Synthesis of iron nanoparticles via chemical reduction with palladium ion seeds

Iron-based electrode material composites for electrochemical sensor application in the environment: A review

This review explores the expanding role of electrochemical sensors across diverse domains such as environmental monitoring, medical diagnostics, and food quality assurance. In recent years, iron-based electrocatalysts have emerged as promising candidates for enhancing sensor performance. Notable for their non-toxicity, abundance, catalytic activity, and cost-effectiveness, these materials offer significant advantages. However, further investigation is needed to fully understand how iron-based materials' physical, chemical, and electrical properties influence their catalytic performance in sensor applications. It explores the overview of electrochemical sensor technology, examines the impact of iron-based materials and their characteristics on catalytic activity, and investigates various iron-based materials, their advantages, functionalization, and modification techniques. Additionally, the review investigates the application of iron-based electrode material composites in electrochemical sensors for real sample detections. Ultimately, continued research and development in this area promise to unlock new avenues for using iron-based electrode materials in sensor applications.

Biosynthesis Optimization of Antibacterial-Magnetic Iron Oxide Nanoparticles from Bacillus megaterium

The occurrence of antibiotic resistance on common bacterial agents and the need to use new generations of antibiotics have led to the use of various strategies for production. Taking inspiration from nature, using bio-imitation patterns, in addition to the low cost of production, is advantageous and highly accurate. In this research, we were able to control the temperature, shake, and synthesis time of the synthesis conditions of Bacillus megaterium bacteria as a model for the synthesis of magnetic iron nanoparticles and optimize the ratio of reducing salt to bacterial regenerating agents as well as the concentration of salt to create iron oxide nanoparticles with more favorable properties and produced with more antibacterial properties. Bacterial growth was investigated by changing the incubation times of pre-culture and overnight culture in the range of the logarithmic phase. The synthesis time, salt ratio, and concentration were optimized to achieve the size, charge, colloidal stability, and magnetic and antibacterial properties of nanoparticles. The amount of the effective substance produced by the bacteria was selected by measuring the amount of the active substance synthesized using the free radical reduction (DPPH) method. With the help of DPPH, the duration of the synthesis was determined to be one week. Characterizations such as UV-vis spectroscopy, FTIR, FESEM, X-ray, and scattering optical dynamics were performed and showed that the nanoparticles synthesized with a salt concentration of 80 mM and a bacterial suspension to salt ratio of 2:1 are smaller in size and have a light scattering index, a PDI index close to 0.1, and a greater amount of reducing salt used in the reaction during one week compared to other samples. Moreover, they had more antibacterial properties than the concentration of 100 mM. As a result, better characteristics and more antibacterial properties than common antibiotics were created on E. coli and Bacillus cereus.

Integrated approach of nano assisted biodegradation of anthracene by Pseudomonas aeruginosa and iron oxide nanoparticles

Poly aromatic hydrocarbons (PAHs) are considered as hazardous compounds which causes serious threat to the environment dua to their more carcinogenic and mutagenic impacts. In this study, Pseudomonas aeruginosa PP4 strain and synthesized iron nanoparticles were used to evaluate the biodegradation efficiency (BE %) of residual anthracene. The BE (%) of mixed degradation system (Anthracene + PP4+ FeNPs) was obtained about 67 %. The FTIR spectra result revealed the presence of functional groups (C-H, -CH3, CC, =C-H) in the residual anthracene. The FESEM and TEM techniques were used to determine the surface analysis of the synthesized FeNPs and the average size was observed by TEM around 5-50 nm. The crystalline nature of the synthesized iron nanoparticles was confirmed by the observed different respective peaks of XRD pattern. The various functional constituents (OH, C-H, amide I, CH3) were identified in the synthesized iron nanoparticles by FTIR spectrum. In conclusion, this integrated nano-bioremediation approach could be an promising and effective way for many environmental fields like cleanup of hydrocarbon rich environment.

