Effect Of Metal Nanoparticles Research Articles

Recent advances in the protective role of metallic nanoparticles in red blood cells.

The interaction of nanoparticles with the biological system has increased with the increasing popularity of nanomedicines. Red blood cells (RBCs) are very sensitive, and abundant cells in the blood. They are highly prone to oxidative damage due to constant interaction with oxygen itself, foreign particles in the blood, and the lack of repair mechanism. The cell membrane of RBCs undergoes lipid peroxidation, protein oxidation, and heme degradation which results in altered membrane permeability, changes in the morphology, and functioning of RBCs. The nanoparticles induce oxidative stress, hemolysis, morphological changes, membrane deformability, and alterations in hemoglobin structure in RBCs. In this review, the effects of metallic nanoparticles and their modifications on the physiology, and life span of RBCsare discussed. The detailed analysis of the antioxidant enzymes-like activity of metal nanoparticles is expected to highlight the beneficial use of these metal nanoparticles in RBCs against oxidative stress and the development of new biosafe nanodrugs.

Controlling size and distribution of Ag nanoparticles in near surface of SiO2 glass by low-energy ion implantation

Ag nanoparticles were embedded in the near surface of SiO2 substrate and fabricated by low-energy ion implantation method in this study. The optical and structural properties of Ag implanted samples were investigated using optical spectroscopy, transmission electron microscope (TEM) and atomic force microscopy (AFM). The grain size and distribution of nanoparticles embedded in the substrate were characterized by TEM and AFM characterization. Results showed that the grain size and depth of distribution of nanoparticles were controlled by changing the ion implantation energy and dose. Furthermore, the Ag nanoparticles embedded near surface of substrate prepared by this low-energy ion implantation method had strong local surface plasmon resonance (LSPR) characteristics. Our work demonstrates a practical means for fabrication of metal nanoparticles with controllable size and distribution using ion implantation technology, which is helpful to the application of local plasmon resonance effect of metal nanoparticles.

Toxic Effects of Nanoparticles on Fish Embryos

Nanoparticles are used widely in the in-drug delivery, diagnostics, cosmetics, paints, electronics, fabrics, solar cells, medicines etc. Their wide application is due to their special properties which include minute size, high reaction rate, increased surface area and quantum effect. Despite their multiple applications, nanoparticles have harmful effects too due to their improper disposal causing their entry into the aquatic environment greatly threatening the ecological security as well as our health. Zebra fishes (Danio rerio) are used more commonly for the evaluation of toxicity and are considered a promising animal model. Studies on Salmon and Labeo rohita have also been used for toxicity evaluation. Nanoparticles affect the embryo more easily than the adult since the embryo are more sensitive. Hence it becomes important for us to study the effect of the nanoparticles on the embryo of the fishes. These nanoparticles have the ability to cross the chorion layer and affect the developing embryo. Since the fishes are a part of the food chain, when these organisms get affected they will eventually harm the humans too. This review focuses on the effect of metal nanoparticles (NPs) like gold(Au), silver(Ag), copper(Cu), platinum and metal oxides nanoparticles like titanium dioxide, aluminium oxide, copper oxide, nickel oxide zinc oxide on the embryonic development of fish embryos. When compared to the other nanoparticles (NPs) like silver, copper and platinum, it has been observed that the gold nanoparticles (Au NPs) showed no toxicity to embryos of zebrafish though few studies contradict this. Aluminium nanoparticles showed no toxicity and role of reactive oxygen species (ROS) in enhancing the toxicity of nanoparticles have also been discussed.

