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Nanoparticle synthesis under environmentally friendly conditions has been conducted utilizing natural resources in order to reduce the reliance on hazardous chemicals. For example, the utilization of microbial synthesis has enabled the production of nanoparticles that exhibit biocompatibility, stability, and safety. Microorganisms facilitate the growth of crystals while preventing aggregation. They serve as both reducing agents and capping agents by offering enzymes, peptides, poly(amino acids), polyhydroxyalkanoate, and polysaccharides. In this review, we present an overview of nanoparticle synthesis based on microorganisms including bacteria, fungi, algae, and actinobacteria, encompassing metals such as gold (Au), silver (Ag), platinum (Pt), palladium (Pd), copper (Cu), titanium dioxide ((TiO2), zinc oxide (ZnO), iron oxide (Fe2O3), and selenium (Se). The nanoparticles typically vary in size from 1 to 100 nm and exhibit various shapes including spherical, rod-shaped, triangular, cubic, and hexagonal shapes. Additionally, this review discusses the mechanisms behind the synthesis of metal nanoparticles by microorganisms, whether they occur intracellularly or extracellularly. [ABSTRACT FROM AUTHOR]

Mercury (Hg2+) as environmental pollutant is a widespread concern due to its cytotoxic effect in humans and animals and needs to be monitored through cost effective methods based on naked-eye detection. Herein, in this study, we extracted and isolated the limonin (LMN) via a facile procedure and then employed it as capping agent for the synthesis of silver nanoparticles (LMN-AgNPs) as a first report. LMN-AgNPs were characterized through Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), Zeta Potential Analyzer (ZPA) and Fourier Transform Infrared (FTIR) spectroscopy. As-formed LMN-AgNPs were recognized as extremely selective and highly sensitive colorimetric sensor for Hg2+ with potential analytical application. The developed sensor showed an outstanding linear correlation with the concentration of Hg2+ in the range of 0.002 − 55 µM via a color change from deep yellow to transparent showing hypsochromic-hypochromic shift with the limit of detection (LOD) and the limit of quantification (LOQ) as low as 0.21 nM and 0.7 nM respectively. The sensor was further allied with smartphone for immediate and on-site quantification of Hg2+. The LOD and LOQ of 0.42 µM and 1.4 µM was true for smartphone based sensing in the range of 7.5–55 µM Hg2+. The detection of Hg2+ was not disrupted by the presence of other metals in either of mentioned cases. The practical applicability of the proposed Hg2+ sensor was tested using spectrophotometric and smartphone based approaches in human serum and urine as well as in tap water samples with acceptable ranges of recovery. As-developed sensor can work as a potential candidate for monitoring of Hg2+ pollution in diverse fields of studies. [ABSTRACT FROM AUTHOR]

Chemical sensors are detecting probes that translate information of analyte into a quantifiable signal for chemical exploration studies. Fabrication of (E)-2-(5-chloro-2-hydroxy-3-iodobenzylidene) hydrazine-1-carboxamide stabilized silver nanoparticles (1c-AgNPs) is one-dimensional synthesis avenue in present study exhibiting the ability of metal cations detection and selectivity of sensing mercury (Hg2+) ions in various samples of water and cosmetic creams. The newly synthesized silver nanoparticles (AgNPs) were comprehensively elucidated by ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR), zeta-sizer, atomic force microscopy (AFM), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and thermal degradation analysis. 33.2 ± 1.3 nm sized polydispersed nanoparticles showed selective, sensitive and efficient detection of Hg2+ ions with detection limit of 0.274 µM by significant quenching in UV-Vis spectral band at 410 nm in real water and cosmetic cream samples. The theoretical findings displayed changes in reactive descriptors, electronic parameters, bond angles, and bond lengths of 1c and conjugated AgNPs using DFT method. The biological application of 1c-AgNPs showed significant synergistic potential as antibacterial agent against Escherichia coli and Staphylococcus aureus compared to ligand. Thus, the newly engineered 1c-AgNPs could be a favorable appliance in nature and health restoration. [ABSTRACT FROM AUTHOR]

In this work, a novel and versatile route was developed, using Latex copolymer to synthesize pure and silver doped mesoporous Ag/TiO2 (MNps) with various silver contents using two-stage processing method. We investigated the influence of both silver doping content and calcination temperature on the physical features and photocatalytic responses of Ag/TiO2. The Ag/TiO2 nanostructures were characterized using multiple analytical techniques like Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive analysis Scope (EDS), X-Ray Diffraction (XRD), and ultraviolet-visible spectroscopy (UV-Vis). The results indicated that mesoporous Ag/TiO2 are obtained in the form of core-shell structured Nps, Where TiO2 nanoparticles (NPs) had a perfect spherical morphology at 400°C, with a size range of 50 to 300 nm, assembled in an orderly manner with primary nano crystallites of silver on the surface with an average size varying from 5 to 10 nm, forming a. The XRD measurements reported the presence of Anatase TiO2 phase and silver nanoparticles. Photocatalytic studies were carried out in model solutions of water and Methylene Blue (MB) dyes under visible irradiation in presence of pure and metal doped mesoporous Ag/TiO2 (MNps). The samples show a sequential combination of adsorption and photocatalytic dye degradation process with variable reaction rate constants depending on the content of doping silver element. Almost 95% removal of methylene blue was achieved using 5 - 7.5% Ag/TiO2 as a photocatalyst; with a combination of 60% dye adsorption and 35% dye photocatalytic degradation after 60 min of under visible light irradiations. [ABSTRACT FROM AUTHOR]

This paper presents the syntheses of SiO2 particles immobilized with Ag nanoparticles and their composite with Au. Ag nanoparticles are present on the surfaces of the SiO2 particles, and Ag+ ions are galvanically replaced with Au3+ ions. Finally, a method for maintaining the color durability and dispersibility of the Ag nanoparticles is demonstrated. The particles are primarily synthesized in three steps: In the first step, Sn2+ ions are adsorbed on the surfaces of the SiO2 particles; in the second step, Ag+ ions are added, which are reduced and simultaneously adsorbed on the surface while Sn2+ is oxidized to Sn4+; in the third step, Au3+ ions are reduced by galvanic replacement and deposited on the Ag surface. Extensive characterization using transmission electron microscopy, scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy reveals that the Ag–Au composite nanoparticles (17.2 ± 4.1 nm) are immobilized on the surface of the SiO2 particles (<1 µm). The morphology and coloration of the SiO2 particles with the immobilized Ag–Au composite nanoparticles remain preserved in nitric acid. This preservation is more pronounced than that observed in SiO2 particles with immobilized Ag nanoparticles. This enhanced durability can be attributed to the formation of stable bonds between Ag and Au. [ABSTRACT FROM AUTHOR]

Modern technology's development is also towards using microorganisms as micro-factories of biomaterials with unique properties and combining the original properties of biosilica extracted from diatoms (microalgae) together with immobilised silver and cerium in nanoparticle forms allowed to obtain a modern composite material with antibacterial activity. The synthesised composites containing heteroepitaxially growing Ag/AgCl/CeO2 complex nanoparticles were studied using different types of instrumental analysis. SEM-EDX and XRD analysis allowed the qualitative and quantitative determination of the elements present and their forms in the composites. TEM permitted analysis of information about the created nanoparticles shape, size and structure specificity. The possible mechanism of nanoparticle formation was suggested. Antibacterial properties of synthesised composites were characterised using a minimum inhibitory concentration test on six selected bacterial strains. Diatomaceous biosilica containing heteroepitaxially growing silver chloride, metallic silver, and cerium (IV) oxide nanoparticles have been prepared for the first time. The proposed method for synthesising composites did not use toxic reagents, making it environmentally friendly. [ABSTRACT FROM AUTHOR]

