The inevitable release of engineered silver nanoparticles（Ag NPs） into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial ...The inevitable release of engineered silver nanoparticles（Ag NPs） into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial roles in the transport and toxicity of Ag NPs, how the water chemistry of environmental waters influences the aggregation and transformation of engineered Ag NPs is still not well understood. In this study, the aggregation of polyvinylpyrrolidone（PVP） coated Ag NPs was investigated in eight typical environmental water samples（with different ionic strengths, hardness, and dissolved organic matter（DOM） concentrations） by using UV–visible spectroscopy and dynamic light scattering. Raman spectroscopy was applied to probe the interaction of DOM with the surface of Ag NPs. Further, the photo-transformation and morphology changes of Ag NPs in environmental waters were studied by UV–visible spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The results suggested that both electrolytes（especially Ca2＋and Mg2＋） and DOM in the surface waters are key parameters for Ag NP aggregation, and sunlight could accelerate the morphology change, aggregation, and further sedimentation of Ag NPs. This water chemistry controlled aggregation and photo-transformation should have significant environmental impacts on the transport and toxicity of Ag NPs in the aquatic environments.展开更多
Silver nanoparticles(AgNPs)have been widely used in many fields,which raised concerns about potential threats to biological sewage treatment systems.In this study,the phosphorus removal performance,enzymatic activity ...Silver nanoparticles(AgNPs)have been widely used in many fields,which raised concerns about potential threats to biological sewage treatment systems.In this study,the phosphorus removal performance,enzymatic activity and microbial population dynamics in constructed wetlands(CWs)were evaluated under a long-term exposure to Ag NPs(0,50,and 200μg/L)for 450 days.Results have shown that Ag NPs inhibited the phosphorus removal efficiency in a short-term exposure,whereas caused no obviously negative effects from a long-term perspective.Moreover,in the coexisting CW system of Ag NPs and phosphorus,competition exhibited in the initial exposure phase,however,cooperation between them was observed in later phase.Enzymatic activity of acid-phosphatase at the moderate temperature(10–20℃)was visibly higher than that at the high temperature(20–30℃)and CWs with Ag NPs addition had no appreciable differences compared with the control.High-throughput sequencing results indicated that the microbial richness,diversity and composition of CWs were distinctly affected with the extension of exposure time at different Ag NPs levels.However,the phosphorus removal performance of CWs did not decline with the decrease of polyphosphate accumulating organisms(PAOs),which also confirmed that adsorption precipitation was the main way of phosphorus removal in CWs.The study suggested that Ag NPs and phosphorus could be removed synergistically in the coexistence system.This work has some reference for evaluating the influences of Ag NPs on the phosphorus removal and the interrelation between them in CWs.展开更多
In this study,micro/nanostructures are fabricated on the surface of 3Cr13 stainless steel via laser etching,and a superhydrophobic coating with silver nanoparticles(AgNPs)is prepared by utilizing the reduction–adsorp...In this study,micro/nanostructures are fabricated on the surface of 3Cr13 stainless steel via laser etching,and a superhydrophobic coating with silver nanoparticles(AgNPs)is prepared by utilizing the reduction–adsorption properties of polydopamine(PDA).We investigate the effect of soaking time from the“one-step method”on the reduction of nano-Ag,surface wettability,and antibacterial properties.Scanning electron microscopy is performed to analyze the distribution of nano-Ag on the surface,whereas X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy are used to analyze the crystal structures and chemical compositions of different surfaces.Samples deposited with PDA on their surface are soaked in a 1H,1H,2H,2H-perfluorodecyltriethoxysilane water–alcohol solution containing AgNO3 for 3 h.Subsequently,a“one-step method”is used to prepare low-adhesion superhydrophobic surfaces containing AgNPs.As immersion progresses,more AgNPs are deposited onto the surface.Compared with the polished surface,the samples prepared via the“one-step method”show significant antibacterial properties against both gram-negative Escherichia coli and gram-positive Staphylococcus aureus.The antibacterial properties of the surface improve as immersion progresses.展开更多
The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles（Ag NPs）,which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability ...The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles（Ag NPs）,which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability of bacteria to produce adenosine triphosphate（ATP）,a molecule necessary for chemical energy transport in cells.The antimicrobial properties of Ag NPs（and Ag＋）make them valued antibacterial展开更多
