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Freshwater contamination by metals can come from a variety of sources and be damaging to wildlife, alter landscapes, and impact human health. Metals removal is desirable not only for improving water quality and preventing adverse effects but also for metals collection and recycling. Nanoadsorption of metals is economically feasible and nanoscale materials exhibit a high surface-area-to-volume ratio that is promising for high adsorption and reactivity. However, the extraordinarily small dimensions of these materials allow them to maneuver biological systems, and combined with high reactivity, this translocation can result in toxicity. In this work, nanoparticles (NPs) composed of a magnetite core coated in hydroxyapatite (HA) and functionalized for adsorption with titanium dioxide (TiHAMNPs) were synthesized. The magnetic core enabled NP retrieval, while HA enhanced adsorption and minimized toxicity. Here, synthesis and characterization are presented, revealing a stable NP structure exhibiting a near neutral surface charge. Results of adsorption studies showed that as compared to silica-coated magnetite nanoparticles (SiMNPs), traditionally used for this application, TiHAMNPs exhibited significantly higher adsorption (43.28% more Cu removal) after 24 h. The equilibrium rate constant for the adsorption of Cu by TiHAMNPs was 0.0003 g/(min*mg) and TiHAMNP adsorption data indicated that TiHAMNPs adsorb metals in a monolayer at the particle surface with a maximum capacity of 2.8 mmol/g. Metabolic and toxicity assays showed TiHAMNPs were highly biocompatible as compared to SiMNPs. This work also explores rare earth element (REE) separation applications of TiHAMNPs, finding that TiHAMNPs may provide a promising alternative for REE retrieval and/or separation. [ABSTRACT FROM AUTHOR]

The necessity for the creation of safe, dependable, biocompatible, and efficient methods to make nanoparticles drives an increasing number of researchers to consider using biological systems as potential eco-friendly nanofactories. Fungi have an innate ability to reduce and oxidize metal ions into metal oxide nanoparticles, thus behaving as nanofactories. In the present study, Trichoderma harzianum was used to prepare ZnO nanoparticles (ZnO NPS). ZnO NPS showed a peak at 370 nm upon testing using UV spectrophotometer and percentages of zinc(72.0±0.2 %) and oxygen(28.0 ±0.3) upon analysis using Edx with an irregular shape, 16.5 nm size and characterized XRD pattern. Soymilk as well as the prepared ZnONPs were investigated either separately or in their mixture (1:1) for their antibacterial and anti-tumor effects. The mixture showed a promising antibacterial impact on Enterococcus faecalis (ATCC29212) and Escherichia coli (ATCC25922) which was confirmed using a transmission electron microscope. ZnONPs mixed with soymilk showed a promising anti-tumor action towards human colorectal adenocarcinoma cell line Caco-2 through boosting apoptotic rate, which was detected by flow cytometry. The current report highlights the possibility of mixing eco-friendly biosynthesized nanoparticles with natural products to enhance their biomedical impact with minimal toxicity as possible innovative pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Nanotechnology has emerged as a promising field in pharmaceutical research, involving producing unique nanoscale materials with sizes up to 100 nm via physiochemical and biological approaches. Nowadays more emphasis has been given to eco-friendly techniques for developing nanomaterials to enhance their biological applications and minimize health and environmental risks. With the help of green nanotechnology, a wide range of green metal, metal oxide, and bimetallic nanoparticles with distinct chemical compositions, sizes, and morphologies have been manufactured which are safe, economical, and environment friendly. Due to their biocompatibility and vast potential in biomedical (antibacterial, anticancer, antiviral, analgesic, anticoagulant, biofilm inhibitory activity) and in other fields such as (nanofertilizers, fermentative, food, and bioethanol production, construction field), green metal nanoparticles have garnered significant interest worldwide. The metal precursors combined with natural extracts such as plants, algae, fungi, and bacteria to get potent novel metal, metal oxide, and bimetallic nanoparticles such as Ag, Au, Co, Cu, Fe, Zr, Zn, Ni, Pt, Mg, Ti, Pd, Cd, Bi2O3, CeO2, Co3O4, CoFe2O4, CuO, Fe2O3, MgO, NiO, TiO2, ZnO, ZrO2, Ag-Au, Ag-Cr, Ag-Cu, Ag-Zn, Ag-CeO2, Ag-CuO, Ag-SeO2, Ag-TiO2, Ag-ZnO, Cu-Ag, Cu-Mg, Cu-Ni, Pd-Pt, Pt-Ag, ZnO-CuO, ZnO-SeO, ZnO-Se, Se-Zr, and Co-Bi2O3. These plant-mediated green nanoparticles possess excellent antibacterial and anticancer activity when tested against several microorganisms and cancer cell lines. Plants contain essential phytoconstituents (polyphenols, flavonoids, terpenoids, glycosides, alkaloids, etc.) compared to other natural sources (bacteria, fungi, and algae) in higher concentration that play a vital role in the development of green metal, metal oxide, and bimetallic nanoparticles because these plant-phytoconstituents act as a reducing, stabilizing, and capping agent and helps in the development of green nanoparticles. After concluding all these findings, this review has been designed for the first time in such a way that it imparts satisfactory knowledge about the antibacterial and anticancer activity of plant-mediated green metal, metal oxide, and bimetallic nanoparticles together, along with antibacterial and anticancer mechanisms. Additionally, it provides information about characterization techniques (UV–vis, FT-IR, DLS, XRD, SEM, TEM, BET, AFM) employed for plant-mediated nanoparticles, biomedical applications, and their role in other industries. Hence, this review provides information about the antibacterial and anticancer activity of various types of plant-mediated green metal, metal oxide, and bimetallic nanoparticles and their versatile application in diverse fields which is not covered in other pieces of literature. [ABSTRACT FROM AUTHOR]

