Search

The present study gives evidence that silver nanoparticles (AgNPs) are spontaneously formed from Ag+ ions in Mueller-Hinton broth, which is frequently used as a standard cultivation medium for many types of bacteria. Silver ions often serve as a reference in the determination of minimum inhibitory concentration (MIC) values of engineered AgNPs. It is thus a question if the MIC values determined for engineered AgNPs are not influenced by the presence of spontaneously formed AgNPs. Furthermore, as shown here, the addition of augmented concentrations of selected amino acids, namely glutamic acid and glutamine, can change the growth and characteristic features of spontaneously formed AgNPs. For the sake of a direct comparison, the influence of the two selected amino acids on characteristics and MIC values determination of engineered AgNPs has been also investigated. The determined MIC values of all investigated systems (i.e., with and without the presence of engineered AgNPs) and their mutual comparison demonstrated that MIC values are slightly influenced by the actual composition of a cultivation medium for bacterial growth. On the other hand, the actual composition of a cultivation medium is crucial for the final characteristics of AgNPs. The changes in characteristic features of spontaneously formed as well as engineered AgNPs are most probably induced by the covalent bonding of amino acids to AgNPs surface which is proven by vibrational spectroscopic techniques.

Graphical abstract Highlights • Ag NPs were dispersed in the cellulose nanofiber aerogel by supercritical CO 2 drying. • Sheet-like structures and Ag NP agglomerates were obtained by conventional drying. • Ag NPs/cellulose nanofiber aerogels showed antifungal and antibacterial activities. Abstract The formation of Ag nanoparticle/cellulose nanofiber (Ag NP/CNF) composite aerogels were investigated using supercritical CO 2 (scCO 2) drying. CNF hydrogel–ethanol solutions were mixed with Ag NP dispersions in ethylene glycol by ball milling. Subsequently, scCO 2 drying and conventional vacuum drying were evaluated for Ag NP/CNF composite aerogel formation. After scCO 2 drying of the CNF hydrogel solution, a sponge-like CNF aerogel was formed with Ag NPs dispersed in the CNF matrix. In contrast, sheet-like structures and Ag NP agglomerates were obtained by conventional drying. The antifungal and antibacterial activities of the obtained Ag NP/CNF aerogels were evaluated. The composites showed good bacterial (for Escherichia coli) and fungal (for Aspergillus niger) inhibition properties. Furthermore, the effects of drying method and the presence of Ag NPs on the properties of the CNF aerogels, such as surface area, porosity, and antibacterial and antifungal activities, were examined. [ABSTRACT FROM AUTHOR]

Ag nanoparticles incorporated onto flour (F)/polyvinyl alcohol (PVA) were performed by green synthesis using gamma irradiation to form (F/PVA/Ag) bio‐based nanocomposite hydrogel. The effect of the hydrogel composition and irradiation dose on the gelation percent was investigated. Characterization of (F/PVA) and (F/PVA/Ag) by Fourier transform infrared spectroscopy and thermogravimetric analysis was was investigated. The formation of Ag nanoparticles in (F/PVA/Ag) was confirmed by UV–Vis spectra, X‐ray diffraction, and transmission electron microscopy. The (F/PVA/Ag) nanocomposite exhibited excellent antibacterial activity against the gram‐positive bacteria Staphylococcus aureus (ATCC 29213) and moderate activity against the gram‐negative bacteria Escherichia coli (ATCC 25922). It exhibited excellent antifungal activity against Candida albicans (ATCC 10231). The results proved that this novel developed (F/PVA/Ag) naocomposite has a great potential for use in biomedical applications such as wound dressing hydrogel. [ABSTRACT FROM AUTHOR]

The hybrid nanocomposite based on poly(3,4-ethylenedioxythiophene)/Ag nanoparticle/reduced graphene oxide (rGO) was prepared by hydrazine hydrate. The nanocomposite materials have been characterized by scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX), and Fourier transform infrared-Attenuated transmission reflectance (FTIR-ATR). Electrochemical performance of the electrodes is studied by cyclic voltammetry (CV), galvanostatic charge-discharge measurements (GCD) and electrochemical impedance spectroscopy (EIS) in 1.0 M H2SO4 solution. We demonstrate a facile and efficient to prepare rGO/Ag/PEDOT nanocomposite for supercapacitor electrode applications. Compared with the PEDOT (Csp= 65.56 F/g at 4 mV/s) the areal capacitance of rGO/Ag/PEDOT nanocomposite (Csp= 612.69 F/g at 4 mV/s) is enhanced with nearly 9.34 times in 1 M H2SO4 solution. In composite electrode, Ag nanoparticles and rGO act as the electrode active materials in chemical polymerization process. In addition, the rGO/Ag/PEDOT nanocomposite showed excellent cycling stability, retaining 101.8% of the initial capacitance with the continuous charge/discharge processes for 1000 cycles. [ABSTRACT FROM AUTHOR]

Abstract The wide use of Ag nanoparticles (Ag NPs) as antimicrobial agents has resulted in a massive release of Ag NPs into environment, such as water and soil. As bryophytes live ubiquitously in water and soil, their tolerance and response to Ag NPs could be employed as an indicator for the harm of Ag NPs to the environment. Herein, we report the study on the physiological and biochemical responses of bryophytes to Ag NPs with different surface coatings at the gametophyte stages: protonema and leafy gametophyte, by using Physcomitrella patens as a model system. We found that Ag NPs, including AgNPs-B (Ag NPs without surface coating), AgNPs-PVP (Ag NPs coated with poly (N -vinyl-2-pyrrolidone)) and AgNPs-Cit (Ag NPs coated with citrate), were toxic to P. patens in terms of growth and development of the gametophyte. The toxicity was closely related to the concentration and surface coating of Ag NPs, and the growth stage of P. patens. The protonema was more sensitive to Ag NPs than the leafy gametophyte. Ag NPs inhibited the growth of the protonema following the trend of AgNPs-B > AgNPs-Cit > AgNPs-PVP. Ag NPs changed the thylakoid and chlorophyll contents, but did not affect the contents of essential elements in the protonema. At the leafy gametophyte stage, Ag NPs inhibited the growth of P. patens following a different order: AgNPs-Cit > AgNPs-B ≈ AgNPs-PVP. Ag NPs decreased the chlorophyll b content and disturbed the balance of some important essential elements in the leafy gametophytes. Both the dissolved fraction of Ag NPs and Ag NPs per se contributed to the toxicity. This study for the first time reveals the effects of Ag NPs on bryophytes at different growth stages, which calls for more attention to the nanoecotoxicology of Ag NPs. Highlights • Ag NPs inhibited the growth of P. patens. • The protonema was more sensitive to Ag NPs than the leafy germetophyte. • Ag NPs inhibited the growth of the protonema: AgNPs-B > AgNPs-Cit > AgNPs-PVP. • Ag NPs inhibited the growth of the leafy germetophyte: AgNPs-Cit > AgNPs-B≈AgNPs-PVP. • Both dissolution and particulate of Ag NPs contributed to the toxicity. [ABSTRACT FROM AUTHOR]

Bacterial cellulose pellicles synthesized by Gluconacetobacter xylinus in the molasses medium were acid hydrolyzed to obtain cellulose nanocrystals. The isolated bacterial cellulose nanocrystals (BCNC) and silver nanoparticles (AgNPs) were used to prepare chitosan (Ch) based nanocomposite films. It was found that the incorporation of BCNC and AgNPs into chitosan films significantly influenced apparent color and transparency of the films. In addition, sensibility to water, water vapor permeability and mechanical properties were greatly improved after formation of nanocomposite. The formation of hydrogen bonds between chitosan and BCNC was detected by FTIR analysis. XRD studies confirmed the appearance of crystalline peaks in the nanocomposite films. The results of DSC showed significant effect of nanocrystals and nanoparticles on thermal stability. FE-SEM micrographs showed that BCNC and AgNPs which dispersed homogenously in chitosan matrix, had an average size of 20–30 and 35–50 nm, respectively. The Ch/AgNPs nanocomposite film exhibited strong antibacterial activity against food borne pathogens. Results of this study suggested that nanocomposite films containing BCNC and AgNPs can be used as an active food packaging material for increasing shelf life of packaged foods. [ABSTRACT FROM AUTHOR]

