Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are...Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are usually toxic and may cause water pollution.In this work,Ag NPs(31.2 nm in diameter)were prepared using the extract of straw,an agricultural waste,as the reducing and stabilizing agent.Experimental analysis revealed that the straw extract contained lignin,the structure of which possesses phenolic hydroxyl and methoxy groups that facilitate the reduction of silver salts into Ag NPs.The surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their aggregation.After the prepared Ag NPs were added to the precursor solution of acrylamide,free radical polymerization was triggered without the need for extra heating or light irradiation,resulting in the rapid formation of an Ag NP-polyacrylamide composite hydrogel.The inhibition zone test proved that the composite hydrogel possessed excellent antibacterial ability due to the presence of Ag NPs.The prepared hydrogel may have potential applications in the fabrication of biomedical materials,such as antibacterial dressings.展开更多
Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,t...Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.展开更多
Silver nanoparticles(AgNPs)synthesized using tartaric acid as a capping agent have a great impact on the reaction kinetics and contribute significantly to the stability of AgNPs.The protective layer formed by tartaric...Silver nanoparticles(AgNPs)synthesized using tartaric acid as a capping agent have a great impact on the reaction kinetics and contribute significantly to the stability of AgNPs.The protective layer formed by tartaric acid is an important factor that protects the silver surface and reduces potential cytotoxicity problems.These attributes are critical for assessing the compatibility of AgNPs with biological systems and making them suitable for drug delivery applications.The aim of this research is to conduct a comprehensive study of the effect of tartaric acid concentration,sonication time and temperature on the formation of silver nanoparticles.Using Response Surface Methodology(RSM)with Face-Centered Central Composite Design(FCCD),the optimization process identifies the most favorable synthesis conditions.UV-Vis spectrum regression analysis shows that AgNPs stabilized with tartaric acid are more stable than AgNPs without tartaric acid.This highlights the increased stability that tartaric acid provides in AgNP ssssynthesis.Particle size distribution analysis showed a multimodal distribution for AgNPs with tartaric acid and showed the smallest size peak with an average size of 20.53 nm.The second peak with increasing intensity shows a dominant average size of 108.8 nm accompanied by one standard deviation of 4.225 nm and a zeta potential of−11.08 mV.In contrast,AgNPs synthesized with polyvinylpyrrolidone(PVP)showed a unimodal particle distribution with an average particle size of 81.62 nm and a zeta potential of−2.96 mV.The more negative zeta potential of AgNP-tartaric acid indicates its increased stability.Evaluation of antibacterial activity showed that AgNPs stabilized with tartaric acid showed better performance against E.coli and B.subtilis bacteria compared with AgNPs-PVP.In summary,this study highlights the potential of tartaric acid in AgNP synthesis and suggests an avenue for the development of stable AgNPs with versatile applications.展开更多
BACKGROUND Pressure ulcer(PU)are prevalent among critically ill trauma patients,posing substantial risks.Bundled care strategies and silver nanoparticle dressings offer potential solutions,yet their combined effective...BACKGROUND Pressure ulcer(PU)are prevalent among critically ill trauma patients,posing substantial risks.Bundled care strategies and silver nanoparticle dressings offer potential solutions,yet their combined effectiveness and impact on patient satisfaction remain insufficiently investigated.AIM To assess the impact of bundled care along with silver nanoparticle dressing on PUs management and family satisfaction in critically ill trauma patients.METHODS A total of 98 critically ill trauma patients with PUs in intensive care unit(ICU)were included in this study.Patients were randomly assigned to either the control group(conventional care with silver nanoparticle dressing,n=49)or the intervention group(bundled care with silver nanoparticle dressing,n=49).The PU Scale for Healing(PUSH)tool was used to monitor changes in status of pressure injuries over time.Assessments were conducted at various time points:Baseline(day 0)and subsequent assessments on day 3,day 6,day 9,and day 12.Family satisfaction was assessed using the Family Satisfaction ICU 24 ques-tionnaire.RESULTS No significant differences in baseline characteristics were observed between the two groups.In the intervention group,there were significant reductions in total PUSH scores over the assessment period.Specifically,surface area,exudate,and tissue type parameters all showed significant improvements compared to the control group.Family satisfaction with care and decision-making was notably higher in the intervention group.Overall family satisfaction was significantly better in the intervention group.CONCLUSION Bundled care in combination with silver nanoparticle dressings effectively alleviated PUs and enhances family satisfaction in critically ill trauma patients.This approach holds promise for improving PUs management in the ICU,benefiting both patients and their families.展开更多
