Morphology Of AgNPs Research Articles

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.

Eco-friendly synthesis of silver nanoparticles from peel and juice C. limon and their antiviral efficacy against HSV-1 and SARS-CoV-2

The growing threat of viral infections requires innovative therapeutic approaches to safeguard human health. Nanomaterials emerge as a promising solution to overcome the limitations associated with conventional therapies. The eco-friendly synthesis of silver nanoparticles (AgNPs) currently represents a method that guarantees antimicrobial efficacy, safety, and cost-effectiveness. This study explores the use of AgNPs derived from the peel (Lp-AgNPs) and juice (Lj-AgNPs) Citrus limon “Ovale di Sorrento”, cultivars of the Campania region. The antiviral potential was tested against viruses belonging to the Coronaviridae and Herpesviridae. AgNPs were synthesized by reduction method using silver nitrate solution mixed with aqueous extract of C. limon peel and juice. The formation of Lp-AgNPs and Lj-AgNPs was assessed using a UV–Vis spectrophotometer. The size, ζ-potential, concentration, and morphology of AgNPs were evaluated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and field emission-scanning electron microscopy (FE-SEM). Cytotoxicity was evaluated in a concentration range between 500 and 7.8 µg/mL on VERO-76 and HaCaT cells, with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium test bromide (MTT). Antiviral activity consisted of virus pre-treatment, co-treatment, cellular pre-treatment, and post-infection tests versus HSV-1 and SARS-CoV-2 at a multiplicity of infections (MOI) of 0.01. Plaque reduction assays and real-time PCR provided data on the antiviral potential of tested compounds. Lp-AgNPs and Lj-AgNPs exhibited spherical morphology with respective diameters of 60 and 92 nm with concentrations of 4.22 and 4.84 × 1010 particles/mL, respectively. The MTT data demonstrated minimal cytotoxicity, with 50 % cytotoxic concentrations (CC50) of Lp-AgNPs and Lj-AgNPs against VERO cells of 754.6 and 486.7 µg/mL. Similarly, CC50 values against HaCaT were 457.3 µg/mL for Lp-AgNPs and 339.6 µg/mL for Lj-AgNPs, respectively. In the virus pre-treatment assay, 90 % inhibitory concentrations of HSV-1 and SARS-CoV-2 were 8.54–135.04 µg/mL for Lp-AgNPs and 6.13–186.77 µg/mL for Lj-AgNPs, respectively. The molecular investigation confirmed the antiviral data, recording a reduction in the UL54 and UL27 genes for HSV-1 and in the Spike (S) gene for SARS-CoV-2, following AgNP exposure. The results of this study suggest that Lp-AgNPs and Lj-AgNPs derived from C. Limon could offer a valid ecological, natural, local and safe strategy against viral infections.

Synergistically controlled in situ growth of silver nanoparticles leading to organization of anisotropic liquid crystalline medium

ABSTRACT An in-depth macroscopic and microscopic investigation is carried out regarding understanding phase ordering and organisation of nematic phase of a room temperature nematic liquid crystal (NLC) MBBA (N-(4-methoxybenzylidene)-4-butylaniline) in the presence of silver nanoparticles (AgNPs) which are synthesised in situ in a single step using MBBA as a template as well as a reducing and stabilising unit. A synergistic effect between anisotropic LC structure and morphologies of AgNPs is observed. The LC-AgNP composite exhibits better thermal stability and phase ordering compared to its neat LC counterpart as indicated by combined study of optical polarization microscopy (OPM) and differential scanning calorimetry (DSC). While OPM study exhibits emergence of smectic mesophase in LC-AgNP composites, DSC manifests significant enhancement in the isotropic temperature and associated enthalpy as well as a change in the kinetic behaviour in LC-AgNP composites compared to neat LC. Also, an alternation in the electronic properties of LC-AgNP composites compared to neat LC is recognised. Such ordering at the macroscopic scale is well supported by our microscopic observations through spectroscopic studies such as Fourier transform infrared (FTIR) and X-ray diffraction (XRD) which provides valuable insights regarding understanding the organisation process more closely.