Terminal C(sp3)-H borylation through intermolecular radical sampling

Hydrogen atom transfer (HAT) processes can overcome the strong bond dissociation energies (BDEs) of inert C(sp3)-H bonds and thereby convert feedstock alkanes into value-added fine chemicals. Nevertheless, the high reactivity of HAT reagents, coupled with the small differences among various C(sp3)-H bond strengths, renders site-selective transformations of straight-chain alkanes a great challenge. Here, we present a photocatalytic intermolecular radical sampling process for the iron-catalyzed borylation of terminal C(sp3)-H bonds in substrates with small steric hindrance, including unbranched alkanes. Mechanistic investigations have revealed that the reaction proceeds through a reversible HAT process, followed by a selective borylation of carbon radicals. A boron-sulfoxide complex may contribute to the high terminal regioselectivity observed.

Characteristics and Antimicrobial Activities of Iron Oxide Nanoparticles Obtained via Mixed-Mode Chemical/Biogenic Synthesis Using Spent Hop (Humulus lupulus L.) Extracts

Iron oxide nanoparticles (IONPs) have many practical applications, ranging from environmental protection to biomedicine. IONPs are being investigated due to their high potential for antimicrobial activity and lack of toxicity to humans. However, the biological activity of IONPs is not uniform and depends on the synthesis conditions, which affect the shape, size and surface modification. The aim of this work is to synthesise IONPs using a mixed method, i.e., chemical co-precipitation combined with biogenic surface modification, using extracts from spent hops (Humulus lupulus L.) obtained as waste product from supercritical carbon dioxide hop extraction. Different extracts (water, dimethyl sulfoxide (DMSO), 80% ethanol, acetone, water) were further evaluated for antioxidant activity based on the silver nanoparticle antioxidant capacity (SNPAC), total phenolic content (TPC) and total flavonoid content (TFC). The IONPs were characterised via UV-vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and Fourier-transform infrared (FT-IR) spectroscopy. Spent hop extracts showed a high number of flavonoid compounds. The efficiency of the solvents used for the extraction can be classified as follows: DMSO > 80% ethanol > acetone > water. FT-IR/ATR spectra revealed the involvement of flavonoids such as xanthohumol and/or isoxanthohumol, bitter acids (i.e., humulones, lupulones) and proteins in the surface modification of the IONPs. SEM images showed a granular, spherical structure of the IONPs with diameters ranging from 81.16 to 142.5 nm. Surface modification with extracts generally weakened the activity of the IONPs against the tested Gram-positive and Gram-negative bacteria and yeasts by half. Only the modification of IONPs with DMSO extract improved their antibacterial properties against Gram-positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Enterococcus faecalis, Bacillus cereus) from a MIC value of 2.5-10 mg/mL to 0.313-1.25 mg/mL.

Application of Iron Nanoparticle-Based Materials in the Food Industry

Due to their different properties compared to other materials, nanoparticles of iron and iron oxides are increasingly used in the food industry. Food technologists have especially paid attention to their ease of separation by magnetic fields and biocompatibility. Unfortunately, the consumption of increasing amounts of nanoparticles has raised concerns about their biotoxicity. Hence, knowledge about the applicability of iron nanoparticle-based materials in the food industry is needed not only among scientists, but also among all individuals who are involved in food production. The first part of this article describes typical methods of obtaining iron nanoparticles using chemical synthesis and so-called green chemistry. The second part of this article describes the use of iron nanoparticles and iron nanoparticle-based materials for active packaging, including the ability to eliminate oxygen and antimicrobial activity. Then, the possibilities of using the magnetic properties of iron nano-oxides for enzyme immobilization, food analysis, protein purification and mycotoxin and histamine removal from food are described. Other described applications of materials based on iron nanoparticles are the production of artificial enzymes, process control, food fortification and preserving food in a supercooled state. The third part of the article analyzes the biocompatibility of iron nanoparticles, their impact on the human body and the safety of their use.

Soft Bioelectronics Based on Nanomaterials

Recent advances in nanostructured materials and unconventional device designs have transformed the bioelectronics from a rigid and bulky form into a soft and ultrathin form and brought enormous advantages to the bioelectronics. For example, mechanical deformability of the soft bioelectronics and thus its conformal contact onto soft curved organs such as brain, heart, and skin have allowed researchers to measure high-quality biosignals, deliver real-time feedback treatments, and lower long-term side-effects in vivo. Here, we review various materials, fabrication methods, and device strategies for flexible and stretchable electronics, especially focusing on soft biointegrated electronics using nanomaterials and their composites. First, we summarize top-down material processing and bottom-up synthesis methods of various nanomaterials. Next, we discuss state-of-the-art technologies for intrinsically stretchable nanocomposites composed of nanostructured materials incorporated in elastomers or hydrogels. We also briefly discuss unconventional device design strategies for soft bioelectronics. Then individual device components for soft bioelectronics, such as biosensing, data storage, display, therapeutic stimulation, and power supply devices, are introduced. Afterward, representative application examples of the soft bioelectronics are described. A brief summary with a discussion on remaining challenges concludes the review.

