Metal-based Nanomaterials Research Articles

Harnessing the Synergistic Interplay between Atomic-Scale Vacancies and Ligand Effect to Optimize the Oxygen Reduction Activity and Tolerance Performance.

Defect engineering is an effective strategy for regulating the electrocatalysis of nanomaterials, yet it is seldom considered for modulating Pt-based electrocatalysts for the oxygen reduction reaction (ORR). In this study, we designed Ni-doped vacancy-rich Pt nanoparticles anchored on nitrogen-doped graphene (Vac-NiPt NPs/NG) with a low Pt loading of 3.5 wt . % and a Ni/Pt ratio of 0.038 : 1. Physical characterizations confirmed the presence of abundant atomic-scale vacancies in the Pt NPs induces long-range lattice distortions, and the Ni dopant generates a ligand effect resulting in electronic transfer from Ni to Pt. Experimental results and theoretical calculations indicated that atomic-scale vacancies mainly contributed the tolerance performances towards CO and CH3OH, the ligand effect derived from a tiny of Ni dopant accelerated the transformation from *O to *OH species, thereby improved the ORR activity without compromising the tolerance capabilities. Benefiting from the synergistic interplay between atomic-scale vacancies and ligand effect, as-prepared Vac-NiPt NPs/NG exhibited improved ORR activity, sufficient tolerance capabilities, and excellent durability. This study offers a new avenue for modulating the electrocatalytic activity of metal-based nanomaterials.

Identifying the dynamic behaviors in complete reconstruction of Co-based complex precatalysts during electrocatalytic oxygen evolution

Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction (OER). Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under operating conditions of OER process. However, most of them undergo incomplete reconstruction with limited thickness of reconstruction layer, leading to low component utilization and arduous exploration of real catalytic mechanism. Herein, we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER. The hollow phytic acid (PA) cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability, in favor of the fast and complete reconstruction. A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH− to form Co(Fe)(OH)x and subsequent potential-driven oxidation to Co(Fe)OOH. The obtained CoFeOOH delivers a low overpotential of 290 mV at a current density of 10 mA cm−2 and a long-term stability. The experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure, accounting for the enhanced OER activity. The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.

Unveiling influences of metal-based nanomaterials on wheat growth and physiology: From benefits to detriments

Metal-based nanomaterials (MNs) are widely used in agricultural production. However, our current understanding of the overall effects of MNs on crop health is insufficient. A global meta-analysis of 144 studies involving approximately 2000 paired observations was conducted to explore the impacts of MNs on wheat growth and physiology. Our analysis revealed that the MN type plays a key role in influencing wheat growth. Ag MNs had significant negative effects on wheat growth and physiology, whereas Fe, Ti, and Zn MNs significantly increased wheat biomass and photosynthesis. Our study also observed a clear dose-specific effect, with a decrease in wheat shoot biomass with increasing MN concentrations. Meanwhile, MNs with small sizes (<25 nm) have no significant impacts on wheat growth. Furthermore, both the root and foliar applications significantly improved wheat growth, with no considerable differences. Using a machine learning approach, we found that the MN type was the main driving factor affecting wheat shoot biomass, followed by MN dose and size. Overall, wheat growth and physiology can be negatively influenced by specific MNs, for which a high dose and small size should be avoided in practical applications. Therefore, our study can provide insights into the future design and safe use of MNs in agriculture and increase the public acceptance of nano-agriculture.

Review on polyaniline-based nanocomposite heterogeneous catalysts for catalytic reduction of hazardous water pollutants.