The impressive role of silver nanoparticles (AgNPs) is well identified for cancer therapy. However, safety concerns have been raised about the adverse effects of high-doses of chemically-synthesized-AgNPs that release many hazardous residues and in turn diminish the anticancer property of AgNPs. Hence, to overcome these side effects and to maintain the anticancer effectiveness of AgNPs at relatively low-doses, the present study utilizes a natural antitumor product Ferula asafoetida (FA) in the preparation of green synthesis of AgNPs and further focuses on its cytotoxic effects, against Lung and Cervical cancer cells. The successful green-synthesis of FA-AgNPs was confirmed via UV–Vis-spectroscopy, TEM, DLS, FTIR and IR. Based on cytotoxicity assay, the average low (6.25 µl) and high (25 µl) doses of FA-AgNPs were observed to cause severe cytotoxic effects on studied cancer cells. Furthermore, our study was also directed to check any possible antitumorigenic-modulatory-effects of low and high doses of FA-AgNPs on the expression of four oncogenes (PIK3CA, KRAS, EGFR and ERBB3). In RT-qPCR analysis, the low and high doses of FA-AgNPs caused significant(p < 0.01) downregulation effects on the expression of PIK3CA and KRAS oncogenes, in treated-cancer cells. This is the first-report on the role of FA-AgNPs that induce strong cytotoxicity with its low-doses. [ABSTRACT FROM AUTHOR]

Metal poisoning in humans can cause health hazards such as insomnia, mental retardation, nervous disorders and blindness. Most of the commonly used toxic metals are mercury, lead and cadmium. Among these toxic metals, mercury (Hg) has been declared to be highly toxic by the World Health Organization and Environmental Protection Agency. In this regard, the determination of Hg2+ in trace quantities plays an important role in the environment. This study investigates the preparation of embonic acid (EA) functionalized silver nanoparticles (AgNP) through eco-friendly approach for detection of mercuric ion in an aqueous environment. UV–Visible spectra analysis confirmed the stability of EA capped AgNP (EA-AgNP) over a period of 6 months. Stability and destabilization of silver nanoparticles in absence and presence of Hg2+ were confirmed by the zeta potential analysis with the value of − 28.5 mV and − 15 mV and High Resolution-Transmission Electronic Microscopy with increasing size of 15 nm to 130 nm respectively. The lower detection limit was found to be 0.5 nM and 50 fM Hg2+ using EA-AgNP by spectrophotometric and spectrofluorometric respectively and also highly selective to mercuric ion in the presence of a host of commonly interfering cations in aqueous system. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticles were synthesized by a novel, environmentally friendly method using low-pressure cold plasma in different ways: for chemical and green synthesis. The "traditional" Ag NP capping agents (sodium citrate, sodium alginate, poly(vinyl alcohol), polyvinylpyrrolidone, Tween-80, sodium carboxymethyl cellulose, and "green" stabilizers (grape and orange pomace) were used in the researched synthesis methods. The synthesized Ag NPs were characterized through different techniques such as UV–Vis, DLS-method, SEM HR-TEM for morphology parameter investigation. It was established that the manifestation of antiradical activity (DPPH method) (30–80% in concentrations of 0.1–1.5 mg/mL) is ensured only when using "green" types of stabilizers, and in this case, the method of synthesis and characteristics of NPs are not of decisive importance. Experimental data and theoretical quantum-chemical calculations have shown that the intensity of the antiradical effect of "green" stabilizers (grape and orange pomace) is largely determined by the content of phenolic and polyphenolic compounds (LC–MS method). The type of stabilizer, which determines the size of the NPs and the zeta potential, has a decisive influence on the intensity of the manifestation of antimicrobial properties. The latter determines the rate of release of silver ions and the intensity of antimicrobial action. [ABSTRACT FROM AUTHOR]

Radix Lithospermi phytonutrients were used to reduce and stabilize the biosynthesized silver nanoparticles (AgNPs). The bioreduction kinetics were explored utilizing a one-variable-at-a-time technique to understand the effects of process parameters. Intense yellow color and a strong peak at 406 nm in the UV–Vis absorption spectra indicated the successful synthesis of AgNPs. The optimized condition showed nano size (12.44 ± 2.5 nm) spherical particles with crystalline (d-spacing = 0.234 nm) nature and well stabilized (zeta potential = − 16.9 mV) by being encapsulated with plant phytonutrients. The XRD confirms the structures of the particles are correlated with crystallographic planes of the face-centered cubic structure of metallic Ag-crystals. The biogenic AgNPs showed excellent antibacterial activity with a bacterial reduction of 93.08% on S. aureus (zones of inhibition = 7.19 ± 0.91 mm) and 91.67% on E. coli (zones of inhibition = 6.23 ± 0.85 mm). The catalytic performance demonstrates nearly 100% dye degradation within 20 min with the kinetic constants (k) of 0.04945 min−1 (r2 = 0.9878) and 0.3235 min−1 (r2 = 0.9363) for mordant blue and naphthol blue-black, respectively. The current study proposes a simple/green synthesis of AgNPs that may be a viable option for bacterial reduction and wastewater treatment. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have been widely studied due to their interesting physicochemical properties and remarkable antibacterial properties. Chemical synthesis methods, including green chemistry, have achieved 0D nanostructures. However, ecological methods have little studied self-assembling Ag nanostructures, such as flowers or dendrites. In this work, Ag dendrites and Ag flower-like morphologies have been successfully synthesized using a one-step green method employing Arctostaphylos pungens Kunth fruit extract at room temperature. The antibacterial properties of both nanostructures were evaluated against Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus bacteria. Scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and infrared spectroscopy (IR) characterized the synthesized products. The morphological changes of the nanostructures come from the variation in the concentration of the precursor salt, silver nitrate (AgNO3). A growth mechanism is proposed that includes the formation of nanospheres and their subsequent transformation into Ag dendrites. Both nanostructures show good antibacterial activity against the tested microorganisms. The Ag dendritic nanostructures presented inhibition zones of 11 mm and 10.7 mm against Escherichia coli and Staphylococcus aureus bacteria. However, the flower-like structure was slightly less effective, presenting 11 and 9.5 mm inhibition zones against the same microorganisms, respectively. [ABSTRACT FROM AUTHOR]

The current study presents a simple, low-cost, and rapid method for producing α-amylase capped silver nanoparticles (AgNPs). The electromagnetic irradiation approach significantly reduced reaction time and resulted in the nucleation of silver ions for nanoparticle formation. The electromagnetic energy (300 nm to 650 nm) and electrical potential (7 mV) have been tuned. This study outlines how electromagnetic energy is irradiated to cause chemical processes in the nucleation and development of silver ions. The incident energy wavelength varies from lower to higher wavelength; the Ag+ reduction rate slows and becomes more kinetically and dynamically regulated. The incident photon energy causes silver ions to reduce, resulting in stable colloidal AgNPs. The formation of particles of various sizes, like UV-light (68.2 nm), Blue light (59.7 nm), Green light (94.4 nm), Yellow light (79.2 nm), Orange light (91.3 nm), Red light (74.2 nm), and Electrical energy (98.3 nm). X-ray diffraction assesses the purity and crystalline nature of AgNPs, while transmission electron microscopy (TEM) was used to analyze the shape and morphology. The approach has been thoroughly documented and confirmed using UV–Visible spectroscopy, DLS, and fluorescence spectroscopy. Particles were deposited on steel electrodes for use in industrial and medicinal applications. [ABSTRACT FROM AUTHOR]