Shape anisotropic magnetic thrombolytic actuators: synthesis and systematic behavior study

Thrombosis-related diseases are undoubtedly the deadliest disorders. During the last decades, numerous attempts were made to reduce the overall death rate and severe complications caused by treatment delays. Significant progress has been made in the development of nanostructured thrombolytics, especially magnetically controlled. The emergence of thrombolytic magnetic actuators, which can deliver tPA to the occlusion zone and perform mechanical disruption of the fibrin network under the application of a rotating magnetic field (RMF), can be considered for the next generation of thrombolytic drugs. Thus, we propose a systematic study of magnetic-field mediated mechanically-assisted thrombolysis (MFMMAT) for the first time. Four types of magnetic particles with different morphology and dimensionality were utilized to assess their impact on model clot lysis under different RMF parameters. Chain-like 1D and sea urchins-like 3D structures were found to be the most effective, increasing thrombolysis efficacy to nearly 200%. The drastic difference was also observed during the dissolution of 3 days old blood clots. Pure plasminogen activator had almost no effect on clot structure during 30 minutes of treatment while applying MFMMAT led to the significant decrease of clot area, thus uncovering the possibility of deep venous thrombosis therapy.

Green Synthesis of Transition-Metal Nanoparticles and Their Oxides: A Review

In recent years, many researchers have begun to shift their focus onto the synthesis of nanomaterials as this field possesses an immense potential that may provide incredible technological advances in the near future. The downside of conventional synthesis techniques, such as co-precipitation, sol-gel and hydrothermal methods, is that they necessitate toxic chemicals, produce harmful by-products and require a considerable amount of energy; therefore, more sustainable fabrication routes are sought-after. Biological molecules have been previously utilized as precursors for nanoparticle synthesis, thus eliminating the negative factors involved in traditional methods. In addition, transition-metal nanoparticles possess a broad scope of applications due to their multiple oxidation states and large surface areas, thereby allowing for a higher reactivity when compared to their bulk counterpart and rendering them an interesting research topic. However, this field is still relatively unknown and unpredictable as the biosynthesis of these nanostructures from fungi, bacteria and plants yield undesired diameters and morphologies, rendering them redundant compared to their chemically synthesized counterparts. Therefore, this review aims to obtain a better understanding on the plant-mediated synthesis process of the major transition-metal and transition-metal oxide nanoparticles, and how process parameters—concentration, temperature, contact time, pH level, and calcination temperature affect their unique properties such as particle size, morphologies, and crystallinity.

Synthesis of magnetic ferrogels: a tool-box approach for finely tuned magnetic- and temperature-dependent properties

Multi responsive hydrogels have many potential applications in the field of medicine as well as technical fields and are of great interest in fundamental research. Here we present the synthesis and characterization of tailored magnetic hydrogels – micro- as well as macrogels – which consist of iron oxide and cobalt ferrite, varying in phase and morphology, embedded in a thermoresponsive polymer. We introduce new ways to synthesize magnetic particles and revisit some common strategies when dealing with particle synthesis. Subsequently we discuss the details of the thermoresponsive matrix and how we can influence and manipulate the thermoresponsive properties, i.e. the lower critical solution temperature. Ultimately, we present the particle-hydrogel composite and show two exemplary applications for particle matrix interactions, i.e. heat transfer and reorientation of the particles in a magnetic field.