Development and characterization of three-dimensional antibacterial nanocomposite sponges of chitosan, silver nanoparticles and halloysite nanotubes.

In this work, we developed novel nanocomposite three-dimensional (3D) scaffolds composed of chitosan (CTS), halloysite nanotubes (HNTs) and silver nanoparticles (AgNPs) with enhanced antimicrobial activity and fibroblast cell compatibility for their potential use in wound dressing applications. A stock CTS-HNT solution was obtained by mixing water-dispersed HNTs with CTS aqueous-acid solution, and then, AgNPs, in different concentrations, were synthesized in the CTS-HNT solution via a CTS-mediated in situ reduction method. Finally, freeze-gelation was used to obtain CTS-HNT-AgNP 3D porous scaffolds (sponges). Morphology analysis showed that synthesized AgNPs were spherical with an average diameter of 11 nm. HNTs' presence did not affect the AgNPs morphology or size but improved the mechanical properties of the scaffolds, where CTS-HNT sponges exhibited a 5 times larger compression stress than bare-CTS sponges. AgNPs in the scaffolds further increased their mechanical strength in correlation to the AgNP concentration, and conferred them improved antibacterial activity against Gram-negative and Gram-positive bacteria, inhibiting the planktonic proliferation and adhesion of bacteria in a AgNP concentration depending on manner. In vitro cell viability and immunofluorescence assays exhibited that human fibroblast (HF) culture was supported by the sponges, where HF retained their phenotype upon culture on the sponges. Present CTS-HNT-AgNP sponges showed promising mechanical, antibacterial and cytocompatibility properties to be used as potential scaffolds for wound dressing applications.

Construction and antibacterial activities of walnut green husk polysaccharide based silver nanoparticles (AgNPs)

In this paper, the size-controllable nano‑silver particles (AgNPs) were synthesized from walnut green husk polysaccharide, and its cytotoxicity and antibacterial activity were evaluated. Firstly, acidic polysaccharide WGHP2 was extracted from walnut green husk, and then the silver ion in AgNO3 was reduced in WGHP2 aqueous solution using NaBH4, so as to synthesize the nano‑silver composite. The nano‑silver composite was characterized by transmission electron microscope, Fourier infrared spectroscopy, ultraviolet-visible spectrometer, scanning electron microscope, inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy. The results show that AgNPs stabilized by WGHP2 are mainly regular spheres with an average particle size distribution of 15.04–19.23 nm. The particle size distribution and morphology of AgNPs changed with the concentration of silver precursor, which is related to the dispersion of silver precursor in polysaccharide aqueous solution and the formation of AgO coordination bond between silver precursor and polysaccharide molecules. These coordination bonds changed the ability of nanoparticles to produce and release Ag+, and thus regulated their antibacterial activity and cytotoxicity, as evidenced by the experimental result of the cytotoxicity of the nano‑silver particle against PC12 cells and the bacteriostatic effect on E.coli and S.aureus. Conclusively, WGHP2-Ag has good stability, antibacterial activity and low cytotoxicity.

Preparation of Green Silver Nanoparticles and Eco-Friendly Polymer-AgNPs Nanocomposites: A Study of Toxic Properties across Multiple Organisms.

This article focuses on the eco-friendly (green) synthesis of silver nanoparticles (AgNPs) and their incorporation into a polymer matrix. For AgNPs synthesis, Lavandula angustifolia (lavender) leaf extract was used as a reducing and stabilizing agent, and as a silver precursor, AgNO3 solution with different concentrations of silver (50, 100, 250, and 500 mg/L) was used. Prepared AgNPs colloids were characterized using UV-vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The spherical morphology of AgNPs with an average size of 20 nm was confirmed across all samples. Further, the antimicrobial properties of the AgNPs were evaluated using the disk diffusion method on algae (Chlorella kessleri) and the well diffusion method on bacteria (Staphylococcus chromogenes, Staphylococcus aureus, and Streptococcus uberis), along with root growth inhibition tests on white mustard (Sinapis alba). Polymer composite (PVA-AgNPs) was prepared by incorporation of AgNPs into the polymer matrix. Subsequently, non-woven textiles and thin foils were prepared. The distribution of AgNPs within the nanocomposites was observed by scanning electron microscopy (SEM). Antibacterial properties of PVA-AgNPs composites were analyzed on bacteria Streptococcus uberis. It was found that not only AgNPs showed good antimicrobial properties, but toxic properties were also transferred to the PVA-AgNPs nanocomposite.