To better understand and utilize the optical reflection behaviors of the nanostructured materials containing small metal nanoparticles (NPs), we once proposed a hypothesis that the recorded characteristic reflection peak should originate from the competition between the localized surface plasmon resonance (LSPR) scattering and absorption of metal NPs. To prove our hypothesis, the Ag- and Au-ion-implanted samples are prepared again by separately introducing 30 keV Ag and Au ions into 0.5-mm-thick SiO2 wafers to a fluence of 6 × 1016 ions/cm2. Especially, the Au-ion-implanted sample is further annealed in flowing nitrogen at different temperatures. Then, using a transmission electron microscope and a fiber spectrometer, all samples' cross-sectional observations and spectral measurements are conducted, respectively. Based on the consistency in peak position and the difference in wavelength range of the absorption and reflection light fields measured from the Ag-ion-implanted sample, the LSPR scattering and absorption of Ag NPs are demonstrated to be coexistent, and their competition are testified to be inevitable and achievable via a filtration process. Besides these indirect evidences for our hypothesis, a direct evidence is also found, which is the blueshift shown by the characteristic reflection peak observed from the rear surface of the Au-ion-implanted sample after annealing. [ABSTRACT FROM AUTHOR]

Highly transparent, conductive nanosheets are extremely attractive for advanced opto-electronic applications. Previously, we have demonstrated that transparent, conductive Au nanosheets can be prepared by UV irradiation of Au nanoparticle (AuNP) monolayers spread on water, which serves as the subphase. However, thick Au nanosheets cannot be fabricated because the method is not applicable to large Au NPs. Further, in order to fabricate nanosheets with different thicknesses and compositions, it is necessary to prepare the appropriate NPs. A strategy is needed to produce nanosheets with different thicknesses and compositions from a single type of metal NP monolayer. In this study, we show that this UV irradiation technique can easily be extended as a nanosheet modification method by using subphases containing metal ions. UV irradiation of 4.7 nm AuNP monolayers on 480 µM HAuCl4 solution increased the thickness of Au nanosheets from 3.5 nm to 36.5 nm, which improved conductivity, but reduced transparency. On the other hand, the use of aqueous AgNO3 and CH3COOAg solutions yielded Au-Ag hybrid nanosheets; however, their morphologies depended on the electrolytes used. In Au-Ag nanosheets prepared on aqueous 500 µM AgNO3, Au and Ag metals are homogeneously distributed throughout the nanosheet. On the other hand, in Au-Ag nanosheets prepared on aqueous 500 µM CH3COOAg, AuNPs still remained and these AuNPs were covered with a Ag nanosheet. Further, these Au-Ag hybrid nanosheets had high conductivity without reduced transparency. Therefore, this UV irradiation method, modified by adding metal ions, is quite effective at improving and diversifying properties of Au nanosheets. [ABSTRACT FROM AUTHOR]

Metal-based nanomaterials (MNMs) have gained particular interest in nanotechnology industry. They are used in various industrial processes, in biomedical applications or to improve functional properties of several consumer products. The widescale use of MNMs in the global consumer market has resulted in increases in the likelihood of exposure and risks to human beings. Human exposure to MNMs and assessment of their potential health effects through the concomitant application of biomarkers of exposure and effect of the most commonly used MNMs were reviewed in this paper. In particular, interactions of MNMs with biological systems and the nanobiomonitoring as a prevention tool to detect the early damage caused by MNMs as well as related topics like the influence of some physicochemical features of MNMs and availability of analytical approaches for MNMs testing in human samples were summarized in this review. The studies collected and discussed seek to increase the current knowledge on the internal dose exposure and health effects of MNMs, highlighting the advantages in using biomarkers in primary prevention and health surveillance. [ABSTRACT FROM AUTHOR]