Influence of heating rate, temperature, pressure on the structure, and phase transition of amorphous Ni material: A molecular dynamics study

The present article is aimed to investigate influence of the heating rate, temperature (T), pressure (P) on the structure and phase transition of amorphous Ni material with heating rate 2 × 105, 2 × 106 and 2 × 107 K/s at T = 300 K; T = 300, 400, 500, 600, 700, 800, 900 and 1000 K at heating rate 2 × 106 K/s; T = 300, 621 and 900 K at P = 1, 2, 3, 4 and 5 GPa by molecular dynamics simulation method with Sutton-Chen embedded potential and periodic boundary conditions. The structure of amorphous Ni material determined through the radial distribution function, the total energy, the size and the average coordination number. The phase transition and the glass transition temperature determined through the relationship between the total energy and temperature. The result shows that when the heating rate increases, the first peak's position for the radial distribution function is 2.45 Å and a constant, the first peak's height, the total energy and the size increase, the average coordination number decreases from 13 to 12. When temperature increases from 300 to 1000 K at P = 0 GPa, the position decreases from 2.45 Å to 2.40 Å, the average coordination number is 13 and a constant, glass transition temperature is 631 K, the total energy increases, the size increases and happens the phase transition from the amorphous state to the liquid state. When pressure increases from 0 GPa to 5 GPa at T = 300, 621 and 900 K, the position decreases, the height increases, the total energy increases, the size decreases, the average coordination number decreases from 13 to 12, that shows with amorphous Ni material when increasing heating rate, T, P lead to structural change, phase transition of materials is significant.

In vivo and in vitro hair growth-promoting effect of silver and iron nanoparticles synthesized via Blumea eriantha DC plant extract

BACKGROUND

Blumea eriantha DC is the Indian medicinal remedy, mainly distributed in the States of India. It possesses wide array of medicinal properties.

AIM

To execute green synthesis approach for the preparation of silver and iron nanoparticles by using alcoholic Blumea ErianthaDC extract and to verify the biological potential of the prepared nanoparticles as a hair growth promoter.

PATIENTS/METHOD

Extract was mixed with silver nitrate and ferric chloride for synthesis of silver and iron nanoparticles, respectively. Prepared nanoparticles were confirmed by UV, FT-IR, SEM, X-ray diffraction, and TEM. The qualitative and quantitative analysis was performed namely hair growth initiation, hair growth completion, hair length, hair weight, histopathological studies, skin thickness, and length of the hair follicle.

RESULTS

The prepared nanoparticles were observed as a blend of spherical and irregular shape with an average particle size of 35nm. The transition of anagen hair follicles was observed in approximately 63.43 % of animals treated with Minoxidil, whereas 2% and 5% Blumea erianthasilver nanoparticles treated animal group exhibited 33.02% and 60.93%, respectively. The animal groups treated with 2% and 5% iron nanoparticles of Blumea Eriantha showed 44.09 and 38.89% in anagen induction, respectively, which suggest the hair growth-promoting potential of the extract of Blumea erianthaDC.

CONCLUSION

Thus, it can be concluded that silver nanoparticles of Blumea Eriantha exhibit promising hair growth promoting activity.

Nanoparticles: Synthesis, Morphophysiological Effects, and Proteomic Responses of Crop Plants

Plant cells are frequently challenged with a wide range of adverse environmental conditions that restrict plant growth and limit the productivity of agricultural crops. Rapid development of nanotechnology and unsystematic discharge of metal containing nanoparticles (NPs) into the environment pose a serious threat to the ecological receptors including plants. Engineered nanoparticles are synthesized by physical, chemical, biological, or hybrid methods. In addition, volcanic eruption, mechanical grinding of earthquake-generating faults in Earth's crust, ocean spray, and ultrafine cosmic dust are the natural source of NPs in the atmosphere. Untying the nature of plant interactions with NPs is fundamental for assessing their uptake and distribution, as well as evaluating phytotoxicity. Modern mass spectrometry-based proteomic techniques allow precise identification of low abundant proteins, protein-protein interactions, and in-depth analyses of cellular signaling networks. The present review highlights current understanding of plant responses to NPs exploiting high-throughput proteomics techniques. Synthesis of NPs, their morphophysiological effects on crops, and applications of proteomic techniques, are discussed in details to comprehend the underlying mechanism of NPs stress acclimation.

