Pure Silver Nanoparticles Research Articles

A Review on Silver Nanoparticles: Synthesis Approaches, Properties, Characterization and Applications.

Nanoparticles are a significant topic due to their applications in various fields, including biology, optics, catalysis, pharmaceutics, health, agriculture, and industry, with biosynthesis processes being quick, easy, and environmentally friendly. Due to their applications across multiple industries, silver nanoparticles, or AgNPs, have become the most desired nanoparticles with the recent development of nanotechnology. The physical, chemical, and biological characteristics of AgNPs are being studied. These characteristics are crucial for limiting the hazards associated with silver nanoparticles while optimizing their potential applications in many fields. A higher degree of toxicity in both the environment and living things could arise from the increasing use of silver nanoparticles in the product. Silver nanoparticles find application in wound care, anti-infective therapy, food, pharmaceutical, and cosmetic industries. As antioxidant, antiviral, anticancer, antifungal, antiinflammatory, and microbiological agents, silver nanoparticles are widely used. Not only must the particles be nanoscale in order for silver nanoparticles to be present, but their production must also be simple and inexpensive to achieve. This paper aims to review the different methods of synthesis of silver nanoparticles, properties, characterization, and their applications. In specific, several chemical and green synthesis approaches for synthesising silver nanoparticles have been discussed. The morphology, size, thermal properties, toxicity properties, electrical properties, catalytic properties, and applications of silver nanoparticles are focused. The main focus is on the effective and efficient synthesis of pure silver nanoparticles and their potential applications.

A facile and greener approach for synthesis of lignin capped-silver nanoparticles (LS-AgNPs) and assessment of their antibacterial and antioxidant properties

Silver nanoparticles have garnered significant attention in research due to their numerous advantageous qualities, such as antimicrobial, antioxidant, and anticancer activities. Several methods have been employed previously to produce these nanoparticles, but green synthesis has gained prominence due to its lack of harmful by-products. In this study, stable and biocompatible lignin-capped silver nanoparticles (LS-AgNPs) have been synthesized using a green approach that utilized nontoxic sodium lignosulfonate as both the reducing and capping agents. Various process parameters, such as pH, temperature, time, and raw material concentration have been optimized to simplify, accelerate and mould the synthesis activity easy and eco-friendly. The morphology and dimensions of the prepared lignin-capped silver nanoparticles (LS-AgNPs) have been characterized using UV–Vis spectroscopy, particle size analyser, X-ray diffraction analysis, Fourier transform infrared spectroscopy and Transmission Electron Microscopy. The produced nanoparticles have an average diameter of 24 nm and a FCC crystalline structure that is capped with lignin components. MBC of LS-AgNPs has been found 4 and 6 ppm against S. aureus and E. coli bacteria, respectively. The IC50 value for antioxidant property has been found 34.37 μg/mL. In summary, the prepared LS-AgNPs have exhibited a synergistic effect resulting from the combination of lignosulfonate and silver particles. The synergistic effect not only enhances antimicrobial activity and antioxidant property remarkably, this approach enables the utilization of biobased silver nanoparticles for various applications with its requirement of minimal quantity to have much lowered toxicity compared to pure silver nanoparticles.

Preparation of pure phase silver nanoparticles: Morphological, optical, binding interactions with bovine serum albumin and antioxidant potential studies

