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
To probe the influence and the adverse-resistance characteristics of wetland plants in presence of silver nanoparticles (AgNPs), the changes in the physiological and biochemical characteristics (including the superoxi...To probe the influence and the adverse-resistance characteristics of wetland plants in presence of silver nanoparticles (AgNPs), the changes in the physiological and biochemical characteristics (including the superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity, soluble protein content, and chlorophyll content) of Typha orientalis exposed to different concentrations of AgNPs solutions (0, 0.1, 1, 20 and 40 mg/L) were explored. Meantime, the accumulation of silver content in these plants was revealed. The results show that under low concentrations of AgNPs, the SOD and POD activities in the leaves of Typha orientalis are strengthened to different degrees. However, high concentrations of AgNPs inhibit the activities of SOD and POD. Under the stress of different concentrations of AgNPs, the CAT activities are inhibited initially and later recovered to some extent. Under the stress of low concentrations of AgNPs, the soluble protein content in the leaves of Typha orientalis increases significantly, but decreases more significantly with increasing concentrations of AgNPs. Low concentrations of AgNPs promote chlorophyll synthesis in the leaves of Typha orientalis , but the chlorophyll content subsequently falls to pre-stress levels. In contrast, high concentrations of AgNPs cause a certain inhibition to generate chlorophyll. Meanwhile, the results show that the silver concentrations of plant tissues increase with the exposure of concentrations of AgNPs and they have a positive relationship with the exposure of concentrations of AgNPs.展开更多
Development of natural based nanomaterial immense interest of researchers involved in eco-friendly biosynthesis of nanoparticles. This research set out to investigate the potential of Allium ampeloprasum leaves extrac...Development of natural based nanomaterial immense interest of researchers involved in eco-friendly biosynthesis of nanoparticles. This research set out to investigate the potential of Allium ampeloprasum leaves extract to synthesize silver nanoparticles (AgNPs), and evaluate their antifungal activity against some toxigenic strains of Aspergillus isolates. In order to achieve this, AgNPs were prepared using plant extracts at room temperature and the formation of AgNPs was visually detected after the color changed to dark brown within few minutes. The biosynthesized AgNPs were characterized using the UV-vis spectroscopy, which confirmed the formation of AgNPs with a maximum peak at 437 nm due to the Plasmon resonance. The main active reduction agents were detected by Fourier Transmission infrared spectroscopy (FTIR). Also, the nanoparticles were characterized using Scanning electron microscope (SEM). The antifungal activity of AgNPs was investigated by agar well diffusion method, which revealed inhibition zones of 8 mm, 10 mm, 11 mm, 11 mm and 14 mm against Aspergillus flavus 1, A. parasiticus, A. flavus 2, A. ochraceus, and A. niger. The minimum inhibition concentration (MIC) was determined using micro broth dilution method. MIC values of AgNPs ranged from 652 - 2500 μg/ml. The fungi treated with AgNPs, were examined with (SEM), it was observed that the treated fungi were damaged. These results suggest that AgNPs have the potential to be used as an ideal eco-friendly approach to control toxigenic fungi.展开更多
The antioxidant of seeds was carried out using extracts from methanol and Silver Nanoparticles from the spice. The SEM shows the shapes, dispersion and agglomeration of the sample, while the EDX confirms the SEM and t...The antioxidant of seeds was carried out using extracts from methanol and Silver Nanoparticles from the spice. The SEM shows the shapes, dispersion and agglomeration of the sample, while the EDX confirms the SEM and the presence of some compounds. The FT-IR reveals the AgNP<sub>s</sub> capping and reducing the particular biomolecule from the functional group for identification. Compounds found in the FT-IR seeds of Capsicum annum are Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol). Monodora myristica are Mo L (Molybdenum), Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol), Mg K (Magnesium). Piper guineense are Ag L (Silver iodide), Ci K (Potassium chloride), C K (Cyanogen chloride), P K (Phenol). The seeds show that the AgNP<sub>S</sub> of CA and MM has a better antioxidant activity than the methanol of CA and MM, while the PG methanol has a better activity than the AgNP<sub>S</sub> PG. The control (Catechin and Galic acid) has a slight overall better DPPH activity than the AgNP<sub>S</sub>. It is important to note that there is a concentration dependency in CA, MM AgNP<sub>S,</sub> PG methanol respectively. Notably, at CA methanol, the conc. at 125 was higher than the conc. at 250. Hence, there is need to create a great part in using plant samples for making tabulated or capsulated drugs for treatment of diseases and using plant silver nanoparticles to develop a healthy food/drug preservative package material “smart packaging” that will enhance shelf-life.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
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
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
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