The Influence of Precursor and Seminyak (Champeria sp.) Leaf Extract Concentrations in Microwave-Assisted Silver Nanoparticle Fabrication

Abstract Silver nanoparticles (AgNPs) possess remarkable characteristics, including high antibacterial efficacy, excellent thermal conductivity, and superior electrical conductivity. However, conventional methods employed for AgNPs synthesis still rely on the use of hazardous chemicals, which pose significant threats to the environment and human health. Recently, the synthesis of AgNPs using green and sustainable methods has gained considerable attention. In this study, concentration of AgNO3 (1; 10 and 100 mM) and Seminyak (Champeria sp.) leaf extract (1 and 2 wt%) were varied to know their influence on the fabrication of AgNPs through a microwave-assisted synthesis approach. The results demonstrated that the precursor and Seminyak leaf extract concentrations significantly influenced the AgNPs properties. Visual and UV-Vis spectroscopy results suggested that AgNPs might only form at 100 mM AgNO3, which is indicated by darker appearance of sample and the presence of broad peak at 400-500 nm. Based on transmission electron microscopy (TEM) results, increasing the Seminyak leaf extract concentrations exhibited enhanced stability and monodispersity of the nanoparticles with the average particle size of 26.8 ± 10.9 nm and 17.8 ± 7.6 nm for 1 and 2 wt%, respectively. The optimized precursor and Seminyak leaf extract concentrations can be utilized to tailor the size and morphology of AgNPs, making them suitable for various applications such as catalyst, electronics, and medicine.

Synthesis, Characterization, and Antibacterial Activity of Silver Nanoparticles Supported on Bovine Bone Powder Using Heterotheca inuloides: An In Vitro Study

This paper reports on the biosynthesis, characterization, as well as the bactericide and cytotoxic properties of silver nanoparticles supported on bovine bone powder (Ag-NPs/BBP). The silver nanoparticles were obtained through the bioreduction of AgNO3, using an infusion of Heterotheca inuloides leaves and flowers as a reducing agent and bovine bone powder as a support. The ratio of Ag-NPs/bovine bone powder was set as 1:10. The characterization was performed with SEM–EDS, XRD, UV–Vis, and TEM, which showed the formation of nanoparticles with an average size of 22.6 ± 10.8 nm and a quasi-spherical Ag-NPs morphology supported on the BBP surface. The nanocomposite exhibited a band gap of 2.19 eV. The minimal inhibitory concentration and the minimal bactericidal concentration against S. aureus, E. coli, and S. epidermidis were determined for each strain. In addition, the cytotoxic evaluation of the Ag-NPs/BBP on J774.2 mouse macrophage cells was performed. The Ag-NPs/BBP exhibited a bactericide effect on the strains studied, and the cytotoxicity had a dose-dependent behavior on the cells studied. Therefore, it was found that the ecofriendly synthesized Ag-NPs supported on bovine bone powder resulted in an effective bactericidal system against the strains studied, without significant cytotoxicity.

Use of Residual Malt from an Artisanal Beer Brewing Process in the Biosynthesis of Silver Nanoparticles Mediated by Nucleating and Structure-Directing Agents.

Biosynthesized silver nanoparticles (AgNPs) are widely used in varied applications, which are morphology dependent. Consequently, a morphology-controlled synthesis is mandatory. Although there are several studies focused on the plant extract-based biosynthesis of metallic nanoparticles, the use of extracts obtained from agro-wastes is scant. Furthermore, information regarding morphology modification through the use of additional agents is even more scarce. Thus, in this study, AgNPs were synthesized using a malt extract (ME) obtained from an artisanal beer brewing process residue. Additionally, sodium chloride (NaCl), gum arabic (GA), and talc (T) were used in an attempt to modify the morphology of AgNPs. XRD, DLS, SEM, and TEM results demonstrate that stable AgNPs of different sizes and shapes were synthesized. FTIR, HPLC analysis, and the quantification of total proteins, free amino acids, reducing sugars, and total polyphenols before and after AgNPs synthesis showed that ME biomolecules allowed them to act as a source of reducing and stabilizing agents. Therefore, this study provides evidence that ME can be successfully used to biosynthesize AgNPs. Additionally, the antibacterial activity of AgNPs against Gram-negative and Gram-positive bacteria was evaluated. Results indicate that AgNPs show a higher antibacterial activity against Gram-positive bacteria.