Pure silver nanoparticles (AgNPs) were synthesized using Senecio madagascariensis plant extract and oleic acid as capping agents. The powder X-ray diffraction patterns of the silver nanoparticles were indexed to the face-centred cubic phase of Ag. TEM images of the nanoparticles revealed polydisperse spherical nanoparticles with particle size of 9 to 22 nm range. The GC-MS revealed terpenes as some phytochemicals extracted, which the FTIR bands corroborated. The results confirmed that increase in oleic acid concentration increased the size of the silver nanoparticles. The nanoparticles' optical band gaps, Eg, were 2.26 – 2.56 eV, which decreased with particle size. The AgNPs exhibited potential antioxidant activity, as demonstrated by the DPPH scavenging assay. The DPPH scavenging activity was highest, with AgNP1 at 80 % and an IC50 of 1.668 μg/mL. Fluorescence and ultraviolet (UV) titrations were used to study the interaction of the silver nanoparticles (AgNP1) with bovine serum albumin (BSA). The Kapp value of the AgNP1 was calculated to be 3.14 × 104 ± 0.02 Lmol−1, KSV calculated as 7.38 × 104 ± 0.12 M−1. In the study, AgNPs bind to BSA potentially through a static quenching mechanism with one binding site that leads to developing a ground state complex. It is proposed that AgNPs bond to BSA's surface spontaneously based on its thermodynamic characteristics and binding constants.

Sonochemical synthesis of silver nanoparticles using orange juice: Cytotoxic behaviour and applications

One-pot open beaker green synthesis of silver nano-particles (Ag NPs) by ultrasound energy at room temperature is presented. Citrus fruit-mediated Ag NPs formation was monitored by observing surface plasmon resonance (SPR) by UV–Visible measurements. Orange juice extract played a dual role as it helped in the surface capping of Ag NPs while being a reducing agent to yield phase pure silver nanoparticles of less than 10 nm diameter. The phase purity and particle diameter were confirmed by X-ray diffraction (XRD) patterns and organic functionality was established by infra-red spectroscopy. The morphology was understood by AFM and SEM. Additionally, the study investigates the antioxidant activity and antimicrobial efficacy of so-synthesized Ag NPs against pathogenic microorganisms such as E. coli. and S. aureus. The study also assesses the anticancer activity of Ag NPs on four different cancer cell lines (A 2780, MDA-MB-231, A 375, and HepG2). The half maximal inhibitory concentration (IC50) of nano-silver sample SS-1 was about 5 μg against A 2780 and MDA-MB-231 cell lines.

Activity of pure flavonoid-based green silver nano particles against breast cancer: A combined experimental and computational investigation

Because of the wide range of applications in various industries, the development of novel nanomaterials is receiving more and more attention nowadays. A green route to synthesize one such versatile nanomaterial, silver nanoparticles (AgNPs) with a pure flavonoid, quercetin has been explored in this study. The reducing and capping mechanism of quercetin was examined using density functional theory (DFT). Dynamic light scattering (DLS), UV–vis spectra (UV–Vis), and Transmission Electron Microscopy (TEM) studies confirmed that the synthesized AgNPs are stable, monodispersed, spherical shaped with an average size of 16 nm. A molecular docking study has identified the epidermal growth factor receptor (EGFR) protein as a potential target for quercetin-capped AgNPs to fight against breast cancer. Molecular dynamics (MD) simulation has quantified the efficiency of quercetin-capped AgNPs over quercetin only in targeting breast cancer. These findings will be helpful in using quercetin-based AgNPs for drug discovery against breast cancer.

Green Synthesis of Uncoated and Olive Leaf Extract-Coated Silver Nanoparticles: Sunlight Photocatalytic, Antiparasitic, and Antifungal Activities.

The circular economy, which attempts to decrease agricultural waste while also improving sustainable development through the production of sustainable products from waste and by-products, is currently one of the main objectives of environmental research. Taking this view, this study used a green approach to synthesize two forms of silver nanoparticles: coated silver nanoparticles with olive leaf extract (Ag-olive) and uncoated pure silver nanoparticles (Ag-pure), which were produced by the calcination of Ag-olive at 550 °C. The extract and the fabricated nanoparticles were characterized by a variety of physicochemical techniques, including high-performance liquid chromatography (HPLC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Adult ticks (Hyalomma dromedarii) (Acari: Ixodidae) were used in this study to evaluate the antiparasitic activity of synthesized nanoparticles and extract. Furthermore, the antifungal activity was evaluated against Aspergillus aculeatus strain N (MW958085), Fuserium oxysporum (MT550034), and Alternaria tenuissiuma (MT550036). In both antiparasitic and antifungal tests, the as-synthesized Ag-olive showed higher inhibition activity than Ag-pure and olive leaf extract. The findings of this research suggest that Ag-olive may be a powerful and eco-friendly antiparasitic and antifungal agent. Ag-pure was also evaluated as a photocatalyst under sunlight for the detoxification of Eri-chrome-black T (EBT), methylene blue (MB), methyl orange (MO), and rhodamine B (RhB).