Nanozymes are nanomaterials that possess intrinsic enzyme mimicking activity. In this study, the application of silver nanoparticles coated filter paper (AgNPs/FP) that exhibits a peroxidase-like catalytic activity as a potential sensor is reported. A simple chemical reduction method was used to produce AgNPs/FP. The formation of the particles on filter paper were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and surface-enhanced Raman spectroscopy (SERS). In the presence of hydrogen peroxide, AgNPs/FP oxidized the colorless o-phenylenediamine (OPD) and 3,3′,5,5′-tetramethylbenzidine (TMB) solutions to a yellow colored 2,3-diaminophenazine (DAP) and deep blue colored oxidized TMB (oxTMB), respectively. In the presence of thiocyanate, however, the peroxidase-like activity was inhibited in a concentration dependent manner. This makes the AgNPs/FP a promising catalyst and employed for colorimetric detection of thiocyanate via inhibition of the peroxidase-like activity. The application can be further extended to other environmentally and biologically important analytes. [ABSTRACT FROM AUTHOR]

New facile way for production of antimicrobial wound healing dress was achieved using freshly fabricated bacterial cellulose (BNC) decorated with in situ formed silver nanoparticles (AgNPs). Herein, BNC was fabricated by using a domestic isolated strain Komagataeibacter hansenii SA1.1. BNC/AgNPs nanocomposites were in situ synthesized by introducing AgNO3 to alkaline BNC at 60 °C for 30 min to attain full chemical reduction of Ag ions which manifested visually by color change. Results signified the successful fabrication of nanofibrillated BC with network structure. Also, AgNPs were successfully assembled on the surface of BNC in spherical shape with distribution uniformity consists of narrow size particles lied in range of 10–40 nm. The hybrid BNC/AgNPs manifested a strong antibacterial activity against Gram negative and Gram positive as well as unicellular fungus. The results from in vitro study demonstrated, undoubtedly, that BNC/AgNPs can be able to promote the wound healing affinity of chronic ulcers through reducing microbial infection besides accelerating the healing by their inflammatory. While, the antioxidant affirmed the potential protection of BNC/AgNPs from oxidative stressors, it was displayed a vital role in the improvement cell propagation and cell proliferation. [ABSTRACT FROM AUTHOR]

Clinically, implant-related bone infections are a serious concern as they reduce the success rate of grafting techniques and increases the risk of morbidity. Clinicians use antibiotics to treat bone grafts. Silver-based components are gaining popularity for their exceptional antimicrobial activity. The current review provides the preparative procedure, characterization methods, and mechanical strength of silver-based composites. Additionally, the assessment includes information on the biocompatibility of silver-based composites and clinical studies for bone tissue engineering. Finally, the review discusses titanium implants coated with silver-based composites, their derivatives, and related studies. Overall, silver-based composites are a potential candidate for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are increasingly recognized as vital nanomaterials in biomedical applications due to their diverse pharmacological properties, including antimicrobial and anti-neoplastic effects, particularly when derived from herbal sources. This study aims to synthesize AgNPs employing a sustainable approach aligned with the principles of the sustainable development goals. The synthesized AgNPs are incorporated with doxorubicin (DOX) and encapsulated within polylactide nanoparticles to enhance their anticancer potency. AgNPs are prepared via the reduction of silver ions using rutin as a reducing agent, with the reaction progress monitored via ultraviolet-visible spectroscopy (UV-vis). Subsequently, the AgNPs are encapsulated into poly(D, L-lactic acid) (PDLLA) nanoparticles alongside doxorubicin. The developed nanoparticles have shown a diameter size of 233 nm with a zeta potential of -21.47 mV. Moreover, the in vitro release profile of the DOX showed a sustained release kinetics over 30 h. Evaluation of the AgNP-DOX-loaded PDLLA nanoparticles reveals enhanced anticancer activity against HeLa and HepG2 cancer cells, highlighting the synergistic efficacy of the combined therapy. These findings underscore the potential of AgNPs-based formulations as promising candidates for advanced cancer therapeutics.Graphical Abstract: Silver nanoparticles (AgNPs) are increasingly recognized as vital nanomaterials in biomedical applications due to their diverse pharmacological properties, including antimicrobial and anti-neoplastic effects, particularly when derived from herbal sources. This study aims to synthesize AgNPs employing a sustainable approach aligned with the principles of the sustainable development goals. The synthesized AgNPs are incorporated with doxorubicin (DOX) and encapsulated within polylactide nanoparticles to enhance their anticancer potency. AgNPs are prepared via the reduction of silver ions using rutin as a reducing agent, with the reaction progress monitored via ultraviolet-visible spectroscopy (UV-vis). Subsequently, the AgNPs are encapsulated into poly(D, L-lactic acid) (PDLLA) nanoparticles alongside doxorubicin. The developed nanoparticles have shown a diameter size of 233 nm with a zeta potential of -21.47 mV. Moreover, the in vitro release profile of the DOX showed a sustained release kinetics over 30 h. Evaluation of the AgNP-DOX-loaded PDLLA nanoparticles reveals enhanced anticancer activity against HeLa and HepG2 cancer cells, highlighting the synergistic efficacy of the combined therapy. These findings underscore the potential of AgNPs-based formulations as promising candidates for advanced cancer therapeutics. [ABSTRACT FROM AUTHOR]

This study developed a novel paper-based sensor for the simultaneous analysis of ascorbic acid (AA) and hydroquinone (HQ). The sensor utilized polyvinyl alcohol (PVA)-stabilized silver nanoparticles (AgNPs-PVA) as the reagent probe and PVA media acted as the filter for separation of the analytes. Polydimethylsiloxane (PDMS) and ethanol serve as the stationary phase and eluent, respectively, exploiting the differences in analyte reactions and solubility to achieve their separation on the filter paper. The circular sensor’s central zone was AA’s detection area, while HQ was detected in the outer ring region. AA induced an immediate color change in the test kit, whereas HQ required a 20-minute elution with ethanol followed by colorimetric analysis. All analytes exhibited relative standard deviations of repeatability and reproducibility below 2.7% and 9.5%, respectively. Under optimal conditions, the linear detection range for HQ was 0.2-2.0 mg⋅L− 1, while AA was 0.1-2.0 mg⋅L− 1. The detection limit was determined to be 0.05 mg⋅L− 1 for AA and 0.1 mg⋅L− 1 for HQ. The recoveries of AA and HQ in cosmetic cream samples ranged from 80 to 110%. The accuracy of the sensor’s measurements was further validated by comparison with the HPLC-DAD method. [ABSTRACT FROM AUTHOR]

In this work, the application of a colorimetric technique was investigated, as a simple method for the differentiation of the size and morphology of silver colloids. Wherein, the different silver colloids, with a wide spectrum of colors, were obtained using various homemade light sources in the visible light range. The synthesis was carried out from silver nitrate in presence of two reducing agents: sodium citrate and sodium borohydride. The plasmonic response and morphology of silver colloids were studied by UV–Vis spectroscopy and by transmission electron microscopy. Here, we have observed a direct correlation between each color and the plasmonic signal of the colloid. Therefore, we can say that the procedure followed in this work led us to a simple and easy way to distinguish the shape and size of silver nanoparticles. [ABSTRACT FROM AUTHOR]

This work presents a design of a simple and sensitive sensing interface consisting of a graphene/poly(1,5-diaminonaphthalene) nanocomposite, denoted as Gr/P(1,5DAN), as an immobilization matrix and graphene decorated with silver nanoparticles (Gr-AgNPs) as an electrochemical label for bisphenol A (BPA). The nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical techniques (CV and EIS). Immunocomplex formation between the anti-BPA antibody (αBPA) and BPA antigen would induce the square wave voltammetric (SWV) peak current variation of Gr-AgNPs labels, and afterward, the concentration of BPA could be indirectly assayed and qualitatively determined. The results indicated a linear relationship between (SWV) response to the BPA concentration in a range of 1.0–8.0 nM, with a limit of detection (LOD) of 0.6 nM. It is a promising attempt for PBA analysis with a low-cost and easy-to-fabricate sensor. [ABSTRACT FROM AUTHOR]