Effects of natural organic matter on the joint toxicity and accumulation of Cu nanoparticles and ZnO nanoparticles in Daphnia magna

Various modern products have metallic nanoparticles (MNPs) embedded to enhance products performance. Technological advances enable nowadays even multiple hybrid nanoparticles. Consequently, the future co-release of multiple MNPs will inevitably result in the presence of MNP mixtures in the environment. An important question is if the responses of mixtures of MNPs can be dealt with in a similar way as with the responses of biota to mixtures of metal salts. Moreover, natural organic matter (NOM) is an important parameter affecting the behavior and effect of MNPs. Herein, we determined the joint toxicity and accumulation of copper nanoparticles (CuNPs) and zinc oxide nanoparticles (ZnONPs) in Daphnia magna in the absence and presence of Suwannee River natural organic matter (SR-NOM), compared to the joint toxicity and accumulation of corresponding metal salts. The results of toxicity testing showed that the joint toxicity of CuNPs + ZnONPs was greater than the single toxicity of CuNPs or ZnONPs. The joint toxic action of CuNPs + ZnONPs was additive or more-than-additive for D. magna. A similar pattern was found in the toxicity of the mixtures of Cu- and Zn-salts from the literature data. The presence of SR-NOM had no significant impact on the joint toxicity of CuNPs + ZnONPs. The calculated component-specific contribution to overall toxicity indicated that SR-NOM increased the relative contribution of dissolved ions released from the MNPs to the toxicity of the binary mixtures at high-effect concentrations of individual MNPs. Moreover, dissolved Zn-ions released from the ZnONPs were found to dominate the joint toxicity of CuNPs + ZnONPs in the presence of SR-NOM. Furthermore, the results of the accumulation experiment displayed that the presence of SR-NOM significantly enhanced the accumulation of either CuNPs or ZnONPs in D. magna exposed to the MNP mixtures.

Changes of Gene Expression Patterns from Aquatic Organisms Exposed to Metal Nanoparticles.

Metal nanoparticles are used in various branches of industry due to their physicochemical properties. However, with intensive use, most of the waste and by-products from industries and household items, and from weathering of products containing nanoparticles, end up in the waters. These pollutants pose a risk to aquatic organisms, one of which is a change in the expression of various genes. Most of the data that focus on metal nanoparticles and their effects on aquatic organisms are about copper and silver nanoparticles, which is due to their popularity in general industry, but information about other nanoparticulate metals can also be found. This review aims to evaluate gene expression patterns in aquatic organisms by metal nanoparticles, specifying details about the transcription changes of singular genes and, if possible, comparing the changes in the expression of the same genes in different organisms. To achieve this goal, available publications tackling this problem are studied and summarized. Nanometals were found to have a modulatory effect on gene expression in different aquatic organisms. Data show both up-regulation and down-regulation of genes. Nano silver, nano copper, and nano zinc show a regulatory effect on genes involved in inflammation and apoptosis, cell cycle regulation and ROS defense as well as in general stress response and have a negative effect on the expression of genes involved in development. Nano gold, nano titanium, nano zinc, and nano iron tend to elevate the transcripts of genes involved in response to ROS, but also pro-apoptotic genes and down-regulate DNA repair-involved genes and anti-apoptotic-involved genes. Nano selenium showed a rare effect that is protective against harmful effects of other nanoparticles, but also induced up-regulation of stress response genes. This review focuses only on the effects of metal nanoparticles on the expression of various genes of aquatic organisms from different taxonomic groups.

Optical Analysis of Hole Patterned Ag Nanoparticle Structure.

A structure with periodic sub-wavelength nanohole patterns interacts with incident light and causes extraordinary optical transmission (EOT), with metal nanoparticles leading to localized surface plasmon resonance (LSPR) phenomena. To explore the effects of metal nanoparticles (NPs), optical analysis is performed for metal NP layers with periodic hole patterns. Investigation of Ag NP arrangements and comparisons with metal film structures are presented. Ag NP structures with different hole configuration are explored. Also, the effects of increasing light incident angle are investigated for metal NP structures where EOT peak at 460 nm wavelength is observed. Moreover, electric field distributions at each transmittance peak wavelengths and optical noise are analyzed. As a result, optical characteristics of metal NP structures are obtained and differences in resonance at each wavelength are highlighted.