Biosynthesis of Silver Based Nanoparticles Using Plant Leaves Extracts and Their Antibacterial Activities

The emergence of antibiotic-resistant bacteria is a major global public health concern. Antibacterial agents are one of the most exciting areas for the use of nanoparticles and have shown great potential as alternative antibacterial agents due to their outstanding physical and chemical properties. The biosynthesis and antibacterial activities of Silver Nanoparticles (AgNPs) could contribute to the development of innovative antimicrobial drugs with potential for a variety of medical applications. The X Ray Diffraction (XRD) results showed that the formed particles were pure silver nanoparticles with a cubic crystal structure and granular size. Fourier-transform infrared (FTIR) also showed that functional aggregates formed, and the thumb region confirmed the presence of silver nanoparticles. In addition, we investigated the Uv-Visible and biological activity of AgNPs. A study of the biological activity of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli, and Klebsiella pneumonia) bacteria showed the importance of nano-silver particle biosynthesis.

Ultrastructure and Surface Composition of Glutathione-Terminated Ultrasmall Silver, Gold, Platinum, and Alloyed Silver-Platinum Nanoparticles (2 nm).

Alloyed ultrasmall silver-platinum nanoparticles (molar ratio Ag:Pt = 50:50) were prepared and compared to pure silver, platinum, and gold nanoparticles, all with a metallic core diameter of 2 nm. They were surface-stabilized by a layer of glutathione (GSH). A comprehensive characterization by high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), differential centrifugal sedimentation (DCS), and UV spectroscopy showed their size both in the dry and in the water-dispersed state (hydrodynamic diameter). Solution NMR spectroscopy (1H, 13C, COSY, HSQC, HMBC, and DOSY) showed the nature of the glutathione shell including the number of GSH ligands on each nanoparticle (about 200 with a molecular footprint of 0.063 nm2 each). It furthermore showed that there are at least two different positions for the GSH ligand on the gold nanoparticle surface. Platinum strongly reduced the resolution of the NMR spectra compared to silver and gold, also in the alloyed nanoparticles. X-ray photoelectron spectroscopy (XPS) showed that silver, platinum, and silver-platinum particles were at least partially oxidized to Ag(+I) and Pt(+II), whereas the gold nanoparticles showed no sign of oxidation. Platinum and gold nanoparticles were well crystalline but twinned (fcc lattice) despite the small particle size. Silver was crystalline in electron diffraction but not in X-ray diffraction. Alloyed silver-platinum nanoparticles were almost fully amorphous by both methods, indicating a considerable internal disorder.

The Origin of the Intracellular Silver in Bacteria: A Comprehensive Study using Targeting Gold-Silver Alloy Nanoparticles.

The bactericidal effects of silver nanoparticles (Ag NPs) against infectious strains of multiresistant bacteria is a well-studied phenomenon, highly relevant for many researchers and clinicians battling bacterial infections. However, little is known about the uptake of the Ag NPs into the bacteria, the related uptake mechanisms, and how they are connected to antimicrobial activity. Even less information is available on AgAu alloy NPs uptake. In this work, the interactions between colloidal silver-gold alloy nanoparticles (AgAu NPs) and Staphylococcus aureus (S. aureus) using advanced electron microscopy methods are studied. The localization of the nanoparticles is monitored on the membrane and inside the bacterial cells and the elemental compositions of intra- and extracellular nanoparticle species. The findings reveal the formation of pure silver nanoparticles with diameters smaller than 10nm inside the bacteria, even though those particles are not present in the original colloid. This finding is explained by a local RElease PEnetration Reduction (REPER) mechanism of silver cations emitted from the AgAu nanoparticles, emphasized by the localization of the AgAu nanoparticles on the bacterial membrane by aptamer targeting ligands. These findings can deepen the understanding of the antimicrobial effect of nanosilver, where the microbes are defusing the attacking silver ions via their reduction,and aid in the development of suitable therapeutic approaches.

