Addition Of AgNPs Research Articles

Antimicrobial potential of linear low-density polyethylene food packaging with Ag nanoparticles in different carriers (Silica and Hydroxyapatite)

Silver nanoparticles incorporation into polymeric packaging aims to prevent microbiological contamination in food products, thus ensuring superior food safety and preservation. In this context, this study aimed to verify the antimicrobial efficacy of linear low-density polyethylene (LLDPE) films incorporated with silver nanoparticles (AgNPs) dispersed in silica (SiO2) and hydroxyapatite (HAP) carriers at different concentrations. AgNPs + carriers polymer films were characterized at 0.2, 0.4, and 0.6% concentrations using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission gun-scanning electron microscope (FEG-SEM), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and migration in acidic and non-acidic simulants. Antimicrobial action was investigated on Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and the Penicillium expansum and Fusarium solani fungi with antimicrobial activity by direct contact test and bacterial imaging by scanning electron microscopy. AgNPs addition to the LLDPE matrix did not interfere with the films' chemical and thermal properties and presented no significant migration to the external medium. For antimicrobial action, silver nanoparticles showed, in most concentrations, an inhibition percentage higher than 90% on all microorganisms studied, regardless of the carrier. However, a greater inhibitory action on S. aureus and between carriers was found, making hydroxyapatite more effective. The results indicated that nanostructured films with AgNPs + hydroxyapatite showed more promising antimicrobial action on microorganisms than AgNPs + silica, making hydroxyapatite with silver nanoparticle potentially useful in food packaging, improving safety and maintaining quality.

Enhanced thermoluminescence, radioluminescence, and optically stimulated luminescence from lithium fluoride and silver nanoparticles composites

Plasmonic properties of metals can increase the sensitivity of ionizing radiation dosimeters. In this work, we study the plasmon resonance of silver nanoparticles (AgNp) to increase the optically stimulated luminescence (OSL) intensity of lithium fluoride (LiF) polycrystals. We produced LiF/Ag nanocomposites with different volumes of a silver nanoparticle dispersion and investigated their OSL response. We also investigated their thermoluminescence (TL) and radioluminescence/scintillation (RL) responses. X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis spectroscopy characterized the synthesized materials. XRD results clearly show the characteristic peaks of LiF and AgNps. TEM images revealed silver nanoparticles with diameters between 80 and 120 nm and LiF crystals with sizes between 1 and 5 μm. Reflectance spectroscopy showed a band around 420 nm, attributed to the plasmon resonance of silver nanoparticles. The responses of the OSL curves to X-ray irradiation were analyzed, showing higher OSL sensitivity with 14 mL AgNp, attributed to the AgNp plasmon resonance. A significant increase in TL and RL intensity could be observed for the LiF/Ag nanocomposites. TL, RL, and OSL results support that addition of AgNps do not lead to the creation of more and new traps or luminescent centers. The increase of TL and RL intensities is therefore related to the coupling of the luminescent centers with the AgNPs plasmons, in an energy-transfer mechanism (plasmon-coupled emission), whereas the enhanced OSL intensity directly correlates with the increased photoionization cross-section of the electronic traps under plasmon resonance conditions (plasmon-coupled excitation). Therefore, these results indicate that AgNp are potential candidates to increase the OSL, TL, and RL intensity from LiF dosimeters.