Abstract We have previously shown that the bactericidal effect of ZnO nanoparticles in the absence of a light source originates from the released Zn2+ ions. The purpose of this study was to explore antibacterial activity arising from photo-induced reactive oxygen species (ROS) of ZnO nanoparticles under UV-A light irradiation. To achieve this, S. aureus and K. pneumoniae bacteria were exposed to three different ZnO nanoparticles under UV-A light. The concentrations of the ZnO nanoparticles were low, such that the antibacterial effect of the dissolved Zn2+ ions was negligible. From various empirical evidence, we found that the oxygen defects of the ZnO crystals enhanced the photogeneration of ROS and consequently, the ZnO nanoplates (NPs) with the polar facets exhibited the most pronounced antibacterial activity under UV-A stimulation. To enhance the antimicrobial activity of the NPs, we successfully synthesized silver-nanoparticle-decorated ZnO NPs and explored their antibacterial activity compared to that of the NPs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag nanoparticles loaded TiO2 nanotubes array was fabricated on Ti substrates. • Multilayered film coating was fabricated to seal TiO2 nanotubes array. • The present system achieved the controlled release of Ag ions. • The modified Ti substrates favored the growth of osteoblasts. • Antibacterial property of Ti substrates was significantly improved. Abstract In orthopedic fields, effective anti-infection property and promotive biocompatibility on surface of titanium implants are two crucial factors for long-term successful implants. Herein, Ag nanoparticles (NPs) loaded TiO 2 nanotubes (TNT) arrays were fabricated on Ti substrates with assistance of ultraviolet irradiation. Then, bioactive multilayer films of chitosan (CHI) and dialdehyde alginate (ADA) pair were deposited onto the Ag-loaded TNT arrays via a layer-by-layer (LBL) self-assembly technique, which could effectively achieve the impactful antibacterial ability of titanium and endow the substrates with favorable biocompatibility. The driving force of the assembling of multilayer films came from two sources, electrostatic interaction and covalent interaction of Schiff-bonds between CHI and ADA. The surface topography and wettability of different samples were characterized by field emission scanning electron microscopy, transmission electron microscopy and contact angle measurements, respectively. In addition, Ag ions release from TNT-Ag and LBL substrate was measured via inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results of a series of biological behaviors of osteoblasts on different substrates in vitro , including lactate dehydrogenase activity assay, cytoskeleton observation and cell viability measurement, confirmed that LBL substrates coated with (ADA-CHI) 10 multilayer films have negligible cytotoxicity and promote osteoblast growth compared with TNT-Ag substrates, which could ascribe to the slow-release of Ag ions and the biocompatibility of (ADA-CHI) 10 multilayer. More importantly, owing to the release of Ag ions, the LBL samples still exhibited a prominent antibacterial activity for S.aureus and E.coli. Characteristics of bacterial adhesion and viability measurement proved that the fabricated Ag-incorporated platform was capable of obviously inhibiting the adhesion and growth of bacteria. Therefore, this approach of surface modification for Ti substrates presented here may provide an alternative strategy to simultaneously meet the desirable osteoblast growth and reduce bacterial infection for implants in clinical application. [ABSTRACT FROM AUTHOR]

Conventional thin-film composite forward osmosis membrane suffers from serious biofouling problem when used for desalination and treating wastewater. However, reported improved strategies are difficult to keep a balance between fouling resistance and membrane performance. To address this challenge, this work presents a simple and efficient surface modification strategy to construct a zwitterion-silver nanocomposite structure via second interfacial polymerization of zwitterion and in situ synthesis of silver nanoparticles (Ag NPs), which improves the polyamide layer in terms of hydrophilicity and transport properties without adversely affecting the selectivity. In addition, the zwitterion-silver modified membrane exhibits significantly biofouling resistance due to the simultaneous improvement of antiadhesive and antimicrobial property. Furthermore, the zwitterion-silver modified membrane with regeneration ability shows a long-term anti-biofouling property. Compared with other reports, the zwitterion-silver nanocomposite modified membrane shows outstanding antifouling property (>96% antimicrobial efficiency), high water flux and excellent selectivity, which highlights its potential for practical applications. [ABSTRACT FROM AUTHOR]

We discuss herein present‐day instrumental limitations to the electrochemical measurement of fast processes occurring at the single‐entity scale. We focus on the effect of filters on potentiostatic experiments in which the monitored current results from partial oxidations of an individual Ag nanoparticle undergoing repeated high‐frequency collisions with an electrode. From analysis of the resulting peak‐shaped current‐time events, we conclude that the average timescale of a single Ag nanoparticle/electrode collision is too short to resolve at the temporal limitations of current instrumentation. These findings are consistent with previously reported random walk model that predicts nanoparticle/electrode interactions at nanosecond timescales. Filtered out: An electroactive nanoparticle undergoes high‐frequency repeated collisions concurrent with multielectron transfer events at a microelectrode, resulting in several current pulses with nanosecond‐scale durations. Electronic filters of the instrument distort the output response, artificially increasing the apparent time scale of a single nanoparticle/electrode collision. [ABSTRACT FROM AUTHOR]

Abstract Firstly, Ag nanoparticle (Ag-NP) was synthesised with environmentally-friendly and green media extracted from Rosmarinus officinalis plants. The structure of Ag-NP was confirmed with the absorption peak related to the Surface Plasmon Resonance at 432 nm through UV–Vis analysis. Subsequence, Ag-NP was composited with pre-synthesised vitamin B9 (VB9) intercalated Layered Double Hydroxide (VB9-LDH) and Ag@VB9-LDH with different percentages was incorporated in the chitosan (CS) as bio-polymeric matrix. The improvement in the physio-chemical properties of prepared nanocomposites (NCs) was confirmed with different spectroscopic techniques. Finally, the effect of polymeric matrix on the antibacterial activity of this compound was examined against two Gram-negative and Gram-positive bacteria. The results of antibacterial test showed the remarkable antibacterial activity for all samples against both bacteria and NC 6 wt% showed greater inhibition zone diameter (19 mm and 11 mm) in compared to the pristine Ag@VB9-LDH (11 mm and 8 mm) for Gram-negative and Gram-positive, respectively. Highlights • Intercalation of LDH samples with biologic and organic Vitamin B9 molecule. • Bio-friendly and low-cost synthesis of Ag-NP through R. officinalis extracted media. • Increasing in the char parameter of CS NCs with Ag@VB9-LDH samples. • Antibacterial activity of samples against bath E. Coli and S. Aureus bacteria. • Increasing in the inhibition zone diameter to 19 mm for CS/Ag@VB9-LDH NC. [ABSTRACT FROM AUTHOR]

