Effect Of Metal Nanoparticles Research Articles

Effect of Metal Nanoparticles in the Field Emission of Silicon Nanowires

In this work, an efficient method is reported for creating a metal nanoparticle (silver) / Si composite structure consisting of a vertical array of silicon nanowires (SiNWs) decorated with silver metal nanoparticles. A two-stage metal-assisted etching method is employed to obtain SiNWs and Silver (Ag) metal nanoparticles are decorated on the SiNWs using the electroless deposition method. It allows the good coverage of silver metal nanoparticles over SiNWs. Scanning Electron Microscopy (SEM) analysis revealed that Ag was covered with SiNWs. High-work function metal nanoparticles such as Ag nanoparticles on SiNWs have been utilized in different applications such as photovoltaics and sensors. The size of SiNWs is determined through the Raman shift. The silicon optical phonon peak showed an increase in redshift and a decrease of full-width at half maxima with a decrease in diameter due to the quantum confinement. The Electron Field Emission (EFE) characteristics of the Agdecorated SiNW films were studied based on the current-voltage measurements and analyzed using the Fowler-Nordheim (F-N) equation. The low turn-on field is obtained through the Ag metal nanoparticles which have wider applications in lowpower operational devices.

Effect of Metal Nanoparticles on Photosynthetic and Antioxidant Enzyme Activities of Soybean

This study presents the effects of nanoscale zerovalent cobalt (NZVC) on the photosynthetic activity and expression of genes related to the photosynthetic apparatus as well as the activity of antioxidant enzymes in soybean (Glycine max L. Merr). Treatment of soybean seeds with NZVC solution (at concentrations of 0.17; 0.33 and 100 mg/kg seed) has increased the efficiency of light energy absorbed by photosystem II, improved photosynthetic efficiency, and maintained the function of photosynthetic apparatus when plant growth is reduced by enhancing the value of photosynthetic parameters (Fo, Fm, Fv/Fm, ETR, FPSII) compared with the control. The expression of genes involved in photosynthesis in soybean leaves was changed by growth time and NZVC treatment concentration. The psaA, Lhca, psbA, and psbB genes had increased expression levels at 17 and 32 days after sowing, then decreased at 70 days after sowing. The expression of the psbE, and Cyt b6f genes was greater than the control during the growth period. Treatment of soybean seeds with high concentrations of NZVC (0.33 and 100 mg/kg seed) did not negatively affect the photosynthetic function of soybean plants. The activity of nitrate and nitrite reductases and antioxidant enzymes including superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase of cobalt-treated plants were better than those of the control. This is a defense mechanism of plants to minimize the harmful effects of these stresses. This result has elucidated the mechanism of increasing the yield of soybean when its seeds were treated with NZVC.

Plastic response of macrophages to metal ions and nanoparticles in time mimicking metal implant body environment.

The paradigm of using metal biomaterials could be viewed from two sides - treatment of wide spectrum of degenerative diseases, and debris release from materials. After implant insertion, metal nanoparticles (NPs) and ions are released not only upon the first contact with cells/tissues, but in continual manner, which is immediately recognized by immune cells. In this work, the effects of metal nanoparticles (TiO2, Ni) and ions (Ni2+, Co2+, Cr3+, Mo6+) on primary human M0 macrophages from the blood samples of osteoarthritic patients undergoing total arthroplasty were studied in order to monitor immunomodulatory effects on the cells in a real-time format. Thehighest NiNPs concentration of 10µg/ml had no effect on any of macrophage parameters, while the Ni2+ ions cytotoxicity limit for the cells is 0.5mM. The cytotoxic effects of higher Ni2+ concentration revealed mitochondrial network fragmentation leading to mitochondrial dysfunction, accompanied by increased lysosomal activity and changes in pro-apoptotic markers. The suppression of M2 cell formation ability was connected to presence of Ni2+ ions (0.5mM) and TiO2NPs (10µg/ml). The immunomodulatory effect of Mo6+ ions, controversially, inhibit the formation of the cells with M1 phenotype and potentiate the thread-like shape M2s with increased chaotic cell movement. To summarize, metal toxicity depends on the debris form. Both, metal ions and nanoparticles affect macrophage size, morphological and functional parameters, but the effect of ions is more complex and likely more harmful, which has potential impact on healing and determines post-implantation reactions.