Green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of orange and lemon peels, as a reducing agent, and silver nitrate salts as a source of silver ions is a promising field of research due to the ve...Green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of orange and lemon peels, as a reducing agent, and silver nitrate salts as a source of silver ions is a promising field of research due to the versatility of biomedical applications of metal nanoparticles. In this paper, AgNPs were synthetized at different reaction parameters such as the type and concentration of the extracts, metal salt concentration, temperature, speed stirring, and pH. The antibacterial properties of the obtained silver nanoparticles against E. coli, as well as the physical and chemical characteristics of the synthesized silver nanoparticles, were investigated. UV-Vis spectroscopy was used to confirm the formation of AgNPs. In addition to green biogenic synthesis, chemical synthesis of silver nanoparticles was also carried out. The optimal temperature for extraction was 65˚C, while for the synthesis of AgNPs was 35˚C. The synthesis is carried out in an acidic environment (pH = 4.7 orange and pH = 3.8 lemon), neutral (pH = 7) and alkaline (pH = 10), then for different concentrations of silver nitrate solution (0.5 mM - 1 mM), optimal time duration of the reaction was 60 min and optimal stirring speed rotation was 250 rpm on the magnetic stirrer. The physical properties of the synthesized silver nanoparticles (conductivity, density and refractive index) were also studied, and the passage of laser light through the obtained solution and distilled water was compared. Positive inhibitory effect on the growth of new Escherichia coli colonies have shown AgNPs synthesized at a basic pH value and at a 0.1 mM AgNO<sub>3</sub> using orange or lemon peel extract, while for a 0.5 mM AgNO<sub>3 </sub>using lemon peel extract.展开更多
Silver nanoparticles are versatile nanomaterials that have found numerous applications in various fields.The use of plant extract for the synthesis of silver is a green and sustainable approach.Clerodendron phlomoides...Silver nanoparticles are versatile nanomaterials that have found numerous applications in various fields.The use of plant extract for the synthesis of silver is a green and sustainable approach.Clerodendron phlomoides leaves extract has been found to contain various phytochemicals,such as phenols,flavonoids,tannins,and alkaloids,which possess reducing and stabilizing properties that can aid the production of silver particles.In this paper,morphological and topographical analyses were performed on silver nanoparticles.The biosynthesized silver nanoparticles showed antimicrobial potential against wound pathogens.SEM and TEM micrographs revealed that the particles were sphere and nanosized,which makes them suitable for various biomedical applications.展开更多
Finely divided silver nanoparticles were synthesized via the hydrothermal method. Arabic gum (AG) was used as both the reductant and steric stabilizer without any other surfactant. By adjusting the reaction temperat...Finely divided silver nanoparticles were synthesized via the hydrothermal method. Arabic gum (AG) was used as both the reductant and steric stabilizer without any other surfactant. By adjusting the reaction temperature, mass ratio of AG to AgNO3, and reaction time, silver nanoparticles with different morphological characteristics could be obtained. The products were characterized by UV-Vis, FTIR, TEM, SEM, and XRD measurements. It was found that temperature and AG played an important role in the synthesis of mono-disperse silver nanoparticles. Well dispersed and quasispherical silver nanoparticles were obtained under the optimal synthesis conditions of 10 mmol/L AgNO3, m(AG)/m(AgN03)= l:1, 160 ℃ and 3 h.展开更多
In this work, we fabricated the polyaniline/silver nanoparticle/multi-walled carbon nanotube (PANI/Ag/MWCNT) composites by in situ polymerization of aniline on the wall of Ag/MWCNTs with different aniline to Ag/MWCN...In this work, we fabricated the polyaniline/silver nanoparticle/multi-walled carbon nanotube (PANI/Ag/MWCNT) composites by in situ polymerization of aniline on the wall of Ag/MWCNTs with different aniline to Ag/MWCNT mass ratios. The chemical structure of the ternary composites was characterized by Fourier transform infrared spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy. Scanning electron microscope and high-resolution transmission electron microscopy were used to observe the morphology of the ternary composites. The results showed that the polyaniline PANI layer was prepared successfully and it covered Ag/MWCNTs completely. In addition, Ag nanoparticles between the MWCNT core and the PANI layer existed in the form of elemental crystal, which could contribute to the electrochemical performance of the composites. Then we prepared the composite electrodes and studied their electrochemical behaviors in 1 mol/L KOH. It was found that these composite electrodes had very low impedance, and exhibited lower resistance, higher electrochemical activity, and better cyclic stability compared with pure PANI electrode. Particularly, when the mass ratio of aniline to Ag/MWCNTs was 5:5, the composite electrode displayed a small equivalent series resistance (0.23 Ω) and low interfacial charge transfer resistance (〈0.25 Ω), as well as 160 F/g of the maximum specific capacitance at a current density of 0.25 A/g in KOH solution. We could conclude that the composite material had potential applications as cathode materials for lithium batteries and supercapacitors.展开更多
Silver nanoparticles with average particles sizes ranging from 2 to 131nm were manipulatively synthesized starting from silver nitrate using different functional group-containing organic modifiers at room temperature....Silver nanoparticles with average particles sizes ranging from 2 to 131nm were manipulatively synthesized starting from silver nitrate using different functional group-containing organic modifiers at room temperature. The effects of the organic modifiers on the morphology of the resulting silver nanoparticles were strongly dependent on the intrinsic properties of the functional groups and the reducibility of the reductant. Numerous ether bonds (-0-)present in polyethylene glycol and Tween-80 were beneficial to the formation of silver nanoparticles with particle sizes of several nanometers in a narrow size distribution in both weak and strong reducing environments. Cetyltrimethylammonium bromide induced the formation of nanosized silver triangle plates in a weak reducing environment. The crystal growth of the silver nanoparticles with particle sizes of more than lOnm was postulated through an adhesion process of small-sized particles followed by a subsequent coalescence process under the present reaction conditions.展开更多
Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m ...Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m M) with dried leaf extract of Pongamia pinnata(L) Pierre. UV-visible spectroscopy studies were carried out to quantify the formation of silver nanoparticles. Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the silver nanoparticles. TEM image divulges that silver nanoparticles are quite polydispersed, the size ranging from 20 nm to 50 nm with an average of 38 nm. Water soluble heterocyclic compounds such as flavones were mainly responsible for the reduction and stabilization of the nanoparticles. Silver nanoparticles were effective against Escherichia coli(ATCC 8739), Staphylococcus aureus(ATCC 6538p), Pseudomonas aeruginosa(ATCC 9027) and Klebsiella pneumoniae(clinical isolate). The move towards extracellular synthesis using dried biomass appears to be cost effective, eco-friendly to the conventional methods of nanoparticles synthesis.展开更多
Silver nanoparticles,endowed with powerful antimicrobial property,are the most widely used nanomaterial in consumer products,with associated risk of their easy access to environment and freshwater ecosystems by surfac...Silver nanoparticles,endowed with powerful antimicrobial property,are the most widely used nanomaterial in consumer products,with associated risk of their easy access to environment and freshwater ecosystems by surface runoff.Although toxic effects of nanosilver on bacterial,fungal and mammalian cells have been documented,its impact on algal growth remains unknown.Pithophora oedogonia and Chara vulgaris are predominant members of photosynthetic eukaryotic algae,which form major component of global aquatic ecosystem.Here we report for the first time that nanosilver has significant adverse effects on growth and morphology of these filamentous green algae in a dose-dependent manner.Exposure of algal thalli to increasing concentrations of silver nanoparticles resulted in progressive depletion in algal chlorophyll content,chromosome instability and mitotic disturbance,associated with morphological malformations in algal filaments.SEM micrographs revealed dramatic alterations in cell wall in nanoparticle-treated algae,characterized with cell wall rupture and degradation in Pithophora.Although these observations underscore severe deleterious effects of nanosilver on aquatic environment,the information can also be exploited as a bioengineering strategy to control unwanted and persistent growth of noxious algal weeds that clog the municipal water supply and water channels and produce fouling of water bodies.展开更多
We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles (NPs). The procedure by which ...We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles (NPs). The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the interaction of the electronic levels of lanthaaide ligands with silver plasmons, dramatic increase of luminescence was observed.展开更多
Silver nanoparticles(Ag NPs)are an effective antibacterial agent,but their application in food packaging is limited due to their easy agglomeration and oxidation.In this study,antibacterial microcapsules were fabricat...Silver nanoparticles(Ag NPs)are an effective antibacterial agent,but their application in food packaging is limited due to their easy agglomeration and oxidation.In this study,antibacterial microcapsules were fabricated using Ginkgo biloba essential oil(GBEO)as core material and chitosan and type B gelatin biopolymer as capsule mate-rials.These antibacterial microcapsules were then modified with green-synthesized Ag NPs,blended into the bio-polymer polylactic acid(PLA),and finally formed as films.Physicochemical properties and antibacterial activity against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were evaluated.Results showed that the prepared antibacterial PLA films exhibited excellent antibacterial activity against foodborne pathogens.Its TVC exceeded the limit value of 7 log CFU/g at 7 days compared with the 5 days of pure PLA films.Therefore,these films can extend the shelf life of grass carp fillets by 2–3 days under refrigeration.展开更多
The silver nanowires(Ag NWs)electrodes,which consist of incompact Ag nanoparticles(NPs)formed by multi-photon photoreduction,usually have poor conductivities.An effective strategy for enhancing conductivity of the Ag ...The silver nanowires(Ag NWs)electrodes,which consist of incompact Ag nanoparticles(NPs)formed by multi-photon photoreduction,usually have poor conductivities.An effective strategy for enhancing conductivity of the Ag NWs elec-trodes is plasmon-enhanced nanosoldering(PLNS)by laser irradiation.Here,plasmon-enhanced photothermal effect is used to locally solder Ag NPs and then aggregates of these NPs grow into large irregular particles in PLNS process.Fi-nite element method(FEM)simulations indicate that the soldering process is triggered by localized surface plasmon-in-duced electric field enhancement at“hot-spots”.The effectiveness of PLNS for enhancing conductivity depends on laser power density and irradiation time.By optimizing the conditions of PLNS,the electrical conductivity of Ag NWs is signific-antly enhanced and the conductivityσs is increased to 2.45×107 S/m,which is about 39%of the bulk Ag.This PLNS of Ag NWs provides an efficient and cost-effective technique to rapidly produce large-area metal nanowire electrodes and capacitors with high conductivity,excellent uniformity,and good flexibility.展开更多