In this study, we describe a modification of a glassy carbon electrode with an ordered mesoporous carbon (OMC)/poly (2‐hydroxyethyl methacrylate) (PHEMA)/Ag nanoparticle composite (GCE/AgNPs‐PHEMA‐CMK‐1) done for the first time and the application of a proposed sensor for the simultaneous determination of acetaminophen (AC) and domperidone (DO). The transmission electron microscopy (TEM), fourier‐transform infrared spectroscopy (FT‐IR), electrochemical impedance spectroscopy (EIS), UV‐vis spectroscopy, and X‐ray powder diffraction (XRD) methods were used for the analysis of the synthesized nanocomposite. The GCE/AgNPs‐PHEMA‐CMK‐1 showed good catalytic activity for the electro‐oxidation of acetaminophen and domperidone in the buffer solution. The pH investigation showed that acetaminophen and domperidone electro‐oxidation is relative to the pH value of the solution. The maximum oxidation process occurred at pH=7.0 and pH=8.0 for acetaminophen and domperidone, respectively, on the surface of the GCE/AgNPs‐PHEMA‐CMK‐1. The GCE/AgNPs‐PHEMA‐CMK‐1 showed a linear range between 0.015–7.5 μM and 0.03–10.8 μM for acetaminophen and domperidone, respectively. The GCE/AgNPs‐PHEMA‐CMK‐1 showed detection limits of 0.005 and 0.01 μM for acetaminophen and domperidone, respectively, by the differential pulse voltammetry (DPV) method. Finally, the GCE/AgNPs‐PHEMA‐CMK‐1 was suggested as a highly powerful tool for the analysis of acetaminophen and domperidone in real samples. [ABSTRACT FROM AUTHOR]

Quadrupolar plasmon resonances that originate from interparticle near-field coupling interaction were observed in arrays composed of small-sized Ag nanoparticles (∼30 nm). The arrays were prepared by a dewetting process, during which hexagonally arranged aluminum pits were used to induce and confine the nucleation and growth of Ag nanoparticles. With the increase in the thickness of the initial Ag film, the particle size increases, and the interparticle spacing decreases to sub-10 nm scale, making adjacent particles strongly coupled. As a result, the quadrupolar resonance mode occurs, and its wavelength remains practically unchanged, while the dipolar mode shifts toward to a longer wavelength by about 80 nm. In comparison, only a dipolar resonance mode was observed in the non-coupled array that has a large interparticle spacing. The coupled array was demonstrated to exhibit much stronger surface enhanced Raman scattering (SERS) activity than that of the non-coupled array, suggesting that the quadrupolar mode can also be viewed as an indication of strong SERS enhancement in arrays composed of small-sized metal nanoparticles. [ABSTRACT FROM AUTHOR]

Improving the sensitivity and stability of Ag nanoparticles-based sensors is crucial for non-enzymatic H 2 O 2 detection. Herein, Ag nanoparticles embedded N-doped carbon nanofibers (Ag/NCNFs) were prepared by electrospinning and subsequent thermal treatment. Characterization results showed that Ag nanoparticles with uniform size were homogeneously embedded in NCNFs porous matrix. Such an embedded structure could well prevent the aggregation of Ag nanoparticles and improve their electrocatalytic ability and stability. The preliminary test results of electrocatalytic activity suggested that Ag/NCNFs displayed obvious characteristic of electrocatalysis for H 2 O 2 reduction. In amperometric experiments, Ag/NCNFs-based sensors exhibited excellent H 2 O 2 analytical performances of wide linear range (0.02–20 mM), low detection limit (0.15 μM), high sensitivity (142.2 μA mM −1  cm −2 ), high selectivity and anti-interference. In addition, the Ag/NCNFs-based sensor had superior reproducibility and excellent stability and the Ag/NCNFs-GCE could maintain 98.4% of the initial current response after storing it at 25 °C for 15 days. More significantly, the as-fabricated sensor could be further used to detect the concentrations of H 2 O 2 in milk samples and displayed satisfactory recoveries and relative standard deviation (RSD). These results manifested that Ag/NCNFs had potential to be utilized as a promising material for constructing non-enzymatic H 2 O 2 sensors. [ABSTRACT FROM AUTHOR]

A novel silver nanoparticle doped diblock copolymer was synthesized by a 3‐step process via bulk polymerization process under nitrogen atmosphere. The above prepared polymer is characterized by FTIR spectroscopy, fluorescence emission spectroscopy, circular dichroism (CD), HRTEM, and FESEM. The sulphamicacid end capped poly(ε‐caprolactone) (P1) system exhibited higher tensile strength than the sulphamicacid bridged diblock copolymer (P2) and nano Ag doped sulphamicacid bridged diblock copolymer (P3) systems. The splinting activity of the diblock copolymers was tested and confirmed the low temperature splinting activity of the diblock copolymer. The Ag nanoparticle catalyzed catalytic reduction of p‐nitrophenol (NiP) was tested, and the apparent rate constant (kapp) was determined as 7.36 × 10−3 sec−1. The thermal studies were carried out by DSC and TGA methods. The TGA study declared that the P1 system has higher degradation temperature than the P2 and P3 systems. The P1 system has higher melting temperature (Tm) (75.5°C) than the P2 and P3 systems. The CD study indicated that the conformation of sulphamicacid was not changed even after the formation of nano Ag doped sulphamicacid bridged diblock copolymer. [ABSTRACT FROM AUTHOR]

The ternary nanocomposites of reduced graphene oxide (rGO), Ag nanoparticles, and polythiophene (PTh), (rGO/Ag/PTh) with different initial feed ratios of [GO]o/[Th]o = 0.2, 0.3 and 0.4 were used in a symmetric supercapacitor device formation. rGO/Ag/PTh nanocomposite has been prepared by in-situ polymerization and chemical reduction of graphene oxide. Fourier transform infrared spectroscopy -Attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM) were employed in order to characterize the composition of the resulting nanocomposites and morphology. The electrochemical behavior of these nanocomposites were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopic (EIS) measurements in 1.0 M H2SO4 solution. As an electroactive material, rGO/Ag/PTh nanocomposite shows good capacitive performance in acidic electrolyte solution, a high specific capacitance (up to Csp = 953.13 F/g at a scan rate of 4 mV/s) at [GO]o/[Th]o = 0.2. Moreover, the rGO/Ag/PTh nanocomposites at [GO]o/[Th]o = 0.2 show high stability with 91.88% specific capacitance saved after 1000 charge/discharge processes. Furthermore, larger energy density (up to E = 28.8 Wh/kg at a scan rate of 5 mV/s and a power density of P = 2843.3 W/kg at a scan rate of 1000 mV/s) of the nanocomposites at [GO]o/[Th]o = 0.2 is obtained in 1 M H2SO4 aqueous electrolyte for two-electrode device formation. This study has revealed that the rGO/Ag/PTh nanocomposite electrode materials may lead to a stable supercapacitor for portable electronic applications. GRAPHICAL ABSTRACT: [ABSTRACT FROM AUTHOR]

Sol-gel derived noble-metal-silica nanocomposites are very useful in many applications. Due to relatively low price, higher conductivity, and higher chemical stability of silver (Ag) compared with copper (Cu), Ag-silica has gained much more research interest. However, it remains a significant challenge to realize high loading of Ag content in sol-gel Ag-silica composite with high structural controllability and nanoparticles’ dispersity. Different from previous works by using multifunctional silicon alkoxide to anchor metal ions, here we report the synthesis of Ag-silica nanocomposite with high loading of Ag nanoparticles by employing acetonitrile bi-functionally as solvent and metal ions stabilizer. The electrical conductivity of the Ag-silica nanocomposite reached higher than 6800 S/cm. In addition, the Ag-silica nanocomposite could simultaneously possess high electrical conductivity and positive conductivity-temperature coefficient by properly controlling the loading content of Ag. Such behavior is potentially advantageous for high-temperature devices (like phosphoric acid fuel cells) and inhibiting the thermal-induced increase of devices’ internal resistance. The strategy proposed here is also compatible with block-copolymer directed self-assembly of mesoporous material, spin-coating of film and electrospinning of nanofiber, making it more charming in various practical applications. [ABSTRACT FROM AUTHOR]