Pharmacological Effect of In Vitro Antioxidant Property and Green Synthesis of Silver Nanoparticles (AgNPs) Utilizing Murraya koenigii Antibacterial Application

ABSTRACT Background: Nonessential heavy metals pose a significant threat to human health due to their toxicity. Mercury, in particular, is identified as a hazardous metal. The study aims to detect mercury using colorimetric analysis with Murraya koenigii, emphasizing the eco-friendliness of the method. Aims and Objectives: The primary objective is to detect mercury using a colorimetric analysis method employing Murraya koenigii. Additionally, the study aims to investigate the eco-friendliness of this detection method. Materials and Methods: Colorimetric analysis was conducted using Murraya koenigii to detect mercury. Ultraviolet-visible (UV-vis) spectroscopy was employed to detect the formation of silver nanoparticles (AgNPs), with a characteristic surface plasmon resonance (SPR) band observed. X-ray diffraction (XRD) data analysis was performed to determine the crystalline nature and size of AgNPs. Scanning electron microscopy (SEM) was utilized to visualize the morphology of AgNPs. Fourier transform infrared (FTIR) spectroscopy was employed to identify functional groups involved in reducing silver ions. Antibacterial properties of synthesized AgNPs were tested against various microorganisms, including Escherichia coli, Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. Results: Mercury was successfully detected using colorimetric analysis with Murraya koenigii. Formation of AgNPs was confirmed by UV-vis spectroscopy, with a characteristic SPR band at 418 nm. AgNPs were found to be crystalline with an average size of 5.20 nm, as determined by XRD analysis. SEM images revealed spherical and polycrystalline AgNPs. FTIR spectra indicated the involvement of the -OH group of compounds in the extract in reducing silver ions. Synthesized AgNPs exhibited antibacterial properties against various microorganisms. Conclusion: A sustainable and eco-friendly method for synthesizing AgNPs using Murraya koenigii extract was successfully developed. This method not only detected mercury but also demonstrated antibacterial properties against various microorganisms. The study underscores the health implications of nonessential heavy metals, emphasizing the importance of eco-friendly detection and mitigation methods.

Microfluidic production of silver nanoparticles demonstrates ability for on demand synthesis of a wide size distribution of particles

Silver nanoparticles (AgNP) can help prevent infection of virus and bacteria. The size and morphology of AgNP can be crucial to function, with smaller nanoparticles (< 20 nm) able to penetrate the cell wall. This is significant as oxidative stress and genotoxicity are associated with some sizes and coatings of AgNP, contraindicating the use of AgNP to reduce infection. We present evidence that a microfluidic chip can synthesize larger sizes and distributions of AgNP from the nano-to-micro size range. We show results from a microfluidic mixing chip that can produce a wide range of nano-to-micro size (~ 24–400 nm) AgNP. Synthesis is based on a modified Turkevich method, using a single-step AgNP synthesis on the microfluidic chip using two chemical components, trisodium citrate (NaCit) and AgNO3. To make AgNP more accessible, we describe the microfluidic chip and conditions capable of synthesis. We also describe how modification of flow rate and chemical reagent concentration change particle diameter during production. In our experiments, we found that AgNP production created a visible adsorption line in the microfluidic device, possibly owing to AgNP surface interaction at the polydimethylsiloxane (PDMS) interface. We characterize these particles with dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Based on optical light microscopy, we hypothesize that AgNP formation primarily occurs at the interface between the two chemical reagent streams. We also conclude that AgNP size increases could be due to interaction with the PDMS surface, which is known to be porous. Future work will help to understand how surface interaction may influence the formation of larger particles.