Water contamination by highly toxic substances has generated serious ecological disturbances and health problems for humans. Hence, decontamination of toxic pollutants using advanced, inexpensive, and eco-friendly approaches is the current demand. Heterogeneous catalyst-based catalytic reduction processes have offered the opportunity to transform hazardous water pollutants into non-hazardous products via sustainable, eco-friendly, and efficient routes and might be a competitive substitute for existing traditional water purification techniques. However, the key challenges linked with pure heterogeneous catalysts include agglomeration and poor dispersion, stability, recovery, and reusability, which result in poor activity and efficiency. Thus, it is essential to produce multipurpose polymer-based composite catalysts using conducting polymers, which are exceptionally good supportive and matrix materials. The blending of metal-based nanomaterials with polyaniline conducting polymers produces highly stable and efficient heterogeneous nanocomposite catalysts with amazing catalytic activity against a wide range of water pollutants. The heterogeneous catalytic reductive degradation of immensely toxic pollutant water has gained substantial curiosity because of its excellent physicochemical and surface characteristics, porous structure, recoverability, and recyclability. Therefore, this review presents the latest efforts to generate various polyaniline-based nanocomposite catalysts using a polyaniline matrix and various nanofiller materials and their potential applications in heterogeneous catalytic reduction degradation of water pollutants.

Applications of Metals and Metal Compounds in Improving the Sensitivity of Microfluidic Biosensors - A Review.

The enhancement of detection sensitivity in microfluidic sensors has been a continuously explored field. Initially, many strategies for sensitivity improvement involved introducing enzyme cascade reactions, but enzyme-based reactions posed challenges in terms of cost, stability, and storage. Therefore, there is an urgent need to explore enzyme-free cascade amplification methods, which are crucial for expanding the application range and improving detection stability. Metal or metal compound nanomaterials have gained great attention in the exploitation of microfluidic sensors due to their ease of preparation, storage, and lower cost. The unique physical properties of metallic nanomaterials, including surface plasmon resonance, surface-enhanced Raman scattering, metal-enhanced fluorescence, and surface-enhanced infrared absorption, contribute significantly to enhancing detection capabilities. The metal-based catalytic nanomaterials, exemplified by Fe3O4 nanoparticles and metal-organic frameworks, are considered viable alternatives to biological enzymes due to their excellent performance. Herein, we provide a detailed overview of the applications of metals and metal compounds in improving the sensitivity of microfluidic biosensors. This review not only highlights the current developments but also critically analyzes the challenges encountered in this field. Furthermore, it outlines potential directions for future research, contributing to the ongoing development of microfluidic biosensors with improved detection sensitivity.

Occupational Exposure to Metal-Based Nanomaterials: A Possible Relationship between Chemical Composition and Oxidative Stress Biomarkers.

Nanomaterials (NMs) are in high demand for a wide range of practical applications; however, comprehensively understanding the toxicity of these materials is a complex challenge, due to the limited availability of epidemiological evidence on the human health effects arising from workplace exposures. The aim of this work is to assess whether and how urinary metal concentrations could be reliable and useful in NM biomonitoring. In the framework of "NanoExplore Project" [EU LIFE17 Grant ENV/GR/000285], 43 not-exposed subjects and 40 exposed workers were recruited to measure exposure to NMs (PCN and LDSA) in the proximity of the workstations and biological biomarkers (urinary metal concentrations-Aluminum (Al), Silica (Si), Titanium (Ti), and Chromium (Cr); urinary OS biomarkers-TAP, Isop, and MDA). The results showed that Si and Ti were directly associated with NM exposure (both PCN and LDSA), as well as with OS biomarkers, especially in exposed workers. Moreover, the mediation analyses showed that Si could account for about 2.8% in the relationship between LDSA and OS biomarkers, possibly by decreasing OS antioxidant defenses in exposed people. In conclusion, our study provides evidence that occupational exposure to mixtures containing NMs can represent an underestimated hazard for exposed people, increasing the body burden and the oxidative balance.