Effect of Metal Nanoparticles on Phosphate Removal from Aqueous Solutions: A review

Effect of Metal Nanoparticles on Phosphate Removal from Aqueous Solutions: A review

Copper and Zinc Particles as Regulators of Cardiovascular System Function-A Review.

Copper and zinc are micronutrients that play a crucial role in many cellular pathways, act as cofactors in enzymatic systems, and hence, modulate enzyme activity. The regulation of these elements in homeostasis is precisely controlled by various mechanisms. Superoxide dismutase (SOD) is an enzyme requiring both copper and zinc for proper functioning. Additionally, there is an interaction between the concentrations of copper and zinc. Dietary ingestion of large amounts of zinc augments intestinal absorption of this trace element, resulting in copper deficiency secondary to zinc excess. The presence of an overabundance of copper and zinc has a detrimental impact on the cardiovascular system; however, the impact on vascular contractility varies. Copper plays a role in the modulation of vascular remodeling in the cardiac tissue, and the phenomenon of cuproptosis has been linked to the pathogenesis of coronary artery disease. The presence of copper has an observable effect on the vasorelaxation mediated by nitric oxide. The maintenance of proper levels of zinc within an organism influences SOD and is essential in the pathogenesis of myocardial ischemia/reperfusion injury. Recently, the effects of metal nanoparticles have been investigated due to their unique characteristics. On the other hand, dietary introduction of metal nanoparticles may result in vascular dysfunction, oxidative stress, and cellular DNA damage. Copper and zinc intake affect cardiovascular function, but more research is needed.

Effect of Metallic Nanoparticles and Ions on Seeds Germinating Under Cadmium Stress

Effect of Metallic Nanoparticles and Ions on Seeds Germinating Under Cadmium Stress

Ag NPs and MoS2 QDs double modified graphene/GaAs near-infrared photodetector

The light absorption enhancement ability of quantum dots (QDs) and the localized surface plasmon resonance (LSPR) effect of metal nanoparticles (NPs) can effectively improve the performance of photodetectors. In this paper, an Ag NPs and MoS2 QDs double modified graphene/GaAs near-infrared photodetector is investigated. The performance of the detector is improved by adopting the LSPR effect of Ag NPs and the dielectric confinement effect of MoS2 QDs. After subsequent testing and analysis, the photodetector responsivity is 21.1 mA W−1 and the detectivity is 8.4 × 1012 cm Hz1/2 W−1 at 808 nm wavelength; the responsivity and detectivity at 1064 nm wavelength can be up to 18.4 mA W−1 and 3.39 × 1012 cm Hz1/2 W−1, respectively. At the same time, under a 4 kHz pulsed illumination, the rise time and fall time are 15.87 μs and 89.95 μs respectively. Compared with previous devices, the new device has lower dark current and higher detectivity while having good responsivity and response time.

Determining the common patterns of the action of nanoparticles of various compositions and structures on physiological and biochemical processes in plants

Technogenic and natural nanomaterials are alien to living systems. The negative effect of nanomaterials may be due to their accumulation in intracellular organelles. The properties of nanoparticles are determined not only by their size, which manifests itself in the activation of a thermodynamic variable, but also by their chemical structure and shape, their ability to aggregate. The effect of metal nanoparticles and oxides of cobalt and titanium on the development and growth of plants has been studied. An important established fact is the ability of oxide nanoparticles, unlike metals themselves, to accumulate in living systems. Transmission electron microscopy, carried out by means of electron microscopic analysis, has revealed interstitial bioaccumulation of nanoparticles of cobalt oxide and titanium oxide in the form of aggregates 80-300 nm in size. If nanoparticles quickly aggregate, they are less dangerous for organisms than single nanoparticles, since a large aggregate of nanoparticles cannot get inside the cell. The rate and dynamics of deposition of nanoparticles of metals and their oxides in water are different. Metal NPs are deposited much more slowly than titanium dioxide. Moreover, the safety of NPs depends on their size and concentration. Biogenic nanoparticles with a size of 35-75 nm have high biological activity, biocompatibility and environmental safety. There is a direct correlation between the energy produced in cells, which is necessary for seed viability, and an increase in the number of protons under the action of metal nanoparticles, which leads to an increase in the permeability of cell membranes and the activity of enzymes and phytohormones.

Label-Free and Bioluminescence-Based Nano-Biosensor for ATP Detection.