Synthesis of Fe/Ni Bimetallic Nanoparticles and Application to the Catalytic Removal of Nitrates from Water

This work investigated the effectiveness of zerovalent iron and Fe/Ni bimetallic nanoparticles in the treatment of water polluted by a high concentration of nitrates. Nanoparticle synthesis was carried out by a sodium borohydride reduction method in the presence of sodium oleate as a surfactant. The particles were characterized by XRD and SEM. Batch experiments were conducted on water samples contaminated by 300 mg L⁻¹ of nitrate. The parameters investigated were the Fe/Ni dosage (0.05, 0.1, 0.2, 0.3, and 0.4 g L⁻¹) and the reaction pH (unbuffered; buffered at pH = 3; initial pH = 3, 5, and 10). The results showed that almost complete nitrate removal (>99.8%) was always achieved after 15 min at a concentration of bimetallic nanoparticles higher than 0.2 g L⁻¹. The optimization of bimetallic nanoparticle dosage was carried out at a fixed pH. Kinetic study tests were then performed at different temperatures to assess the effect of temperature on the nitrate removal rate. By fixing the pH at acidic values and with an operating temperature of 303 K, nitrates were completely removed after 1 min of treatment.

Magnetic Properties of FeNi₃ Nanoparticle Modified Pinus radiata Wood Nanocomposites

Magnetic FeNi₃ nanoparticles were synthesized in the internal structure of wood through an in situ fabrication approach. The morphology, crystalline phase and chemical composition of the FeNi₃ modified wood was investigated by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). SEM confirmed that the magnetic nanoparticles were densely dispersed in the wood matrix. The magnetic hysteresis loops showed that the magnetism of composites is dependent on the amount of FeNi₃ loading. The saturation magnetization of magnetic wood increases from 6.3 to 10.8 emu/g with an increase of FeNi₃ loading from 12 to 18 wt %. Furthermore, magnetic wood showed significant directional dependence. The presented work will provide a feasible pathway for producing wood composite products.

Green synthesis of metal oxide nanostructures using naturally occurring compounds for energy, environmental, and bio-related applications

This review summarizes the synthesis and functional applications of metal oxide nanostructures synthesized using plant-derived phytochemicals for energy, environmental, and biomedical applications.

Development and Characterization of Gastroretentive High-Density Pellets Lodged With Zero Valent Iron Nanoparticles

The objective of the present study is to improve iron bioavailability using high-density gastroretentive pellets of zero valent iron nanoparticles (ZVINPs). ZVINPs were prepared by the chemical reduction method and were characterized for surface morphology, surface charge, and thermal properties. High-density gastroretentive pellets of iron nanoparticles were prepared using spheronization technique. Pellets were characterized for its micromeritic properties, in vitro drug release, and ex vivo permeability. The pharmacokinetic parameters, organ distribution, and toxicity of the optimized pellets were investigated in Wistar rats. In vivo results revealed more than 2-fold increases in oral bioavailability of iron by pellets compared to plane ferrous sulfate. Toxicological studies of the carriers indicated no evidence of liver damage in acute treatment; however, few complications were observed in chronic treatment groups. These results indicated that ZVINPs pellets successfully improve the oral iron bioavailability but need to obtain more information on repeated dose toxicity to initiate the clinical evaluation of investigational products.

Next-Generation Magnetic Nanocomposites: Cytotoxic and Genotoxic Effects of Coated and Uncoated Ferric Cobalt Boron (FeCoB) Nanoparticles In Vitro

Metal nanoparticles (NPs) have unique physicochemical properties and a widespread application scope depending on their composition and surface characteristics. Potential biomedical applications and the growing diversity of novel nanocomposites highlight the need for toxicological hazard assessment of next-generation magnetic nanomaterials. Our study aimed to evaluate the cytotoxic and genotoxic properties of coated and uncoated ferric cobalt boron (FeCoB) NPs (5-15 nm particle size) in cultured normal human dermal fibroblasts. Cell proliferation was assessed via ATP bioluminescence kit, and DNA breakage and chromosomal damage were measured by alkaline comet assay and micronucleus test. Polyacryl acid-coated FeCoB NPs [polyacrylic acid (PAA)-FeCoB NPs) and uncoated FeCoB NPs inhibited cell proliferation at 10 μg/ml. DNA strand breaks were significantly increased by PAA-coated FeCoB NPs, uncoated FeCoB NPs and l-cysteine-coated FeCoB NPs (Cys-FeCoB NPs), although high concentrations (10 μg/ml) of coated NPs (Cys- and PAA-FeCoB NPs) showed significantly more DNA breakage when compared to uncoated ones. Uncoated FeCoB NPs and coated NPs (PAA-FeCoB NPs) also induced the formation of micronuclei. Additionally, PAA-coated NPs and uncoated FeCoB NPs showed a negative correlation between cell proliferation and DNA strand breaks, suggesting a common pathomechanism, possibly by oxidation-induced DNA damage. We conclude that uncoated FeCoB NPs are cytotoxic and genotoxic at in vitro conditions. Surface coating of FeCoB NPs with Cys and PAA does not prevent but rather aggravates DNA damage. Further safety assessment and a well-considered choice of surface coating are needed prior to application of FeCoB nanocomposites in biomedicine.