Physical methods for preparation of nanomaterials, their characterization and applications: a review

AbstractNanotechnology refers to nanomaterials of different dimensions, ranging in size from 1 to 100 nm. Shape and size, as well as properties of nanomaterials, depend on the materials based on their production. Nanomaterials are classified according to the type of substrate into carbon-based nanomaterials, metal-based nanomaterials, ceramic nanomaterials, lipid-based nanomaterials, semiconductor nanomaterials, and polymer nanomaterials. There are many physical methods that are widely used to produce nanomaterials, among these methods are inert gas condensation (IGC), physical evaporation, electric arc discharge, sputtering, and laser methods. Many characterization analysis techniques of nanomaterials, including ultraviolet–visible (UV–V) spectroscopy, XRD (X-ray diffraction), BET (Brunauere emmette teller), FESEM (Field emission scanning electron microscopy), FTIRS (Fourier transform infrared spectroscopy), TEM (Transmission electron microscopy) and Zeta size analysis. The unique properties that distinguish nanomaterials, allows them to penetrate many applications that directly serve the world. Nanomaterials have been utilized in various applications in the environment, agriculture, food industries, medical industries, chemical processing, and military industries.

Synthesis of organic-inorganic hybrid nanocomposites modified by catalase-like catalytic sites for the controlling of kiwifruit bacterial canker.

Kiwifruit bacterial canker, caused by Pseudomonas syringae pv. Actinidiae (Psa), is one of the most important diseases in kiwifruit, creating huge economic losses to kiwifruit-growing countries around the world. Metal-based nanomaterials offer a promising alternative strategy to combat plant diseases induced by bacterial infection. However, it is still challenging to design highly active nanomaterials for controlling kiwifruit bacterial canker. Here, a novel multifunctional nanocomposite (ZnO@PDA-Mn) is designed that integrates the antibacterial activity of zinc oxide nanoparticles (ZnO NPs) with the plant reactive oxygen species scavenging ability of catalase (CAT) enzyme-like active sites through introducing manganese modified polydopamine (PDA) coating. The results reveal that ZnO@PDA-Mn nanocomposites can efficiently catalyze the conversion of H2O2 to O2 and H2O to achieve excellent CAT-like activity. In vitro experiments demonstrate that ZnO@PDA-Mn nanocomposites maintain the antibacterial activity of ZnO NPs and induce significant damage to bacterial cell membranes. Importantly, ZnO@PDA-Mn nanocomposites display outstanding curative and protective efficiencies of 47.7% and 53.8% at a dose of 200 μg mL-1 against Psa in vivo, which are superior to those of zinc thiozole (20.6% and 8.8%) and ZnO (38.7% and 33.8%). The nanocomposites offer improved in vivo control efficacy through direct bactericidal effects and decreasing oxidative damage in plants induced by bacterial infection. Our research underscores the potential of nanocomposites containing CAT-like active sites in plant protection, offering a promising strategy for sustainable disease management in agriculture.

Gene expression profiles and protein-protein interaction networks in THP-1 cells exposed to metal-based nanomaterials

We analyzed gene expression in THP-1 cells exposed to metal-based nanomaterials (NMs) [TiO2 (NM-100), ZnO (NM-110), SiO2 (NM-200), Ag (NM-300 K)]. A functional enrichment analysis of the significant differentially expressed genes (DEGs) identified the key modulated biological processes and pathways. DEGs were used to construct protein–protein interaction networks. NM-110 and NM-300 K induced changes in the expression of genes involved in oxidative and genotoxic stress, immune response, alterations of cell cycle, detoxification of metal ions and regulation of redox-sensitive pathways. Both NMs shared a number of highly connected protein nodes (hubs) including CXCL8, ATF3, HMOX1, and IL1B. NM-200 induced limited transcriptional changes, mostly related to the immune response; however, several hubs (CXCL8, ATF3) were identical with NM-110 and NM-300 K. No effects of NM-100 were observed. Overall, soluble nanomaterials NM-110 and NM-300 K exerted a wide variety of toxic effects, while insoluble NM-200 induced immunotoxicity; NM-100 caused no detectable changes on the gene expression level.