The antibacterial potential of silver nanoparticles（AgNPs） resulted in their increasing incorporation into consumer,industrial and biomedical products.Therefore,human and environmental exposure to AgNPs（either as a...The antibacterial potential of silver nanoparticles（AgNPs） resulted in their increasing incorporation into consumer,industrial and biomedical products.Therefore,human and environmental exposure to AgNPs（either as an engineered product or a contaminant）supports the emergent research on the features conferring them different toxicity profiles.In this study,30 ran AgNPs coated with citrate or poly（ethylene glycol）（PEG） were used to assess the influence of coating on the effects produced on a human hepatoma cell line（HepG2）,namely in terms of viability,apoptosis,apoptotic related genes,cell cycle and cyclins gene expression.Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile.At the concentrations used（11 and 5 μg/mL corresponding to IC50 and-IC10 levels,respectively） the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2（anti-apoptotic gene）and BAX（pro-apoptotic gene） were both downregulated.Moreover,both AgNPs affected HepG2 cell cycle progression at the higher concentration（11 μg/mL） by increasing the percentage of cells in S（synthesis phase） and G2（Gap 2 phase） phases.Considering the cell-cycle related genes,the expression of cyclin B1 and cyclin E1 genes were decreased.Thus,this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression,cell cycle dynamics and cyclin regulation in a similar way.More research is needed to determine the properties that confer AgNPs at lower toxicity,since their use has proved helpful in several industrial and biomedical contexts.展开更多
Chitosan(CS)nanofibers containing silver nanoparticles(AgNPs)were prepared by in-situ reducing method.A water soluble carboxymethyl chitosan(CMCT)was applied for the preparation of AgNPs.The impact factor such as the ...Chitosan(CS)nanofibers containing silver nanoparticles(AgNPs)were prepared by in-situ reducing method.A water soluble carboxymethyl chitosan(CMCT)was applied for the preparation of AgNPs.The impact factor such as the concentration of CMCT,silver nitrate(AgNO_3)content,temperature and the heating time during the preparation of AgNPs were studied.The result showed that the proper value of the concentration of CMCT,AgNO_3content,temperature and the heating time were set as0.1%,20μL AgNO_3(1.7 mol/L),90°and 3 h,separately and the maximum concentration of AgNPs could be acquired.To solve the spinnability of chitosan nanofiber,a super high molecular weight polyethylene oxide(PEO)was introduced to the system,and a new mixed solvent system was prepared by adding acetic acid,dimethyl sulfoxide(DMSO)and several drops of Triton X-100TMto distilled water.CS/PEO(80/20)with the concentration of 3%was dissolved in the mixed solvent to prepare electrospinning solution for CS/PEO(80/20)nanofiber fabrication.The CS containing AgNPs electrospun solution could be prepared by replacing the distilled water to silver nanoparticle solution during the preparation of mixed solvent.Ultraviolet visible(UV-Vis)spectra and transmission electron microscope(TEM)results showed that silver nanoparticles were prepared successfully.CS membranes with and without AgNPs were acquired via a traditional electrospinning equipment.These two nanofiber membranes were characterized by scanning electron microscope(SEM)images and mechanical testing.It could be noticed from the SEM images that there was a good morphology and random distribution for the nanofibers with an average fiber diameter of 180 nm.The mechanical property results showed that the addition of AgNPs decreased the mechanical strength significantly but the mechanical strength could still support wound dressing application.展开更多
The widely use of silver nanoparticles(AgNPs) as antimicrobial agents gives rise to potential environmental risks. AgNPs exposure have been reported to cause toxicity in animals.Nevertheless, the known mechanisms of A...The widely use of silver nanoparticles(AgNPs) as antimicrobial agents gives rise to potential environmental risks. AgNPs exposure have been reported to cause toxicity in animals.Nevertheless, the known mechanisms of AgNPs toxicity are still limited. In this study, we systematically investigated the toxicity of AgNPs exposure using Drosophila melanogaster.We show here that AgNPs significantly decreased Drosophila fecundity, the third-instar larvae weight and rates of pupation and eclosion in a dose-dependent manner. AgNPs reduced fat body cell viability in MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)assays. AgNPs caused DNA damage in hemocytes and S2 cells. Interestingly, the mRNA levels of the entire metallothionein gene family were increased under AgNPs exposure as determined by RNA-seq analysis and validated by qRT-PCR, indicating that Drosophila responded to the metal toxicity of AgNPs by producing metallothioneins for detoxification. These findings provide a better understanding of the mechanisms of AgNPs toxicity and may provide clues to effect on other organisms, including humans.展开更多