Humic Polyelectrolytes Facilitate Rapid Microwave Synthesis of Silver Nanoparticles Suitable for Wound-Healing Applications.

This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes-humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and leonardite and one sodium fulvate isolated from natural brown water seeped through peat deposits were used in this study. The dynamics of the growth rate of AgNPs was characterised by UV-VIS spectroscopy by measuring the intensity of surface plasmon resonance at 420 nm. Transmission electron microscopy was used to characterise the size and morphology of AgNPs. Dynamic light scattering was used to determine size distributions of the synthesised AgNPs in the solutions. It was established that both conventional and microwave syntheses assisted with the coal humates produced small-size AgNPs in the range from 4 to 14 nm, with the maximum share of particles with sizes of (6 ± 2) nm by TEM estimates. The peat fulvate yielded much larger NPs with sizes from 10 to 50 nm by TEM estimates. DLS measurements revealed multimodal distributions of AgNPs stabilised with HS, which included both single NPs with the sizes from 5 to 15 nm, as well as their dominating aggregates with sizes from 20 to 200 nm and a smaller portion of extra-large aggregates up to 1000 nm. The given aggregates were loosely bound by humic polyelectrolyte, which prevented the coalescence of AgNPs into larger particles, as can be seen in the TEM images. The significant acceleration in the reaction time-a factor of 60 to 70-was achieved with the use of MW irradiation: from 240 min down to 210-240 s. The coal humate stabilised AgNPs showed antimicrobial properties in relation to S. aureus. A conclusion was made regarding the substantial advantages of microwave synthesis in the context of time and scaling up for the large-scale production of AgNP-HS preparations with antimicrobial properties suitable for external wound-healing applications.

PVP-capped silver nanoparticles for efficient SERS detection of adenine based on the stabilizing and enrichment roles of PVP.

Apolyvinylpyrrolidone-capped (PVP-capped) strategy is reportedto synthesize Ag NPs on silicon wafers via galvanic replacement reaction for SERS detection of adenine, where PVP acts as stabilizing agent in synthesis and efficient enrichment in detection. The morphologies of Ag NPs are optimized with uniform particle size by adjusting synthesis conditions, which hold excellent SERS performances like a high enhancement factor of 1.42 × 106, good uniform, reproducibility, and transferable nature. With the protection of the capped PVP, the Ag NPs keep excellent SERS properties even against harsh conditions of high temperature (100 ℃) and strong acid and base for 24h. Utilizing the structural feature of PVP with abundant carbonyl groups, the PVP-capped Ag NPs achieve efficient enrichment of adenine through hydrogen bonding and π-interactions, which is analyzed by density functional theory. Quantitative detection of adenine is performed with a wide linear range from 10-4 to 10-8M and a low limit of detection of 1nM. Detection of adenine in human urine samples is achieved with a recovery of 99.1-103.4% and an RSD of less than 5%.

Green synthesis of silver nanoparticles using aqueous leaf extract of Saussurea obvallata for efficient catalytic reduction of nitrophenol, antioxidant, and antibacterial activity

Of several noble metal nanoparticles, silver nanoparticles (AgNPs) have attracted special attention due to their distinct properties, such as favorable electrical conductivity, chemical stability, and catalytic and antibacterial activities. Green synthesis of AgNPs using plant extracts containing phytochemical agents has attracted considerable interest. This environmentally friendly approach is more biocompatible and cost-efficient and has the capability of supporting large-scale synthesis. This study developed an eco-friendly method for the preparation of AgNPs using the aqueous leaf extract of Saussurea obvallata as reducing and capping agents. Ultraviolet visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses were conducted to characterize the synthesized AgNPs. The morphology of AgNPs was found to be spherical with an average crystallite size of 12 nm and a maximum absorbance at 410 nm. 10 mg of AgNPs had potential to reduce 4-nitrophenol to 4-aminophenol in 16 min and exhibited strong biological activities against the Gram-negative bacteria Escherichia coli (12 mm) and Gram-positive bacteria Enterococcus faecalis (13 mm). The antioxidant activity of the synthesized AgNPs was investigated against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and exhibited up to 61.21% ± 0.02% at an AgNPs concentration of 500 μg/mL.