Ag species in the Ag loaded Ga 2 O 3 (Ag/Ga 2 O 3 ) photocatalysts were investigated with regard to changes in their structures and the chemical states before and after the photocatalytic CO 2 reduction with water. Ag clusters with the size of around one nanometer in as prepared 0.1 wt% Ag/Ga 2 O 3 sample became larger metallic Ag nanoparticles with the size of several nanometers after the reaction. In the 1.0 wt% Ag/Ga 2 O 3 sample, Ag nanoparticles having the AgGaO 2 interface structure decomposed to aggregated Ag metal particles after the reaction. Such transition in the morphology and chemical states of Ag species could explain the variations in photocatalytic activities of these samples during the reaction, and suggested that at least metallic Ag particles would function as effective co-catalysts. In-situ FT-IR measurements of the Ag/Ga 2 O 3 samples before and after the reaction, we could not detect CO 2 molecules adsorbing on metallic Ag nanoparticles in dark. Under light irradiation, however, the absorption bands originated from the photo-adsorbed CO 2 species on Ag metal nanoparticles appeared. Thus, we detected the interaction of CO 2 molecules and metallic Ag nanoparticles as the effective co-catalysts for CO 2 reduction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highly ordered TiO2 nanotube (TiO2 NT) arrays were prepared by anodic oxidizing method on the surface of the Ti substrate. Nitrogen-doped TiO2 nanotube (N-TiO2 NT) arrays were carried out by ammonia solution immersion, and Ag nanoparticles loaded N-doped TiO2 nanotube (Ag/N-TiO2 NT) arrays were obtained by successive ionic layer adsorption and reaction (SILAR) technique. The samples were characterized by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) emission spectra, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy (DRS). The result indicated that the diameter and wall thickness of the TiO2 NT are 100-120 and 20-30 nm, respectively. Moreover, the morphology and structure of the highly ordered TiO2 NTs were not affected by N-doping. Furthermore, Ag nanoparticles were evenly deposited on the surface of TiO2 NTs in the form of elemental silver. Finally, the photocatalytic activity of Ag/N-TiO2 NTs was evaluated by degradation of methyl orange (MO) under visible-light irradiation. The Ag/N-TiO2 NTs exhibited enhanced photocatalytic properties, which could reach 95% after 90-min irradiation. [ABSTRACT FROM AUTHOR]

In this study, a ternary composite consisting of Ag nanoparticles (NPs) embedded reduced graphene oxide (rGO) and Ni(OH) 2 have been synthesized through microwave-assisted reaction. In this system, the rGO serves as conductive substrate to support the Ni(OH) 2 and prevent the Ni(OH) 2 from restacking. Moreover, the Ag NPs anchored on rGO can create a nanoscale spacers between the rGO/Ni(OH) 2 sheets which avoids the π-π interaction between rGO substrates leading to further increase in surface area. In addition, the decoration of Ag NPs also can improve the electrical conductivity of the composites leading to better contact between rGO and Ni(OH) 2 . As a result of the unique nanoarchitecture, the Ag-rGO/Ni(OH) 2 composite exhibits high specific capacitance of 1220 F/g at 1 A/g, which is much higher than that of pristine Ni(OH) 2 (588 F/g). Moreover, the ternary composite also shows superior capacitance retention and cycling stability up to 2000 cycles. Asymmetric supercapacitors based on Ag-rGO/Ni(OH) 2 electrode and the activated carbon are also assembled. The asymmetric supercapacitors have a maximum energy density of 41.2 Wh/kg at a power density of 375 W/kg with excellent cycling stability. The results indicate the importance of rational design and synthesis of Ag-rGO/Ni(OH) 2 for high-performance energy storages. [ABSTRACT FROM AUTHOR]

The colorimetric and fluorescent properties of polydiacetylene (PDA) have been assessed for chemosensors and ultrafast biosensor applications. The low quantum efficiency, however, has delayed the further development of PDA based practical devices. Here, we synthesized a hybrid nanostructure of PDA with Ag nanoparticles of core. A core-shell type Ag@PDA blue phase nanoparticles showed significantly enhanced Raman scattering, whereas it dramatically decreased after the thermal treatment inducing phase transition of PDA to red. On the other hand the Ag@PDA red phase nanoparticles showed an evidently increasing fluorescence accompanying with the shortened lifetime. These unusual reinforced optical properties is attributed to the core Ag nanoparticles providing the surface selection rule and the surface enhancement effects by the localized surface plasmon. Consequently, our result demonstrates the hybrid structure of PDA with metal nanoparticles to be an alternative to overcome the limit of PDA for high performance devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A super-thick PDA-shelled nanofibrous membrane was successfully obtained. • Hydrogen bond between PDA and water molecules was studied theoretically. • The obtained evaporator display an efficient evaporation rate of 1.91 kg m−2 h−1. Polydopamine (PDA) has been regarded as a meaningful and auxiliary photothermal material owing to its natural mussel foot protein-like functional groups, which can be facilely adhered to other substrates. Nevertheless, simply depositing a uniform and thick PDA shell on the fiber surface remains a challenge. Herein, a uniform super-thick PDA-shelled dopamine/polyacrylonitrile nanofibrous membrane (D-PAN@PDA NFM) with outstanding flexibility and mechanical stability was successfully constructed by the electrospinning and self-polymerization methods. Coupled with plasma Ag nanoparticles, the fabricated D-PAN@PDA@Ag core–shell NFM-based evaporator performed an efficient evaporation rate of 1.91 kg m−2 h−1 under one-sun irradiation, and the corresponding energy conversion efficiency can reach to 85.5%. Interestingly, the absorption of PDA molecules could be enhanced when it was combined with water molecules, which was further demonstrated through density functional theory calculation. This work provides a new pathway for the construction of photothermal fibrous membranes, expanding their potential application in the photothermal fields. [ABSTRACT FROM AUTHOR]

The photocatalyst must be low cost, high performing, and recyclable for efficient water treatment applications. Herein, we deposited TiO 2 and Ag-dispersed TiO 2 thin films via sol-gel spin coating and post-deposit annealing at 400 °C for 50 min. The physical properties of TiO 2 and Ag: TiO 2 thin films were analyzed by X-ray, Raman analysis, Atomic Force Microscope, Scanning Electron Microscopy, Electron Dispersive Spectroscopy, Transmission Electron Microscopy, and UV–visible transmittance spectroscopy. The structural evaluation established that the films were of anatase phase without any peaks related to metallic Ag or Ag oxides. The scanning transmission electron microscopy images demonstrated the presence of Ag nanoparticles with a diameter of ∼8 nm distributed on the film surface. The cross-sectional images from the high-angle annular dark-field scanning transmission electron microscopy confirmed the presence of Ag nanoparticles along the thickness of the Ag: TiO 2 thin films. The optical bandgap of the Ag: TiO 2 samples red shifted from 3.35 eV to 3.00 eV when the doping concentration reached 8 wt%. Photocatalysis showed by all samples were analyzed following the degradation of methylene blue (MB) with UV-light illumination. The Ag: TiO 2 thin films demonstrated a substantial improvement in photocatalytic efficiency. The 4 wt% Ag doped TiO 2 sample degraded 98% of MB in 180 min, a degradation efficiency 60% higher than the undoped samples. [Display omitted] • Ag nanoparticle dispersed TiO 2 thin films by simple sol gel technique. • Structural analysis revealed pure anatase phase. • Absorption edge shift to lower energy and enhanced photo response by Ag incorporation. • STEM cross sectional images demonstrated the distribution of Ag particles throughout the films. • Ag doping boosted the photocatalysis of TiO 2 thin films by 60%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly sensitive SERS substrate for trace catechol in seawater. • Facile preparation of Ag nanoparticles modified MXene film on Al plate. • Detection limit of catechol is up to 1 × 10−7 mol L−1 in seawater. In this study, MXene films with an ordered layered structure were fabricated on Al plates via electrodeposition. Next, the Ag nanoparticles were modified on the MXene films through in situ reduction. Meanwhile, their surface enhanced Raman scattering effect for trace catechol was directly explored in catechol aqueous solution. It was found that these MXene films possess very strong surface enhanced Raman scattering effect for trace catechol in water. The detection limit is up to 5 × 10−8 mol L−1. In addition, these films possess high selectivity, excellent signal repeatability (relative standard deviation < 5.86%, spot-to-spot), high reproducibility (relative standard deviation < 5.86%, batch-to-batch) and good stability. More interestingly, the aforementioned films possess excellent salt tolerance and are highly sensitive to trace catechol in seawater. The detection limit is up to 1 × 10−7 mol L−1 in seawater. Moreover, there exists a good linear relationship between Raman signal intensity and catechol concentration within a broad concentration range of catechol (1 × 10−5 mol L−1 –1 × 10−7 mol L−1). These results imply that these MXene films possess great potential in timely monitoring of catechol in seawater. And its large-scale preparation and application might be simple and easy. [ABSTRACT FROM AUTHOR]