Organophosphates (OPs) being the most widely used (~ 36%) pesticides, are infamous for presence of their traces in surface waters and serious health hazards to humans and animals. Hence, rapid, efficient, easy to use, and cost-effective methods must be explored for their remediation in contaminated waters. Amongst the different pesticide removal methods, adsorption is extensively used as it is economic unit process which is easy to operate and renders no residual by-product. Moreover, nano-sized adsorbents with novel physico-chemical properties may even be more effectively employed for sorptive removal of OPPs in contaminated waters. The review provides an overview of organophosphate pesticides (OPPs) in terms of usage, environmental contamination, and toxicity. Nanomaterials (e.g., carbon nano-structures, metal nanoparticles and oxides, quantum dots, and metal organic frameworks) categorized into inorganic, organic, and hybrid nanomaterials employed for adsorptive removal of OPPs from aqueous phase have been discussed. The parameters that determine their adsorption efficiency have been discussed, calculated, and compared for different nanostructures. The operating mechanisms behind adsorption of OPPs on nanomaterials are mainly electrostatic interactions, H-bonding, and Π-Π stacking (carbon-based nanomaterials), and exchange or sharing of electrons between vacant active site of nanocomposite and OPP molecules (in case of hybrid materials). Diffusion mechanism and rate-limiting steps have been explored via intra-particle diffusion model. The factors influencing the efficiency of adsorbents such as pH, temperature, adsorbent concentration, and incubation time have also been included. The review further recapitulates the details of thermodynamic studies of adsorption process which give information about the spontaneity and exothermic/endothermic nature of the process. The review concludes with summary and future prospects of sorptive removal of OPPs in water. Adsorption of OPPs onto different nanosorbents via variety of interactions [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalysts have favorable ECSA, multiple active centers, and sufficient mass transport. • PtCo nanoparticles (about 2.5 nm) are uniformly distributed and firmly anchored in the matrix. • The synergistic effect of PtCo, Co 9 S 8 and Co-N strengthens the catalytic performance. • Strong chemical/electronic interactions enhance the anchoring of PtCo NPs on the carrier. • The catalysts exhibit more excellent ORR and HER performance than the Pt/C. The development of low-Pt bifunctional electrocatalysts with excellent performance for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is critical for the advancement of the hydrogen economy. Here, we have integrated low-loading Pt and Co metals into N, S doped porous carbon nanosheets to obtain composite catalysts encapsulating PtCo alloy nanoparticles (PtCo2@Co 9 S 8 / N -CNS and PtCo2@ N -CNS). The acquired PtCo nanoparticles, with dimensions of about 2.5 nm, are uniformly distributed and firmly anchored in N, S doped carbon nanosheets with large specific surface areas and rich pore structure, forming multiple active centers and effectively preventing the aggregation of metal nanoparticles. The PtCo2@Co 9 S 8 / N -CNS and PtCo2@ N -CNS display high ORR catalytic mass activity of 1.65 A mg Pt -1 and 1.01 A mg Pt -1 in 0.1 M HClO 4. The PtCo2@ N -CNS catalyst exhibits excellent HER performance in 0.5 M H 2 SO 4 , with a mass activity (at 50 mV) 4.3 times higher than that of Pt/C. The PtCo2@Co 9 S 8 / N -CNS and PtCo2@ N -CNS also exhibit stronger ORR and HER stability than Pt/C after accelerated durability tests. The superior catalytic activity performance of catalysts can be attributed to the synergistic effect of multiple active centers of PtCo, Co 9 S 8 and Co-N in the catalysts. The confinement of PtCo nanoparticles by Co metal and N, S doped porous nanosheets derived from graphitic carbon nitride (g-C 3 N 4) as the template, which can effectively prevent the corrosion and migration of the catalysts under acidic conditions, enhances the catalytic stability of the materials. This study provides a new perspective for the development of economical and efficient bifunctional low-Pt catalysts. [ABSTRACT FROM AUTHOR]

Alginate is among the widely applied polysaccharide‐based biomaterial owing to its natural occurrence, chemical versatility, non‐toxicity, environmental friendliness, unique biocompatibility, biodegradability, and mucoadhesive attributes. Nevertheless, it is associated with some demerits, such as inadequate mechanical features and biological activity that hamper broad‐spectrum biomedical scope. Different biopolymeric and nanomaterials have been incorporated into the alginate framework to develop robust nanoplatforms with desired functionalities to overcome this inadequacy. Hybrids of alginate with biopolymers and nanostructured materials improve its mechanical and physicochemical characteristics and may also boost its biological activity. This review aimed to summarize the ongoing progress in alginate‐based nanoplatforms for potential applications in biomedical sectors. Combining alginate with biopolymers (chitosan, starch) and nanostructured materials (silica nanoparticles, graphene oxide nanoparticles, carbon nanotubes/nanorods, and metal oxide nanoparticles) are particularly discussed for drug delivery, wound dressing, tissue engineering, and 3D bioprinting applications. The ongoing challenging facets and futuristic directions on alginate blends are also spotlighted. The alginate‐based hybrids will likely demonstrate biocompatibility, enhanced cell adhesion, cell proliferation, desired mechanical strength, and excellent mineralization. Therefore, they are considered bio‐inspired materials for futuristic biomedical applications. [ABSTRACT FROM AUTHOR]