Green synthesis of silver nanoparticles using Saccharum officinarum leaf extract for antiviral paint

Abstract In this study, silver nanoparticles (AgNPs) were synthesized via an eco-friendly approach using an extract from sugarcane leaves (Saccharum officinarum). The optimal synthesis conditions were determined to be a pH of 10, yielding AgNPs with an average size of 11.7 ± 2.8 nm. This was substantiated by UV-vis spectral analysis, transmission electron microscopy, and field emission transmission electron microscope coupling with selected area electron diffraction. The synthesized AgNPs exhibited notable antibacterial efficacy against two prominent pathogens, namely Staphylococcus aureus and Escherichia coli, with minimum inhibitory concentration values of 20 and 2.5 ppm, respectively. Further extending the applications of AgNPs, they were successfully integrated into architectural paints at varying concentrations to create antiviral coatings. The addition of AgNPs influenced several properties of the paints, including viscosity, hiding power, and color characteristics. Notably, our findings revealed that the antiviral paint containing 80 ppm of AgNPs effectively hindered virus propagation, exhibiting a remarkable reduction of over 90% when compared to the control, measured by 50% tissue culture infectious dose.

Exploring the effects of silver nanoparticle addition on the properties of paraffin wax phase change material

Ability of phase change materials (PCMs) to store and release significant amount of energy during phase transition has attracted a lot of attention in recent years. However, low thermal characteristics of pure PCMs has been a major limitation in their application for thermal energy storage (TES) systems. In this study, thermal properties of paraffin wax A46 (PW-A46) based composites with the addition of silver nanoparticles (Ag NPs) have been investigated. PW-A46 was chosen as the PCM due to its high latent heat of fusion and low cost, while Ag NPs are known for their high thermal conductivity and have been utilized in various composites to improve thermal properties. Ag NPs were added to the paraffin wax at three different weight percentages of 0.3, 0.5, and 0.7 weight percent (wt.%), and composites were prepared using an ultrasonic probe sonicator. Fourier-transform infrared spectroscopy (FTIR) has been done to study chemical bonding and interactions between paraffin and Ag NPs. No new peaks were observed in the FTIR spectra, indicating that addition of Ag NPs did not cause any significant changes in chemical structure of PW-A46. Thermogravimetric analysis (TGA) results showed that composites were stable up to 230°C, indicating their potential for high-temperature thermal energy storage (TES) applications. UV-Vis results demonstrated a 77% increase in the absorbance of the 0.7 wt.% of AgNPs with A46-PW (PW/0.7Ag) composite. Overall, the results suggested that addition of Ag NPs to paraffin wax can improve the optical and thermal characteristics of pure PCM for potential applications.

Addition of Silver Nanoparticles to Composite Edible Films and Coatings to Enhance Their Antimicrobial Activity and Application to Cherry Preservation.

The aim of this study was to examine the potential enhancement of the antimicrobial activity of edible films, composed of (i) chitosan (CH), cellulose nanocrystals (CNC) and beta-cyclodextrin (CD) (50%-37.5%-12.5%) and (ii) hydroxypropyl methylcellulose (HPMC), cellulose nanocrystals (CNC) and beta-cyclodextrin (CD) (50%-37.5%-12.5%), with silver nanoparticle (AgNP) incorporationat levels 5, 10 and 15% v/v. According to the results, the AgNP addition led to very high antimicrobial activity of both films, reducing by more than 96% the microbial growth of the Gram-negative bacterium Escherichia coli (E. coli) in all cases. On the other hand, by adding AgNPs to films, their thickness as well as oxygen and water vapor permeability decreased, while their transparency increased. Furthermore, the contribution of these specific edible films to preserve cherries under cold storage was investigated. All edible coatings resulted in an improvement of the fruit properties under consideration, and especially the color difference, hardness and total microbial load.

Synergistic antibacterial effect of Persicaria odorata synthesised silver nanoparticles with antibiotics on drug-resistant bacteria