The present study was aimed to evaluate the antifeedant, larvicidal, pupicidal, biochemical effects of Vernonia anthelmintica seeds mediated AgNPs against Spodoptera litura, Helicoverpa armigera, Culex quinquefasciatus and Aedes aegypti. The potential antifeedant activity of synthesized AgNPs were 86.90% and 89.83% and larvicidal activity of (LC50) 56.42 μg/mL and 63.65 μg/mL against S. litura and H. armigera respectively. Furthermore, larval growth duration was increased as 13.66 and 15.85 days on S. litura and H. armigera as compared to control 7.83 and 8.05 days. The AgNPs caused larvicidal activity of (LC50) 45.14 µg/mL and 53.23 µg/mL against Ae. aegypti and Cx. quinquefasciatus. The increased α esterase level of 85.00, 85.33 0.49 and 0.53 μg napthol produced/min/mg larval protein and β esterase level of 92.66, 101.67, 0.53 and 0.48 μg napthol produced/min/mg larval protein and glutathione S-transferase enzyme level of 146.33, 160.00, 0.75 and 0.65 μmol/min/mg larval proteins on S. litura, H. armigera, Ae. aegypti and Cx. quinquefasciatus. The damaged midget cells and peritrophic membrane was observed on treated larvae of S. litura, H. armigera, Ae. aegypti and Cx. quinquefasciatus. Conclusively, biosynthesised of AgNPs using V. anthelmintica seeds were used as potential biopesticide for controlling S. litura and H. armigera, Ae. aegypti and Cx. quinquefasciatus. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) progression is a complex process, with an interplay of multiple molecular signaling pathways. Cyclooxygenase-2 (COX-2) and NF-κB are important hallmark proteins responsible for the transition from inflammation to colon cancer. Due to the adverse effects of chemotherapeutic drugs, there is an imperative need to develop new drugs, and recently, nanoparticles found to be promising strategy in tumor detection, prevention and treatment of cancer. Biosynthesis of silver nanoparticles (AgNPs) was achieved with the help of Eucalyptus globulus L. leaf extract. Using a typical XRD pattern, NanoSight and TEM technique, the size and shape of the biogenic AgNPs were determined as ~ 20 nm and spherical. The cytotoxicity study exhibited a dose-dependent effect against HCT116 cells, with an inhibitory concentration (IC50) of 1.152 µg/ml. In addition, AgNPs effectively inhibited the proliferation, colony formation, with increased ROS production compared to untreated cells. Further, mechanistic analysis revealed that AgNPs arrested the cell cycle, downregulated the expression of antiapoptotic, inflammatory, stem cell markers, and upregulated the apoptotic genes in HCT116 cells. In conclusion, for the first time, we report the green synthesis of AgNPs using E. globulus leaf extract that has potential anticancer activity with dual inhibitory action on COX-2 and NF-κB expression. [ABSTRACT FROM AUTHOR]

This study was aimed to evaluate the antibacterial and biofilm inhibitory activity of Penicillium chrysogenum-derived silver nanoparticles (AgNPs) against the standard and pathogenic Acinetobacter baumannii using a 96-well microtiter plate-based method. The AgNPs were characterized by using UV–Vis, TEM, AFM, XRD, DLS, Zeta potential, and FT-IR. The nanoparticles (NPs) were fabricated with a spherical shape and an average hydrodynamic diameter of 48.2 nm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs were found to be 4 and 32 µg/mL respectively, whereas the MIC and MBC of tetracycline were found to be 1024 and 8192 µg/mL against A. baumannii (ATCC 19606). The AgNPs and tetracycline represented considerable biofilm inhibitory activity against both the standard and pathogenic A. baumannii at the studied concentrations. However, the AgNPs depicted higher potency to inhibit the process of biofilm formation of some pathogenic A. baumannii species compared to tetracycline. The AgNPs at the concentration of 0.5*MIC (2 µg/mL) inhibited above 90% biofilm inhibition, whereas tetracycline reached 90% biofilm inhibition at the concentration of 4*MIC (4096 µg/mL) against A. baumannii (ATCC 19606). However, further studies are required to evaluate the biofilm inhibitory efficacy of biogenic AgNPs in vivo. [ABSTRACT FROM AUTHOR]

Different growth stages of Penicillium notatum, P. purpurogenum and P. aculeatum were evaluated for their potential for zirconium nanoparticle (Zr-NP) biosynthesis by total protein content assay. Fungal secreted protein concentrations for all three species were higher at deceleration phase. For optimizing biosynthesis conditions with respect to Zr-NP size, different pH values and ZrCl4 concentrations were tested and analyzed. The artificial neural network (ANN) modeling was then applied to find the best conditions. A feed-forward ANN model was used to make a connection between the output as the size of Zr-NPs, with three input variables, including pH, ZrCl4 concentration and fungal species. An optimal multi-layer perceptron neural network was finally designed to model the experimental data for which the correlation coefficients R2 at each phase (training, validation and test sets) were calculated to be 0.9946, 0.9952 and 0.9997, respectively. The accuracy of the model was confirmed through validation experiments. [ABSTRACT FROM AUTHOR]

In this report we demonstrate the use of Citrus japonica (CJ) leaf extract for the first time as biological liquid to work as capping as well as reducing agent for synthesizing extremely stable silver nanoparticles (AgNPs) from its precursor silver salt. Different parameters such as pH, speed of reaction, silver salt concentrations and leaf extract were optimized for the formation of CJ-AgNPs. CJ-AgNPs were then characterized through techniques like Ultra-violet visible (UV–Vis) spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), Zeta-potential analysis (ZPA) and dynamic light scattering (DLS). As-formed CJ-AgNPs were verified as highly sensitive, extremely selective, stable, economical, eco-friendly and rapidly responsive colorimetric sensor for Hg2+ detection based on color change in solution from yellow to brownish. The dynamic range of developed sensor worked linearly in the range of 0.3–7.3 µM with R2 value of 0.999 and limit of (LOD) and limit of quantification (LOQ) as 0.09 µM and 0.30 µM respectively. The sensor demonstrated negligible interference under the influence of ions like Mg2+, Zn2+, Cu2+, Co2+, Pb2+, Cd2+ and Fe2+ and corresponding anions. The developed sensor was successfully applied to detect Hg2+ at low level in some real water samples. [ABSTRACT FROM AUTHOR]

The advancement in conservationist strategies for development of nanoparticles is elemental to the subject of nanotechnology. Green protocols are highly preferred over conventional methods as they are environmentally benign. Certain phytochemicals in plant extracts exhibit natural tendencies of bio-reduction of salts. They also possess the ability of stabilizing these reduced particles by capping them. In present study leaf extract of Catharanthus roseus, an evergreen subshrub has been utilized for production of AgNPs and CuO-NPs. Synthesized nanoparticles were evaluated for their cadmium, chromium removal and antibacterial potential against S. aureus. AgNPs and CuO-NPs were optimized by varying salt concentration, leaf extract concentration and time interval to obtain better yield. UV–Vis spectroscopy was used to detect biogenic AgNPs and CuO-NPs. Wavelength range used for AgNPs and CuO-NPs was 300–700 and 200–700 nm successively. The morphology of nanoparticles was determined to be spherical and within 100 nm using SEM images. FT-IR investigation confirmed the presence of amines and alcohols in AgNPs. IR spectra of CuO-NPs revealed the ubiety of aldehydes/ ketones and carboxylic acids. The average distribution for silver was 602.9 nm and for copper was1066 nm as confirmed by DLS analysis. Further zeta-potential for AgNPs and CuO-NPs was recorded -16.4 mV and -6.18 mV. Kirby Bauer test for S.aureus show maximum ZOI i.e. 16 mm in case of AgNP (50 µl) and 10 mm in case of CuO-NP (50 µl). Highest chromium and cadmium removal was observed in case of biogenic silver nanoparticles i.e. 47.84% and 5.68% respectively. This is the first work that presents a comparative study of biogenic AgNPs and CuO-NPs from the leaf extract of Catharanthus roseus. Our findings can also help in improving the current scenario of metalloid pollution in soil and water environments. Hence, proper scaling up can make biogenic AgNPs and CuO-NPs a noteworthy tool in industries as well. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticles (AgNPs) were in situ generated on the surface of cellulose matrix using leaf extract of cissampelos pareira (LCP) by environmentally benign green synthesis. The morphological and structural properties of synthesized cellulose silver nanocomposites (Cel/LCP/Ag-NCs) were characterized by different spectral studies such as UV–visible spectroscopy, SEM, TEM, FT-IR, AFM, DRS, PL, Lifetime, XPS and XRD. Silver nanoparticles were obtained in the cellulose matrix with an average size of 34.26 nm and with antioxidant activity which has been evaluated by ABTS (70.34% at 100 µg/mL) and DPPH (81.65% at 100 µg/mL) methods. The antimicrobial properties of cellulose, Cel/LCP, Cel/LCP (10 mM, 30 mM and 50 mM AgNO3), tested on 13 microorganisms were determined using disk diffusion method. The most effective nanocomposites (Cel/LCP/10, 30 and 50 mM AgNO3), Cel/LCP/50 mM AgNO3 afforded the best antimicrobial properties because increasing the concentration of AgNO3 solution, the zone of inhibition also increased. The prepared cellulose silver nanocomposites synthesized by leaf extract of cissampelos pareira shows the potential to be applied in the future development of therapeutics and biomedical applications. [ABSTRACT FROM AUTHOR]