Shape Dependence of Silver-Nanoparticle-Mediated Synthesis of Gold Nanoclusters with Small Molecules as Capping Ligands.

In this study, differently shaped silver nanoparticles used for the synthesis of gold nanoclusters with small capping ligands were demonstrated. Silver nanoparticles provide a reaction platform that plays dual roles in the formation of Au NCs. One is to reduce gold ions and the other is to attract capping ligands to the surface of nanoparticles. The binding of capping ligands to the AgNP surface creates a restricted space on the surface while gold ions are being reduced by the particles. Four different shapes of AgNPs were prepared and used to examine whether or not this approach is dependent on the morphology of AgNPs. Quasi-spherical AgNPs and silver nanoplates showed excellent results when they were used to synthesize Au NCs. Spherical AgNPs and triangular nanoplates exhibited limited synthesis of Au NCs. TEM images demonstrated that Au NCs were transiently assembled on the surface of silver nanoparticles in the method. The formation of Au NCs was observed on the whole surface of the QS-AgNPs if the synthesis of Au NCs was mediated by QS-AgNPs. In contrast, formation of Au NCs was only observed on the edges and corners of AgNPts if the synthesis of Au NCs was mediated by AgNPts. All of the synthesized Au NCs emitted bright red fluorescence under UV-box irradiation. The synthesized Au NCs displayed similar fluorescent properties, including quantum yields and excitation and emission wavelengths.

Green synthesis of silver nanoparticles using extracts of Mikania cordata leaves and evaluation of their antioxidant, antimicrobial and cytotoxic properties

The synthesis of silver nanoparticles using plant extracts is a promising field of research due to the versatile biomedical application of metal nanoparticles. In the present study, silver nanoparticles (AgNPs) were synthesized using the aqueous extract of Mikania cordata leaves where extract act as both reducing and capping agents. Successful biosynthesis of AgNPs had been studied using UV Spectrophotometry that recorded the surface plasmonic resonance peak at around 451 nm. The structural properties and morphology of AgNPs were confirmed by scanning electron microscope with Energy dispersive X-ray (SEM/EDX), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) spectroscopic techniques. In antioxidant assays, AgNPs were found as strong free radical scavenger as ascorbic acid (standard) with the values of 10.06 (EC50, μg/mL) and 20.94 (EC50, μg/mL) for DPPH and ABTS radicals, respectively. In antimicrobial study, the effectiveness of synthesized AgNPs was observed as follows: Shigella boydii > Staphylococcus aureus > Shigella dysenteriae > Escherichia coli. Moreover, the results of cytotoxic assay indicated that AgNPs inhibited the growth of EAC cells in dose-dependent manner. Overall results of this study suggested that the synthesized AgNPs from Mikania cordata leaves have the merits to use in the field of nanomedicines.

Properties and antimicrobial activity of wheat-straw nanocellulose-arabinoxylan acetate composite films incorporated with silver nanoparticles

In the current study, the novel eco-friendly and biodegradable nanocomposite films (NC-AXAc) were prepared from wheat-straw NC and AXAc with improved functional properties. NC derived from wheat-straw cellulose has a fibre-like structure with mean-particle size in the 340–520 nm range. AX derived AXAc was prepared with Degree of Substitution (DS) in the range of 1.85–1.89. Furthermore, to enhance antimicrobial properties, AgNPs were prepared via the reduction method using NaBH4 and added into the concentration of 4 × 10−4M into the emulsion forming composite films. The silver nanoparticles (AgNPs) incorporated in the composite exhibited an average size of 40–70 nm and a surface plasmon resonance (SPR) absorption peak at 395 nm. The high-resolution XPS spectrum of the Ag element showed that the two peaks at around 374.2 eV (Ag3d3/2) and 368.2 eV (Ag3d5/2) clearly revealed the metallic Ag existence in composite films. SEM analysis revealed the coarse and heterogeneous morphology of AgNPs incorporated films. The AgNPs incorporated composites exhibited good mechanical, thermal stability, and antimicrobial activity. The results suggested that AgNPs incorporated NC-AXAc composites could be used as a potential biodegradable antimicrobial nanocomposite in active food packaging systems for shelf-life extension of perishable commodities.