A bioluminescence-based assay for ATP can measure cell viability. Higher ATP concentration indicates a higher number of living cells. Thus, it is necessary to design an ATP sensor that is low-cost and easy to use. Gold nanoparticles provide excellent biocompatibility for enzyme immobilization. We investigated the effect of luciferase proximity with citrate-coated gold, silver, and gold-silver core-shell nanoparticles, gold nanorods, and BSA-Au nanoclusters. The effect of metal nanoparticles on the activity of luciferases was recorded by the luminescence assay, which was 3-5 times higher than free enzyme. The results showed that the signal stability in presence of nanoparticles improved and was reliable up to 6 h for analytes measurements. It has been suggested that energy is mutually transferred from luciferase bioluminescence spectra to metal nanoparticle surface plasmons. In addition, we herein report the 27-base DNA aptamer for adenosine-5'-triphosphate (ATP) as a suitable probe for the ATP biosensor based on firefly luciferase activity and AuNPs. Due to ATP application in the firefly luciferase reaction, the increase in luciferase activity and improved detection limits may indicate more stability or accessibility of ATP in the presence of nanoparticles. The bioluminescence intensity increased with the ATP concentration up to 600 µM with a detection limit of 5 µM for ATP.

Unveiling facet effects in metallic nanoparticles to design an efficient plasmonic nanostructure

We investigated the role of nanoparticle surface morphology (facets) in estimating the plasmonic properties of nanoparticle-on-a-mirror design or NPOM in the presence of a thicker (20 nm) dielectric layer. Nanoparticle surface morphology differences ranging from smoother surface to multi-facets in the form of a sphere (NSOM), cube (NCOM), and singe bottom faceted sphere (SBF-NSOM) shapes have been employed. Three significant optical properties were observed. Better longer wavelength near-field and far-field resonance spectral positions from NCOM are achieved. Near-field enhancement extracted from SBF-NSOM outperformed NCOM by more than ∼ two times. Plasmonic gap mode enhancement is absent for NSOM in the presence of a larger dielectric layer. The availability of plasmonic gap modes in NCOM and SBF-NSOM, even at a 20 nm thick dielectric layer, is highly beneficial for various plasmonic applications. These differences in optical properties are understood by the role of NP facets in influencing the plasmonic cavity region.

Oxidative stress in tumor-bearing animals and self-dependent antitumor effect of metal nanoparticles.

e15055 Background: Enhanced generation of reactive oxygen species (ROS) is an important factor in cell damage when exposed to metal nanoparticles (NPs), which can be used to develop antitumor strategies based on ROS level modulation. However, an increase in ROS can cause oxidative stress in the body. The aim of this study was to evaluate the parameters of the redox-regulating system in the blood erythrocytes of tumor-bearing rats at different efficiencies of exposure to copper NPs (CuNPs) and iron NPs (FeNPs). Methods: Outbred male rats with transplantable fusiform cell fibrosarcoma (S45) were treated with copper (group S45+CuNPs, n = 37) or iron NPs (group S45+FeNPs, n = 33). During 15 days, 35 rats received 8 intratumoral injections and 35 rats received 8 intraperitoneal injections of NPs in total doses of 10 mg/kg bw, the control S45 rats (n = 20) received saline i.p. Levels of malondialdehyde (MDA) and glutathione (GSH), the activities of catalase (CA), superoxide dismutase (SOD), and glutathione peroxidase (GPO) in the red blood cells were determined one week after the end of the treatment. Results: Complete or near complete tumor regression was recorded in 13 (35 %) rats with CuNPs treatment and 6 (27%) rats with FeNPs treatment. Decrease in tumor size by 30 to 80% in 14 (38%) rats in CuNPs group and in 14 (43%) rats in FeNPs group was observed. In other cases, tumor growth in rats with S45 treated with metal nanoparticles was similar to animals in the control group. The values of the studied parameters in rats with complete tumor regression after exposure to CuNPs did not differ from those in the group of healthy rats. Unidirectional changes in the studied parameters were observed in rats with partial S45 regression or with no effect. GPO activity increased by 43-57% (p = 0.02-0.002) and GSH level by 20-27% (p = 0.034-0.005), but MDA level was 62-65% (p = 0.027-0.007) higher than normal values. Animals with complete tumor regression after the administration of FeNPs showed changes in the activity of peroxide-inactivating enzymes: an increase in GPO by 84% (p = 0.009) and a decrease in catalase by 31% (p = 0.016) relative to normal values. In animals with partial response or without response, GPO activity increased by 75% and 57%, respectively (p = 0.031-0.042), while CA activity decreased by an average of 37% (p = 0.002-0.0002). No increase in MDA was observed in the S45+FeNPs group. The levels of MDA in rats of the control group were increased by 46% (p = 0.0032), which was combined with an increase in GSH by 19%, a decrease in catalase activity by 16%, and an increase in GPO activity by 41% (p˂0.05 in all cases), compared to the values in intact animals. Conclusions: Regardless of the route of administration, copper and iron NPs did not cause an increase in oxidative stress in rats with fibrosarcoma. The maximum antitumor effect of metal NPs was accompanied by normalization or positive reorganization of the redox-regulating system of erythrocytes.