Nanocellulose is an abundant green resource that, owing to the larger surface area, length, and diameter of the fibers, can be used as a framework for loading Ag nanoparticles and serve as substrate for surface enhancement Raman scattering (SERS). These properties would cause the hydroxyl groups on the surface to adsorb the Ag ions and reduce them to Ag seed to form a load fulcrum. This paper presents a convenient and environmentally friendly method for the fabrication of silver-nanocellulose composites (NCF-Ag). A commonly used pesticide, carbendazim (CBZ), was used as a SERS probe to evaluate the properties of NCF-Ag. The results showed that NCF-Ag possesses good homogeneity, reproducibility, and stability. Additionally, CBZ was found to have a low limit of detection (LOD), i.e., 1.0 × 10−8 M, which indicates the possibility for trace analysis. Furthermore, it presents good linearity with R2 = 0.98 at 1007 and 1270 cm−1 in the range from 10−4~10−7 M CBZ.

Silver nanoparticles (Ag NPs) tarnish easily upon exposure to ambient air, and eventually lose their ability as a plasmonic sensor via weakened localized surface plasmon resonance (LSPR). We have demonstrated the enhancement in plasmonic sensitivity of tarnished Ag NP aggregates to vapors of volatile organic compounds (VOCs) such as ethanol and butanol by Ar plasma exposure. The response of Ag NP aggregates to the VOC vapors was examined by measuring the change in optical extinction spectra before and after exposure to the vapors. The sensitivity of Ag NP aggregates decreased gradually when stored in ambient air. The performance of tarnished Ag NPs for ethanol sensing was recovered by exposure to argon (Ar) plasma for 15 s. The reduction from oxidized Ag to metallic one was recognized, while morphological change was hardly noticeable after the plasma exposure. We conclude, therefore, that a compositional change rather than a morphological change occurred on Ag NP surfaces enhances the sensing ability of tarnished Ag NP aggregates to the VOC vapors. [ABSTRACT FROM AUTHOR]

Core/shell nanorods of MnO 2 /carbon embedded with Ag nanoparticles (MCA) were successfully fabricated via a facile and effective hydrothermal and reduction method in situ. Typically, a MCA-1.5 sample (1.5 g·L −1 glucose reactant) exhibited the highest specific capacitance of 628 F·g −1 at the current density of 1 A·g −1 in three-electrode systems. Particularly, a fabricated asymmetric supercapacitor, using MCA-1.5 and active carbon as the positive and negative electrodes, respectively, delivered a maximum energy density of 48.3 W·h·kg −1 at power density of 851.7 W·kg −1 and exhibited a superior, long cycle life, showing ∼98.5% specific capacitance retention after 2000 cycles. The practical energy-storage applicability of this device was demonstrated by the operation of an LED bulb when a duo of two such devices was charged. These results indicated that synthesized ternary nanocomposites have potential applications as supercapacitor electrodes in energy storage systems. [ABSTRACT FROM AUTHOR]

Ag nanoparticle-decorated self-floating porous black TiO 2 foams (Ag-FBTFs) are fabricated by facile wet-impregnation and high-temperature surface hydrogenation strategy, utilizing self-floating porous black TiO 2 foams (FBTFs) with 3D macro-mesoporous architectures as hosts. The composites are evidently investigated by X-ray diffraction (XRD), Raman, N 2 adsorption, diffuse reflectance spectroscopy (DRS), transmission electron microscope (TEM), scanning electron microscopy (SEM), scanning Kelvin Probe (SKP), surface photovoltage spectroscopy (SPS) and photoluminescence (PL). The results show that the small Ag nanoparticles with diameter of 3–4 nm are decorated on the surface of FBTFs uniformly, which extend the photoresponse to visible-light region and show obvious surface plasmon resonance (SPR). The Ag-FBTFs exhibit excellent solar-driven photocatalytic performance for complete mineralization of some high-toxic organic contaminants. The enhancement can be attributed to the 3D macro-mesoporous networks facilitating the diffusion of reactants and products, the floating feature and small Ag nanoparticle-decoration favoring light-harvesting and spatial separation of photogenerated electron-hole pairs due to SPR effect. This novel SPR-enhanced solar-driven floating photocatalyst will have potential application in fields of natural environment. [ABSTRACT FROM AUTHOR]

Ordered Ag-g-C 3 N 4 /SBA-15 was successfully synthesized using SBA-15 as a template and support. The samples were characterized by TEM, XRD, XPS, N 2 adsorption-desorption. The results showed that metallic silvers with diameter 15 nm were distributed on the surface of g-C 3 N 4 thin-layered. The specific surface area of the composite was 563.4 m 2 g −1 . As the final products for ozonation, oxalic acid was used to investigate its catalytic ability in heterogeneous photocatalytic ozonation under simulated solar light irradiation. Ordered Ag-g-C 3 N 4 /SBA-15 with the mass ratio of silver nitrate/dicyandiamide around 4% was found to be the most efficient for oxalic acid degradation. The kinetic constant was 1.60 and 2.52 times as high as that of solar light/Ag-g-C 3 N 4 /O 3 and solar light/g-C 3 N 4 /O 3 process, respectively. It demonstrated that both the Ag nanoparticles and improved specific surface area contributed to the enhancement, which promoted the decomposition of O 3 and increased the active sites in reaction. The synergy index for photocatalytic ozonation of oxalic acid was calculated to be 5.71, which indicated a superior synergistic effect between photocatalysis and ozonation. In addition, 4% Ag-g-C 3 N 4 /SBA-15 samples showed good stability in photocatalytic ozonation process by cycled for four times, and the mechanism was also confirmed in this study. It is suggested that Ag-g-C 3 N 4 /SBA-15 composites is a promising catalyst for the practical application of photocatalytic ozonation. [ABSTRACT FROM AUTHOR]