Titanium dioxide(TiO2)has a long history of application in blood contact materials,but it often suffers from insufficient anticoagulant properties.Recently,we have revealed the photocatalytic effect of TiO2 also induc...Titanium dioxide(TiO2)has a long history of application in blood contact materials,but it often suffers from insufficient anticoagulant properties.Recently,we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties.However,for long-term vascular implant devices such as vascular stents,besides anticoagulation,also anti-inflammatory,anti-hyperplastic properties,and the ability to support endothelial repair,are desired.To meet these requirements,here,we immobilized silver nanoparticles(AgNPs)on the surface of TiO2 nanotubes(TiO2-NTs)to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties.The photo-functionalized TiO2-NTs showed protein-fouling resistance,causing the anticoagulant property and the ability to suppress cell adhesion.The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property.The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property,a strong inhibitory effect on smooth muscle cells(SMCs),and low toxicity to endothelial cells(ECs).The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs,and therefore has enormous potential in the field of cardiovascular implant devices.Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility.展开更多
In this paper, silver nanoparticles （AgNPs） and AgNPs/reduced graphene oxide （RGO） nanocomposites were prepared using lemon juice under microwave irradiation （MWI） and UV light irradiation. AgNPs with face-cente...In this paper, silver nanoparticles （AgNPs） and AgNPs/reduced graphene oxide （RGO） nanocomposites were prepared using lemon juice under microwave irradiation （MWI） and UV light irradiation. AgNPs with face-centered cubic structure RGO peaks were observed by X-ray diffraction. The UV-Vis spectrum showed modifications in the absorption peaks of the AgNPs with the concentration of the precursor solution and irradiation time, and the optimized condition was obtained for 20 min MWI and 60 s of UV light. Raman analysis confirmed the presence of RGO as D and G bands in the spectrum. Transmission electron microscopy analyses confirmed that the AgNPs of size ranging from 3 to 8 nm were anchored onto the RGO sheets. The antibacterial properties of the AgNPs/RGO nanocomposites were investigated using gram-negative bacteria. The results revealed that AgNPs/RGO nanocomposites consisting of approximately 5 wt% AgNPs can achieve antibacterial performance similar to that of neat AgNPS. This method can be useful for the applications of AgNPs-based nanocomposites, where minute amount of silver will be utilized.展开更多
With increasing emission of silver nanoparticles(AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubi...With increasing emission of silver nanoparticles(AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubiquitous freshwater microalgae, was evaluated. AgNPs exerted a minor inhibitory effect at low doses. Non-targeted metabolomic studies were conducted to understand and analyze the effect of AgNPs on algal cells from a molecular perspective. During the 48 hr of exposure to AgNPs, 30 metabolites were identified, of which nine had significant changes compared to the control group. These include D-galactose, sucrose, and D-fructose.These carbohydrates are involved in the synthesis and repair of cell walls. Glycine, an important constituent amino acid of glutathione, increased with AgNP exposure concentration increasing, likely to counteract an increased intracellular oxidative stress. These results provide a new understanding of the toxicity effects and mechanism of AgNPs. These metabolites could be useful biomarkers for future research, employed in the early detection of environmental risk from AgNPs.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB14020101)the External Cooperation Program of Chinese Academy of Sciences (No.GJHZ1206)+1 种基金the National Natural Science Foundation of China (No.21337004)the Young Scientists Fund of RCEES (No.RCEES-QN-20130028F)
文摘The inevitable release of engineered silver nanoparticles（Ag NPs） into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial roles in the transport and toxicity of Ag NPs, how the water chemistry of environmental waters influences the aggregation and transformation of engineered Ag NPs is still not well understood. In this study, the aggregation of polyvinylpyrrolidone（PVP） coated Ag NPs was investigated in eight typical environmental water samples（with different ionic strengths, hardness, and dissolved organic matter（DOM） concentrations） by using UV–visible spectroscopy and dynamic light scattering. Raman spectroscopy was applied to probe the interaction of DOM with the surface of Ag NPs. Further, the photo-transformation and morphology changes of Ag NPs in environmental waters were studied by UV–visible spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The results suggested that both electrolytes（especially Ca2＋and Mg2＋） and DOM in the surface waters are key parameters for Ag NP aggregation, and sunlight could accelerate the morphology change, aggregation, and further sedimentation of Ag NPs. This water chemistry controlled aggregation and photo-transformation should have significant environmental impacts on the transport and toxicity of Ag NPs in the aquatic environments.