Efficient transformation in characteristics of cations supported-reduced graphene oxide nanocomposites for the destruction of trichloroethane

Experiments were conducted to investigate the use of graphene-oxide supported metallic nanocomposites for improving the degradation of trichloroethane (TCA) by sodium percarbonate (SPC). Two methods of production, chemical reduction (CR) and solvo-thermal (ST), were tested for preparation of single (Fe) and binary (Fe-Cu) nanocomposites supported by reduced graphene oxide (rGO). A variety of analytical techniques including N2 adsorption Brunauer-Emmett-Teller (BET), x-ray diffraction (XRD), fourier-transfrom infrared spectroscopy (FTIR), and transmisison electron microscopy (TEM) were applied to characterize the physicochemical and microstructural properties of the synthesized nanocomposites. The characterization indicated that the CR method produced nanocomposites that comprised only mesoporous structure. Conversely, both micro and mesoporous structures were present for samples produced with the ST method. The synthesized single and bimetallic composites produced from the ST method showed higher surface areas, i.e. 93.6 m²/g and 119.2 m²/g as compared to the ones synthesized via the CR method, i.e. 13.8 m²/g and 38.0 m²/g respectively. The results of FTIR and XRD analyses confirmed that the ST method produced highly crystalline nanocomposites. SEM and TEM analysis validated that metallic particles with definite morphology well distributed on the surface of rGO. X-ray photoelectron spectroscopy (XPS) analysis confirmed the homogeneity nanocomposites and occurrence of variation in copper oxidation states during degradation process. EDS mapping validate the homogeneous distribution of Cu and Fe at reduced graphene oxide surface. The Fe-Cu/rGO (ST) activated SPC system effectively degraded TCA (92%) in 2.5 h at low nanocomposite dose compared to the Fe-Cu/rGO (CR) and only Fe, for which the maximum degradation efficiencies achieved were 81% and 34%. In conclusion, excellent catalytic characteristics were observed for the ST-synthesized single and bimetallic (Fe/rGO, Fe-Cu/rGO) catalysts. These catalysts were successful in improving the degradation of TCA via activated SPC.

Molecular dynamics study of microscopic structures, phase transitions and dynamic crystallization in Ni nanoparticles

Snapshot of solid Ni nano-particles with (a) 4000, (b) 5324, (c) 6912 and (d) 8799 atoms at 300 K. The atoms are coloured according to their structures: red for FCC, blue for HCP, black for BCC and yellow for amorphous.

Magnetic Fe3O4@poly(propylene fumarate-co-ethylene glycol) core–shell biomaterials

MagP®-NH₂/(P(PF-co-EG)) core–shell biocomposites show antibacterial activity and magnetic-field tunable mechanical properties, hence they could be used as scaffolds for soft-tissue replacement.

Calix-Based Nanoparticles: A Review

Calixarenes are considered as third generation supramolecules with hollow cavity-like architecture whereas nanoparticles are small entities with dimensions in the nanoscale. Many exciting achievements are seen when the calix system merges with nanoparticles which produces many fascinating facets in all fields of contemporary chemistry. The properties of nanoparticles which are tuned by calixarenes find applications in sensing, catalysis, molecular recognition, etc. Here, we have reviewed the chemistry of calix-based nanoparticles, and emphasis is laid on the modified, reducing, templated and stabilizing roles of calixarenes. This review covers the research being carried out in the domain of calix protected metal nanoparticles during last 18 years under the canopy of important 109 references. This article contains 58 figures which include 81 easy to understand structures. Calix-protected nanoparticles have enthralled researchers in the field of nanoscience with a tremendous growth in its applications, which heralds much promise to become in future a separate area of research.