Effect of metal nanoparticles on microbial community shift and syntrophic metabolism during anaerobic digestion of Azolla microphylla

Supplementation of anaerobic digesters with conductive nanoparticles (NPs) is considered as a potential approach for augmenting methanogenesis, however, their impact on microbial diversity, methanogenesis routes and metabolic pathways appear to differ depending on the substrate and operational conditions. Hence, in the present study, using metagenomics and KEGG pathway analysis, an attempt was made to gain an insight into the influence of two NPs viz., Fe3O4 and Ni, on the microbial composition and metabolic pathways during anaerobic digestion (AD) of Azolla microphylla. Results showed that addition of both Fe3O4 and Ni NPs at optimal concentration significantly accelerated the substrate degradation rate (89.8%) thereby enhancing the biomethane yield by 49.1% in anaerobic reactor (M3) supplemented with NPs as compared to control (M0). The dominance of microbial species (Enterococcus sp.) belonging to Firmicutes phylum in M3 reactor, indicated an efficient hydrolysis of Azolla biomass, owing to abundance of glycoside hydrolase (GH)-coding genes in their genome. Metagenomic analysis showed the enrichment of Geobacter sp. and Methanosaeta harundinacea in NPs-amended reactor confirming syntrophic metabolism of AD intermediate products that could have resulted in enhanced hydrogenotrophic methanogenesis via DIET. Predominance of Fe (III) reducing acetoclastic methanogen Methanosarcina acetivorans in NPs-fed reactor might also have been attributed to enhanced methane production. KEGG pathway analysis also showed an enhancement of major metabolic pathways viz., Carbohydrate metabolism, Methane metabolism and Lipid metabolism, in M3 reactor which further signifies the stimulatory effect of NPs.

The Effect of Noble Metals on Co Gas Sensing Properties of In2O3 Nanoparticles

Three types of In2O3 nanoparticles decorated with Au, Pd and Pt nanoparticles, respectively, were synthesized by thermal decomposition method, and the effects of metal nanoparticles on their phase, microstructure, chemical state, carrier types were investigated with XRD, SEM/TEM, and XPS. Additionally, sensing properties to CO gas, such as sensitivity, etc., were examined with sensing apparatus. Au-decorated In2O3 nanoparticles exhibited the highest sensitivity to CO gas, with S = 5.59 at a 10 ppm CO gas concentration at 50 °C compared to Pd or Pt-decorated In2O3 nanoparticles. This can be interpreted as a much higher adsorption of oxygen molecules on the In2O3 surface due to the high oxygen vacancies in the In2O3 lattice, which generates an electron depletion region in the outer layer of In2O3 to sharply increase the resistance or the spill-over effect due to Au nanoparticles on In2O3. Au nanoparticles were observed in the TEM images and confirmed by XPS analysis.

Metal nanoparticle antibacterial effect оn antibiotic-resistant strains of bacteria

The rapid formation of microbial resistance to modern antibacterial drugs requires to search for new, alternative therapies. It is known that some organisms, such as plants, algae, fungi, are able to convert inorganic metal ions into metal nanoparticles due to the recovery process carried out by proteins, sugars and metabolites contained in the tissues and cells of these organisms. At the same time, many plants (e.g., plantain, yarrow, wormwood, turmeric long, calendula, marsh bagulnik, etc.) and metals (copper, silver, gold, zinc, etc.) themselves have antibacterial properties, so that metal nanoparticles obtained by biological method, or via “Green” synthesis method, from extracts of such plants can become a current alternative to many modern antibacterial drugs. The antibacterial mechanism of action of nanoparticles depends on the type of microorganisms affected, as well as on the type of nanoparticles, their concentration, size, and how they are obtained. Based on this, the study of the antibacterial effect of nanoparticles is one of the promising directions of solving the problem of microbial antibiotic resistance. There was examined antibacterial effect of metal nanoparticles containing silver, copper and gold obtained by biological method from the salts of AgNO3, CuSO4, H[AuCl4] metals, respectively, and the extract of the plant — turmeric long (lat. Curcuma longa) — related to the following bacteria strain collection: E. coli (ATCC 25922), S. aureus (ATCC 25923), MRSA (ATCC 38591) and polyresistant clinical strains isolated from patients of the Regional clinical hospital (Krasnoyarsk) — К. рneumoniae, strain 104, P. аeruginosa, strain 40, P. аeruginosa, strain 215, А. baumannii, strain 210, А. baumannii, strain 211. Study allowed to identify the minimum suppressive concentration of nanoparticles by the method of serial dilutions (MUK 4.2.1890-04) with azurin dye. It was proved that metal nanoparticles exhibit different antibacterial efficacy depending on the type of nanometals used and bacterial cultures. Copper nanoparticles have the highest antibacterial activity, and gold nanoparticles have the lowest. The most marked antibacterial effect was observed against clinical polyresistant strains. Metal nanoparticles can become an alternative to the currently known antibacterial drugs, but despite the high efficiency of nanoparticles against polyresistant to antibacterial drugs microorganisms in vitro, it is necessary to take into account their possible toxic effect on live tissues, which requires further study in experiments in vivo.