基金supported by the National Natural Science Foundation of China:“The ecological effect and fate of typical nanoparticles in constructed wetland”(No.51479034)the Fundamental Research Funds for the Central Universities(No.2242019K40064)the Graduate Innovation Project of Jiangsu Province(No.KYCX18—0125)
文摘Silver nanoparticles(AgNPs)have been widely used in many fields,which raised concerns about potential threats to biological sewage treatment systems.In this study,the phosphorus removal performance,enzymatic activity and microbial population dynamics in constructed wetlands(CWs)were evaluated under a long-term exposure to Ag NPs(0,50,and 200μg/L)for 450 days.Results have shown that Ag NPs inhibited the phosphorus removal efficiency in a short-term exposure,whereas caused no obviously negative effects from a long-term perspective.Moreover,in the coexisting CW system of Ag NPs and phosphorus,competition exhibited in the initial exposure phase,however,cooperation between them was observed in later phase.Enzymatic activity of acid-phosphatase at the moderate temperature(10–20℃)was visibly higher than that at the high temperature(20–30℃)and CWs with Ag NPs addition had no appreciable differences compared with the control.High-throughput sequencing results indicated that the microbial richness,diversity and composition of CWs were distinctly affected with the extension of exposure time at different Ag NPs levels.However,the phosphorus removal performance of CWs did not decline with the decrease of polyphosphate accumulating organisms(PAOs),which also confirmed that adsorption precipitation was the main way of phosphorus removal in CWs.The study suggested that Ag NPs and phosphorus could be removed synergistically in the coexistence system.This work has some reference for evaluating the influences of Ag NPs on the phosphorus removal and the interrelation between them in CWs.
基金the National Natural Science Foundation of China(52175207)the National Science and Technology Fund Project of China(2020-JCJQ-JJ-378).
文摘In this study,micro/nanostructures are fabricated on the surface of 3Cr13 stainless steel via laser etching,and a superhydrophobic coating with silver nanoparticles(AgNPs)is prepared by utilizing the reduction–adsorption properties of polydopamine(PDA).We investigate the effect of soaking time from the“one-step method”on the reduction of nano-Ag,surface wettability,and antibacterial properties.Scanning electron microscopy is performed to analyze the distribution of nano-Ag on the surface,whereas X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy are used to analyze the crystal structures and chemical compositions of different surfaces.Samples deposited with PDA on their surface are soaked in a 1H,1H,2H,2H-perfluorodecyltriethoxysilane water–alcohol solution containing AgNO3 for 3 h.Subsequently,a“one-step method”is used to prepare low-adhesion superhydrophobic surfaces containing AgNPs.As immersion progresses,more AgNPs are deposited onto the surface.Compared with the polished surface,the samples prepared via the“one-step method”show significant antibacterial properties against both gram-negative Escherichia coli and gram-positive Staphylococcus aureus.The antibacterial properties of the surface improve as immersion progresses.
