its on Oral Pathogenic Bacteria

In present study, biosynthesis of Au–Ag alloy nanoparticles (NPs) using Commelina nudiflora aqueous extract as a stabilizing and reducing agent is reported. The crystalline nature, size, shape and composition of synthesized Au–Ag alloy NPs were characterized by UV–Vis spectrophotometer, field emission scanning electron spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscope, X-ray diffraction and fourier transform-infrared spectroscopy (FT-IR). The synthesized Au–Ag alloy NPs exhibited different ranges of sizes between 20 and 80 nm with different morphology such as spherical, rod and triangular. FT-IR spectral data revealed that the plant extract contains amine, alcohol, phenol and alkane molecules which are critically involved in the formation of Au–Ag alloy NPs. Finally, the biosynthesized Au–Ag alloys NPs exhibited a strong minimum inhibitory, minimum bactericidal activity against selected oral pathogenic bacteria. The present study gives an important suggestion on plant extract mediated synthesis bimetallic NPs (Au–Ag alloy) emphasis on oral pathogenic bacteria activities.