Enhanced light trapping in GaN thin films with Al nanoparticles for photocathode applications

In this paper, the light absorption model of GaN thin film with metal nanoparticle array is constructed based on COMSOL Multiphysics software, and the effect of metal nanoparticles on the light absorption performance of GaN thin film is studied. Compared with Au and Ag, Al nanoparticle array can enhance the absorption of ultraviolet light in GaN thin film, and the structure of Al nanoparticles deposited on the surface of GaN films has high light trapping properties. Therefore, Al nanoparticle array, as a method of improving the ultraviolet absorption performance of GaN, can provide some references for the design of ultraviolet photocathode, which will contribute to the development of high-efficient ultraviolet photocathode.

Effects of metal nanoparticles on tight junction-associated proteins via HIF-1\u03b1/miR-29b/MMPs pathway in human epidermal keratinocytes

BackgroundThe increasing use of metal nanoparticles in industry and biomedicine raises the risk for unintentional exposure. The ability of metal nanoparticles to penetrate the skin ranges from stopping at the stratum corneum to passing below the dermis and entering the systemic circulation. Despite the potential health risks associated with skin exposure to metal nanoparticles, the mechanisms underlying the toxicity of metal nanoparticles on skin keratinocytes remain unclear. In this study, we proposed that exposure of human epidermal keratinocytes (HaCaT) to metal nanoparticles, such as nickel nanoparticles, dysregulates tight-junction associated proteins by interacting with the HIF-1α/miR-29b/MMPs axis.MethodsWe performed dose-response and time-response studies in HaCaT cells to observe the effects of Nano-Ni or Nano-TiO2 on the expression and activity of MMP-2 and MMP-9, and on the expression of tight junction-associated proteins, TIMP-1, TIMP-2, miR-29b, and HIF-1α. In the dose-response studies, cells were exposed to 0, 10, or 20 μg/mL of Nano-Ni or Nano-TiO2 for 24 h. In the time-response studies, cells were exposed to 20 μg/mL of Nano-Ni for 12, 24, 48, or 72 h. After treatment, cells were collected to either assess the expression of mRNAs and miR-29b by real-time PCR or to determine the expression of tight junction-associated proteins and HIF-1α nuclear accumulation by Western blot and/or immunofluorescent staining; the conditioned media were collected to evaluate the MMP-2 and MMP-9 activities by gelatin zymography assay. To further investigate the mechanisms underlying Nano-Ni-induced dysregulation of tight junction-associated proteins, we employed a HIF-1α inhibitor, CAY10585, to perturb HIF-1α accumulation in one experiment, and transfected a miR-29b-3p mimic into the HaCaT cells before Nano-Ni exposure in another experiment. Cells and conditioned media were collected, and the expression and activities of MMPs and the expression of tight junction-associated proteins were determined as described above.ResultsExposure of HaCaT cells to Nano-Ni resulted in a dose-dependent increase in the expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 and the activities of MMP-2 and MMP-9. However, exposure of cells to Nano-TiO2 did not cause these effects. Nano-Ni caused a dose-dependent decrease in the expression of miR-29b and tight junction-associated proteins, such as ZO-1, occludin, and claudin-1, while Nano-TiO2 did not. Nano-Ni also caused a dose-dependent increase in HIF-1α nuclear accumulation. The time-response studies showed that Nano-Ni caused significantly increased expressions of MMP-2 at 24 h, MMP-9 at 12, 24, and 48 h, TIMP-1 from 24 to 72 h, and TIMP-2 from 12 to 72 h post-exposure. The expression of miR-29b and tight junction-associated proteins such as ZO-1, occludin, and claudin-1 decreased as early as 12 h post-exposure, and their levels declined gradually over time. Pretreatment of cells with a HIF-1α inhibitor, CAY10585, abolished Nano-Ni-induced miR-29b down-regulation and MMP-2/9 up-regulation. Introduction of a miR-29b-3p mimic into HaCaT cells by transfection before Nano-Ni exposure ameliorated Nano-Ni-induced increased expression and activity of MMP-2 and MMP-9 and restored Nano-Ni-induced down-regulation of tight junction-associated proteins.ConclusionOur study herein demonstrated that exposure of human epidermal keratinocytes to Nano-Ni caused increased HIF-1α nuclear accumulation and increased transcription and activity of MMP-2 and MMP-9 and down-regulation of miR-29b and tight junction-associated proteins. Nano-Ni-induced miR-29b down-regulation was through Nano-Ni-induced HIF-1α nuclear accumulation. Restoration of miR-29b level by miR-29b-3p mimic transfection abolished Nano-Ni-induced MMP-2 and MMP-9 activation and down-regulation of tight junction-associated proteins. In summary, our results demonstrated that Nano-Ni-induced dysregulation of tight junction-associated proteins in skin keratinocytes was via HIF-1α/miR-29b/MMPs pathway.