Sustainable Nanotechnology- Green Synthesis Methods for Silver Nanoparticles

Silver has a long history of being an excellent substance in its field of medicine Because of their special qualities, they have been used for a wide range of products, including antibacterial agents, household, industrial, and healthcare-related items, coatings for medical devices, drug delivery, and eventually to increase the tumor-killing effects of anticancer drugs. By the help of nanotechnology pure silver nanoparticles is obtained. The bioreduction of metal ions into their elemental form in the size range of 1–100 nanometers (nm) is known as "green synthesis," and it requires the use of plants or plant parts. As a result, the biological activities are increased and the toxicity level is decreased when AgNPs are synthesised using a green method. Scientists and researchers from various fields are becoming more and more interested in synthesising nanoparticles, particularly silver nanoparticles. However, they are unsure of the proper procedures to follow and the safety precautions to take when synthesising AgNPs, which is why the main goal of this paper is to provide a detailed methodology for the environmentally friendly synthesis of silver nanoparticles.

Theoretical study of Ag and Au triple core-shell spherical plasmonic nanoparticles in ultra-thin film perovskite solar cells.

This work demonstrates the enhancement of the power conversion efficiency of thin film organic-inorganic halide perovskites solar cells by embedding triple-core-shell spherical plasmonic nanoparticles into the absorber layer. A dielectric-metal-dielectric nanoparticle can be substituted for embedded metallic nanoparticles in the absorbing layer to modify their chemical and thermal stability. By solving Maxwell's equations with the three-dimensional finite difference time domain method, the proposed high-efficiency perovskite solar cell has been optically simulated. Additionally, the electrical parameters have been determined through numerical simulations of coupled Poisson and continuity equations. Based on electro-optical simulation results, the short-circuit current density of the proposed perovskite solar cell with triple core-shell nanoparticles consisting of dielectric-gold-dielectric and dielectric-silver-dielectric nanoparticles has been enhanced by approximately 25% and 29%, respectively, as compared to a perovskite solar cell without nanoparticles. By contrast, for pure gold and silver nanoparticles, the generated short-circuit current density increased by nearly 9% and 12%, respectively. Furthermore, in the optimal case of the perovskite solar cell the open-circuit voltage, the short-circuit current density, the fill factor, and the power conversion efficiency have been achieved at 1.06 V, 25 mAcm-2, 0.872, and 23.00%, respectively. Last but not least, lead toxicity has been reduced due to the ultra-thin perovskite absorber layer, and this study provides a detailed roadmap for the use of low-cost triple core-shell nanoparticles for efficient ultra-thin-film perovskite solar cells.

Improved room temperature ethanol vapors sensing using silver nanoparticles decorated graphitic carbon nitride (Ag-gCN) nanocomposite

In the present study the sensing behavior of pure graphitic carbon nitride (gCN) and silver nanoparticles decorated gCN (Ag-gCN) is investigated towards ethanol vapors. The XRD, HRTEM and EDS study confirms the successful synthesis of gCN and Ag-gCN. The sensing response (100 ppm) of pure gCN enhances to 14.87 % from 6.67 % with the addition of Ag. The response/recovery time also reduces to several folds for Ag-gCN. The sensor also shows good linearity and stability.

Synthesis and Catalytic Study of NiAg Bimetallic Core-Shell Nanoparticles.