Pollution of water by leaking industrial dyes has become a major problem for aquatic organisms and human-being. Polluted water treatment methods need efficient alternatives to conventional dye removing techniques. In this study, the catalytic activity of cellulose based silver nanocomposite against the pollutant methylene blue dye was searched. Cellulose based silver nanocomposite was synthesized by using in situ green synthesis method with Laurus nobilis extract. UV–VIS, FTIR, SEM, TEM, EDS, XRD, BET analyses were used to characterization of synthesized nanocomposite. Electron microscopy results confirmed that 25 nm diameter silver nanoparticles were supporting the 25 nm width cellulose nanofibers. Elemental composition of confirmed by UV–VIS, FTIR, XRD and EDS results which including silver and cellulose specific peaks. BET results showed that nanocomposite have 11.1 nm pore size with 199,8508 m2/g specific surface area. Catalytic activity of nanocomposite was performed against methylene blue in the presence of NaBH4. Catalytic activity was traced for up to 120 min and complete removal of methylene blue dye was estimated as 1 h. Moreover, the recycled nanocomposite was found reusable without activity loss for three times. These results offer an easy, eco-friendly and reusable dye removing material for wastewaters which were polluted by industrial dyes. [ABSTRACT FROM AUTHOR]

The present study was designed to the synthesis of pH- responsive silver nanoparticles (AgNPs) by green route approach using Labeo rohita (L. rohita) fish scale aqueous extract. The synthesized AgNPs were optimized by various pH (5–9) ranges and characterized by Ultraviolet–Visible spectroscopy (UV–Vis), X-ray diffraction crystallography (XRD), Fourier transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), Zeta potential, and dynamic light scattering (DLS) analysis. Surface Plasmon Resonance (SPR) bands observed at 400–405 nm range in UV–Visible spectrum and this SPR band was preliminary confirmation of AgNPs synthesis. FT-IR spectral results show that different functional groups acted as definitive reduction and capping agents for the formation of AgNPs. Microscopy analysis confirm that AgNPs are spherical in shape with average particle size of 42.9 to 80.1 nm in range and confirmed that the 65.19% of Ag ions present in AgNPs by EDAX analysis. In addition, the antimicrobial activity of AgNPs revealed potential activity against different pathogens. Among those pathogens, Staphylococcous aureus showed higher zone of inhibition (8.2 ± 1.4 mm) at 100 μg/mL. In addition, S. aureus inhibition was proved by SEM morphological analysis, which indicates cell wall damaged. Overall, this present investigation confirms that green route AgNPs are potential source for biomedical applications. [ABSTRACT FROM AUTHOR]

Gastric cancer is a major human health threat and finding novel and effective anticancer compounds against it is crucially important. Silver nanoparticles (NPs) have promising anticancer potential with minimal side effects. Functionalization of Ag NPs with magnetic compounds could provide novel features, including targeted drug delivery and photothermal therapy. In this work, green synthesis and characterization of MgFe2O4@Ag nanocomposite were performed. The anticancer potential of the nanocomposite against adenocarcinoma gastric (AGS) cells was investigated using MTT, flow cytometry, Hoechst staining, and caspase-3 activation assays. Also, the relative expression of the Bax and Bcl-2 genes in nanocomposite treated cells was investigated. Proper synthesis and crystallinity of the MgFe2O4@Ag NPs were confirmed by the Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses. Scanning and transmission electron microscopy indicated the spherical shape of the NPs with the size range of 23–53 nm. Lack of elemental impurities and good stability of the NPs was confirmed by energy dispersive X-ray (EDX) mapping and measuring zeta potential (− 35.5 mv), respectively. The MgFe2O4@Ag NPs showed a significantly higher antiproliferative potential against AGS cells (IC50 = 43 µg/mL), than human embryonic kidney cells (HEK293) cells (IC50 = 158 µg/mL). Moreover, flow cytometry and Hoechst staining confirmed apoptosis induction in treated AGS cells. Also, the activity of the caspase-3 protein and expression of the Bax gene among MgFe2O4@Ag treated cells was significantly increased to 1.8 and 1.21 folds, respectively, while the Bcl-2 gene was down-regulated to 0.68 folds. This study revealed the promising anticancer potential of MgFe2O4@Ag NPs to be used for gastric cancer treatment after further characterization using in-vitro and in-vivo assays. [ABSTRACT FROM AUTHOR]

Spherical shaped silver nanoparticles with the average size of 68.7 nm were synthesized from eco-friendly and environmentally safe approach using serum carrier protein 'fetuin-A' as stabilizing agent (named as F-AgNPs). Protein capping provided excellent stability at variable temperature (~ 25–85 °C), pH (~ 4–8), salt concentrations (~ 1.5 M) and storage period (≥ 3 months). Synthesized F-AgNPs were extensively characterized using UV–visible, Fourier transform infrared, circular dichroism and intrinsic fluorescence spectroscopy, dynamic light scattering, atomic force and scanning electron microscopy, energy dispersive spectroscopic measurements. F-AgNPs were proved as highly sensitive and selective colorimetric dual sensor for iodide (I−) and ferrous (Fe2+) ions with significant linearity (1–8 and 1–10 µM, respectively), detection limits (LOD = 0.5 and 0.47 µM, respectively) and percent recoveries in real environmental (tap water) and biological (human plasma and urine) samples with adequate test performance. Cumulatively, obtained results revealed that this simple and biocompatible nanosensor has great potential for applications not only in analytical chemistry but also for biological investigations. [ABSTRACT FROM AUTHOR]