With the rapid development of nanotechnology and increasingly broad bio-application of engineered nanomaterials, their bio- hazards have become a serious public concern. It is believed that the chemical nature, partic...With the rapid development of nanotechnology and increasingly broad bio-application of engineered nanomaterials, their bio- hazards have become a serious public concern. It is believed that the chemical nature, particle size, morphology, and surface chemistry of nanomaterials are key parameters that influence their toxicity. Although cultured ceils have been widely used to evaluate nanomaterial toxicity, it remains unclear whether the passage of these cells affects the evaluation results. In the pre- sent study, Ba/F3 cells transfected with the BCR-ABL gene were subcultured to study the effect of passage number on cell sta- bility and their cellular responses upon exposure to nanomaterials. The results demonstrated that proliferation, cellular senes- cence, BCR-ABL gene expression, cell cycle and apoptosis were stable across multiple passages. Senescence and BCR-ABL gene expression of cells from different passage cells were unchanged when treated with silver nanoparticles (AgNPs). In addi- tion, the cells at multiple passage numbers were all arrested in the G2/M phase and apoptosis was induced by the AgNPs. These nanoparticles could enter cells via endocytosis and localize in the cndosomes, which were also not influenced by passage number. These data suggest that short-term passage would not affect cultured cell stability and toxicity assessment using these cells would be consistent when maintained appropriately.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
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 aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to c...The aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to cobalt chromium alloys and pure titanium using a hydrothermal method, according to the reaction: AgNO3+NaBH4-, Ag+1/2H2+1/2B2H6+NaNO3. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of the alloys when in contact with osteogenic precursor cells (MC3T3-E1) from mice and mesenchymal stem cells (BMSC) from rats. The antibacterial properties of dental alloys incorporating three different concentrations (10, 4, and 2 μmol/L)of AgNPs were tested on Staphylococcus aureus (SA)and Streptococcus mutans (MS). High cytotoxicity values were observed for all dental alloys that contained 0% of AgNPs (the control groups). The incorporation of AgNPs reduced cytotoxicity values. No significant difference was observed for antibacterial performance when comparing dental alloys containing AgNPs to the respective control groups. The results demonstrated that the cobalt chromium alloys and pure titanium all had cytotoxicity to MC3T3-E1 and BMSC and that the incorpo- ration of AgNPs could reduce this cytotoxicity. The concentrations of AgNPs adopted in this study were found to have no antibacterial action against SA or MS.展开更多
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The National Natural Science Foundation of China(No.51479034,5151101102)
文摘To probe the influence and the adverse-resistance characteristics of wetland plants in presence of silver nanoparticles (AgNPs), the changes in the physiological and biochemical characteristics (including the superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity, soluble protein content, and chlorophyll content) of Typha orientalis exposed to different concentrations of AgNPs solutions (0, 0.1, 1, 20 and 40 mg/L) were explored. Meantime, the accumulation of silver content in these plants was revealed. The results show that under low concentrations of AgNPs, the SOD and POD activities in the leaves of Typha orientalis are strengthened to different degrees. However, high concentrations of AgNPs inhibit the activities of SOD and POD. Under the stress of different concentrations of AgNPs, the CAT activities are inhibited initially and later recovered to some extent. Under the stress of low concentrations of AgNPs, the soluble protein content in the leaves of Typha orientalis increases significantly, but decreases more significantly with increasing concentrations of AgNPs. Low concentrations of AgNPs promote chlorophyll synthesis in the leaves of Typha orientalis , but the chlorophyll content subsequently falls to pre-stress levels. In contrast, high concentrations of AgNPs cause a certain inhibition to generate chlorophyll. Meanwhile, the results show that the silver concentrations of plant tissues increase with the exposure of concentrations of AgNPs and they have a positive relationship with the exposure of concentrations of AgNPs.
文摘Development of natural based nanomaterial immense interest of researchers involved in eco-friendly biosynthesis of nanoparticles. This research set out to investigate the potential of Allium ampeloprasum leaves extract to synthesize silver nanoparticles (AgNPs), and evaluate their antifungal activity against some toxigenic strains of Aspergillus isolates. In order to achieve this, AgNPs were prepared using plant extracts at room temperature and the formation of AgNPs was visually detected after the color changed to dark brown within few minutes. The biosynthesized AgNPs were characterized using the UV-vis spectroscopy, which confirmed the formation of AgNPs with a maximum peak at 437 nm due to the Plasmon resonance. The main active reduction agents were detected by Fourier Transmission infrared spectroscopy (FTIR). Also, the nanoparticles were characterized using Scanning electron microscope (SEM). The antifungal activity of AgNPs was investigated by agar well diffusion method, which revealed inhibition zones of 8 mm, 10 mm, 11 mm, 11 mm and 14 mm against Aspergillus flavus 1, A. parasiticus, A. flavus 2, A. ochraceus, and A. niger. The minimum inhibition concentration (MIC) was determined using micro broth dilution method. MIC values of AgNPs ranged from 652 - 2500 μg/ml. The fungi treated with AgNPs, were examined with (SEM), it was observed that the treated fungi were damaged. These results suggest that AgNPs have the potential to be used as an ideal eco-friendly approach to control toxigenic fungi.