文摘The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles（Ag NPs）,which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability of bacteria to produce adenosine triphosphate（ATP）,a molecule necessary for chemical energy transport in cells.The antimicrobial properties of Ag NPs（and Ag＋）make them valued antibacterial
基金the projects CICECOAveiro Institute of Materials(Ref.FCT UID/CTM/50011/2013)CESAM(Ref.FCT UID/AMB/50017/2013)+5 种基金financed by national funds through the FCT/MECco-financed by the European Regional Development Fund(FEDER)under the PT2020 Partnership AgreementFunding to the project FCOMP-01-0124-FEDER-021456(Ref.FCT PTDC/SAU-TOX/120953/2010)by FEDER through COMPETEnational funds through FCT,and the FCT-awarded grants(SFRH/BD/81792/2011SFRH/BPD/111736/2015SFRH/BPD/74868/2010)
文摘The antibacterial potential of silver nanoparticles（AgNPs） resulted in their increasing incorporation into consumer,industrial and biomedical products.Therefore,human and environmental exposure to AgNPs（either as an engineered product or a contaminant）supports the emergent research on the features conferring them different toxicity profiles.In this study,30 ran AgNPs coated with citrate or poly（ethylene glycol）（PEG） were used to assess the influence of coating on the effects produced on a human hepatoma cell line（HepG2）,namely in terms of viability,apoptosis,apoptotic related genes,cell cycle and cyclins gene expression.Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile.At the concentrations used（11 and 5 μg/mL corresponding to IC50 and-IC10 levels,respectively） the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2（anti-apoptotic gene）and BAX（pro-apoptotic gene） were both downregulated.Moreover,both AgNPs affected HepG2 cell cycle progression at the higher concentration（11 μg/mL） by increasing the percentage of cells in S（synthesis phase） and G2（Gap 2 phase） phases.Considering the cell-cycle related genes,the expression of cyclin B1 and cyclin E1 genes were decreased.Thus,this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression,cell cycle dynamics and cyclin regulation in a similar way.More research is needed to determine the properties that confer AgNPs at lower toxicity,since their use has proved helpful in several industrial and biomedical contexts.
基金National Natural Science Foundations of China(Nos.31470941,31271035)Science and Technology Commissions of Shanghai Municipality,China(Nos.15JC1490100,15441905100)+3 种基金Ph.D.Programs Foundation of Ministry of Education of China(No.20130075110005)Light of Textile Project,China(No.J201404)Yantai Double Hundred Talent Plan,China(No.XY-04-16-06)“111 Project”Biomedical Textile Materials Science and Technology,China(No.B07024)
文摘Chitosan(CS)nanofibers containing silver nanoparticles(AgNPs)were prepared by in-situ reducing method.A water soluble carboxymethyl chitosan(CMCT)was applied for the preparation of AgNPs.The impact factor such as the concentration of CMCT,silver nitrate(AgNO_3)content,temperature and the heating time during the preparation of AgNPs were studied.The result showed that the proper value of the concentration of CMCT,AgNO_3content,temperature and the heating time were set as0.1%,20μL AgNO_3(1.7 mol/L),90°and 3 h,separately and the maximum concentration of AgNPs could be acquired.To solve the spinnability of chitosan nanofiber,a super high molecular weight polyethylene oxide(PEO)was introduced to the system,and a new mixed solvent system was prepared by adding acetic acid,dimethyl sulfoxide(DMSO)and several drops of Triton X-100TMto distilled water.CS/PEO(80/20)with the concentration of 3%was dissolved in the mixed solvent to prepare electrospinning solution for CS/PEO(80/20)nanofiber fabrication.The CS containing AgNPs electrospun solution could be prepared by replacing the distilled water to silver nanoparticle solution during the preparation of mixed solvent.Ultraviolet visible(UV-Vis)spectra and transmission electron microscope(TEM)results showed that silver nanoparticles were prepared successfully.CS membranes with and without AgNPs were acquired via a traditional electrospinning equipment.These two nanofiber membranes were characterized by scanning electron microscope(SEM)images and mechanical testing.It could be noticed from the SEM images that there was a good morphology and random distribution for the nanofibers with an average fiber diameter of 180 nm.The mechanical property results showed that the addition of AgNPs decreased the mechanical strength significantly but the mechanical strength could still support wound dressing application.