Objective: To synthesis silver nanoparticles(Ag NPs) by using extract of saffron(Crocus sativus L.) wastages and to test their antibacterial activity against six bacteria.Methods: In this paper, the synthesis of Ag NP...Objective: To synthesis silver nanoparticles(Ag NPs) by using extract of saffron(Crocus sativus L.) wastages and to test their antibacterial activity against six bacteria.Methods: In this paper, the synthesis of Ag NPs using aqueous extract of saffron wastage as a green method without any chemical stabilizer and reducer is demonstrated. The synthesized Ag NPs were determined by UV–vis spectrum, high resolution transmission electron microscopy, X-ray diffraction, and Fourier transmission infrared spectroscopy analysis.Results: UV–vis spectrum showed a peak at 450 nm due to excitation of surface plasmon vibrations. Fourier transmission infrared spectroscopy showed that nanoparticles were capped with plant secondary metabolites. X-ray diffraction analysis also demonstrated that the size range of the synthesized nanoparticles was 12–20 nm. Transmission electron microscope image illustrated Ag NPs with spherical shape and an average size of15 nm. The result of antibacterial activities showed that the biosynthesized Ag NPs had an inhibiting activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Shigella flexneri and Bacillus subtilis.Conclusions: The biosynthesized Ag NPs showed significant antibacterial effect against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Shigella flexneri and Bacillus subtilis, so, it can be used in biomedical applications.展开更多
Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed ...Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed aggregates.This letter describes a way of synthesising silver nanoparticles and their protection to aggregate by silica gel.The combination of catalytic quantities of immobilized silver nanoparticles with reductive ability of NaBH_4 efficiently reduces aromatic nitroarenes to the corresponding amines in aqueous medium.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen and carboxylic acid groups.The silver particles immobilized on silica gel are stable in the presence of oxygen for several months.展开更多
The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m ...The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m M silver nitrate. 100 m M glucose was found to quicken the rate of reaction of silver nanoparticles synthesis.UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesized silver nanoparticles were further characterized by using Nanoparticle Tracking Analyzer(NTA),Transmission Electron Microscope and Energy Dispersive X-ray spectra. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope(40 X). The synergistic effect of silver nanoparticles along with antibiotics in biofilm quenching was found to be effective. In the near future, silver nanoparticles could be used in the treatment of infections caused by highly antibiotic resistant biofilm.展开更多
This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a fill...This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a filler loading of 78 wt.%,83 wt.%and 88 wt.%and cured at 150℃and 180℃,respectively.The results show that the electrical and thermal conductivities of ECAs were improved with the increasing of filler loading and curing temperature.Adding silver NPs in silver flakes negatively affected the electrical and thermal conductivities of ECAs at a low filler mass fraction of 78 wt.%,because the segregation of NPs enlarged the average distance of silver flakes;while it positively influenced the electrical and thermal conductivities of ECAs at a loading ratio of 88 wt.%,probably due to NPs filling in the gaps between silver flakes or even sintering together with each other or with silver flakes,especially when curing at high temperature of 180℃.展开更多
Silver nanoparticles synthesized by dried biomass of Lactobaciluus acidophilus 01 strain was evaluated against toxicity of genomic DNA isolated from bacteria(E.coli) fungi(Beauveria bassiana) algae(Seenedesmus acutus)...Silver nanoparticles synthesized by dried biomass of Lactobaciluus acidophilus 01 strain was evaluated against toxicity of genomic DNA isolated from bacteria(E.coli) fungi(Beauveria bassiana) algae(Seenedesmus acutus) and human blood adopting standard condition was discussed in the present study.Synthesized silver nanoparticles were characterized by UV-Vis spectroscopy and SEM.The UV-Vis spectroscopy revealed the formation of silver nanoparticles by yielding the typical silver plasmon absorption maxima at 430 nm and SEM micrograph indicates the uniform spherical particles within the size range of 45?60 nm.The energy dispersive X-ray spectroscopy(EDX) of the nanoparticle confirmed the presence of elemental silver signal as strong peak.The above synthesized silver nanoparticles didn't cause any toxic effect on all the tested genomic DNA at all tested concentrations which reveals nil genomic nanoparticles induced toxicity.展开更多
Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency (RF) ma...Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency (RF) magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52203209)the State Key Laboratory of Solid Waste Reuse for Building Materials,China(No.SWR-2022-009)the Fundamental Research Funds for the Central Universities,China(No.FRF-IDRY22-012)。
文摘Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial property.However,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are usually toxic and may cause water pollution.In this work,Ag NPs(31.2 nm in diameter)were prepared using the extract of straw,an agricultural waste,as the reducing and stabilizing agent.Experimental analysis revealed that the straw extract contained lignin,the structure of which possesses phenolic hydroxyl and methoxy groups that facilitate the reduction of silver salts into Ag NPs.The surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their aggregation.After the prepared Ag NPs were added to the precursor solution of acrylamide,free radical polymerization was triggered without the need for extra heating or light irradiation,resulting in the rapid formation of an Ag NP-polyacrylamide composite hydrogel.The inhibition zone test proved that the composite hydrogel possessed excellent antibacterial ability due to the presence of Ag NPs.The prepared hydrogel may have potential applications in the fabrication of biomedical materials,such as antibacterial dressings.