A convenient and economical colorimetric chemo-sensor was developed for glutamic acid (Glu) detection in actual samples. The nanoscale sensor was synthesized by coating silver ions with sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The sensor, exhibited color change from yellow to pink when cross linked with Glu molecules and showed strong quenched in peak at 426 nm with the appearance of another absorption peak between 490 nm and 620 nm. The interaction mechanism of Glu and AOT-AgNPs was discussed with sophisticated analytical techniques i.e. Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Atomic force microscopy (AFM), and Dynamic light scattering (DLS). The results suggested that Glu interacted with the spheres of AOT-AgNPs through non-covalent bonding and electrostatic attractions of RNH3+ and COOH− groups, which caused time dependent complexation. In this manner, rapid method having detection and quantification limits of 1.64 µM and 4.98 µM in between 0.1 µM and 200 µM was achieved. Furthermore, this technique exhibited high selectivity toward Glu over a range of amino acids, biological relevant metal ions and molecules. Moreover, Glu molecules were effectively detected in physiological fluids with satisfactory recoveries in acceptable limit. Hence, this research offers an on-site colorimetric detection for Glu under easy operational conditions for vitro/non-invasive analyses. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) coated by an aqueous emulsion of copolymer were elaborated in a short time using polyol process and microwave (MW) heating. This approach is based on reducing AgNO3 powder in the presence of two main components; ethylene glycol as a dispersed medium and an industrial copolymer (latex) as protecting agent. The structural, morphological and optical properties of the prepared silver nanoparticles have been investigated by UV–Vis spectroscopy, Infrared Spectroscopy (IR), X Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). It was found that all these properties are strongly correlated to the latex copolymer concentration and the MW heating process. The absorption band was determined by UV Visible spectra, showing several bands (localized surface Plasmon band) in the visible region at wavelengths between 410 and 430 nm. The TEM analysis of the obtained products indicates the presence of straight nanowires and dispersed, spherical silver nanoparticles with well-controlled size ranging from 7 to 20 nm. The X Ray Diffraction showed that silver nanoparticles synthesized exhibit face centered cubic (fcc) structure. The infrared spectra show the strong coordination between the surface of silver particles and molecules of latex by O–H and C=O groups. Antimicrobial activity of latex/Ag NPs against E. coli, Staphylococcus aureus, and Pseudomonas aeruginosa has been also demonstrated. The results indicated that latex/AgNPs may damage the structure of bacterial cell membrane. [ABSTRACT FROM AUTHOR]

We report here the utility of Sida acuta Burm. f. root extract-mediated silver nanoparticles in catalytic degradation of organic dyes such as methyl orange (MO), methylene blue (MB), bromophenol blue (BPB), and congo red (CR) in the presence of NaBH4. Monodispersed nanosilver particles were characterized using UV–Visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering particle size-zeta potential analysis (DLS-Zeta) and fourier transform infrared spectroscopy (FTIR). TEM images demonstrated spherical uniform nanocrystals (10–50 nm). Catalytic removal of dyes by time-stable AgNPs was studied in a time-dependent manner. Reactions displayed pseudo-first-order rate and rate constants were figured out for removal of different dyes by the nanocatalyst. The dye removal ability of genetically transformed 'hairy root' nanoparticles (HR-AgNPs) was more pronounced in comparison with that by nanoparticles prepared from natural root extract (NR-AgNPs). Efficiency of degrading MO, MB, BPB and CR, to the extent as high as 85.99%, 79.10%, 82.65% and 70.12%, respectively were achieved in 30 min by employing HR-AgNPs; the rate constants being 0.0812, 0.0616, 0.0646, and 0.0498 min−1, respectively. This adsorptive removal ability of such biogenic nanoparticles could be explored in wastewater treatment for removal of toxic pollutant dyes. [ABSTRACT FROM AUTHOR]

Herein we are reporting, the in-situ synthesis of polydopamine capped silver nanoparticles (PDA-AgNPs) and its cysteamine (CYS) and tetracycline (TC) drugs sensor applications. The synthesized PDA-AgNPs was characterized by UV–Visible, Fourier Transformed–Infrared, X-Ray Diffraction, Zeta Potential, and High Resolution-Transmission Electron Microscope techniques. We have utilized PDA-AgNPs as probes for the detection of CYS and TC by spectrophotometry method. The addition of CYS has led to a decrease in the absorption of PDA-AgNPs. The yellow color solution becomes colorless and observed the aggregated particles in the TEM image. In contrast, the addition of TC, into the same solution, absorption of PDA-AgNPs was increased. The color of the solution became dark yellow and the particles are obtained de-aggregation. Based on the Surface Plasmon Resonance (SPR) band absorption changes, the detection limit of CYS and TC was calculated to be 180 nM and 17 nM, respectively. Interestingly, 600-fold of common interferences did not interfere with the detection of CYS and TC. PDA-AgNPs was successfully utilized to detect CYS and TC in serum, urine, and drug samples. Finally, we have prepared a paper-based colorimetric kit for on-site monitoring of CYS and TC. [ABSTRACT FROM AUTHOR]

An eco-benign procedure was developed to synthesize ultrafine and discrete spherical shape silver nanoparticles (5–20 nm) in the presence of ionic liquid. Different types of leaves extract, including Cymbopogon nardus, Polygonum minus, Allium Cepa, and Petroselinum crispum, were used as a green reducing and capping agents for the synthesis process. The Ag nanoparticles were denoted as AgCN, AgPM, AgAC, and AgPC, respectively. Notably, it was demonstrated that the Ag nanoparticles' size could simply be altered by varying the amount of total phenolic content (TPC) using different leaves. It was indicated from the characterization results that the AgPC nanoparticles' size was nine-fold smaller compared to the conventional Ag nanoparticles due to the high amount of total phenolic compounds (TPC) in the Petroselinum crispum. The results also revealed that ionic liquid and phenolic compounds had a synergistic effect on reducing silver ions (Ag+) into silver nanoparticles (Ag) and the stabilization of the nanoparticles. The order obtained for the degradation of methylene blue (MB) was AgPC > AgPM > AgCN > AgAC > Ag was influenced by a large amount of TPC and led to a decrease in particle size and enhanced photocatalytic activity. The AgPC remained effective and stable even after five subsequent cycles. [ABSTRACT FROM AUTHOR]

In this study, a simple approach was developed based on imidacloprid stabilized silver nanoparticle (Imida-AgNPs) for the sensitive detection of paraquat pesticide. Experimental parameters were optimized for the synthesis of the proposed sensor. Imida-AgNPs, synthesized under the optimized reaction condition were characterized by UV–Vis spectrophotometer, Fourier transform infrared (FT-IR) spectroscopy and atomic force microscopy (AFM). The Imida-AgNPs were spherical in shape with an average size of 40–70 nm. The stability of Imida-AgNPs was checked towards changes in temperature, time, pH, and salinity. The synthesized Imida-AgNPs were tested as a colorimetric sensor to detect a trace amount of paraquat for the first time. The developed sensor was green, simple, selective and economical. The calibration curve for detection of paraquat was found linear over the concentration range of 20–180 µM. The standard deviation (SD) was found to be 0.0019 µM with relative standard deviation (RSD) of 0.027%. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.27 µM and 19 µM respectively. Importantly, the sensor was successfully employed for the detection of paraquat in real samples. [ABSTRACT FROM AUTHOR]

The current work focusses on the silver nanoparticles (Ag-NPs) that are conveniently green synthesized by Mangifera indica gum powder extract. The absorbance is measured by UV–Vis spectrophotometer at a wavelength of 455 nm that represents the Surface Plasmon Resonance of Ag-NPs. Fourier Transform-Infra Red (FT-IR) spectroscopy confirms the functional groups and reaction mechanisms involved in the green synthesis of Ag-NPs. The elemental analysis of Ag-NPs is carried out by Energy dispersive X-ray (EDAX) spectrum and its surface morphology was studied by High resolution transmission electron microscopy (HR-TEM). The average size of Ag-NPs is found to be around 19 nm in diameter. The crystalline nature of the Ag-NPs is investigated by X-ray diffraction (XRD) and Selected area diffraction (SAED). The Ag-NPs shows better antioxidant activity against free radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide anion. Ag-NPs effect on reduction mild steel corrosion is examined using non electrochemical methods. It is proved from experimental tests that the inhibition efficiency increases with increased concentrations of Ag-NPs. The photocatalytic activity of the prepared Ag-NPs under visible light irradiation is assessed by the degradation of methylene blue (MB) dye. [ABSTRACT FROM AUTHOR]