This publication presents the synthesis of core-shell nanoparticles, where the core was Ni, and the shell was a Ag-Ni nano alloy. The synthesis was based on the reduction of Ni and Ag ions with sodium borohydride in the presence of trisodium citrate as a stabilizer. In order to determine the phase composition of the obtained nanoparticles, an XRD study was performed, and in order to identify the oxidation states of the nanoparticle components, an XPS spectroscopic study was performed. The composition and shape of the particles were determined using the HR-TEM EDS test. The obtained nanoparticles had a size of 11 nm. The research on catalytic properties was carried out in the model methylene blue reduction system. The investigation of the catalytic activity of colloids was carried out with the use of UV-Vis spectrophotometry. The Ag-Ni alloy was about ten times more active than were pure silver nanoparticles of a similar size.

Ag-Cu nanoalloys: An electrochemical sensor for H2O2 detection

Nanoalloys (Ag-Cu)-based electrochemical sensor for H2O2 detection has been fabricated. Pure silver (Ag) nanoparticles (NPs) and silver-copper (Ag-Cu) nanoalloys have been synthesized by using chemical reduction methodology while ratios of precursors vary as 9:1, 8:2, 7:3 and 6:4. Characterization of the prepared samples has been carried out by X-ray diffraction (XRD) which revealed the face centered cubic crystal structure of Ag NPs and Ag-Cu nanoalloys. An average crystallite size of powdered samples was calculated from XRD analysis to be 20–50 nm. Scanning electron microscopy exhibits spherical distribution of nanoparticles of the prepared alloys. A red shift was measured using UV–visible spectroscopy corresponding to the increase of copper contents in Ag-Cu nanoalloys. Cyclic voltammetric (CV) response of nanoalloys modified glassy carbon electrode was recorded in phosphate buffer of pH 7.4 in the absence and presence of H2O2. CV results demonstrate reduction of H2O2 at 0 V. Charge transfer resistance (Rct) has been calculated from electrochemical impedance spectroscopy and is considered as sensing parameter in the present study. Among all the compositions, Ag-Cu (9:1) nanoalloys have shown the best sensing performance towards detection of H2O2 having limit of detection (LOD) and limit of quantification (LOQ) of 152 µM and 508 µM, respectively.

Influence of temperature on the physical properties and bio-activity of pure (ligand-free) EB PVD silver nanoparticles

Influence of temperature on the physical properties and bio-activity of pure (ligand-free) EB PVD silver nanoparticles

Facile synthesis of pure silicon zeolite-confined silver nanoparticles and their catalytic activity for the reduction of 4-nitrophenol and methylene blue

Supported noble metal heterogeneous catalysts have been proven to be effective for the treatment of toxic organic pollutants. Herein, ultrafine Ag nanoparticles (NPs) with an average size of approximately 4.37 nm was decorated on the surface of pure silicon zeolite nanoparticle (PSZN) and confined in pore channels through a low-cost and environmentally friendly in-situ reduction strategy. The prepared Ag/PSZN nanocomposites showed ultrahigh catalytic activity for the reduction of 4-nitrophenol (4-NP) (∼200 s, 17.29 × 10-3 s−1) and methylene blue (MB) (∼4 min, 76.53 × 10-2 min−1), which outperforms the majority of the previously reported Ag-based catalysts. The excellent catalytic performance is due to the large loading amount (Wt = 16.8 %) and ultrasmall size of Ag NPs, which provides abundant active sites. Moreover, it showed outstanding recyclability of 93 % and 86 % removal of 4-NP and MB, respectively, after 10 cycle reactions, and stability after 300 days of storage at room temperature. This work offers new insights into the fabrication of Ag-based catalysts for efficiently removing organic pollutants from aqueous solutions.