基金supported by the China Scholarship Council (CSC) (No.202206020149)the Academic Excellence Foundation of BUAA for PhD Students,the Funding Project of Science and Technology on Reliability and Environmental Engineering Laboratory (No.6142004210106).
文摘Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.
基金funded by the Directorate of Research and Community Service (DRPM,Direktorat Riset dan Pengabdian Kepada Masyarakat)ITS through the ITS Research Local Grant (No:1665/PKS/ITS/2023).
文摘Silver nanoparticles(AgNPs)synthesized using tartaric acid as a capping agent have a great impact on the reaction kinetics and contribute significantly to the stability of AgNPs.The protective layer formed by tartaric acid is an important factor that protects the silver surface and reduces potential cytotoxicity problems.These attributes are critical for assessing the compatibility of AgNPs with biological systems and making them suitable for drug delivery applications.The aim of this research is to conduct a comprehensive study of the effect of tartaric acid concentration,sonication time and temperature on the formation of silver nanoparticles.Using Response Surface Methodology(RSM)with Face-Centered Central Composite Design(FCCD),the optimization process identifies the most favorable synthesis conditions.UV-Vis spectrum regression analysis shows that AgNPs stabilized with tartaric acid are more stable than AgNPs without tartaric acid.This highlights the increased stability that tartaric acid provides in AgNP ssssynthesis.Particle size distribution analysis showed a multimodal distribution for AgNPs with tartaric acid and showed the smallest size peak with an average size of 20.53 nm.The second peak with increasing intensity shows a dominant average size of 108.8 nm accompanied by one standard deviation of 4.225 nm and a zeta potential of−11.08 mV.In contrast,AgNPs synthesized with polyvinylpyrrolidone(PVP)showed a unimodal particle distribution with an average particle size of 81.62 nm and a zeta potential of−2.96 mV.The more negative zeta potential of AgNP-tartaric acid indicates its increased stability.Evaluation of antibacterial activity showed that AgNPs stabilized with tartaric acid showed better performance against E.coli and B.subtilis bacteria compared with AgNPs-PVP.In summary,this study highlights the potential of tartaric acid in AgNP synthesis and suggests an avenue for the development of stable AgNPs with versatile applications.
文摘BACKGROUND Pressure ulcer(PU)are prevalent among critically ill trauma patients,posing substantial risks.Bundled care strategies and silver nanoparticle dressings offer potential solutions,yet their combined effectiveness and impact on patient satisfaction remain insufficiently investigated.AIM To assess the impact of bundled care along with silver nanoparticle dressing on PUs management and family satisfaction in critically ill trauma patients.METHODS A total of 98 critically ill trauma patients with PUs in intensive care unit(ICU)were included in this study.Patients were randomly assigned to either the control group(conventional care with silver nanoparticle dressing,n=49)or the intervention group(bundled care with silver nanoparticle dressing,n=49).The PU Scale for Healing(PUSH)tool was used to monitor changes in status of pressure injuries over time.Assessments were conducted at various time points:Baseline(day 0)and subsequent assessments on day 3,day 6,day 9,and day 12.Family satisfaction was assessed using the Family Satisfaction ICU 24 ques-tionnaire.RESULTS No significant differences in baseline characteristics were observed between the two groups.In the intervention group,there were significant reductions in total PUSH scores over the assessment period.Specifically,surface area,exudate,and tissue type parameters all showed significant improvements compared to the control group.Family satisfaction with care and decision-making was notably higher in the intervention group.Overall family satisfaction was significantly better in the intervention group.CONCLUSION Bundled care in combination with silver nanoparticle dressings effectively alleviated PUs and enhances family satisfaction in critically ill trauma patients.This approach holds promise for improving PUs management in the ICU,benefiting both patients and their families.