Overview of the Influence of Silver, Gold, and Titanium Nanoparticles on the Physical Properties of PEDOT:PSS-Coated Cotton Fabrics.

Metallic nanoparticles have been of interest to scientists, and they are now widely used in biomedical and engineering applications. The importance, categorization, and characterization of silver nanoparticles, gold nanoparticles, and titanium nanoparticles have been discussed. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is the most practical and reliable conductive polymer used in the manufacturing of conductive textiles. The effects of metallic nanoparticles on the performance of PEDOT:PSS thin films are discussed. The results indicated that the properties of PEDOT:PSS significantly depended on the synthesis technique, doping, post-treatment, and composite material. Further, electronic textiles known as smart textiles have recently gained popularity, and they offer a wide range of applications. This review provides an overview of the effects of nanoparticles on the physical properties of PEDOT:PSS-coated cotton fabrics.

Effect of metallic nanoparticles on microalgal growth and lipid accumulation for biodiesel production

Effect of metallic nanoparticles on microalgal growth and lipid accumulation for biodiesel production

Effects of Metal Nanoparticles and Other Preparative Materials in the Environment on Plants: From the Perspective of Improving Secondary Metabolites.

The influence of preparation material residues in wastewater and soil on plants has been paid more and more attention by researchers. Secondary metabolites play an important role in the application of plants. It was found that nanomaterials can increase the content of plant secondary metabolites in addition to their role in pharmaceutical preparations. For example, 800 mg/kg copper oxide nanoparticles (NPs) increased the content of p-coumaric acid in cucumber by 225 times. Nanoparticles can cause oxidative stress in plants, increase signal molecule, and upregulate the synthase gene expression, increasing the content of secondary metabolites. The increase of components such as polyphenols and total flavonoids may be related to oxidative stress. This paper reviews the application and mechanism of metal nanomaterials (Ag-NP, ZnO-NP, CeO2-NP, Cds-NP, Mn-NP, CuO-NP) in promoting the synthesis of secondary metabolites from plants. In addition, the effects of some other preparative materials (cyclodextrins and immobilized molds) on plant secondary metabolites are also involved. Finally, possible future research is discussed.

Interface modulation and physical properties of heterostructure of metal nanoparticles and two-dimensional materials

<sec>Two-dimensional (2D) material has atomic smooth surface, nano-scale thickness and ultra-high specific surface area, which is an important platform for studying the interface interaction between metal nanoparticles (NPs) and 2D materials, and also for observing the surface atomic migration, structural evolution and aggregation of metal NPs in real time and <i>in situ</i>. By rationally designing and constructing the interfaces of metal NPs and 2D materials, the characterization of the interface structure on an atomic scale is very important in revealing the structure-property relationship. It is expected that the investigation is helpful in understanding the mechanism of interaction between metal and 2D materials and optimizing the performance of the devices based on metal-2D material heterojunctions.</sec><sec>In this review, the recent progress of interface modulation and physical properties of the heterostructure of metal NPs and 2D materials are summarized. The nucleation, growth, structural evolution and characterization of metal NPs on the surface of 2D materials are reviewed. The effects of metal NPs on the crystal structure, electronic state and energy band of 2D materials are analyzed. The possible interfacial strain and interfacial reaction are also included. Because of the modulation of electrical and optical properties of 2D materials, the performance of metal NPs-2D material based field effect transistor devices and optoelectronic devices are improved. This review is helpful in clarifying the physical mechanism of microstructure affecting the properties of metal NPs-2D material heterostructures on an atomic scale, and also in developing the metal-2D material heterostructures and their applications in the fields of electronic devices, photoelectric devices, energy devices, etc.</sec>

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.