基金supported by the Natural Science Foundation of Beijing, China (No. 5212012)the National Natural Science Foundation of China (No. 31801190)the 2115 Talent Development Program of China Agricultural University。
文摘The widely use of silver nanoparticles(AgNPs) as antimicrobial agents gives rise to potential environmental risks. AgNPs exposure have been reported to cause toxicity in animals.Nevertheless, the known mechanisms of AgNPs toxicity are still limited. In this study, we systematically investigated the toxicity of AgNPs exposure using Drosophila melanogaster.We show here that AgNPs significantly decreased Drosophila fecundity, the third-instar larvae weight and rates of pupation and eclosion in a dose-dependent manner. AgNPs reduced fat body cell viability in MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)assays. AgNPs caused DNA damage in hemocytes and S2 cells. Interestingly, the mRNA levels of the entire metallothionein gene family were increased under AgNPs exposure as determined by RNA-seq analysis and validated by qRT-PCR, indicating that Drosophila responded to the metal toxicity of AgNPs by producing metallothioneins for detoxification. These findings provide a better understanding of the mechanisms of AgNPs toxicity and may provide clues to effect on other organisms, including humans.
基金the National Natural Science Foundation of China(nos.31870958,31700821,and 81771988).
文摘Titanium dioxide(TiO2)has a long history of application in blood contact materials,but it often suffers from insufficient anticoagulant properties.Recently,we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties.However,for long-term vascular implant devices such as vascular stents,besides anticoagulation,also anti-inflammatory,anti-hyperplastic properties,and the ability to support endothelial repair,are desired.To meet these requirements,here,we immobilized silver nanoparticles(AgNPs)on the surface of TiO2 nanotubes(TiO2-NTs)to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties.The photo-functionalized TiO2-NTs showed protein-fouling resistance,causing the anticoagulant property and the ability to suppress cell adhesion.The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property.The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property,a strong inhibitory effect on smooth muscle cells(SMCs),and low toxicity to endothelial cells(ECs).The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs,and therefore has enormous potential in the field of cardiovascular implant devices.Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility.
基金supported by the Internal Research Grant,Alfaisal University(IRG 2014,No.4050101011410)
文摘In this paper, silver nanoparticles （AgNPs） and AgNPs/reduced graphene oxide （RGO） nanocomposites were prepared using lemon juice under microwave irradiation （MWI） and UV light irradiation. AgNPs with face-centered cubic structure RGO peaks were observed by X-ray diffraction. The UV-Vis spectrum showed modifications in the absorption peaks of the AgNPs with the concentration of the precursor solution and irradiation time, and the optimized condition was obtained for 20 min MWI and 60 s of UV light. Raman analysis confirmed the presence of RGO as D and G bands in the spectrum. Transmission electron microscopy analyses confirmed that the AgNPs of size ranging from 3 to 8 nm were anchored onto the RGO sheets. The antibacterial properties of the AgNPs/RGO nanocomposites were investigated using gram-negative bacteria. The results revealed that AgNPs/RGO nanocomposites consisting of approximately 5 wt% AgNPs can achieve antibacterial performance similar to that of neat AgNPS. This method can be useful for the applications of AgNPs-based nanocomposites, where minute amount of silver will be utilized.
基金supported by the National Natural Science Foundation of China (No.21677097)the National Science and Technology Major Projects of Water Pollution Control and Management of China (No.2014ZX07206001)the National Research Foundation (NRF),Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) Program
文摘With increasing emission of silver nanoparticles(AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubiquitous freshwater microalgae, was evaluated. AgNPs exerted a minor inhibitory effect at low doses. Non-targeted metabolomic studies were conducted to understand and analyze the effect of AgNPs on algal cells from a molecular perspective. During the 48 hr of exposure to AgNPs, 30 metabolites were identified, of which nine had significant changes compared to the control group. These include D-galactose, sucrose, and D-fructose.These carbohydrates are involved in the synthesis and repair of cell walls. Glycine, an important constituent amino acid of glutathione, increased with AgNP exposure concentration increasing, likely to counteract an increased intracellular oxidative stress. These results provide a new understanding of the toxicity effects and mechanism of AgNPs. These metabolites could be useful biomarkers for future research, employed in the early detection of environmental risk from AgNPs.