Here, we demonstrate that TiO 2 nanowires (NWs) can be significantly driven by visible light through the decoration with Ag nanoparticles (NPs) (Ag-decorated TiO 2 NWs). The Ag-decorated TiO 2 NWs show remarkably photoelectrochemical (PEC) water splitting performance under illumination with λ > 420 visible light due to surface plasmon resonance (SPR) of Ag NPs. In this work, low power of the used light source (100 mW/cm 2 ) was not capable of heating the Ag-decorated TiO 2 nanowire photoanode enough to directly split water. In addition, under irradiation with λ > 420 nm visible light, no photocurrent was produced by TiO 2 nanowire photoanode indicates that electron transitions between valence band and conduction band do not take place in prepared anatase TiO 2 NWs. Meanwhile, the SPR energy (2.95–2.13 eV < 3.2 eV) is insufficient to excite TiO 2 NWs to generate electro-hole pairs through SPR-enhanced electromagnetic fields. Thus the remarkably visible-light-responsive PEC water splitting activity of Ag-decorated TiO 2 NWs is not attributed to local heating caused by SPR-mediated photothermal process, large enhancement of electromagnetic fields induced by SPR and scattering of resonant photons. We propose that the visible light PEC water splitting performance of Ag-decorated TiO 2 NWs is attributed to electron transfer from Ag NPs to the conduction band of TiO 2 NWs mediated by SPR. In addition, a Schottky barrier established at the interface of Ag NPs and TiO 2 NWs prevents these transferred electrons from returning to the Ag NPs and significantly retarded the recombination of electron-hole pairs in the Ag NPs, also contributing to visible-light-driven PEC water splitting performance. So the remarkably visible-light-driven PEC water splitting performance of Ag-decorated TiO 2 NWs is attributed to the synergistic effects of electron transfer mediated by SPR and the Schottky barrier between Ag NPs and TiO 2 NWs. The achieved Ag-decorated TiO 2 NWs can be added to these previously prepared TiO 2 photocatalysts mainly driven by SPR of Au NPs for the development of new visible light photocatalysts. [ABSTRACT FROM AUTHOR]

Hybrid organic/inorganic thin film nanocomposites based on poly(styrene)- b-poly(butadiene)- b-poly(methyl methacrylate) triblock copolymer and silver nanoparticles are prepared and characterized. In order to improve the compatibility of nanoparticles with the polymeric matrix, their surface is modified with dodecanethiol surfactant, which enables a good dispersion of nanoparticles through the triblock copolymer, without the formation of aggregates. By atomic force microscopy (AFM), the dispersion level of nanoparticles is analyzed, together with their effect on the thin film surface morphology, for nanocomposites up to 15 wt% of nanoparticles. Dielectric properties of nanocomposites are studied by dielectric relaxation spectroscopy (DRS), analyzing the effect of nanoparticles on dielectric properties. Even if conductivity and permittivity of composites increase with nanoparticle content, percolation threshold is found to be at around 15% in volume. Morphologically analyzed nanocomposites are, in this way, below the threshold. [ABSTRACT FROM AUTHOR]

In this work, NaY zeolite was synthesized by an inexpensive raw material i.e. silica extracted from rice husk ash by using two-step seeding process. It was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH) and scanning electron microscopy (SEM). The results confirmed that the well-shaped zeolite Y with high crystallinity and proper porosity was formed. Then, the zeolite NaY modified carbon paste electrode was used as a platform for preparation of silver nanoparticles (AgY/CPE). The FE-SEM confirmed the formation of Ag nanoparticles on the surface of electrode. The modified electrode was used for electrocatalytic reduction of H 2 O 2 in phosphate buffer solution (pH = 7.0). The proposed sensor could detect the H 2 O 2 in the linear range of 0.02–5.0 mM with a detection limit of 1.4 μM at a signal to noise ratio of 3 and response time of 5 s. The sensitivity of the sensor was 650.7 μA mM −1 cm −2 . Furthermore, it exhibited no interference with some biological species such as glucose, ascorbic acid, sucrose and uric acid. [ABSTRACT FROM AUTHOR]

An Ag nanoparticle sintering is a promising die attach method for use in high-temperature electronics and could potentially be substituted for conventional high Pb-containing solders. An electroless Ni/immersion Au (ENIG) is a common surface finish for solder, wire bonding, and Ag nanoparticle sintering. However, there is no report on the influence of ENIG defects on the shear strength and bonding quality of Ag nanoparticle sintered joint. In this study, the relationship between the presence of ENIG defects and shear strength of Ag nanoparticle sintered joint after bonding and isothermal aging test using two types of ENIG surface finished Cu substrates (with ENIG defects and without defects) was investigated. The initial shear strength of Ag sintered joint showed similar values of approximately 36 MPa despite the presence of ENIG defects. However, the ENIG defects could affect the shear strength degradation of Ag sintered joint after thermal aging at 250 °C. This degradation came from the Ni oxidation by the presence of ENIG defects and subsequent brittle fracture of joint alone the Ni oxidation layer. [ABSTRACT FROM AUTHOR]

This paper describes a general strategy that uses dopamine as a stable anchor to present protein molecules on the surface of silicon microspheres via self-assembled method (SAM), and after the removal of templates, the bovine serum albumin (BSA) microcapsules were successfully prepared. Two self assembling methods are described here, one is using glutaraldehyde (GA) as crosslinking agent to modify multilayer protein on the surface of silicon microspheres; In another way, dopamine is used as a anchor layer to graft the BSA monolayers onto silicon templates. The BSA coated silicon microspheres and BSA hollow microcapsules were characterized by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The biocompatibility of the BSA coated silicon microspheres was evaluated in vitro by MTT method. Then the polydopamine (PDA) hollow microcapsules was prepared using SiO 2 nanoparticles as the templates, and Ag namoparticles was then modified on the PDA capsules. The catalytic performance of SiO 2 @ PDA@Ag microspheres for methylene blue (MB) was studied. And the Escherichia coli and Staphylococcus aureus was used as the indicator bacteria to investigate the antimicrobial activity of the obtained SiO 2 @ PDA@Ag microspheres. [ABSTRACT FROM AUTHOR]

The use of dye-sensitized solar cells (DSSCs) is widespread owing to their high power conversion efficiency (PCE) and lowcost of manufacturing. We preparedmulti-shaped Ag nanoparticles (NPs) and introduced them into DSSCs to further enhance their PCE. The maximum absorption wavelength of the multi-shaped Ag NPs is 420 nm, including the shoulder with a full width at half maximum (FWHM) of 121 nm. This is a broad absorption wavelength compared to spherical Ag NPs, which have a maximum absorption wavelength of 400 nm without the shoulder of 61 nm FWHM. Therefore, when multi-shaped Ag NPs with a broader plasmon-enhanced absorption were coated on a mesoporous TiO2 layer on a layer-by-layer structure in DSSCs, the PCE increased from 8.44% to 10.22%, equivalent to an improvement of 21.09% compared to DSSCs without a plasmonic layer. To confirm the plasmon-enhanced effect on the composite film structure in DSSCs, the PCE of DSSCs based on the composite film structure with multi-shaped Ag NPs increased from 8.58% to 10.34%, equivalent to an improvement of 20.51% compared to DSSCs without a plasmonic layer. This concept can be applied to perovskite solar cells, hybrid solar cells, and other solar cells devices. [ABSTRACT FROM AUTHOR]

A simple and environmentally friendly approach was developed to fabricate silver nanoparticle (Ag NP)-decorated porous reduced graphene oxide (grGO) using glucose as a crosslinking and reducing agent. Physicochemical analysis, such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission-scanning electron microscopy (FE-SEM) were used to confirm the structural, morphological characteristics of the as-prepared samples. The electrocatalytic activity of Ag/grGO towards glucose oxidation was examined by cyclic voltammetry and amperometry. The fabricated sensor showed excellent sensitivity of 725.0 μA cm mM with a rapid response time of 11 s. Furthermore, the hybrids showed significant antibacterial activity against Escherichia coli with 99.76% antibacterial efficiency after 18 h. [ABSTRACT FROM AUTHOR]