文摘The antioxidant of seeds was carried out using extracts from methanol and Silver Nanoparticles from the spice. The SEM shows the shapes, dispersion and agglomeration of the sample, while the EDX confirms the SEM and the presence of some compounds. The FT-IR reveals the AgNP<sub>s</sub> capping and reducing the particular biomolecule from the functional group for identification. Compounds found in the FT-IR seeds of Capsicum annum are Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol). Monodora myristica are Mo L (Molybdenum), Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol), Mg K (Magnesium). Piper guineense are Ag L (Silver iodide), Ci K (Potassium chloride), C K (Cyanogen chloride), P K (Phenol). The seeds show that the AgNP<sub>S</sub> of CA and MM has a better antioxidant activity than the methanol of CA and MM, while the PG methanol has a better activity than the AgNP<sub>S</sub> PG. The control (Catechin and Galic acid) has a slight overall better DPPH activity than the AgNP<sub>S</sub>. It is important to note that there is a concentration dependency in CA, MM AgNP<sub>S,</sub> PG methanol respectively. Notably, at CA methanol, the conc. at 125 was higher than the conc. at 250. Hence, there is need to create a great part in using plant samples for making tabulated or capsulated drugs for treatment of diseases and using plant silver nanoparticles to develop a healthy food/drug preservative package material “smart packaging” that will enhance shelf-life.
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 Key Basic Research Program of China(Grant Nos.2011CB933500 and 2011CB933501)the National Natural Science Foundation of China(Grant Nos.60725101 and 50872021)+3 种基金the International Cooperation Program awarded by MOST(Ministry of Science and Technology) of China(Grant No.2008DFA51180)the Natural Science Foundation of Jiangsu Province in China(Grant Nos.SBE201077305,BK2009013 and BK2009592)the Graduate Research and Innovation Program of Jiangsu Province in China(Grant No.CXZZ-0172)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘With the rapid development of nanotechnology and increasingly broad bio-application of engineered nanomaterials, their bio- hazards have become a serious public concern. It is believed that the chemical nature, particle size, morphology, and surface chemistry of nanomaterials are key parameters that influence their toxicity. Although cultured ceils have been widely used to evaluate nanomaterial toxicity, it remains unclear whether the passage of these cells affects the evaluation results. In the pre- sent study, Ba/F3 cells transfected with the BCR-ABL gene were subcultured to study the effect of passage number on cell sta- bility and their cellular responses upon exposure to nanomaterials. The results demonstrated that proliferation, cellular senes- cence, BCR-ABL gene expression, cell cycle and apoptosis were stable across multiple passages. Senescence and BCR-ABL gene expression of cells from different passage cells were unchanged when treated with silver nanoparticles (AgNPs). In addi- tion, the cells at multiple passage numbers were all arrested in the G2/M phase and apoptosis was induced by the AgNPs. These nanoparticles could enter cells via endocytosis and localize in the cndosomes, which were also not influenced by passage number. These data suggest that short-term passage would not affect cultured cell stability and toxicity assessment using these cells would be consistent when maintained appropriately.
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.
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Project supported by the Public Welfare Projects of Science Technology Department of Zhejiang Province(No.2013c33139)the Natural Science Foundation of Zhejiang Province(No.LZ14C200001),China
文摘The aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to cobalt chromium alloys and pure titanium using a hydrothermal method, according to the reaction: AgNO3+NaBH4-, Ag+1/2H2+1/2B2H6+NaNO3. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of the alloys when in contact with osteogenic precursor cells (MC3T3-E1) from mice and mesenchymal stem cells (BMSC) from rats. The antibacterial properties of dental alloys incorporating three different concentrations (10, 4, and 2 μmol/L)of AgNPs were tested on Staphylococcus aureus (SA)and Streptococcus mutans (MS). High cytotoxicity values were observed for all dental alloys that contained 0% of AgNPs (the control groups). The incorporation of AgNPs reduced cytotoxicity values. No significant difference was observed for antibacterial performance when comparing dental alloys containing AgNPs to the respective control groups. The results demonstrated that the cobalt chromium alloys and pure titanium all had cytotoxicity to MC3T3-E1 and BMSC and that the incorpo- ration of AgNPs could reduce this cytotoxicity. The concentrations of AgNPs adopted in this study were found to have no antibacterial action against SA or MS.