Undoubtedly, nanoparticles are one of the ideal choices for achieving challenges related to bio sensing, drug delivery, and biotechnological tools. After gaining success in biomedical research, scientists are exploring various types of nanoparticles for achieving sustainable agriculture. The active nanoparticles can be used as a direct source of micronutrients or as a delivery platform for delivering the bioactive agrochemicals to improve crop growth, crop yield, and crop quality. Till date, several reports have been published showing applications of nanotechnology in agriculture. For instance, several methods have been employed for application of nanoparticles; especially metal nanoparticles to improve agriculture. The physicochemical properties of nanoparticles such as core metal used to synthesize the nanoparticles, their size, shape, surface chemistry, and surface coatings affect crops, soil health, and crop-associated ecosystem. Therefore, selecting nanoparticles with appropriate physicochemical properties and applying them to agriculture via suitable method stands as smart option to achieve sustainable agriculture and improved plant performance. In presented review, we have compared various methods of nanoparticle application in plants and critically interpreted the significant differences to find out relatively safe and specific method for sustainable agricultural practice. Further, we have critically analyzed and discussed the different physicochemical properties of nanoparticles that have direct influence on plants in terms of nano safety and nanotoxicity. From literature review, we would like to point out that the implementation of smaller sized metal nanoparticles in low concentration via seed priming and foliar spray methods could be safer method for minimizing nanotoxicity, and for exhibiting better plant performance during stress and non-stressed conditions. Moreover, using nanomaterials for delivery of bioactive agrochemicals could pose as a smart alternative for conventional chemical fertilizers for achieving the safer and cleaner technology in sustainable agriculture. While reviewing all the available literature, we came across some serious drawbacks such as the lack of proper regulatory bodies to control the usage of nanomaterials and poor knowledge of the long-term impact on the ecosystem which need to be addressed in near future for comprehensive knowledge of applicability of green nanotechnology in agriculture. [ABSTRACT FROM AUTHOR]

Green synthesis is a unique and eco-friendly method of producing nanoparticles that employs plant extracts as reducing and stabilizing agents. This approach offers numerous advantages, including low cost, biocompatibility, sustainability, and ease of operation. ZnO has been applied in various fields such as optical, electrical, magnetic, catalytic, and biological. Drawbacks such as high band gap of 3.37 eV, faster recombination of generated electron hole pair, lower antibacterial activity hinders ZnO nanoparticles utilization. Metal doping is a technique that modifies the nanoparticle's characteristics by adding impurities into their lattice which improves optical, electrical, magnetic, catalytic, and biological properties of the host material. Silver doped zinc oxide (Ag/ZnO) is one of the promising materials for metal doped nanoparticles due to its enhanced antibacterial, anticancer, sensing, and photocatalytic capabilities. In this paper, we reviewed plant mediated green synthesis of Ag/ZnO nanoparticles and their multifunctional properties for biomedical and environmental application as well as proposed mechanisms of their action. [ABSTRACT FROM AUTHOR]

Complex hierarchical metamaterials are currently the focus of many cutting‐edge studies due to their potential to advance such critically important areas of technology as energy storage and transformation, sensing, photovoltaics, nano‐medicine, antibacterial and self‐regenerating materials. However, the deterministic design of novel hierarchical metamaterials remains problematic due to the lack of efficient, highly reliable methods for controlling the internal structure and architecture of materials. A comprehensive advanced model is proposed to simulate the formation of complex hierarchical metamaterials with a controllable structure. The control is achieved via selective deposition of noble metal nanoparticles (Au, Au, Pd, Pt). Moreover, the novel method for the nanofabrication is theoretically examined and experimentally verified. This approach allows for the sophisticated spatiotemporal control of growth conditions and, as a result, achieving the targeted internal structure of metamaterials. This opens a way to the deterministic design and formation of complex multi‐material metamaterials on the basis of metal oxides and noble metal nanoparticles. Moreover, a fundamental insight related to the longstanding question about the prevalence of bottom‐up versus top‐down growth for various materials and systemswhich is challenging to directly verify experimentally is presented. [ABSTRACT FROM AUTHOR]

Present worldwide difficulties in healthcare and the environment have motivated the investigation and research of novel materials in an effort to find novel techniques to address the current challenges and requirements. In particular, the use of nanomaterials has demonstrated a significant promise in the fight against bacterial infections and the problem of antibiotic resistance. Metal nanoparticles and carbon-based nanomaterials in particular have been highlighted for their exceptional abilities to inhibit many types of bacteria and pathogens. In order for these materials to be as effective as possible, synthetic techniques are crucial. Therefore, in this review article, we highlight some recent developments in the design and synthesis of various nanomaterials, including metal nanoparticles (e.g., Ag, Zn, or Cu), metal hybrid nanomaterials, and the synthesis of multi-metallic hybrid nanostructured materials. Following that, examples of these materials' applications in antimicrobial performance targeted at eradicating multi-drug resistant bacteria, material protection such as microbiologically influenced corrosion (MIC), or additives in construction materials have been described. [ABSTRACT FROM AUTHOR]

For the past years, fused deposition modeling (FDM) technology has received increased attention in the applications of industrial manufacturing fields, particularly for rapid prototyping, small batch production and highly customized products, owing to the merits of low-cost, user-friendliness and high design freedom. To further expand the application potential and promote the performance of the as-manufactured products, many efforts have been spent on the development of suitable materials for FDM applications. In recent years, the involvement of nanomaterials in the FDM-based polymer matrix, which has been demonstrated with great opportunities to enhance the performance and versatility of FDM printed objects, has attracted more and more research interest and the trend is expected to be more pronounced in the next few years. This paper attempts to provide a timely review regarding the current research advances in the use of nanomaterials to reinforce polymer filaments for the FDM technique. Polymer composite filaments based on nanomaterials such as carbon nanotubes, nanoclay, carbon fibers, graphene, metal nanoparticles and oxides are discussed in detail regarding their properties and applications. We also summarized the current research challenges and outlooked the future research trends in this field. This paper aims at providing a useful reference and guidance for skilled researchers and also beginners in related fields. Hopefully, more research advances can be stimulated in the coming years. [ABSTRACT FROM AUTHOR]