Modified-TiO2 Nanotube Arrays as a Proficient Photo-Catalyst Nanomaterial for Energy and Environmental Applications

Recently, TiO2 nanotube arrays (TNTAs) have attracted researcher’s attention in the fields of energy production and environmental remediation applications; this is mainly due to their unique optoelectronic characteristics, corrosion resistance, chemical and mechanical stability. In this study, the ability of employing of TiO2 nanotube arrays-based catalysts in the field of photocatalytic CO2 reduction has been investigated. Possible modification strategies have been presented for improving the TNTAs performance by using different types of nanomaterials including graphitic carbon nitrides (g-C3N4), metal-organic frame work (MOF), reduced graphene oxide (RGO) and gold nanoparticles (Au NPs). The TNTAs composites were characterized using XRD and FESEM analyses and the results revealed the successful synthesis of these composites. The TNTAs and their composites exhibited good results for the photo-conversion of CO2 into CH4 gas product. This study gives new ideas for making and developing low-cost Ti metal-based nanomaterials which can be used in the future for recycling the CO2 gas emissions into useful solar fuels.

Application of metal-based nanomaterials in lithium batteries

Due to the current lithium-ion battery performance there are still many deficiencies, battery performance needs to be improved, so people through the synthesis of metal-based nanomaterials, and its application in lithium batteries to improve the electrochemical performance of batteries. This paper summarizes the application of some metal nanomaterials in lithium batteries, such as silver, platinum and gold. These metal nanomaterials can not only be used in the positive electrode as a supported catalyst to solve the problems of low charge and discharge overpotential, insufficient battery capacity, and unstable cycle performance, but also can be used in the anode. Among them, TiO2 nanoparticles used in the anode can enhance lithium ion diffusion and charge transfer, which can provide higher battery capacity, rate performance and cycle stability for lithium batteries. Lithium batteries are expected to become a new generation of all-round use of energy in the future, not only because it is significantly less than the traditional fuel cell pollution to the environment, lithium batteries also have a higher performance limit than fuel cells, so how to improve the capacity of the existing lithium batteries, cycle stability and other performance is the direction that people need to study.

Nanoparticles as Drug Delivery Carrier-synthesis, Functionalization and Application.

In recent years, advancements in chemistry have allowed the tailoring of materials at the nanoscopic level as needed. There are mainly four main types of nanomaterials used as drug carriers:metal-based nanomaterials, organic nanomaterials, inorganic nanomaterials, and polymer nanomaterials. The nanomaterials as a drug carrier showed advantages for decreased side effects with a higher therapeutic index. The stability of the drug compounds is increased by encapsulation of the drug within the nano-drug carriers, leading to decreased systemic toxicity. Nano-drug carriers are also used for controlled drug release by tailoring system-made solubility characteristics of nanoparticles by surface coating with surfactants. The review focuses on the different types of nanoparticles used as drug carriers, the nanoparticle synthesis process, techniques of nanoparticle surface coating for drug carrier purposes, applications of nano-drug carriers, and prospects of nanomaterials as drug carriers for biomedical applications.

Comparative biotoxicity study for identifying better alternative insecticide especially green nano-emulsion which used as mosquitocides

This research work was planned to test biosafety of different nanomaterials on the different animals models. These nanoparticles were previously used as potential insecticides of mosquito larvae. The biosafety of these nanoproducts were evaluated on certain organs of non target animals that associated with mosquito breeding sites in Egypt. Animal organs such as the kidneys of rats, toads, and the fish’s spleen were used as models to study the biological toxicity of these nanomaterials. After 30 days of the animals receiving the nanomaterials in their water supply, different cell mediated immune cells were assessed in these tissues. Both TNF-α and BAX immuno-expression were also used as immunohistochemical markers. Histopathology was conducted to detect the effect of the tested nanoproducts at the tissue level of the liver and kidneys of both the rats and toads. Green nanoemulsion of the lavender essential oil was relatively more effective, safe, and biodegradable to be used as insecticides against mosquito larvae than the metal-based nanomaterials.

Metal-Based Nanomaterials for the Sensing of NSAIDS.