For many years, combination therapies with two or more antimicrobial agents have gained interest to address the problem of emerging antibiotic resistance. Several studies have shown that the addition of AgNPs enhances the antimicrobial activity of antibiotics against resistant pathogens. However, the antibacterial activity of phytosynthesised silver nanoparticles (AgNPs) in combination with antibiotics has not been extensively studied. Therefore, this study aimed to investigate the antibacterial activity of the phytosynthesised AgNPs with different antibiotics against two common pathogenic bacteria, namely methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. A green method was used to produce AgNPs, where Persicaria odorata extract acted as a reducing and stabilising agent in the aqueous synthesis process. The production of AgNPs was verified through various analytical techniques, including ultraviolet–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray. Notably, strong absorption spectrum corresponding to the surface plasmon resonance peaks of AgNPs was found at 436 nm, with particles ranging from 10 to 35 nm. The disc diffusion technique was used to investigate the antibacterial activity of AgNPs, both alone and in combination with antibiotics. Initially, the MRSA and P. aeruginosa showed 100 % resistance to antibiotics, especially ampicillin. However, the disc diffusion result exhibit a significant increase in the inhibition zone when ampicillin-AgNPs, cefoxitin-AgNPs and chloramphenicol-AgNPs were used in combination. In short, the findings of this study showed that AgNPs exhibit a promising synergy when used in combination with antibiotics, opening up possibilities for future combination therapies against antibiotic-resistant pathogens.

Improved physical, thermal, and biological properties of green synthesized Ag-containing nanocomposites of a novel chitosan-based blend

Different material compositions are being prepared to improve the physiochemical properties of chitosan biopolymer and thus to create new areas of use. This study presents new chitosan(CS)-based products based on synthetic polymers and biosynthesized AgNPs, prioritizing environmentally friendly synthesis methods. Methacrylate-based functional CP copolymer was prepared by the free radical polymerization method. Thanks to the amide, ester groups, and fluorine atoms in the side branch of the CP, a compatible polymer blend (CS-CP) was prepared by the environmentally friendly hydrothermal method through hydrogen bonds with CS. Again, with green synthesis applications, AgNPs were prepared from Prunus spinosa extract by hydrothermal method, and new nanocomposites were produced by adding CS-CPs at different weight ratios. The initial decomposition temperature of 245 °C, which indicates the thermal stability of CS-CP as determined by TGA, was increased to 268 °C with the addition of 7 % AgNPs. Adding CP to CS lowered the glass transition temperature, and this trend continued in nanocomposites with the addition of AgNPs. When CP was blended with CS, the oxidative stress index of CS increased from 18.26 AU to 65.45 AU. It was determined that this oxidative effect increased up to 181 AU when AgNPs were added. Thanks to this feature of the produced nanocomposites, it was found that the MIC (100–250 µg/mL for E. coli, 250–500 µg/mL for S. aureus and for 500–1000 µg/mL C. Albicans) values of CS against microorganisms decreased, and the antimicrobial activity increased. In addition, in studies with cancer (A549 and G361) cells, it was determined that even at low (25 µg/mL) doses, nanocomposites that included 5 % and 7 % AgNPs in their formula had anticarcinogenic activity. Further studies on biocompatibility may be recommended to confirm possible commercial benefits from the materials produced in future research.

Evaluation of Physical Properties of Denture Base Resins Containing Silver Nanoparticles of Aloe barbadensis Miller, Morinda citrifolia, and Boesenbergia rotunda and Its Anti-microbial Effect: An In Vitro Study.