The creation of new nanomaterials with improved characteristics, as well as the development of new approaches to obtain such materials is an urgent task in science and technology. One of the promising directions in obtaining improved nanomaterials is the use of precursors in the form of multicomponent metal nanoparticles. Thermal oxidation of bimetallic Ti/Al nanoparticles obtained by electrical explosion of wires was investigated in this work. Ti/Al nanoparticles have been found to be completely oxidized with the formation of composite TiO2/Al2O3 nanoparticles after calcination at 900 °C. The formation of TiO2 phase with a rutile structure on heating to 500 °C, and the formation of TiO2 phases with a rutile and anatase structure, as well as α-Al2O3 on heating to 700 °C have been established, in addition to the residue of unoxidized metals. Complete oxidation of Ti/Al nanoparticles occurs when heated to 900 °C. The photochemical activity of TiO2/Al2O3 composite nanoparticles obtained at 900 °C was studied. The degradation of methyl orange dye reached 55% under UV irradiation for 120 min. [ABSTRACT FROM AUTHOR]

The role of nanotechnology is increasingly important in our society. Through it, scientists are acquiring the ability to understand the structure and properties of materials and manipulate them at the scale of atoms and molecules. Nanomaterials are at the forefront of the rapidly growing field of nanotechnology. The synthesis of nanostructured materials, especially metallic nanoparticles, has attracted tremendous interest over the past decade due to their unique properties, making these materials excellent and indispensable in many areas of human activity. These special properties can be attributed to the small size and large specific surface area of nanoparticles, which are very different from those of bulk materials. Nanoparticles of different sizes and shapes are needed for many applications, so a variety of protocols are required to produce monodisperse nanoparticles with controlled morphology. The purpose of this review is firstly to introduce the reader to the basic aspects related to the field of nanotechnology and, secondly, to discuss metallic nanoparticles in greater detail. This article explains the basic concepts of nanotechnology, introduces methods for synthesizing nanoparticles, and describes their types, properties, and possible applications. Of many methods proposed for the synthesis of metal nanoparticles, a chemical reduction is usually preferred because it is easy to perform, cost-effective, efficient, and also allows control of the structural parameters through optimization of the synthesis conditions. Therefore, a chemical reduction method is discussed in more detail—each factor needed for the synthesis of nanoparticles by chemical reduction is described in detail, i.e., metal precursors, solvents, reducing agents, and stabilizers. The methods that are used to characterize nanomaterials are described. Finally, based on the available literature collection, it is shown how changing the synthesis parameters/methods affects the final characteristics of nanoparticles. [ABSTRACT FROM AUTHOR]

In the recent past, materials with unique properties were the versatile tools of modern technology. Metal oxide nanoparticles (NPs) are of incredible consideration because of their uncommon electrical, optical and attractive synergistic properties. One such metal oxide, tin oxide (SnO2), is widely applied and successfully researched as an n-type semiconductor in the field of electronics, as an optoelectronic sensor, as a gas sensor, as a transparent oxide in solar cells, etc. The success of these applications depends on the special qualities of SnO2 nanoparticles, which vary depending on size, manufacturing processes, dopants, etc. The present study illustrates the synthesis of pure, nickel (Ni), neodymium (Nd) doped, and Ni–Nd co-doped SnO2 NPs via low cost one step hydrothermal synthesis. X-ray diffraction study was utilized for the structural analysis and crystallite size measurement. A considerable decrease in crystallite size and band gap is obtained from the doped and co-doped samples. Scanning electron and transmission electron microscope images show an almost spherical particle with uniform size. The decolorization efficiency of methyl orange, rhodamine-6G, and eriochrome dyes was enhanced by the addition of dopants. The electrical properties of the proposed samples at various temperatures and frequencies were also reported. [ABSTRACT FROM AUTHOR]