Cadmium sulfide and zinc oxide nanoparticles were prepared, characterized and used as electrode modifiers for the sensing of two non-steroidal anti-inflammatory drugs (NSAIDs): naproxen and mobic. The structural and morphological characterization of the synthesized nanoparticles was carried out by XRD, UV-Vis spectroscopy, FTIR and scanning electron microscopy. The electrode's enhanced surface area facilitated the signal amplification of the selected NSAIDs. The CdS-modified glassy carbon electrode (GCE) enhanced the electro-oxidation signals of naproxen to four times that of the bare GCE, while the ZnO-modified GCE led to a two-fold enhancement in the electro-oxidation signals of mobic. The oxidation of both NSAIDs occurred in a pH-dependent manner, suggesting the involvement of protons in their electron transfer reactions. The experimental conditions for the sensing of naproxen and mobic were optimized and, under optimized conditions, the modified electrode surface demonstrated the qualities of sensitivity and selectivity, and a fast responsiveness to the target NSAIDs.

Modulation of Metal Homeostasis for Cancer Therapy.

Metal ions such as iron, zinc, copper, manganese, and calcium are essential for normal cellular processes, including DNA synthesis, enzyme activity, cellular signaling, and oxidative stress regulation. When the balance of metal homeostasis is disrupted, it can lead to various pathological conditions, including cancer. Thus, understanding the role of metal homeostasis in cancer has led to the development of anti-tumor strategies that specifically target the metal imbalance. Up to now, diverse small molecule-based chelators, ionophores, metal complexes, and metal-based nanomaterials have been developed to restore the normal balance of metals or exploit the dysregulation for therapeutic purposes. They hold great promise in inhibiting tumor growth, preventing metastasis, and enhancing the effectiveness of existing cancer therapies. In this review, we aim to provide a comprehensive summary of the strategies employed to modulate the homeostasis of iron, zinc, copper, manganese, and calcium for cancer therapy. Their modulation mechanisms for metal homeostasis are succinctly described, and their recent applications in the field of cancer therapy are discussed. At the end, the limitations of these approaches are addressed, and potential avenues for future developments are explored.

Recent Advances in Nanomaterials-Based Adsorbents for Organophosphorus Contaminant Removal in Water: An Overview

The presence of organophosphorus contaminants (OPCs) in water is a major concern due to their toxicity and adverse effects on human health and the environment. Traditional water treatment methods such as coagulation, sedimentation, and filtration are not always effective in removing OPCs from water, making it necessary to explore alternative methods. Nanomaterials, due to their unique physical, chemical and biological properties, have emerged as promising adsorbents for the removal of OPCs from water. This review article focusses on the recent developments in the use of nanomaterials as adsorbents for the removal of OPCs from water. The article covers various types of nanomaterials, including carbon-based nanomaterials, metal-based nanomaterials and other hybrid nanomaterials. The mechanisms of OPC adsorption by nanomaterials, such as electrostatic interactions, hydrogen bonding, and Van der Waals forces, are also discussed. The article further highlights the factors affecting the adsorption capacity of nanomaterials, such as pH, temperature, and concentration of OPCs. Additionally, the article examines the challenges associated with the application of nanomaterials in water treatment, such as the potential release of nanomaterials into the environment and the need for cost-effective and scalable synthesis methods.

Elucidating the Mode of Action of Hybrid Nanoparticles of Cu/Zn Against Copper-Tolerant Xanthomonas euvesicatoria.

The widespread presence of tolerance to copper in Xanthomonas species has resulted in the need to develop alternative approaches to control plant diseases caused by xanthomonads. In recent years, nanotechnological approaches have resulted in the identification of novel materials to control plant pathogens. With many metal-based nanomaterials having shown promise for disease control, an important question relates to the mode of action of these new materials. In this study, we used several approaches, such as scanning electron microscopy, propidium monoazide quantitative polymerase chain reaction, epifluorescence microscopy, and RNA sequencing to elucidate the mode of action of a Cu/Zn hybrid nanoparticle against copper-tolerant strains of Xanthomonas euvesicatoria. We demonstrate that Cu/Zn did not activate copper resistance genes (i.e., copA and copB) in the copper-tolerant bacterium but functioned by disrupting the bacterial cell structure and perturbing important biological processes such as cell respiration and chemical homeostasis.