Introduction The denture bases fabricated from polymethylmethacrylate (PMMA) have some disadvantages, such as surface prone to microbial growth and biofilm accumulation, which contributes to the onset and dissemination of infections among denture wearers. Therefore, the purpose of this in vitro study was to evaluate the flexural strength, hardness, and antimicrobial effect of denture base resin incorporated with 0.05% and 0.1% silver nanoparticles (AgNPs) of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root). Materials and methods A total of 84 PMMAsamples were used and were divided into three groups. Flexural strength tests were performed on Group 1 PMMAblocks. Group 2 involved hardness testing of PMMAblocks, whereas Group 3 involved antimicrobial activity. Each group was subsequently split into seven subgroups with differing concentrations of AgNPs: Sub Group 1: control (no AgNPs),Sub Group 2: 0.05% aloe vera AgNPs, Sub Group 3: 0.1% aloe vera AgNPs, Sub Group 4: 0.05% noni AgNPs, Sub Group 5: 0.1% of noni AgNPs,Sub Group 6: 0.05%finger root AgNPs, and Sub Group 7: 0.1% finger root AgNPs.The flexural strength was evaluated usinga universal testing machine (Instron 8801). Surface hardness was measured using a Vickers tester (Tukon 1102). For the antimicrobial activity analysis, the samples were incubated in a suitable culture broth containing Candida albicans for 24 hours. Microbial colony count (colony-forming unit (CFU)/mL) was estimated to evaluate the microbial adhesion to the surface of the denture base materials. Statistical analysis The flexural strength, hardness, and CFU between the groups were analyzed using one-way analysis of variance (ANOVA) followed by multiple comparisons with Tukey's honest significant difference (HSD) test (α=0.05). The level of statistical significance was determined at p<0.05. Results It was observed that the mean flexural strength was maximum in PMMA incorporated with 0.05% of aloe vera AgNPs and least in PMMA incorporated with 0.1% noni AgNPs. It was seen that a steady loss in flexural strength is observed from 0.05% to 0.1%. The mean hardness was maximum in PMMA incorporated with 0.1% of noni AgNPs and least in PMMA incorporated with 0.05% aloe vera AgNPs. It was also found that the hardness was directly proportional to the number of nanoparticles. With an increase in the weight percentage of nanoparticles, a steady increase in hardness was seen in all the test groups. In our study, the results showed that finger root 0.1% showed the least CFU with a significant reduction of C. albicans adherence; therefore, it indicates higher anti-fungal activity. Aloe vera 0.05% showed the lowest inhibition of C. albicans,suggesting the least anti-fungal activity. Conclusion Within the limitations of this study, It can thus be concluded that the addition of AgNPs incorporated with plant extracts of Aloe barbadensis miller (aloe vera), Morinda citrifolia (noni), and Boesenbergia rotunda (finger root) can alter the flexural strength, hardness, and microbial adhesion of PMMA. In our study, it can be concluded that flexural strength increases with the addition of AgNPs of 0.5% concentration after which a steady loss is seen. However, the hardness and antimicrobial activity increased with an increase in the concentration of AgNPs in all three plant extracts.

Revolutionary solar evaporation system: Harnessing the power of bacterial cellulose/Ag NPs/polypyrrole with its promoted antibacterial applications

Extensive research is being conducted on a promising technology that utilizes solar energy and photothermal materials to address the global challenges of freshwater scarcity and energy shortage. Real-world applications of this technology require materials with specific properties such as mechanical flexibility and antimicrobial characteristics. Herein, a self-supporting membrane for interfacial photothermal water evaporation is developed, incorporating bacterial cellulose (BC) as a resilient and hydrophilic backbone material, along with Polypyrrole（PPy）loading and silver nanoparticles (Ag NPs) doping. The addition of Ag NPs not only enhances the antibacterial properties of the material, but also improves light absorption through plasma resonance, resulting in enhanced photothermal conversion efficiency. Experimental results demonstrate that the BC/Ag/PPy hybridized membrane exhibits an outstanding photothermal evaporation efficiency of 91%. Additionally, the membrane maintains a stable evaporation rate and favorable mechanical properties. With its exceptional performance, this BC/Ag/PPy membrane offers a practical solution for long-term seawater desalination applications.