The fluorescent silver nanoparticles were synthesized using trisodium citrate as a reducing and stabilizing agent in a microwave-assisted reduction process. The influence of synthesizing parameters such as reaction duration, temperature, and trisodium citrate concentration (100, 200, and 400 ppm) were examined on the characteristics and fluorescent properties of synthesized silver nanoparticles (AgNPs). The formation of AgNPs was studied by UV–Vis absorption spectroscopy, X-ray diffraction, ATR-FTIR spectra, and scanning electron microscopy. The low concentration compared to the high concentration of trisodium citrate resulted in a prolonged reduction process, and also the high concentration resulted in the formation of smaller AgNPs (44 nm). The fluorescence emission spectra of the synthesized colloidal AgNPs demonstrated a quite explicit emission peak centered around 335 nm. However, the higher reaction temperature (above 100 °C) resulted in a sharp and narrow emission peak. The synthesized silver nanoparticles exhibited a suitable fluorescent property, which was reliant on the size of synthesized AgNPs. [ABSTRACT FROM AUTHOR]

In order to investigate the physicochemical properties and bioactivities of AgNPs prepared using green and chemical approaches and further explore the related antibacterial mechanism, one kind of chemical AgNPs (C-AgNPs) and three kinds of green AgNPs (G-AgNPs) mediated with aqueous extracts of Morus alba L. were prepared and characterized. All G-AgNPs displayed higher antioxidant activities in DPPH radical scavenging, reducing power and total antioxidant assays than C-AgNPs and extracts. Meanwhile, all G-AgNPs exerted significantly (P < 0.05) enhanced antimicrobial activities against various pathogens compared with C-AgNPs and extracts. Among prepared AgNPs, ML-AgNPs mediated with aqueous extract of Morus alba L. leaves exhibited the most powerful antibacterial effect with the largest inhibition zones (13.11 ± 0.76 mm for S. aureus, 13.27 ± 0.22 mm for E. coli) and the lowest minimum inhibition concentrations against S. aureus (6.125 μg/ml) and E. coli (3.125 μg/ml). ML-AgNPs could inhibit the growths of S. aureus and E. coli in time- and dose-dependent modes, and even could disrupt the bacterial structure integrality resulting in the leakage of intracellular contents. G-AgNPs, especially ML-AgNPs, with remarkable bioactivities could replace C-AgNPs as related agents applied in agriculture and medicine. [ABSTRACT FROM AUTHOR]

The present work presented a synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using the aqueous extract of waste banana stem (WBS), Musa paradisiaca Linn. The reduction and formation of MNPs have been characterized by several analysis techniques such as X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The techniques showed that average particle size of WBS-AgNPs and WBS-AuNPs in crystalline nature was in ranges of 7–13 nm and 11–14 nm, respectively. The synthesized nanoparticles were used to evaluate antibacterial activity and catalysis. The WBS-AgNPs showed strong antibacterial activity against B. subtilis and E. coli. The largest zone of inhibition against B. subtilis (14.2 mm) and E. coli (9.3 mm) was found at concentrations of 4.0 ppm and 2.0 ppm, respectively. The excellent catalytic application of both the nanoparticles for the reduction of 4-nitrophenol was confirmed via study on their kinetics. The normalized kinetic constants (knor) of WBS-AgNPs and WBS-AuNPs were found to be 1.72 × 10–3 s−1 mg−1 and 2.45 × 10–3 s−1 mg−1, respectively. [ABSTRACT FROM AUTHOR]

Ciprofloxacin drug caped silver nanoparticles (Cp-AgNPs) have been produced via fast, economical and one-pot synthesis method for the first time. An amply consumed antibacterial drug ciprofloxacin (Cp) has been employed as the stabilizing agent for the AgNPs at biologically relevant conditions. Several spectrophotometric measurements, transmission electron microscopy (TEM), dynamic light scattering (DLS) measurements, theoretical studies using density functional theory (DFT) and antibacterial activity studies have been utilized for the physico-chemical characterization of the Cp-AgNPs assembly systems to justify their efficiency as potential therapeutics against antibacterial infection. The Cp-AgNPs assembly has been utilized for antibacterial activity studies involving Escherichia colii bacterial strain. Dose dependent studies showed that, decreasing drug concentration using Cp-AgNPs would retain its efficacy successfully. Absence of any hazardous chemical in the whole process of synthesis and their therapeutic efficacy will definitely make these Cp-AgNPs assembly system to act as an effective therapeutic agent to treat bacterial infection. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are effective antibacterial agent but lack of stability and rapid aggregation limits their antibacterial efficiency in biomedical applications. To overcome these shortcomings, various strategies have been adopted so far but those strategies are not much effective at room temperature and in absence of external stimuli. Thus, herein, we have successfully grafted AgNPs into copper and guanosine 5′-monophosphate (Cu/GMP) metal organic frameworks at room temperature without using any external stimuli. The loading encapsulation ratio of AgNPs into Cu/GMP was approx. 99.83% at neutral pH. The AgNPs@Cu/GMP was characterized by various techniques, such as energy-dispersive x-ray spectroscopy, transmission electron microscopy, x-ray diffraction and Fourier transforms infrared spectroscopy. All these techniques have confirmed the loading of AgNPs into Cu/GMP (MOFs). Furthermore, antimicrobial activities of AgNPs, Cu/GMP and AgNPs@Cu/GMP were assessed against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacterium. As compared to pure AgNPs, the composite material AgNPs@Cu/GMP had shown significant growth of inhibition zones against tested bacteria. The stability of AgNPs@Cu/GMP was remarkable, i.e., six times higher than free AgNPs even after 15 days. These results make AgNPs encapsulated into Cu/GMP a promising antimicrobial candidate and is expected to deliver an advance platform to pharmaceuticals and biomedical applications. [ABSTRACT FROM AUTHOR]

Since green synthesis of silver nanoparticles (AgNPs) is a simple, safe, cost-effective and eco-friendly method, AgNPs appear to be promising anti-cancer agents in the medical field. In this study, the biosynthesis of AgNPs was performed using aqueous extract of Satureja rechingeri Jamzad. Their anti-cancer activity was evaluated on the AGS gastric cancer cell line. The characteristics of the AgNPs were evaluated and approved by transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and Dynamic light scattering (DLS). The cytotoxic effect of AgNPs on the AGS cell line was evaluated by MTT assay for 24 h. Flow cytometry technique was performed to evaluate apoptosis using AnnexinV-FITC kit as well as cell cycle analysis. The expression of pro-apoptotic and anti-apoptotic genes was evaluated using Real-Time PCR. The average size of AgNPs was calculated at 62 ± 1 nm. The biosynthesized nanoparticles inhibited AGS cell growth in a time- and dose-dependent manner. Flow cytometry results confirmed apoptotic cell death. Also biosynthesized AgNPs caused up-regulation of pro-apoptotic genes; caspase-3, caspase-9 and Bax and down-regulation of Bcl2 gene and inhibited the expression of cyclin D1 and cyclin E genes. The cell cycle analysis revealed the cancer cells arrest in the G0/G1 phase. It appears that AgNPs synthesized by Satureja rechingeri Jamzad have a high potential for use as an anti-cancer drug for the treatment of gastric cancer. [ABSTRACT FROM AUTHOR]

Sols of core–shell silver nanoparticles (AgNPs) are synthesized by electrochemical method. The method provides the ability to adjust the particle size by changing both the concentration of oleic acid and the residence time τ0 in the organic phase. We synthesized AgNPs with oleic acid (OA) concentration of 0.25% (AgNPs & 0.25% OA) and 0.75% (AgNPs & 0.75% OA). These nanoparticles have been studied using modern physical–chemical methods. Differential thermal analysis curves indicate the chemical nature of bond ligand in the secondary shell; this conclusion is confirmed by quantum chemical simulation and semi-empirical calculation. In the electron paramagnetic resonance spectra of silver-containing sols AgNPs & 0.25% OA and AgNPs & 0.75% OA complex wide asymmetric signals of 500–800 G and g-factor of 2.09–2.13 are recorded, in addition, in the spectra of AgNPs with bilayer the pronounced ferromagnetic contribution is observed. The change of the oleic acid layers of the particles affects the dimension of the nanocrystallites that are being formed and the manifestation of their magnetism. Trial registration number and date of registration JCS-P-20-03-0188.R1, 22-Sep-2020 (02-Mar-2020) [ABSTRACT FROM AUTHOR]