A review of the effects of metallic nanoparticles on fish

Many important discoveries have been made in the field of nanotechnology in the last 40 years. Since then, nanoparticles became nearly ubiquitous. With their spreading use, safety concerns have warranted extensive research of nanotoxicity. This paper offers information about the occurrence, transport, and behaviour of metallic nanoparticles in the aquatic environment. It further summarizes details about parameters that dictate the toxicity of nanoparticles and discusses the general/common mechanisms of their toxicity. This review also focuses on fish exposure to nanoparticles, including the possibility of trophic transport through the food chain. Information on some of the most frequently used metallic nanoparticles, such as silver, gold, and titanium dioxide, is further elaborated on.

Investigating the impact of metallic nanoparticles on performance of nanowire‐based plasmonic photodetectors

In this study, the authors have theoretically investigated the effects of metallic nanoparticles (NPs) on the performance of nanowire-based plasmonic photodetectors. For this goal, they propose a novel structure for plasmonic photodetectors in which the metallic NPs are deposited on a semiconductor nanowire sandwiched between two ohmic contacts. To calculate the eigenstates of the system, they have solved the Schrodinger equation for the nanowire in a nanostructure system with metallic NPs. Obtaining the system's eigenstates, the nanowires absorption coefficient, dielectric constant, and refractive index have been calculated. Also, the dependency of these parameters on the input wavelength has discussed. Besides, to find out the impact of metallic NPs, they have calculated the current of the system. They also have made a comparison of the system's responsivity in the simple condition (where there are no NPs effects) and the hybrid condition, in which the effects of NPs are also be considered. In fact, the effects of the NPs in the enhancement of the electrical field, and their role in the scattering of the field are the main fields of studies in this work.

Effect of metal nanoparticles in anaerobic digestion production and plant uptake from effluent fertilizer

Nanoparticle (NP) use can increase biological activity and adversely impact the environment. This study was the first to quantify biogas increases with NP mixtures during continuous anaerobic digestion (AD) of poultry litter and NP uptake in crops through tracking: 1) CH4 and H2S production from a NP mixture (Fe, Ni, and Co) in 30 L continuous digester (AD1) for 278 days compared to a control digester (AD2) without NP addition, 2) NP degradation during digestion, 3) using AD effluent with and without NP addition as a fertilizer, and 4) plant uptake of NPs. With NP inclusion, CH4 production increased by 23.7%, and H2S was reduced by 56.3%. The AD1 effluent had 1,160–19,400% higher NP concentrations and the lettuce biomass had 21.0–1,920% more NPs than lettuce fertilized with the AD2 effluent. This study showed that the effects of NPs remaining in the AD effluent must be considered.