APTES-mediated Cu2(OH)3(NO3) Nanomaterials on the Surface of Silicone Catheters for Abscess

Metal-based nanomaterials have remarkable bactericidal effects; however, their toxicity cannot be disregarded. To address this concern, we developed a simple synthesis route for antibacterial catheters using metal-based nanomaterials to reduce toxicity while harnessing their excellent bactericidal properties. The grafting agent (3-aminopropyl)triethoxysilane (APTES) forms -NH2 groups on the catheter surface, onto which copper ions form a nanomaterial complex known as Cu2(OH)3(NO3) (defined as SA-Cu). The synthesized SA-Cu exhibited outstanding contact antibacterial effects, as observed through scanning electron microscopy (SEM), which revealed cell membrane crumbing and bacterial rupture on the catheter surface. Furthermore, SA-Cu exhibited excellent biosafety characteristics, as evidenced by the cell counting kit-8 (CCK-8) assay, which showed no significant cytotoxicity. SA-Cu demonstrated sustained antimicrobial capacity, with in vivo experiments demonstrating over 99% bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) for two weeks. The transcriptome sequencing results suggested that SA-Cu may exert its bactericidal effects by interfering with histidine and purine metabolism in MRSA. This study presents a straightforward method for synthesizing antimicrobial silicone catheters containing copper nanomaterials using copper ions.

Hydrolysis-Induced Cu2O Networks and the Triggered Peroxidase-Mimic Activity by Cr6+ under Neutral Conditions.

The current small-scale synthesis and relatively large size of Cu2O have limited its practical applications. Herein, we developed a hydrolysis strategy to prepare phase-pure Cu2O networks composed of small granules (ca. 25 nm) on a gram scale. The preparation involves in situ hydrolyzing the Hx[CuxCl2x] complexes prereduced in N,N'-dimethylformamide (DMF). The DMF-soluble Hx[CuxCl2x] complexes are critical for the homogeneous nucleation of CuCl seeds and subsequent hydrolysis, allowing for separate control over the nucleation and growth stages to regulate the formation of Cu2O networks. The novel Cu2O networks possess numerous exposed active sites and hierarchical porosities, conferring high catalytic activity and fast mass transfer capability. The inherent peroxidase-mimic activity of Cu2O is severely inhibited under neutral conditions but can be triggered by Cr6+, enabling the colorimetric assay of Cr6+ with the assistance of the oxidation-induced color change of 3,3',5,5'-tetramethylbenzidine. Through density functional theory calculation, we confirmed that the attachment of Cr6+ on the Cu2O surface reduced the dissociation energy of H2O2, enhancing the enzyme-mimic activity. The colorimetric detection method demonstrated a sensitive and specific assay capability for Cr6+ (LOD = 0.095 μM). Our work offers a straightforward protocol for novel design of metal or metal-based nanomaterials for nanozymes or other applications.

A review on metal/metal oxide nanoparticles in food processing and packaging.

Consuming hygienic and secure food has become challenging for everyone. The preservation of excess food without negatively affecting its nutritional values, shelf life, freshness, or effectiveness would undoubtedly strengthen the food industry. Nanotechnology is a new and intriguing technology that is currently being implemented in the food industry. Metal-based nanomaterials have considerable potential for use in packaging and food processing. These materials have many advanced physical and chemical characteristics. Since these materials are increasingly being used in food applications, there are certain negative health consequences related to their toxicity when swallowed through food. In this article, we have addressed the introduction and applications of metal/metal oxide nanoparticles (MNPs), food processing and food packaging, applications of MNPs-based materials in food processing and food packaging, health hazards, and future perspectives.