文摘Green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of orange and lemon peels, as a reducing agent, and silver nitrate salts as a source of silver ions is a promising field of research due to the versatility of biomedical applications of metal nanoparticles. In this paper, AgNPs were synthetized at different reaction parameters such as the type and concentration of the extracts, metal salt concentration, temperature, speed stirring, and pH. The antibacterial properties of the obtained silver nanoparticles against E. coli, as well as the physical and chemical characteristics of the synthesized silver nanoparticles, were investigated. UV-Vis spectroscopy was used to confirm the formation of AgNPs. In addition to green biogenic synthesis, chemical synthesis of silver nanoparticles was also carried out. The optimal temperature for extraction was 65˚C, while for the synthesis of AgNPs was 35˚C. The synthesis is carried out in an acidic environment (pH = 4.7 orange and pH = 3.8 lemon), neutral (pH = 7) and alkaline (pH = 10), then for different concentrations of silver nitrate solution (0.5 mM - 1 mM), optimal time duration of the reaction was 60 min and optimal stirring speed rotation was 250 rpm on the magnetic stirrer. The physical properties of the synthesized silver nanoparticles (conductivity, density and refractive index) were also studied, and the passage of laser light through the obtained solution and distilled water was compared. Positive inhibitory effect on the growth of new Escherichia coli colonies have shown AgNPs synthesized at a basic pH value and at a 0.1 mM AgNO<sub>3</sub> using orange or lemon peel extract, while for a 0.5 mM AgNO<sub>3 </sub>using lemon peel extract.
文摘Silver nanoparticles are versatile nanomaterials that have found numerous applications in various fields.The use of plant extract for the synthesis of silver is a green and sustainable approach.Clerodendron phlomoides leaves extract has been found to contain various phytochemicals,such as phenols,flavonoids,tannins,and alkaloids,which possess reducing and stabilizing properties that can aid the production of silver particles.In this paper,morphological and topographical analyses were performed on silver nanoparticles.The biosynthesized silver nanoparticles showed antimicrobial potential against wound pathogens.SEM and TEM micrographs revealed that the particles were sphere and nanosized,which makes them suitable for various biomedical applications.
文摘Finely divided silver nanoparticles were synthesized via the hydrothermal method. Arabic gum (AG) was used as both the reductant and steric stabilizer without any other surfactant. By adjusting the reaction temperature, mass ratio of AG to AgNO3, and reaction time, silver nanoparticles with different morphological characteristics could be obtained. The products were characterized by UV-Vis, FTIR, TEM, SEM, and XRD measurements. It was found that temperature and AG played an important role in the synthesis of mono-disperse silver nanoparticles. Well dispersed and quasispherical silver nanoparticles were obtained under the optimal synthesis conditions of 10 mmol/L AgNO3, m(AG)/m(AgN03)= l:1, 160 ℃ and 3 h.
基金This work was supported by the Doctoral Program of Higher Education of China (No.20110010110007) and the Beijing Municipal Natural Science Foundation (No.2102035).
文摘In this work, we fabricated the polyaniline/silver nanoparticle/multi-walled carbon nanotube (PANI/Ag/MWCNT) composites by in situ polymerization of aniline on the wall of Ag/MWCNTs with different aniline to Ag/MWCNT mass ratios. The chemical structure of the ternary composites was characterized by Fourier transform infrared spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy. Scanning electron microscope and high-resolution transmission electron microscopy were used to observe the morphology of the ternary composites. The results showed that the polyaniline PANI layer was prepared successfully and it covered Ag/MWCNTs completely. In addition, Ag nanoparticles between the MWCNT core and the PANI layer existed in the form of elemental crystal, which could contribute to the electrochemical performance of the composites. Then we prepared the composite electrodes and studied their electrochemical behaviors in 1 mol/L KOH. It was found that these composite electrodes had very low impedance, and exhibited lower resistance, higher electrochemical activity, and better cyclic stability compared with pure PANI electrode. Particularly, when the mass ratio of aniline to Ag/MWCNTs was 5:5, the composite electrode displayed a small equivalent series resistance (0.23 Ω) and low interfacial charge transfer resistance (〈0.25 Ω), as well as 160 F/g of the maximum specific capacitance at a current density of 0.25 A/g in KOH solution. We could conclude that the composite material had potential applications as cathode materials for lithium batteries and supercapacitors.