Effects of metal nanoparticles on freshwater rotifers may persist across generations

Nanotechnology has become one of the fastest growing industries in the current century because nanomaterials (NMs) are present in an ever-expanding range of consumer products increasing the chance of their release into natural environments. In this study, the impacts of two metal nanoparticles (Ag-NPs and CuO-NPs) and their equivalent ionic forms (Ag+ and Cu2+) were assessed on the lentic freshwater rotifer Brachionus calyciflorus and on its ability to adapt and recover through generations. In our study, Ag-NPs and CuO-NPs inhibited the rotifer population growth rate and caused mortality at low concentrations (< 100 μg L−1). Ag-NPs and CuO-NPs decreased in the medium when organisms were present (48 h exposure: 51.1 % and 66.9 %, respectively), similarly Ag+ and Cu2+ also decreased from medium in presence of the organisms (48 h: 35.2 % and 47.3 %, respectively); although the metal concentrations removed from the medium were higher for nanoparticles than metal ions, metal ions showed higher effects then their respective nanoparticle forms. Rotifer populations exposed for 4 generations to the toxicants were able to recover the population growth rate, but some rotifers showed developmental delay and inability to reproduce even after the removal of the toxicants. Intracellular accumulation of reactive oxygen species as well as plasma membrane damage were found in the rotifers at concentrations corresponding to EC10 (Ag-NPs = 1.7 μg L-1, Ag+ = 4.5 μg L-1, CuO-NPs = 46.9 μg L-1, Cu2+ = 35 μg L-1) of the population growth rate. Our results showed, for the first time, that effects of metal nanoparticles and metal ions on rotifer populations may persist along several generations. This should be taken into account when assessing risks of metal nanoparticles in freshwaters.

Inhibition of Estrogenic Response of Yeast Screen Assay by Exposure to Non-Lethal Levels of Metallic Nanoparticles

In order to investigate the effects of metallic nanoparticles (NPs) on the performance of in vitro bioassay, zinc oxide NP (ZnO NP), aluminum oxide NP (Al2O3 NP), bare silver NP (Ag NP), and Ag NP capped with citrate (Agcit NP) were evaluated with yeast (Saccharomyces cerevisiae Y190) two-hybrid system (YES assay), carrying Japanese medaka estrogen receptors (mERs) in the presence of 17β-estradiol (E2, 10−6 M), a reference chemical for estrogenic activity. The distribution of NPs in the yeast was also examined by field-emission transmission electron microscopy (FE-TEM). The results show that TEM analysis revealed that NPs were present inside the yeast and accumulated deep inside the cell organelles, suggesting that cell death was caused by NPs. However, despite no significant change of mortality, the E2 estrogenic activities in yeast exposed to ZnO NP and Al2O3 NP were dose-dependently reduced. For Ag NP and Agcit NP, such phenomenon observed in the exposure of ZnO NP and Al2O3 NP did not occur. From the observations, we found that ZnO NP and Al2O3 NP in the environmental media could result in underestimated estrogenicity of endocrine-disrupting compounds when evaluated by YES assay.

Effect of metallic nanoparticles on tumor growth: In vivo study.