The convenient preparation of stable aryl-coated zerovalent iron nanoparticles

A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs) based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs) were prepared by simple chemical reduction of iron(III) chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material.

Electrically conductive magnetic nanowires using an electrochemical DNA-templating route

The fabrication of electrically conducting magnetic nanowires has been achieved using electrochemical DNA-templating of iron. In this approach, binding of the Fe(2+) cations to the DNA "template" molecules has been utilised to promote growth along the molecular axis. Formation of Fe within the product material was verified by XRD and XPS studies, which confirmed an iron/oxide "core-shell" structure. The effectiveness of the DNA duplex to direct the metal growth in one dimension was highlighted by AFM which reveals the product material to comprise high aspect ratio nanostructured architectures. These "nanowires" were observed to have morphologies consisting of densely packed linear arrangements of metal particles along the template, with wire diameters up to 26 nm. The structures were confirmed to be electrically conductive, as expected for such Fe-based materials, and to display superparamagnetic behaviour, consistent with the small size and particulate nature of the nanowires.

Rod-Shaped Magnetite Nano/Microparticles Synthesis at Ambient Temperature

Here, we reported room temperature synthesis of Fe3O4rod-shaped nano/microparticles by chemical reduction method from FeCl3precursor and NaBH4as the reducing agent in the presence of the pyrrole as a capping agent. The magnetic Fe3O4particles were characterized by several methods, such as SEM, XRD, FTIR, and TGA. The average aspect ratio of Fe3O4rod-shaped particles was ~2.8. These particles were redispersed in deionised water to form a colloidal solution and showed magnetic properties. This economical synthesis route is scalable, and Fe3O4particles can be exploited for various applications such as MRI contrast enhancement, biodiseperations, Ni-Fe batteries, and as a catalyst.

Single crystal iron nanocube synthesis via the surface energy driven growth method

Single crystal iron nanocubes are produced by simply heating a bilayer film. This surface energy driven growth (SEDG) method exploits the difference in surface energies of the components (γ(Fe) ~ 2.2 J m(-2) versus γ(Nd) ~ 0.7 J m(-2)) in the binary alloy Fe-Nd system to produce nanocubes of the higher energy Fe component. The dimensions of the cubes range from tens to hundreds of nanometers in size and can be controlled by changing the initial thickness of iron in the deposited Fe-Nd bilayer prior to annealing at 700 °C. The composition and structure of the nanocubes was confirmed by transmission electron microscopy analysis as single crystal bcc iron in the α-phase. The cubes were found to exist as core-shell structures with the α-phase encased by an intermetallic Fe-Nd phase, characteristic of the SEDG growth mechanism.

Effect of Lithium Ions on Copper Nanoparticle Size, Shape, and Distribution

Copper nanoparticles were synthesized using lithium ions to increase the aqueous electrical conductivity of the solution and precisely control the size, shape, and size distribution of the particles. In this study, the conventional approach of increasing particle size by the concentration of copper ions and PGPPE in a copper chloride solution was compared to increasing the concentration of lithium chloride when the copper chloride concentration was held constant. Particle size and shape were characterized by TEM, and the size distribution of the particles at different concentrations was obtained by particle size analysis. Increasing the concentration of copper ion in the solution greatly increased the aqueous electric conductivity and the size of the particles but led to a wide size distribution ranging from 150 nm to 400 nm and rough particle morphology. The addition of lithium ions increased the size of the particles, but maintains them in a range of 250 nm. In addition the particles exhibited spherical shape as determined by TEM. The addition of lithium ions to the solution has the potential to synthesize nanoparticles with optimal characteristics for printing applications by maintaining a narrow size range and spherical shape.