文摘Silver nanoparticles with average particles sizes ranging from 2 to 131nm were manipulatively synthesized starting from silver nitrate using different functional group-containing organic modifiers at room temperature. The effects of the organic modifiers on the morphology of the resulting silver nanoparticles were strongly dependent on the intrinsic properties of the functional groups and the reducibility of the reductant. Numerous ether bonds (-0-)present in polyethylene glycol and Tween-80 were beneficial to the formation of silver nanoparticles with particle sizes of several nanometers in a narrow size distribution in both weak and strong reducing environments. Cetyltrimethylammonium bromide induced the formation of nanosized silver triangle plates in a weak reducing environment. The crystal growth of the silver nanoparticles with particle sizes of more than lOnm was postulated through an adhesion process of small-sized particles followed by a subsequent coalescence process under the present reaction conditions.
文摘Extract of oven dried leaves of Pongamia pinnata(L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the treatment of aqueous solution of AgNO_3(1m M) with dried leaf extract of Pongamia pinnata(L) Pierre. UV-visible spectroscopy studies were carried out to quantify the formation of silver nanoparticles. Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the silver nanoparticles. TEM image divulges that silver nanoparticles are quite polydispersed, the size ranging from 20 nm to 50 nm with an average of 38 nm. Water soluble heterocyclic compounds such as flavones were mainly responsible for the reduction and stabilization of the nanoparticles. Silver nanoparticles were effective against Escherichia coli(ATCC 8739), Staphylococcus aureus(ATCC 6538p), Pseudomonas aeruginosa(ATCC 9027) and Klebsiella pneumoniae(clinical isolate). The move towards extracellular synthesis using dried biomass appears to be cost effective, eco-friendly to the conventional methods of nanoparticles synthesis.
基金supported by grants received by Anjali Dash from DST Women Scientist Scheme (DST WOSA)by D.Dash from the Department of Biotechnology (DBT),Govt.of Indiathe Indian Council of Medical Research (ICMR)
文摘Silver nanoparticles,endowed with powerful antimicrobial property,are the most widely used nanomaterial in consumer products,with associated risk of their easy access to environment and freshwater ecosystems by surface runoff.Although toxic effects of nanosilver on bacterial,fungal and mammalian cells have been documented,its impact on algal growth remains unknown.Pithophora oedogonia and Chara vulgaris are predominant members of photosynthetic eukaryotic algae,which form major component of global aquatic ecosystem.Here we report for the first time that nanosilver has significant adverse effects on growth and morphology of these filamentous green algae in a dose-dependent manner.Exposure of algal thalli to increasing concentrations of silver nanoparticles resulted in progressive depletion in algal chlorophyll content,chromosome instability and mitotic disturbance,associated with morphological malformations in algal filaments.SEM micrographs revealed dramatic alterations in cell wall in nanoparticle-treated algae,characterized with cell wall rupture and degradation in Pithophora.Although these observations underscore severe deleterious effects of nanosilver on aquatic environment,the information can also be exploited as a bioengineering strategy to control unwanted and persistent growth of noxious algal weeds that clog the municipal water supply and water channels and produce fouling of water bodies.
基金supported by the Institute of Physical Chemistry of the Polish Academy of Sciences
文摘We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles (NPs). The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the interaction of the electronic levels of lanthaaide ligands with silver plasmons, dramatic increase of luminescence was observed.
基金supported by the National Key R&D Program of China(Grant No.2020YFD0900905).
文摘Silver nanoparticles(Ag NPs)are an effective antibacterial agent,but their application in food packaging is limited due to their easy agglomeration and oxidation.In this study,antibacterial microcapsules were fabricated using Ginkgo biloba essential oil(GBEO)as core material and chitosan and type B gelatin biopolymer as capsule mate-rials.These antibacterial microcapsules were then modified with green-synthesized Ag NPs,blended into the bio-polymer polylactic acid(PLA),and finally formed as films.Physicochemical properties and antibacterial activity against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were evaluated.Results showed that the prepared antibacterial PLA films exhibited excellent antibacterial activity against foodborne pathogens.Its TVC exceeded the limit value of 7 log CFU/g at 7 days compared with the 5 days of pure PLA films.Therefore,these films can extend the shelf life of grass carp fillets by 2–3 days under refrigeration.
文摘The silver nanowires(Ag NWs)electrodes,which consist of incompact Ag nanoparticles(NPs)formed by multi-photon photoreduction,usually have poor conductivities.An effective strategy for enhancing conductivity of the Ag NWs elec-trodes is plasmon-enhanced nanosoldering(PLNS)by laser irradiation.Here,plasmon-enhanced photothermal effect is used to locally solder Ag NPs and then aggregates of these NPs grow into large irregular particles in PLNS process.Fi-nite element method(FEM)simulations indicate that the soldering process is triggered by localized surface plasmon-in-duced electric field enhancement at“hot-spots”.The effectiveness of PLNS for enhancing conductivity depends on laser power density and irradiation time.By optimizing the conditions of PLNS,the electrical conductivity of Ag NWs is signific-antly enhanced and the conductivityσs is increased to 2.45×107 S/m,which is about 39%of the bulk Ag.This PLNS of Ag NWs provides an efficient and cost-effective technique to rapidly produce large-area metal nanowire electrodes and capacitors with high conductivity,excellent uniformity,and good flexibility.