The Role of Silver Nanoparticles in Response of In Vitro Boysenberry Plants to Drought Stress

Drought is one of the leading abiotic factors limiting morphological and physiological activities in blackberry cultivation. In this study, the effects of silver nanoparticles (AgNPs) on some morphological and biochemical processes in boysenberry (Rubus ursinus Chamisso and Schlenhtendal) under drought stress were investigated. The experiment was performed with three drought stress levels simulated with Polyethylene Glycol (PEG) (0, 4, 8%) and three AgNP treatments (0, 0.1, 0.2 mg L−1) in vitro conditions. Drought stress reduced root and shoot development of boysenberry plants grown in vitro. The addition of AgNPs significantly alleviated the adverse effect of drought stress and increased the plant growth parameters. Antioxidant activity of superoxide dismutase (SOD) and catalase (CAT) enzymes increased in boysenberry leaves when treated with AgNPs under drought conditions, while the amount of malondialdehyde (MDA) decreased. As a result of the study, 0.1 mg L−1 AgNPs is recommended as the most effective dose to promote the growth and development of in vitro boysenberry plants under drought stress.

Biodegradable nanocomposites prepared from poly(butylene adipate terephthalate) and silver nanoparticles for applications as disposable medical equipments

AbstractSilver nanoparticles (AgNPs) were prepared using polyvinylpyrrolidone (PVP) as reducing and stabilizing agent. AgNPs were then embedded in a biodegradable poly(butylene adipate terephthalate) (PBAT) matrix by solution casting. The resulted PBAT/AgNPs nanocomposite films were characterized using various analytical techniques such as scanning electron microscopy (SEM), colorimeter, Ultraviolet–visible (UV–vis) spectroscopy, Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), thermogravimetric analysis (TGA), mechanical tests and water vapor permeability measurements. The composite films appeared smooth on surface with some agglomeration of AgNPs. The addition of AgNPs led to color changes, and strongly improved the thermal stability, UV barrier performance, mechanical properties and water vapor barrier performance of composite films. Importantly, PBAT/AgNPs films present outstanding antibacterial activity against gram‐positive bacteria (Escherichia coli) and gram‐negative bacteria (Staphylococcus aureus). Moreover, composite films exhibit good stability under accelerated aging conditions and during high‐pressure sterilization. Therefore, biodegradable PBAT/AgNPs nanocomposite materials could present great potential for applications as disposable medical equipments.

Antibacterial efficacy and osteogenic potential of mineral trioxide aggregate-based retrograde filling material incorporated with silver nanoparticle and calcium fluoride

Background/purposeThe retrograde filling material, particularly mineral trioxide aggregate (MTA) employed in apicoectomy, should possess high antibacterial efficacy and osteogenic potential. We evaluated the antibacterial efficacy, biocompatibility, and osteogenic potential following the addition of silver nanoparticles (AgNPs) and calcium fluoride (CaF2) in retrograde filling material of MTA. Materials and methodsMTA was mixed with four different solvents. Group 1 (G1): distilled water, Group 2 (G2): 50 ppm AgNPs, Group 3 (G3): 1 wt% CaF2, and Group 4 (G4): 50 ppm AgNPs and 1 wt% CaF2. The pH variation of each group was monitored, while the surface roughness was measured. The antibacterial efficacy against Enterococcus faecalis (E. faecalis) and the viability of murine pre-osteoblast (MC3T3) were evaluated for each group using colorimetric assays. The gene expression levels of osteogenic potential marker (OCN, ALPL, and RUNX2) in MC3T3 cells for each group were quantified using real-time-qPCR. Statistical analysis was performed at α = 0.05 level of significance. ResultsWhen comparing the levels of antibacterial efficacy, the order of effectiveness was G4>G2>G3>G1 (P < 0.05). In the cell viability test, owing to MTA-eluted growth medium having a positive effect on MC3T3 cell proliferation, G1–4 exhibited a statistically increased cell viability compared to the control (P < 0.05). However, G2–4 did not result in a statistically significant difference when compared to G1 (P < 0.05). Moreover, G4 exhibited the highest gene expression among the four groups (P < 0.05). ConclusionThe addition of AgNPs and CaF2 to MTA could be a promising option for use as a new retrograde filling material.