Photoluminescence Study of Silver Nanoparticles Decorated on Multiwall Carbon Nanotubes (MWCNTs) by Spectroflourometer

Multiwall carbon nanotubes (MWCNTs) have recently attracted much attention due to their appealing properties in several domains. Multiwall carbon nanotubes (MWCNTs) were functionalized in this research study and then decorated with silver nanoparticles. Fourier transform Infrared Spectroscopy (FTIR) was used to check the successful attachment of hydroxyl (OH) and carboxyl (C=O) groups with MWCNTs. XRD analysis was used to check the crystallite size of silver nanoparticles and the decoration of silver nanoparticles on MWCNTs. Pure Carbon nanotubes (CNTs) show luminescence in an infrared region having approximately 1.3 eV absorption band. At room temperature, our hybrid material's photoluminescence (PL) spectra indicate only one peak in the UV region and many high-intensity peaks in the visible region. These PL results show the change in the band structure of Ag/MWCNTs composite compared to pure silver nanoparticles and carbon nanotubes. Therefore, it unlocks the possibilities to use this hybrid material for bio-sensing and bio-imaging devices, chemical sensing devices, optoelectronics devices, drug delivery devices, cancer cell detection, and environment detection devices.

In–Vitro Antibacterial and Antifungal Efficacy of Greenly Fabricated Senna alata Leaf Extract Silver Nanoparticles and Silver Nanoparticle-Cream Blend

Nanoparticles biosynthesis has been extensively studied for its biomedical applications. In this study, the in-vitro antibacterial and antifungal activity of greenly fabricated silver nanoparticles (NPs) from Senna alata leaf extract (SaAgNPs) and silver nanoparticle cream blend (SaAgNPs-cream blend) were investigated. The SaAgNPs were characterized using UV-visible spectrophotometry, FTIR, SEM, TGA, DLS, EDX, and XRD. The presence of surface plasmon band around 500 nm indicates AgNPs formation and functional groups such as alkenes, carboxylic acids, and alkyl aryl ether responsible for capping and stabilization of the nanoparticles. The SaAgNPs were spherical and 1.00 µm in size; TGA shows the formation of stable SaAgNPs, DLS shows 1.8 % intensity with 1905 nm average diameter and a polydispersity index of 0.595. EDX analysis confirmed the formation of pure silver nanoparticles. SaAgNPs supported the production of cosmetically acceptable SaAgNPs-cream blend with appropriate pH and viscosity. SaAgNPs and the SaAgNPs cream-blends had antibacterial activity against all and some of the test bacterial and fungal isolates. SaAgNPs had the highest activity against Pseudomonas aeruginosa 27853, Rhizopus sp. and Candida tropicalis with a zone of 16 mm and 30 mm. The cream-blends had activity against 68.75 % and 75 % of the test bacteria and fungi with the highest activity against Streptococcus epidermidis B (7.0 mm) and Candida albicans B (8.0 mm). In conclusion, the crude Senna alata leaf extracts, the bio-fabrication SaAgNPs and SaAgNPs-cream blend have antibacterial antifungal potentials which can be effectively utilized for the control of pathogenic bacteria and fungi.

Interaction Insight of Pullulan-Mediated Gamma-Irradiated Silver Nanoparticle Synthesis and Its Antibacterial Activity.

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV–Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410–420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles.

Titanium Nanotube Modified With Silver Cross-Linked Basic Fibroblast Growth Factor Improves Osteoblastic Activities of Dental Pulp Stem Cells and Antibacterial Effect.

Titanium modifications with different silver loading methods demonstrate excellent antibacterial properties. Yet pure silver nanoparticles with limited bioactive properties may delay regeneration of bone surrounding the dental implant. Therefore, loading silver with bioactive drugs on titanium surfaces seems to be a very promising strategy. Herein, we designed a silver (Ag) step-by-step cross-linking with the basic fibroblast growth factor (bFGF) by polydopamine (PDA) and heparin on titanium nanotube (TNT) as its cargo (TNT/PDA/Ag/bFGF) to improve the implant surface. Our results showed that TNT/PDA/Ag/bFGF significantly enhanced the osteogenic differentiation of dental pulp stem cells (DPSCs). It also showed an excellent effect in bacterial inhibition and a reduction of pro-inflammatory factors through inhibition of M1 macrophage activity. These results showed that bFGF cross-linked silver coating on TNTs presented good osteogenic differentiation and early anti-infiammatory and antibacterial properties. Together, this novel design on titanium provides a promising therapeutic for dental implants.