e15650 Background: The aim of the study was to assess the effect of metallic nanoparticles on growth of transplanted ascitic tumor sarcoma 37 in mice. Methods: Nanoparticles (NP) of transition metals were experimentally developed and kindly provided us by Prof. V.B. Borodulin. Ultradispersed metallic powders (NP Cu, NP Zn, NP Fe) 30-100 nm sized were dispersed by ultrasound in 0.85% NaCl before use and daily administrated intraperitoneally to tumor-bearing mice with ascitic sarcoma 37. Injections of NP 500 µl (10 µg/ml) were performed for 4 days, and 4 days after the completion of the course mice were sacrificed. The control group received 0.85% NaCl. Ascitic fluid volume was measured and living cells were counted. Results: In all the tumor-bearing mice the progression of ascites was noted: it was maximal in controls, less in animals having received NP Fe and NP Cu, minimal – in mice after injection of NP Zn. The volume of the latter was 0.78±0.31 ml in comparison with control data: 1.79±0.66 ml (p &lt; 0.05); it was also less than in mice after administration of NP Cu (2.16±0.68 ml) and NP Fe (3.3±1.3 ml). Similar difference was seen in the amount of tumor cells in ascitic fluid: (1.67±0.5)х106/ml after the injection of NP Zn and (27.7±2.86)х106/мл in the control group. Effect of NP Cu and NP Fe was less pronounced than of NP Zn though obvious in spite of the noted tendency of the increase of the ascitic fluid volume. The most significant changes were observed when absolute amount of living tumor cells was counted per one mouse – it was minimal after NP Zn administration (0.636±0.2)х106/ml and maximal in the control group (23.98±10.5)х106/ml), i.e. only 2.6% of tumor cells had survived after NP Zn injection. Conclusions: Our results demonstrate that metallic NP were able to produce antitumor in vivo without any supplements like laser or hyperthermia: the effect was likely to depend upon the metal and was the highest in NP Zn compared to NP Cu and Fe.

Degradation of norfloxacin with peroxymonosulfate activated by nanoconfinement Co3O4@CNT nanocomposite

In this work, the tube-filled nanocomposites Co3O4@CNTs were successfully prepared and applied for the first time in the permonosulfate (PMS) system to degrade norfloxacin (NX). Characterization results showed that Co3O4 nanoparticles served as independent templates and were randomly distributed onto the surface of the internal cavity of CNTs. After five cycles, the removal rate of NX decreased by only 4.5%, indicating its high catalytic activity and stability. This study also proposed a potential mechanism based on Co3O4@CNT/PMS system catalysis in which 1O2 was the main cause of NX degradation. DFT calculation results confirmed that the electronic activity of Co3O4 filled CNTs increased, and that the Co3O4 nanoparticles filled in the tube were the main catalytic sites of Co3O4@CNTs for NX degradation. This work provided the first insight into the effects of metal nanoparticles in the confined structure of CNTs on PMS activation.

Effect of metallic nanoparticles on amyloid fibrils and their influence to neural cell toxicity

The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases. The influence of nanoparticles on amyloid stability yields great interest due to the small size and high surface area-to-volume ratio of nanoparticles. Various physico-chemical parameters play a role in the interaction of proteins and nanoparticles in solution, thus influencing the disaggregation of preformed fibrils. We have examined the influence of two kinds of metallic nanoparticles on lysozyme amyloid fibrils using a multi-technique approach and focalized their impact on cytotoxicity on human neuroblastoma cells (SH-SY5Y). In particular, fluorescence, infrared and circular dichroism spectroscopies, optical and atomic force microscopy experiments have been carried out; the results are analyzed to rationalize the effects of these complexes on neural cell viability. It is remarkable, that the fibrils in the presence of AuNPs, unlike fibrils alone or with AgNPs, do not generate a significant cytotoxic effect even at high concentration and an amyloid degradation effect is visible.

Effect of nanoparticles on the dewetting of bismuth films

ABSTRACT We report on the effect of metallic nanoparticles on the liquid-state dewetting behaviour of bismuth films. The nanoparticles and the films were grown by thermal evaporation and subjected to annealing under ambient conditions. Dewetting was analysed by morphological studies of TEM images and by calculating the surface exposure of the films. Our results show that the addition of Ag and Au destabilizes the film, while Cu has the opposite effect. This is explained by the formation of solid solutions for Bi–Au and Bi–Ag, which lower the melting point. Cu nanoparticles stabilize the film by pinning the dewetting front. This mechanism is different from solid-state dewetting where stabilization is due to the reduction in pinhole formation at the grain and triple boundaries. This study provides insight into the role of nanoparticles on the stability of metallic films and can be extended to other low melting metallic systems.