In recent years, nanomaterials have attracted the research intervention of experts in the fields of catalysis, energy, biomedical testing, and biomedicine with their unrivaled optical, chemical, and biological properties. From basic metal and oxide nanoparticles to complex quantum dots and MOFs, the stable preparation of various nanomaterials has always been a struggle for researchers. Microfluidics, as a paradigm of microscale control, is a remarkable platform for online stable synthesis of nanomaterials with efficient mass and heat transfer in microreactors, flexible blending of reactants, and precise control of reaction conditions. We describe the process of microfluidic preparation of nanoparticles in the last 5 years in terms of microfluidic techniques and the methods of microfluidic manipulation of fluids. Then, the ability of microfluidics to prepare different nanomaterials, such as metals, oxides, quantum dots, and biopolymer nanoparticles, is presented. The effective synthesis of some nanomaterials with complex structures and the cases of nanomaterials prepared by microfluidics under extreme conditions (high temperature and pressure), the compatibility of microfluidics as a superior platform for the preparation of nanoparticles is demonstrated. Microfluidics has a potent integration capability to combine nanoparticle synthesis with real-time monitoring and online detection, which significantly improves the quality and production efficiency of nanoparticles, and also provides a high-quality ultra-clean platform for some bioassays. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) have found use in broad range of applications such as in catalysis and nanomedicine. Despite the fact that thiol-based AuNPs have been widely studied, they suffer from relative instability in various conditions, such as high and low temperatures, pH variations, and are prone to oxidation. Over the last decade, N-heterocyclic carbenes (NHCs) have been under spotlight as suitable ligands to stabilize metal nanoparticles and surfaces. Although NHC-functionalized AuNPs have been shown to outperform their thiol-based analogs in terms of stability, their applications in nanomedicine have not been realized. Hybrid nanomaterials, such as AuNPs tagged with π-conjugated molecules with aggregation-induced emission (AIE) property, are promising candidates to develop fluorescent materials for cellular imaging. The combination of NHC-stabilized AuNPs with AIE to form stable, fluorescent hybrid AuNPs is of significant interest to open the door to develop new NHC-based nanomaterials. Herein, we report the synthesis and characterization of water-soluble fluorescent NHC-decorated AuNPs for potential applications in nanomedicine. Their stability in biologically relevant conditions is investigated. [ABSTRACT FROM AUTHOR]

The ambition to combat the issues affecting the environment and human health triggers the development of biosynthesis that incorporates the production of natural compounds by living organisms via eco-friendly nano assembly. Biosynthesized nanoparticles (NPs) have various pharmaceutical applications, such as tumoricidal, anti-inflammatory, antimicrobials, antiviral, etc. When combined, bio-nanotechnology and drug delivery give rise to the development of various pharmaceutics with site-specific biomedical applications. In this review, we have attempted to summarize in brief the types of renewable biological systems used for the biosynthesis of metallic and metal oxide NPs and the vital contribution of biogenic NPs as pharmaceutics and drug carriers simultaneously. The biosystem used for nano assembly further affects the morphology, size, shape, and structure of the produced nanomaterial. The toxicity of the biogenic NPs, because of their pharmacokinetic behavior in vitro and in vivo, is also discussed, together with some recent achievements towards enhanced biocompatibility, bioavailability, and reduced side effects. Because of the large biodiversity, the potential biomedical application of metal NPs produced via natural extracts in biogenic nanomedicine is yet to be explored. [ABSTRACT FROM AUTHOR]

The synthesis of highly efficient heterogeneous catalysts with uniformly dispersed noble metal particles and a suitable size is crucial for various industrial applications. However, the high cost and rarity of noble metals limit their economic efficiency, making it essential to improve the catalytic performance with lower noble metal loading. Herein, a two-step method was developed for the synthesis of uniformly dispersed ~3 nm Pt nanoparticles (NPs), strongly anchored on Ni(OH)2 nanosheets (NSs), which was proven by adequate structural characterizations. XPS analysis demonstrated that Ni(OH)2 NSs with abundant oxygen vacancies provided sufficient anchor sites for Pt NPs and prevented their agglomeration. The catalytic performance of Ptn/Ni(OH)2 (n (represents the addition amount of Pt precursors during the synthesis, μmol) = 5, 10, 15, and 20) NSs with controllable Pt loading were evaluated via the reduction of 4-nitrophenol to 4-aminophenol as a model reaction. The Pt10/Ni(OH)2 NSs exhibited the best activity and stability, with a reaction rate constant of 0.02358 s−1 and negligible deterioration in ten reaction cycles. This novel synthetic method shows potentials for the synthesis of highly efficient noble-metal-supported catalysts for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Metal nanoparticles have gained considerable attention as versatile nanomaterials due to their size- and shape- dependent electrical, electronic, optical, and catalytic properties. Various physical and chemical approaches have been investigated for synthesizing metal nanoparticles, specifically gold nanoparticles due to their biocompatibility, antioxidant potentials, catalytic activity, and other promising characteristics. As the chemical based approaches have led to questions on toxicity, plant-based sources and microorganisms like bacteria, fungi and algae have been evaluated for synthesizing metal nanoparticles. Gold nanoparticles derived from biological sources are expected to have different properties than those derived from chemical sources, allowing for a wider range of applications. This review provides an overview of the myriad of sources explored for the synthesis of gold nanoparticles which have found useful applications in several fields. The general approach for synthesizing gold nanoparticles is provided followed by the major applications in specific fields namely medicine, biology, electrochemistry and catalysis. Additionally, the possible challenges and future prospects of biosynthesis of nanoparticles have been highlighted. This work could provide an update on the recent advances in the applications of biogenic nanoparticles for future developments. [ABSTRACT FROM AUTHOR]