Composites of cis‐ and trans‐polyisoprene blend filled with silver nanoparticles: Dynamic mechanical, mechanical, and thermal analysis

AbstractIn this article, polymer nanocomposites of polyisoprene with specific blend ratio 25/75 wt% of cis‐polyisoprene (CPI) and trans‐polyisoprene (TPI) with varying concentration (0.1, 1, and 5 wt%) of so synthesized silver nanoparticles (AgNPs) have been prepared and characterized through x‐ray diffraction, transmission electron microscope and scanning electron microscope. Experimental results on dynamic mechanical analysis show that addition of AgNPs to CPI/TPI blend reduces storage modulus, activation energy and fragility while enhances damping, however, glass transition temperature remains unaffected. Other mechanical properties such as toughness and tensile strength first increases on addition of AgNPs in the CPI/TPI blend, but a decrease is noticed on further increase of AgNPs concentration. Young's modulus shows a drastic decrease on addition of AgNPs into CPI/TPI blend, however, an increase is observed at higher concentration of AgNPs. Thermal analysis results show that thermal conductivity enhances with the enhancement in concentration of AgNPs into CPI/TPI blend.Highlights Addition of AgNPs into CPI/TPI blend reduces storage modulus, activation energy and fragility Incorporation of AgNPs into CPI/TPI blend enhances damping but does not change glass transition temperature. Increase in concentration of AgNPs in CPI/TPI blend increases the thermal conductivity.

High thermoelectric power factor in Bi1.2Na0.8Te3/Ag-NPs composites

Novel matrix composites of Na-doped Bi2Te3 with Ag nanoparticles included were prepared and studied in this article. Alloys of Bi1.2Na0.8Te3 were prepared by direct temperature melting at high temperature. Ag nanoparticles were incorporated into the system at different amounts. X-ray diffraction and scanning electron microscopy were used to examine structural, crystallographic, and morphological aspects The addition of silver caused a shift in the structure, resulting in the division of the structure into two main sections. Initially, Bi1.2Na0.8Te0.6 phase was successfully doped with Ag without any changes. Then, the phase exhibited a notable shift, due to a change in the lattice parameters, as the amount of Ag increases to x = 0.06 and 0.08 wt%. A change in the atomic order is caused by the successful replacement of Ag inside composites, which created a new structure of Bi1.2Na0.8AgxTe3. The layered bulk structure was observed by SEM investigations. Various particle sizes were observed revealing the incorporation of Ag-nanoparticles. The thermoelectric properties were studied between 273K and 473K. The four-probe approach was used to calculate electrical conductivity, and a typical differential technique was used to get the Seebeck coefficient. The Ag-incorporated Bi1.2Na0.8Te3 alloys showed quite a higher Seebeck coefficient, in comparison to the Ag-free compound. The thermoelectric power factor was calculated, and the maximum value was obtained at 30 × 102 μW/mK2 for Bi1.2Na0.8Te0.6 at room temperature. The value is quite high and encouraging for applications in thermoelectric devices. A considerable reduction in overall thermal conductivity of the studied system was observed after the addition of Ag-NPs, according to thermal conductivity studies. The lowest thermal conductivity was achieved by adding Ag-NPs at 0.08% in the Bi1.2Na0.8Te3/Ag0.08 composite. An interesting room temperature-ZT was achieved at 0.56.

Effect of calcium carbonate nanoparticles, silver nanoparticles and advanced platelet-rich fibrin for enhancing bone healing in a rabbit model

This study aimed to evaluate the efficacy of calcium carbonate nanoparticles (CCNPs) to induce new bone formation in a critical size segmental bone defect in rabbit’s radius when used alone, combined with silver nanoparticles (AgNPs) as a paste, or as a composite containing CCNPs, AgNPs, and advanced platelet-rich fibrin (A-PRF). Thirty-six adult apparently healthy male New Zealand White rabbits aging from 5 to 6 months and weighting 3.5 ± 0.5 kg were used. The animals were divided into four groups; control group, CCNPs group, CCNPs/AgNPs paste group, and CCNPs/AgNPs/A-PRF composite group. The animals were investigated at 4, 8, and 12 weeks post-implantation in which the healing was evaluated using computed tomographic (CT) and histopathological evaluation. The results revealed that CCNPs/AgNPs paste and CCNPs/AgNPs/A-PRF composite has a superior effect regarding the amount and the quality of the newly formed bone compared to the control and the CCNPs alone. In conclusion, addition of AgNPs and/or A-PRF to CCNPs has reduced its resorption rate and improved its osteogenic and osteoinductive properties.