The binding of ciprofloxacin (CIP) to human holo-transferrin (HTF) in the presence of silver nanoparticles (AgNPs) has been investigated by fluorescence quenching and circular dichroism (CD) techniques as well as resonance light scattering under physiological conditions. It was determined that the intrinsic fluorescence of HTF was quenched by CIP in the presence of AgNPs through static quenching, thus confirming that a CIP-HTF complex was formed in both the binary and ternary systems. However, the analysis of HTF fluorescence quenching in these binary and ternary systems indicated that the AgNPs were affected upon complex formation between CIP and HTF and that the binding affinity between them became more substantial when the AgNPs coexisted with the drug. Fluorescence quenching proved that HTF had one class of binding sites for CIP in both binary and ternary systems. CD spectra indicated that the secondary structure of HTF changed when increasing the CIP concentration and during the simultaneous presence of CIP and AgNPs, which led to decreased contents of a-helix and ß-sheet structures in HTF, inducing destabilization of the protein. [ABSTRACT FROM AUTHOR]

Ag/ZnO nanotetrapods are synthesized in mass production via a simple thermal-evaporation/hydrothermal route, and Ag nanoparticles are randomly coated on ZnO nanotetrapods. Ag/ZnO nanotetrapods can co-use the solar and mechanical energy to degrade various organic pollutants, and the solar-photocatalytic activity is significantly enhanced by the piezo-assistance. For instance, under ultrasonic stimulation (200 W) and solar illumination (500 W), Ag/ZnO nanotetrapods can completely degrade methyl orange (MO) within 25 min. The high piezo/solar-photocatalytic efficiency of Ag/ZnO nanotetrapods can be ascribed to the coupling of surface plasmon resonance and piezophototronic effect in the solar-photocatalytic process. The localized surface plasmon resonance effect of Ag nanoparticles can increase the visible light absorption. Ag/ZnO interface can facilitate the interfacial charge transfer and induce the separation of photo-induced charge carriers. The piezoelectric field originated from the deformation of ZnO nanotetrapods can further enhance the separation of photo-induced electron/hole pairs. Our results imply that Ag/ZnO nanotetrapods have great potentials of using sustainable energy in the nature for environmental remediation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop a novel dual thermo- and pH-responsive silver nanocomposite hydrogel (SNH) for drug release applications. This smart SNH was prepared in a facile one-pot method by in situ reduction of silver ions in salep solution and then grafting of poly(vinylpyrrolidone-co-acrylic acid) onto it. The SNH was characterized by transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX), thermo-gravimetric analysis (TGA), Fourier transform infrared (FT-IR), UV-Vis spectroscopy, and cyclic voltammetry. The dependence of swelling properties of the prepared SNH on the reaction variables (such as monomer, Ag NO, and cross-linker concentrations), temperature, pH, and salt was investigated. The potential of obtained SNH was examined for the deferasirox release from prepared hydrogel under different temperatures and pHs. The evaluation of release mechanism and determination of diffusion coefficients were also studied. In addition, SNH showed good antibacterial potentials. The results of this study provide valuable information regarding the development of dual stimuli-sensitive SNH for biomedical applications. [ABSTRACT FROM AUTHOR]

Infection is a serious complication after nasal packing that otolaryngologists seek to avoid. The aim of this study is to investigate the use of silver (Ag) nanoparticle, which serves as antimicrobial agents, with nasal tampons. The study design is an experimental animal model and the setting is tertiary referral center. Twenty-four rats were randomized into the following four groups: (1) control group ( n = 6); (2) silicone nasal splint (SNS) group ( n = 6); (3) polypropylene-grafted polyethylene glycol (PP-g-PEG) amphiphilic graft copolymer-coated SNS group ( n = 6); and (4) Ag nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) amphiphilic graft copolymer-coated SNS group ( n = 6). These tampons were applied to rats for 48 h, after which they were removed in a sterile manner, and the rats were sacrificed. The nasal septa of the rats were excised, and assessments of tissue changes in the nasal mucosa were compared among the groups. The removed tampons were microbiologically examined, and quantitative analyses were made. When the groups were compared microbiologically, there were no significant differences in bacterial colonization rates of coagulase-negative Staphylococcus spp. among the three groups ( p = 0.519), but there was a statistically significant difference among bacterial colonization rates of Heamophilus parainfluenzae and Corynebacterium spp. ( p = 0.018, p = 0.004). We found that H. parainfluenzae grew less robustly in the Ag-PP-g-PEG than the PP-g-PEG group ( p = 0.017). However, we found no significant difference between the Ag-PP-g-PEG and SNS groups, or between the SNS and PP-g-PEG groups. The growth of Corynebacterium spp. did not differ significantly between the Ag-PP-g-PEG and SNS groups ( p = 1.000). When Group 4 was compared with Group 2, the former showed less inflammation. Compared with other tampons, Ag-PP-g-PEG amphiphilic graft copolymer-coated silicone nasal tampons caused less microbiological colonization and inflammation. Therefore, the use of these tampons may prevent secondary infections and reduce the risk of developing complications by minimizing tissue damage. [ABSTRACT FROM AUTHOR]

Based on the near-field optical theory, the near-field characteristics of Ag nanoparticle within the near-field scope of a metallic AFM tip irradiated by optical fiber probe laser are carried out with finite element method. As the laser transmits in optical fiber probe, the light of the various modes is gradually turned off, remaining the HE11mode laser. Meanwhile, the evanescent field can be produced at the confined aperture, which will also stimulate the near-field enhancement phenomenon of metallic AFM tip and Ag nanoparticle with those extrema appearing in the apex of AFM tip, the upper and lower parts of Ag nanoparticle, and the upper and lower sharp boundary positions at the end of the tapered fiber probe. The related mechanism is revealed and near-field optical characteristics are also analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple, green, and environment-friendly approach for the synthesis of AgNPs using aqueous Murraya koenigii leaf extract. • The AgNPs act as potent catalyst for dye degradation and in the reduction reaction of 4-nitrophenol within short time period. • The AgNPs are efficient for the selective colorimetric sensing of Hg2+ and Fe3+ ions in water. • The AgNPs reveal excellent antimicrobial properties against both gram-positive and gram-negative bacteria. Industrial waste containing organic pollutants like nitrophenols, dye pigments, trace of heavy metals, and harmful bacteria accounts for a substantial portion of threatening pollutants that cause devastating effects to human health and the ecosystem nowadays. In this regards, our aim is to synthesize silver nanoparticles (AgNPs) using aqueous Murraya Koenigii leaf extract through a simple easy and green approach. A sharp peak around 419 nm in UV–Visible spectroscopy primarily confirms the synthesis of the AgNPs which is further characterized by XRD, FT-IR, SEM, EDX, TEM, SAED, DLS particle size, and zeta potential analyzer techniques. Crystalline nanoparticles possessing spherical morphology with an average size of ∼ 18 nm revealed from XRD, SEM, TEM and DLS particle size analysis. The negative zeta potential value (-20.4 mV) of the nanoparticles (NPs) indicates high stability. The synthesized NPs showed excellent catalytic properties towards the degradation of methylene blue (MB), rose bengal (RB), eosin yellow (EY), phenol red (PR), and crystal violet (CV) dyes in a very short period of time with rate constants of 8.24 × 10-3 s−1, 17.37 × 10-3 s−1, 7.58 × 10-3 s−1, 7.14 × 10-3 s−1, and 11.73 × 10-3 s−1 respectively. Synthesized AgNPs also act as an efficient catalyst for the reduction of 4-nitrophenol (4np) to 4-aminophenol (4ap) in presence of NaBH 4 as reducing agent with a rate constant of 8.94 × 10-3 s−1. Furthermore, the synthesized NPs exhibit promising antimicrobial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli) bacteria. The highest zone of inhibition was found against gram-positive S. aureus bacteria. The colorimetric sensing property of the synthesized NPs was demonstrated against eleven different metal ions (Cr3+, Mg2+, Fe2+, Co2+, Zn2+, Cd2+, Hg2+, Cs+1, Cu2+, Pb2+, and Fe3+)and found that NPs are effective detection of Fe3+ and hazardous Hg2+ ions in water which was confirmed by a visual color change and UV–Visible spectroscopic analysis. [ABSTRACT FROM AUTHOR]