In comparison to single Noble metal nanoparticles (NPs), bimetallic nanoparticles allow fine-tuning of the optical and photothermal properties. Considering the fact that both Au and Ag plasmonic NPs exhibit strong and enhanced optical absorption in the visible spectrum, the composition of these two materials is notably intriguing. Therefore, the combination of these two metals as an alloy of Aux–Ag(1−x) will provide better control of optical and thermoplasmonic properties by changing the size and composition. The proposed computer simulation work examines the thermal effects of Au–Ag alloy nanospheres under surface plasmon resonance (SPR) due to the coherent oscillation of conduction electrons within the NPs. It is demonstrated that the SPR of Aux–Ag(1−x) alloy nanospheres could be easily altered by varying the radius and also the composition of alloys (in water ambience). The rise of steady-state temperature is calculated by the integration of Ag into spherical Au NPs, as demonstrated by photothermal heat transfer research. Absorption of light by metallic alloy nanospheres was studied by changing the composition of such alloy spheres with a possibility to alter the SPR absorption range, which is tuned from 392 to 580 nm. This investigation of the optical and photothermal properties of bimetallic Au–Ag alloy nanospheres offers a thorough scientific understanding towards the synthesis of new custom plasmonic nanostructured materials. Schematic of the photo-thermal conversion process in spherical NPs along with its temperature profile. [ABSTRACT FROM AUTHOR]

This review article comprehensively discusses the various electrochemical approaches for measuring and detecting oxidative stress biomarkers and enzymes, particularly reactive oxygen/nitrogen species, highly reactive chemical molecules, which are the byproducts of normal aerobic metabolism and can oxidize cellular components such as DNA, lipids, and proteins. First, we address the latest research on the electrochemical determination of reactive oxygen species generating enzymes, followed by detection of oxidative stress biomarkers, and final determination of total antioxidant activity (endogenous and exogenous). Most electrochemical sensing platforms exploited the unique properties of micro- and nanomaterials such as carbon nanomaterials, metal or metal oxide nanoparticles (NPs), conductive polymers and metal-nano compounds, which have been mainly used for enhancing the electrocatalytic response of sensors/biosensors. The performance of the electroanalytical devices commonly measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in terms of detection limit, sensitivity, and linear range of detection is also discussed. This article provides a comprehensive review of electrode fabrication, characterization and evaluation of their performances, which are assisting to design and manufacture an appropriate electrochemical (bio)sensor for medical and clinical applications. The key points such as accessibility, affordability, rapidity, low cost, and high sensitivity of the electrochemical sensing devices are also highlighted for the diagnosis of oxidative stress. Overall, this review brings a timely discussion on past and current approaches for developing electrochemical sensors and biosensors mainly based on micro and nanomaterials for the diagnosis of oxidative stress. [ABSTRACT FROM AUTHOR]

Atrazine is a common triazine herbicide that is persistent in the environment due to its water solubility and slow degradation. Some of the effects of atrazine exposure include immune suppression, carcinogenicity, hormone disruptions, and reproductive anomalies; thus its determination is of great importance. This minireview provides a summary of the most recent developments in electrochemical sensors that target atrazine by using nanoscale materials as electrode modifiers, such as metal/metal oxide nanoparticles, carbonaceous materials, and conducting polymers. Analytical parameters such as the linear dynamic range, detection limit, and detection method, are compiled and compared with the experimental conditions. Lastly, the future directions, difficulties, and opportunities for developing new sensing technology are presented. [ABSTRACT FROM AUTHOR]

This editorial discusses the importance of nanoparticles and nanomaterials in various fields such as energy, storage, bioimaging, biosensors, catalysts, nanomedicine, batteries, solar energy, and bioenergy. The special issue presents research on different types of nanoparticles and nanomaterials, including organic, inorganic, polymeric, biomolecules, and bio-nanomaterials. The synthesis and characterization of nanoparticles and nanomaterials are highlighted as crucial for engineering their physicochemical properties. The issue also emphasizes the need to consider and minimize the toxicity and environmental effects of nanoparticles. The editorial concludes by stating that continuous research is necessary to fully realize the potential applications of nanoparticles and nanomaterials in various fields. [Extracted from the article]

In recent years, research has focused on developing materials exhibiting outstanding mechanical, electrical, thermal, catalytic, magnetic and optical properties such as graphene/polymer, graphene/metal nanoparticles and graphene/ceramic nanocomposites. Two-dimensional sp2 hybridized graphene has become a material of choice in research due to the excellent properties it displays electrically, thermally, optically and mechanically. Noble nanomaterials also present special physical and chemical properties and, therefore, they provide model building blocks in modifying nanoscale structures for various applications, ranging from nanomedicine to catalysis and optics. The introduction of noble metal nanoparticles (NPs) (Au, Ag and Pd) into chemically derived graphene is important in opening new avenues for both materials in different fields where they can provide hybrid materials with exceptional performance due to the synergistical result of the specific properties of each of the materials. This review presents the different synthetic procedures for preparing Pt, Ag, Pd and Au NP/graphene oxide (GO) and reduced graphene oxide (rGO) composites. [ABSTRACT FROM AUTHOR]