Hydrodynamic and heat transfer investigations of multi-phase nanofluid flow in the phase change material of silver nanoparticles dispersed in water/wax-paraffin

Using phase change materials (PCM) significantly contributes to thermal energy storage. Due to their high melting heat, PCM is a material that can store heat without causing noticeable changes in temperature (Temp). Paraffin is one of the types of PCM, and compared to other PCMs, it is more resistant and has a lower price, and at the same time, it has higher safety. In the upcoming research, silver nanoparticles (Ag-NPs) with different atomic ratios (10, 20, 30, and 50%) have been evaluated on the thermal behavior of water/wax-paraffin hybrid nanofluid (NF) in a Fe nanochannel using the molecular dynamics (MD) simulation. The results illustrated that NPs positively and significantly affect the thermal conductivity (TC) of water-paraffin wax (PW) /Ag-NPs hybrid NF. By increasing the atomic ratio of Ag-NPs from 10 to 50%, the value of TC has increased from 0.381 to 0.476 W/m.K Also, the addition of Ag-NPs by 50% has led to an increase in the maximum values of density (Den.), Temp, and velocity (Vel) to 0.1425 atom/Å3, 3.57E-4 Å/fs, and 488.42 K.

The enhanced properties of amplified spontaneous emission and organic light emitting diodes based on Ag NPs doped hole transfer layer

The organic semiconductor lasers (OSLs) have been seen as a promising light source for future applications. Lower amplified spontaneous emission (ASE) threshold of the organic gain medium and optimized device structures are key factors to realize electrically pumped OSLs. In this paper, the silver nanoparticles (Ag NPs) doped PEDOT: PSS buffer layer was used to improve the ASE performance of BUBD-1 molecule and the optoelectronic performance of the corresponding organic light-emitting diodes (OLEDs). Compared with the reference device with pure PEDOT: PSS buffer layer, the lowest ASE threshold was obtained in CBP: 45 wt%BUBD-1 blend film at the optimal volume ratio 1:3 of PEDOT: PSS: Ag NPs, decreased by 6 times. Then the Ag NPs doped PEDOT: PSS buffer layer was used as both buffer layer and the hole transport layer in the OLEDs devices with CBP: 45 wt% BUBD-1 blend films as the emission layer. At the optimal volume ratio of PEDOT: PSS to Ag NPs, the maximum brightness increased more than 2 times to 7823 cd/m2, and the maximum EQE increased nearly 2 times to 2.81%. The improved ASE performance of CBP: 45 wt%BUBD-1 blend films and optoelectronic properties of corresponding OLED devices can be attributed to both the localized surface plasmon resonance (LSPR) effect and the increased hole mobility caused by the addition of Ag NPs. The introduction of Ag NPs to the hole transfer layer of OLED devices may provide a potential method to realize the electrically pumped OSLs with the planar structures.

Isotopic-based evidence for reduced benthic contributions to fish after a whole-lake addition of nanosilver.