Impact of Fe and Ag nanoparticles on seed germination and differences in bioavailability during exposure in aqueous suspension and soil

The potential environmental toxicity of zero-valent iron nanoparticles (nZVI) and three types of nanosilver differing in average particle size from 1 to 20 nm was evaluated using seed germination tests with ryegrass, barley, and flax exposed to 0-5000 mg L(-1) nZVI or 0-100 mg L(-1) Ag. For nZVI, germination tests were conducted both in water and in two contrasting soils to test the impact of assumed differences in bioavailability of nanoparticles. Inhibitory effects were observed in aqueous suspensions at 250 mg L(-1) for nZVI and 10 mg L(-1) for Ag. Reduction in shoot growth was a more sensitive endpoint than germination percentage. Complete inhibition of germination was observed at 1000-2000 mg L(-1) for nZVI. For Ag, complete inhibition was not achieved. The presence of soil had a modest influence on toxicity, and inhibitory effects were observed at 300 mg nZVI L(-1) water in soil (equivalent to 1000 mg nZVI kg(-1) soil). Complete inhibition was observed at 750 and 1500 mg L(-1) in sandy soil for flax and ryegrass, respectively, while for barley 13% germination still occurred at 1500 mg L(-1) . In clay soil, inhibition was less pronounced. Our results indicate that nZVI at low concentrations can be used without detrimental effects on plants and thus be suitable for combined remediation where plants are involved. Silver nanoparticles inhibited seed germination at lower concentrations, but showed no clear size-dependent effects, and never completely impeded germination. Thus, seed germination tests seem less suited for estimation of environmental impact of

Metal nanoparticles in liquid phase catalysis; from recent advances to future goals

Metal nanoparticles have attracted much attention over the last decade owing to their unique properties, different to their bulk counterparts, which pave the way for their application in different fields from materials science and engineering to biomedical applications. Of particular interest, the use of metal nanoparticles in catalysis has brought superior efficiency in terms of activity, selectivity and lifetime to heterogeneous catalysis. This article reviews the recent developments in the synthesis routes and the catalytic performance of metal nanoparticles depending on the solvent used for various organic and inorganic transformations. Additionally, we also discuss the prevalent complications and their possible solutions plus future prospects in the field of nanocatalysis.

Hierarchical superparamagnetic magnetite nanowafers from a resin-bound [Fe(bpy)3]2+ matrix

The brilliant red [Fe(bpy)(3)](2+) complex upon immobilization on a strongly acidic cation exchanger or in situ formation of the same cationic complex onto a resin matrix and subsequent modified hydrothermolysis (MHT) at approximately 110 degrees C produces unusually stable hierarchical magnetite (Fe(3)O(4)) nanowafers. The slow hydrothermolysis, oxidation, and subsequent dehydration of the complex on the solid-liquid interface produce stable hierarchical nanostructures. The isolation of neat Fe(3)O(4) (uncapped) particles from the resin matrix as hierarchical nanowafers was achieved by magnetically stirring a CH(3)CN suspension of nanocomposites. The solid resin support not only aids nanowafer formation on its surface but also provides unique stability to the magnetite particles, where nanowafer oxidation is largely retarded. The utility of the as-prepared porous nanocomposite and characterization of the nanoparticles are promising for nanotechnological and soft ferromagnetic applications.

Characteristics of two types of stabilized nano zero-valent iron and transport in porous media

Nano-scale zero-valent iron (NZVI) has been shown to be suitable for remediating contaminated aquifers. However, they usually aggregate rapidly and result in a very limited migration distance that inhibits their usefulness. This study employed poly acrylic acid (PAA) and carboxymethyl cellulose (CMC) to synthesize two types of stabilized styles of NZVI with finer sizes (namely PNZVI and CNZVI). The mobility of stabilized NZVI was also demonstrated on the basis of transport in porous media. The results show that the PNZVI has a uniform particle size of 12 nm. However, tens of CNZVI particles with diameters of 1-3 nm were packed into secondary particles. Both the PNZVI and the CNZVI exhibited amorphous structures, and the stabilizer was bound to particle surfaces in the form of bidentate bridging via the carboxylic group, which could provide both electrostatic and steric repulsion to prevent particle aggregation. This study also proposes presumed stabilized configurations of PNZVI and CNZVI to reasonably illustrate their different dispersed suspension types. On the basis of the breakthrough curves and mass recovery, this study observed that the mobility of PNZVI in classic Ca(2+) concentration of groundwater was superior to CNZVI. Nonetheless, the mobility of CNZVI would be decreased less significantly than PNZVI when encountering high Ca(2+) concentrations (40 mM). Presumably, increasing the pore flow velocity would enhance the mobility of stabilized NZVI. Overall, the results of this study indicate that PNZVI has the potential to become an effective reactive material for in situ groundwater remediation.