The Ag@Co3O4 layered composite has excellent peroxidase-like properties and can be used for the detection of ascorbic acid. [Display omitted] • Ag@Co3O4 composites with a layered structure were synthesized, which constituted. • A colorimetric inspection platform together with TMB to detect AA. • Ag@Co3O4 composites with a layered structure exhibited enhanced peroxidase-like catalytic activity. • The Ag@Co3O4 colorimetric inspection platform hold great potential for detection of AA. Co 3 O 4 nanosheets were synthesized by precipitation method. Ag nanoparticles was successfully reduced from AgNO 3 solution and loaded onto Co 3 O 4 nanosheets to synthesize Ag@Co 3 O 4 nanosheets. Ag@Co 3 O 4 layered composites had obvious peroxidase-like characteristics. In the presence of hydrogen peroxide, Ag@Co 3 O 4 layered composites could oxidize 3,3′,5,5′-tetramethylbenzidine (TMB, colorless) to oxidize TMB (ox-TMB, blue). Ascorbic acid (AA) selectively inhibited the peroxidase-like activity of Ag@Co 3 O 4 layered composites, reducing ox-TMB (blue) to TMB (colorless). With the increase of AA concentration, a large amount of ox-TMB was reduced to TMB and the solution faded from blue gradually. Correspondingly, the increase of AA concentration directly led to the gradual decrease of the absorbance of the reaction solution at 652 nm. The Ag@Co 3 O 4 colorimetric detection platform with a detection limit of 0.59 μM and a linear range of 2–60 μM was rapid, sensitive and selective. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag NPs/APT nanocomposites were synthesized by olive leaf extract mediated method. • APT nanorods provide active sites to controllable size and dispersion of Ag NPs. • Nanocomposites loading with 5% Ag NPs shows good antibacterial performance. • Nanocomposites almost has no cytotoxicity in vitro to mouse fibroblasts L-929. In order to achieve good stability and dispersion of silver nanoparticles (Ag NPs), and effectively improve its antibacterial activity and bio-friendliness, a novel Ag NPs /attapulgite (Ag NPs/APT) nanocomposite was prepared through a green approach mediated by olive leaf extract. TEM analysis showed that smaller and uniformly distributed Ag NPs were formed on the surface of APT nanorods attributed to the support anchoring effect of APT, which contributed to the enhancement of the antibacterial activities of Ag NPs/APT nanocomposite. The antibacterial properties of Ag NPs/APT nanocomposite were examined with the colony-counting method, and the results showed that Ag NPs/APT nanocomposite with loading amount of 5 wt% showed strong antibacterial performance, and its minimum bactericidal concentration against E. coli was 0.5 mg/mL, which is close to that of pure Ag NPs. In addition, Ag NPs/APT nanocomposite almost had no cytotoxicity to mouse fibroblasts L-929, which is much safer biologically than pure Ag NPs. Therefore, considering the good bio-performance and cleaner and eco-friendly synthesis process, the green-formed Ag NPs/APT nanocomposite may have huge potential applications in the antibacterial field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Kapok fiber (KF) mediate self-reduction synthesis of KF/AgNPs micro/nano architecture. • KF act as reductant and microreactor to convert more Ag+ to small AgNPs controllably. • KF/AgNPs is underwater superoleophobic, underoil superhydrophobic and liquid-storing. • KF/AgNPs has high efficiency (>99.8 %) and flux to purify real stable oil–water system. • KF/AgNPs can resist bacteria, absorb microplastic, and recovered 96.4% Ag after used. The ubiquitous existence of harmful contaminants in water is recognized as a major threat to aquatic ecosystems and human health, and renewable, economical, and superefficient new materials are needed to eliminate these dangers. Here, the ultrasmall silver nanoparticles (AgNPs) anchored Kapok fiber (KF) (KF/AgNPs) composite capable of efficiently separating various oil–water systems and eliminating other pollutants or bacteria was prepared by a green self-reducing reaction process using natural KF as the "microreactor" and water as the only solvent. The introduction of AgNPs endows KF/AgNPs with significantly improved liquid storage capacity, underwater superoleophobicity and underoil superhydrophobicity, so it shows excellent switchable oil–water separation capability. The oil–water separation efficiencies under gravity reached 99.90 % for the oil-in-water (O/W) emulsion (water flux: 1300 L·m−2·h−1), 99.91 % for the water-in-oil (W/O) emulsion (oil flux: 1500 L·m−2·h−1), and 99.80 % for the immiscible oil–water mixture (flux: 1900 L·m−2·h−1). In addition, KF/AgNPs composite can serve as absorbents to remove oil slicks from sewage (removal efficiency: 99.95 %; absorption capacity: 42.3 g/g) and adsorbents to rapidly remove microplastics in actual natural waters (concentration: 10 mg/L and can inhibit the growth of E. coli bacteria. After use, approximately 96.4 % of Ag was recovered from spent composite, and an excellent biochar adsorbent for the dye was obtained simultaneously. [ABSTRACT FROM AUTHOR]

[Display omitted] • Addition of Ag or Ni into Prussian-Blue-based electrode improves cycle stability. • Addition of Ag or Ni into Prussian-Blue-based electrode enhances battery capacity. • Surface electrons of the Ag/Ni nanoparticles participated in redox reactions. • It is essential to use bare metallic nanoparticles for an effective enhancement. The poor cyclability of Prussian-blue-analogue (PBA) based rechargeable Li-ion batteries places a limitation on their practical applications. Here, we demonstrate that the addition of bare Ag or Ni nanoparticles (NPs) into the vicinity of the nano-sized PBA particles can effectively improve the electrochemical performance of the batteries, leading toward a higher energy storage capacity. The addition of 14 mass-percent of 13.6 mm Ag NPs into the vicinity of the 120 nm K 0.58 Co[Co(CN) 6 ] NPs gives rise to a 260 % increase in the stabilized full specific capacity C F , and the addition of 14 mass-percent of 12.4 nm Ni NPs gives rise to an 86 % increase of the stabilized C F. The addition of Ag or Ni NPs was also found to enhance the C F for the 80 nm Na 0.46 Co[ Fe (CN) 6 ]-based Li-ion batteries but the effect was smaller. It is the participations of the redox reactions of weakly bonded surface electrons on the Ag/Ni NPs that enhances the energy storage capacity of the battery. [ABSTRACT FROM AUTHOR]

Polystyrene microsphere (emulsion polymerization) was grafted on pure multiwalled carbon nanotube and amine-modified multiwalled carbon nanotube. Silver nanoparticle was also decorated on nanotube using chemical reduction (dimethylformamide). Amine-modified multiwalled carbon nanotube secures better silver attachment on nanotube wall. Polystyrene/Ag–amine-modified multiwalled carbon nanotube depicted fine dispersion in polymer latex due to modification. The 10% decomposition temperature and maximum degradation temperature of polystyrene/Ag–amine-modified multiwalled carbon nanotube was increased to 352 and 424°C. Antibacterial properties of nanocomposite were studied against respiratory track demolishing Gram-positiveStaphylococcus aureusbacteria and two Gram-negative bacteria (Escherichia coliandPseudomonas aeruginosa). Ag nanoparticle was found responsible to potential death rate of microbes. [ABSTRACT FROM AUTHOR]