Silver nanoparticles (AgNPs) are added as antibacterial and anti-odor agents to a wide range of textiles, with high potential for release into aquatic environments via domestic wastewater. Previous work demonstrating the negative impacts of AgNP exposure on periphyton production suggests benthic primary production could be reduced in aquatic ecosystems impacted by AgNP discharge. To evaluate the potential for AgNPs to alter benthic-pelagic coupling in aquatic ecosystems, tissue-stable isotope ratios of carbon and nitrogen from northern pike (Esox lucius) and yellow perch (Perca flavescens) were measured before, during, and after the addition of AgNPs to a whole-lake ecosystem, and compared to those collected from a nearby reference lake. A shift in carbon isotope ratios toward more negative values was observed in both P. flavescens and E. lucius collected from the lake where AgNPs were added, with no shift in similar magnitude observed in E. lucius from the reference lake. Consequently, Bayesian estimates of benthic energy consumed decreased by 32% for P. flavescens and by 40% for E. lucius collected after AgNP additions relative to pre-addition estimates, greater in magnitude or opposite in direction of trends observed in our reference lake. Analyses suggest no changes in fish nitrogen isotope ratios related to AgNP additions. We hypothesize that the observed reduction in littoral energy use of fish reported here is a response to AgNP settling in littoral benthic habitats-the main habitat in lakes supporting periphyton-as AgNP has been shown elsewhere to significantly reduce the rates of periphyton production. Further, our study highlights the need to broaden the scope of risk assessments for AgNPs and other emerging contaminants prone to settling to consider habitat-specific impacts on resource utilization by organisms after their release into aquatic ecosystems.

A novel approach in remediation of diclofenac from environmental water samples using silver nanocomposite polymer inclusion membrane

Diclofenac is an efficient anti-inflammatory drug used as an antipyretic and analgesia in human and animal medicine. As such they are indiscriminately consumed with or without the prescription of a physician which has led to usage above recommendation, wasted, and improper disposition; thus, has become persistently found in aqueous environment. As a result of their low solubility, they adhere strictly to biosolids during wastewater treatment which leads to incomplete removal of this contaminant by conventional wastewater treatment plants. Hence, the need for other water treatment technologies to remove this environmental stressor. Polymer inclusion membranes (PIMs) used in this study were impregnated with silver nanoparticles (AgNPs) and were investigated for the complete removal of DCF. Under optimum conditions, the best membrane's performance with 100 % transport efficiency was recorded at pH 3, with 5 % AgNPs. Further addition of AgNPs >5 % reduced the efficiency of the membranes in terms of water uptake capacity, ion-exchange capacity, permeability and transport efficiency. The stability/reusability was investigated over a 12-cyclic mass transfer. The stability of the membrane was evaluated based on the percentage mass loss and transport efficiency over the successive cycle. Thus, after the 7th cycle, about 15 % weight of the membrane was lost with a decline in transport efficiency. However, the nanocomposite PIM maintained stability with no mass losses or further decline in transport efficiency after the 7th cycle. Finally, the nanocomposite membrane was used to preconcentrate DCF from wastewater samples, and it recorded an enrichment factor between 23.5 and 24.8 and a transport efficiency between 94.1 and 99.2 %.

Green synthesis of silver nanoparticles and degradation of AZO-dyes using Cestrum diurnum plant extract, and antimicrobial activities of AgNP’s.

Nanoparticles play an important role now days in different fields like drug delivery, diagnostics, therapy, engineering, energy, healthcare and Environment. The goal of this study was to synthesize Silver Nanoparticles from extract of C. dirnum plant, degradation of azo-dyes with synthesized AgNP’s and finding bioactivity of AgNP’s against bacteria’s. The UV-Visible analysis of solution after addition of AgNP’s showed that the addition of silver NP’s reduced the absorbance peak of methyl orange from 2.87 to 1.0 and absorbance peak of methyl red decreased from 2.92 to 1.75. Green synthesis concepts can be used to create metal nano-particles, which have a promising future in the Azo-dye breakdown process. C. diurnum leaf extract acts as a reducing agent to synthesize metal nano-particles, providing environmentally friendly and energy-efficient alternatives. Bioactivity of AgNP's against gram negative and gram-positive bacteria were tested which gave strong inhibition against bacteria.