基金Supported by Department of Chemistry,University of Birjand(Grant No.4567:12/10/93)with cooperation of Birjand University of Medical Sciences
文摘Objective: To synthesis silver nanoparticles(Ag NPs) by using extract of saffron(Crocus sativus L.) wastages and to test their antibacterial activity against six bacteria.Methods: In this paper, the synthesis of Ag NPs using aqueous extract of saffron wastage as a green method without any chemical stabilizer and reducer is demonstrated. The synthesized Ag NPs were determined by UV–vis spectrum, high resolution transmission electron microscopy, X-ray diffraction, and Fourier transmission infrared spectroscopy analysis.Results: UV–vis spectrum showed a peak at 450 nm due to excitation of surface plasmon vibrations. Fourier transmission infrared spectroscopy showed that nanoparticles were capped with plant secondary metabolites. X-ray diffraction analysis also demonstrated that the size range of the synthesized nanoparticles was 12–20 nm. Transmission electron microscope image illustrated Ag NPs with spherical shape and an average size of15 nm. The result of antibacterial activities showed that the biosynthesized Ag NPs had an inhibiting activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Shigella flexneri and Bacillus subtilis.Conclusions: The biosynthesized Ag NPs showed significant antibacterial effect against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Shigella flexneri and Bacillus subtilis, so, it can be used in biomedical applications.
基金supports for this work by Shahid Chamran University Research Council
文摘Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed aggregates.This letter describes a way of synthesising silver nanoparticles and their protection to aggregate by silica gel.The combination of catalytic quantities of immobilized silver nanoparticles with reductive ability of NaBH_4 efficiently reduces aromatic nitroarenes to the corresponding amines in aqueous medium.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen and carboxylic acid groups.The silver particles immobilized on silica gel are stable in the presence of oxygen for several months.
基金Pravara Institute of Medical Sciences, Loni (MS), India for the financial support
文摘The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m M silver nitrate. 100 m M glucose was found to quicken the rate of reaction of silver nanoparticles synthesis.UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesized silver nanoparticles were further characterized by using Nanoparticle Tracking Analyzer(NTA),Transmission Electron Microscope and Energy Dispersive X-ray spectra. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope(40 X). The synergistic effect of silver nanoparticles along with antibiotics in biofilm quenching was found to be effective. In the near future, silver nanoparticles could be used in the treatment of infections caused by highly antibiotic resistant biofilm.
基金Project was supported by the Natural Science Foundation of Guangdong Province(No.2019A1515011844)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(ZHD201801 and 31512050201).
文摘This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a filler loading of 78 wt.%,83 wt.%and 88 wt.%and cured at 150℃and 180℃,respectively.The results show that the electrical and thermal conductivities of ECAs were improved with the increasing of filler loading and curing temperature.Adding silver NPs in silver flakes negatively affected the electrical and thermal conductivities of ECAs at a low filler mass fraction of 78 wt.%,because the segregation of NPs enlarged the average distance of silver flakes;while it positively influenced the electrical and thermal conductivities of ECAs at a loading ratio of 88 wt.%,probably due to NPs filling in the gaps between silver flakes or even sintering together with each other or with silver flakes,especially when curing at high temperature of 180℃.
文摘Silver nanoparticles synthesized by dried biomass of Lactobaciluus acidophilus 01 strain was evaluated against toxicity of genomic DNA isolated from bacteria(E.coli) fungi(Beauveria bassiana) algae(Seenedesmus acutus) and human blood adopting standard condition was discussed in the present study.Synthesized silver nanoparticles were characterized by UV-Vis spectroscopy and SEM.The UV-Vis spectroscopy revealed the formation of silver nanoparticles by yielding the typical silver plasmon absorption maxima at 430 nm and SEM micrograph indicates the uniform spherical particles within the size range of 45?60 nm.The energy dispersive X-ray spectroscopy(EDX) of the nanoparticle confirmed the presence of elemental silver signal as strong peak.The above synthesized silver nanoparticles didn't cause any toxic effect on all the tested genomic DNA at all tested concentrations which reveals nil genomic nanoparticles induced toxicity.
基金Project supported by the Natural Science Foundation of Beijing,China(Grant No.4072007)the National Natural Science Foundation of China(Grant Nos.60876006 and 60376007)
文摘Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency (RF) magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film.