Eco-friendly green synthesis of silver nanoparticles from Aegle marmelos leaf extract and their antimicrobial, antioxidant, anticancer and photocatalytic degradation activity

The present research work, green synthesis of silver nanoparticles (Ag NPs) was synthesized from silver ions using the reducing and capping agents of Aegle marmelos leaf extract. Initially, UV–vis spectrophotometry absorption of the Surface Plasmon Resonance centre at 450 nm was confirmed the formation of Ag NPs. Preliminary phytochemical and FT-IR analysis indicate the identification of secondary metabolised flavonoids that act as the reducing and capping agent of the synthesized Ag NPs. Transmission electron microscope analysis, morphology of Ag NPs shown by transmission electron microscopy is spherical with a size range of ∼30–50 nm. The synthesized Ag NPs were investigate the in-vitro anticancer, antimicrobial and antioxidant activity, results shows the potential activity against the standard drugs. The Ag NPs also revealed the cytotoxicity against MDA-MB-231 human breast cancer cells. The MTT assay shows the IC50 values at 125 ± 4.26 μg/mL of Ag NPs compared to the untreated cells of negative control. The Ag NPs was excellent photocatalyst act as degradation of environmentally polluted Basic Fuchsin dye within 18 min.

Preparation and characterization of carboxymethyl chitosan/κ-carrageenan/silver nanoparticles sponge for wound dressing

A carboxymethyl chitosan/κ-carrageenan (CMCS/κ-C) sponge incorporating green silver nanoparticles (AgNPs) for wound dressing was prepared. The particle size and morphology of AgNPs and the morphology characterization of CMCS/κ-C sponge was investigated. The results showed that the particle size distribution of AgNPs prepared by CMCS was around 10 nm, the best mass ratio of CMCS and κ-C in the sponge was 1:1. Its tensile strength, elongation at break, porosity, water vapor transmission rate, water absorption was 1.51 ± 0.18 MPa, 37.09 ± 1.03 %, 70.24 ± 6.84 %, 1339.27 ± 32.48 g/m²/day, and 2690.26 ± 144.60 %, respectively. The CMCS/κ-C sponge incorporated with AgNPs could inhibit the proliferation of E. coli and S. aureus, and no toxicity to L929 cells, showed good biocompatibility. It could heal wounds in SD rats on the 12th day, the wound healing rate reached 92.82 ± 2.14 %. Therefore, CMCS/κ-C/AgNPs sponge have potential application as wound dressing.

Synthesis of Silver Nanoparticles using Cellulose and Starch Extracted from Brewer Spent Grain: Assessment of their Antimicrobial and Preservatives Activities

Non-porous materials like cellulose and starch can be extracted from agro- industrial wastes and incorporated with nanoparticles for effective biotechnological purposes. In this study, silver nanoparticles (AgNps), silver-cellulose nanoparticles (AgNps-C) and silver-starch nanoparticles (AgNps-S) were characterized by UV-visible spectroscopy. Fourier transform infrared spectroscopy (FTIR) was used to identify viable biomolecules involved in capping and active stabilization of AgNps. Average sizes and morphologies of AgNps, AgNps-C and AgNps-S were further analyzed by scanning electron microscopy (SEM) and the percentage composition of each element was investigated by energy-dispersive X-ray spectroscopy (EDS). Antimicrobial activity of the synthesized AgNPs-C and AgNPs-S was tested against multiple antibiotic resistance microorganisms isolated from fish and meat. Zones of inhibition displayed by AgNPs-C and AgNPs-S ranged from 8.00 to 13.30 mm and 5.00 to 10.30 mm, respectively. The Minimum inhibitory concentration (MIC) for AgNPs-C and AgNPS-S ranged from 125 µg/mL to 500 µg/mL and 500 µg/mL to 1000 µg/mL, respectively. AgNPS-S and AgNPs-C inhibited the growth of microorganisms associated with spoilage of fish and meat. The bio-applications of AgNP –C and AgNP-S can be exploited in food industries as preservative agent or incorporated to packaging materials to elongate the shelf life of food products and reduce the side effects attributed to chemical preservative agents.