The present study reports an efficient phyto-mediated and photo-catalyzed synthesis of silver nanoparticles (AgNPs) from root tuber extract of Chlorophytum borivilianum and demonstrates its phytotoxicity during seedling growth of Peltophorum pterocarpum. A time course analysis of the appearance of SPR peak during incubation of reaction mixture under the exposure of various light treatments suggested the influence of light spectral quality on the biosynthesis of AgNPs. Irradiation of reaction mixture with blue LEDs (BL) induced the rapid synthesis of spherical particles smaller in size compared to other treatments. The reaction mixture optimized for the synthesis of AgNPs remains same for all the exposure conditions. FTIR spectra indicated the presence of steroidal saponins and their influence in bioreduction and capping of biosynthesized AgNPs. A bioreduction mechanism insensitive to the variations in spectral quality was proposed suggesting borivilianoside H, a steroidal saponin, as the bioreductant. The toxic impact of AgNPs was more pronounced with the particles synthesized under BL exposure particularly at rooting stage. The findings suggest the influence of LED lighting not only on the biosynthesis of AgNPs but also on its phytotoxicity. [ABSTRACT FROM AUTHOR]

The present study reports the synthesis of silver nanoparticles (AgNPs) using haloalkaliphilic Streptomyces spp. characterization, and antifungal activity thereof. The UV visible spectra of synthesized AgNPs showed a characteristic absorption peak at 430 nm, due to the excitation of Surface Plasmon Resonance. Scanning electron microscopy and transmission electron microscopy images showed spherical shape NPs with an average particle size of 16.4 ± 2.2 nm. The crystalline structure of the AgNPs was confirmed by X-ray diffraction (XRD). Zeta potential analyses revealed that NPs were negatively charged (− 8.12 ± 3.87 mV). The synthesized AgNPs are significantly active against phytopathogenic fungi, Fusarium verticillioides and Ustilago maydis. Microscopic, histo- and bio-chemical investigation of AgNPs against F. verticillioides revealed that AgNPs at 100 μg concentration inhibits the hyphal growth and conidia germination, and ~ 42.85% reduction of ergosterol biosynthesis. The results of propidium iodide staining and high relative cell membrane conductivity confirmed AgNPs mediated damage to the membrane. Moreover, the AgNPs synthesized by Streptomyces spp. inhibit the growth of F. verticillioides could be due to the inhibition of ergosterol biosynthesis and membrane damage. In our knowledge, this is the first report demonstrating the anti F. verticillioides activity of AgNPs synthesized by Streptomyces spp. [ABSTRACT FROM AUTHOR]

Delonix regia has bioactive phytochemicals present in leaves, seeds, roots, and flowers. Considering that these compounds are common in extracts used for silver nanoparticles (AgNPs) biosynthesis, this study investigated the potential of D. regia seeds aqueous extract (DRE) in different concentrations to produce AgNPs (DRE-AgNPs). DRE composition was investigated by qualitative assays, and physico-chemical/structural characterization of AgNPs was performed by UV–Visible spectroscopy, dynamic light scattering (DLS), Zeta potential, and atomic force microscopy (AFM). Antibacterial effect of DRE-AgNPs was evaluated against Escherichia coli and Staphylococcus aureus. DRE presented mainly tannins and saponins. Additionally, the absorbance of each DRE-AgNPs was positively correlated to DRE concentration. At higher DRE concentrations, AgNPs were larger, regarding Z average; tended to monodispersity; and presented more negative Zeta potentials. Hydrodynamic diameters of DRE-AgNPs were measured by number distribution and only AgNPs synthesized with DRE 2 mg ml−1 (DRE-AgNPs 2) presented a single population of particles. Thus, DRE-AgNP 2 was analyzed by AFM and exhibited a spherical shape and an average height of 18.39 ± 1.59 nm. Most of DRE-AgNPs presented antibacterial effects against E. coli and S. aureus at 128 or 256 µmol l−1. In conclusion, different DRE concentrations modulated physico-chemical characteristics of AgNPs with antibacterial activity. [ABSTRACT FROM AUTHOR]

Current study discloses eco-friendly one pot robust method for the synthesis of silver nanoparticles by employing novel bark extract of the medicinal plant Terminalia bellerica Roxb. Synthesized silver nanoparticles (B-AgNPs) were found spherical and crystalline, as confirmed by UV–visible spectroscopy, XRD, TEM and FTIR. Catalytic potential of B-AgNPs was assessed by reductive degradation of various waste water pollutants, such as 4-nitrophenol, methyl orange, methylene blue and eosin yellow that fitted well to pseudo first order kinetics. B-AgNPs were found most efficient towards the reduction of 4-nitrophenol and removed 88.7% of it in 60 min. An artificial neural networks (ANNs) model based on experimental data was developed to describe the nonlinear behavior of the catalytic process that was found most accurate for the reductive degradation of eosin yellow. Antioxidant activity, evaluated by standard DPPH and ABTS assays, was dose dependent and B-AgNPs were found two fold potent in DPPH radical scavenging than the standard used. These results suggest that B-AgNPs could be a sustainable source of technological innovation in wastewater treatment and management of oxidative stress related health disorders. [ABSTRACT FROM AUTHOR]

An environmentally benign solvothermal process was introduced to synthesize monodisperse silver nanoparticles (Ag NPs). Silver nitrate (AgNO3) was reduced by ethanol which was also used for recyclable solvent. The as-synthesized Ag NPs were stabilized by oleate. Effects of reaction temperature, reaction time, AgNO3 concentration as well as molar ratio of sodium oleate and AgNO3 on the formation and surface plasmon resonance (SPR) were determined by means of UV–Vis spectrophotometer. TEM and XRD were used to characterize the size, morphology and crystalline structure of Ag NPs. The excessive AgNO3 over sodium oleate and high concentration of AgNO3 are favorable for the synthesis of monodisperse Ag NPs in large scale. The characteristic SPR absorption of Ag NPs centers at ca. 430 nm despite of reaction temperature, reaction time and even AgNO3 concentration. The nucleation and growth of Ag NPs completed in a very short period of time, showing the high efficiency of our synthetic route for the synthesis of uniform Ag NPs. [ABSTRACT FROM AUTHOR]

The search for new more effective nanoparticles based antimicrobial agents has been under way in recent decades. Silver nanoparticles are hydrophobic and have a negative charge. We report on the preparation of Ag–Cu bimetallic nanoparticles with various silver contents synthesized by electric explosion of two twisted wires of the metals in argon atmosphere. The method allows to obtain nanoparticles of a given composition, has high performance and scalability. Nanoparticles were investigated using X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive analysis and microelectrophoresis techniques. We evaluated the antibacterial activity of the nanoparticles against Gram-negative E. coli and Gram-positive methicillin resistance S. aureus MRSA. Our study showed that the synthesized nanoparticles have a positive zeta potential of about 30 mV at pH 7.2 and high antimicrobial activity against the tested bacteria strains, which is close to the activity of silver nanoparticles with a size of 20 nm. The high antimicrobial activity of the nanoparticles is due to the prolonged slow release of silver and copper ions, which makes nanoalloys more effective than Cu and Ag metallic nanoparticles. The synthesized nanoparticles have high antimicrobial activity and demonstrate the potential for their use as promising new generation antibacterial agents effective against resistant microorganisms. [ABSTRACT FROM AUTHOR]