This Special Issue highlights the last decade's progress regarding new nanostructured materials. In this regard, the development of nanoscale syntheses and innovative characterization tools that resulted in the tailored design of nanostructured materials with versatile abilities in many applications were investigated. Various types of engineered nanostructures, usually metal nanoparticles or nanoporous metal oxides, have been synthesized for various applications. This Special Issue covers the state-of-the-art of advanced nanoparticles in many disciplines (chemistry, pharmacy, nanomedicine, agriculture, catalysis, and environmental science). The crystallite sizes depended on the annealing temperature and type of doping ion. A combination of rigid and soft particles could simultaneously enhance both the tensile properties and the fracture toughness, which could not be achieved by the single-phase particles independently. The surface charge and in vitro corrosion resistance are key parameters characterizing biomaterials in the interaction of the implant with the biological environment. Solar energy in the presence of a photocatalyst can be effectively converted into electricity/fuel, break down chemical and microbial pollutants, and help water purification. The saturation magnetization, remanent magnetizations, coercivity, and anisotropy were found to depend on the doping ion, annealing temperature, and particle size. The efficiency of the photocatalysis reaction depends on several factors, including light absorption capacity/light intensity, the type of photocatalyst used, the concentration of a photocatalyst and contaminant particles, the pH of the reaction medium, etc. The variety of color pigments and coloring properties of the targeted application in the ceramic industry was also of interest. [ABSTRACT FROM AUTHOR]

The appearance and increasing number of microorganisms resistant to the action of antibiotics is one of the global problems of the 21st century. Already, the duration of therapeutic treatment and mortality from infectious diseases caused by pathogenic microorganisms have increased significantly over the last few decades. Nanoscale inorganic materials (metals and metal oxides) with antimicrobial potential are a promising solution to this problem. Here we discuss possible mechanisms of pathogenic microorganisms' resistance to antibiotics, proposed mechanisms of action of inorganic nanoparticles on bacterial cells, and the possibilities and benefits of their combined use with antibacterial drugs. The prospects of using metal and metal oxide nanoparticles as carriers in targeted delivery systems for antibacterial compositions are also discussed. [ABSTRACT FROM AUTHOR]

The study of nanoparticles (NPs) and their application in different areas of research, including biomedicine, is attracting the attention of researchers worldwide. Numerous investigations published during the last 20 years cover the fabrication of new materials in the nanoscale, and several uses have been proposed. Metallic nanoparticles (MNPs) have generated a high level of interest, based on improved optical, electrical and magnetic properties, ease of manufacturing, small sizes, and easy functionalization. However, when it comes to Biomedicine, particle aggregation, possible toxicity, and the need for effective cell internalization, still demand active investigation. The main strategy to overcome these drawbacks is possibly the use of capping agents to increase the stability of the particles in dispersion, their biocompatibility and functionalization. In this review, important concepts and characteristics of MNPs, are collected and described. The importance of surface coating for biomedical applications of metallic nanoparticles as well as the most used capping agents and metallic nanomaterials, are also discussed. Finally, the text includes examples and essential characteristics for the biomedical use of MNPs, including the consideration of important challenges. Aspects such as relevant biological activity, increased biocompatibility and functionalization potential are among the most desirable attributes of a capping agent. [ABSTRACT FROM AUTHOR]

In recent years, the bottom-up approach has emerged as a powerful tool in the fabrication of functional nanomaterials through the self-assembly of nanoscale building blocks. The cues embedded at the molecular level provide a handle to control and direct the assembly of nano-objects to construct higher-order structures. Molecular recognition among the building blocks can assist their precise positioning in a predetermined manner to yield nano- and microstructures that may be difficult to obtain otherwise. A well-orchestrated combination of top-down fabrication and directed self-assembly-based bottom-up approach enables the realization of functional nanomaterial-based devices. Among the various available molecular recognition-based "host–guest" combinations, cyclodextrin-mediated interactions possess an attractive attribute that the interaction is driven in aqueous environments, such as in biological systems. Over the past decade, cyclodextrin-based specific host–guest interactions have been exploited to design and construct structural and functional nanomaterials based on cyclodextrin-coated metal nanoparticles. The focus of this review is to highlight recent advances in the self-assembly of cyclodextrin-coated metal nanoparticles driven by the specific host–guest interaction. [ABSTRACT FROM AUTHOR]

Amorphous chromium oxide confined Ni/NiO nanoparticles-assembled nanosheets are designed for highly efficient and stable overall urea splitting. [Display omitted] Applications of urea oxidation reaction (UOR) in various sustainable energy-conversion systems are greatly hindered by its slow kinetics. Herein, we demonstrate an in - situ confined synthesis method that produces amorphous chromium oxide confined Ni/NiO nanoparticles-assembled nanosheets (Ni/NiO@CrO x) with fast reaction kinetics towards UOR. The confinement effect of the in - situ generated CrO x overlay contributes to ultrafine Ni/NiO nanoparticles, bringing about rich Ni/NiO and NiO/CrO x interfaces. In - situ Raman and electrochemical characterization show that both CrO x and metallic Ni can promote the formation of the NiOOH species and the electron transfer, leading to high intrinsic activity and fast reaction kinetics. At 1.40 V vs. reversible hydrogen electrode, the Ni/NiO@CrO x delivers a current density of 275 mA cm−2, which is about 2.6 and 6.1 times as large as those of the NiO@CrO x and NiO, respectively. In addition, the protective effect of the CrO x overlay leads to robust working stability towards UOR. Further, the Ni/NiO@CrO x nanosheets are used as bifunctional catalysts for overall urea splitting, and a small electrolysis cell voltage of 1.44 V is needed to reach the benchmark current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

Nanoscale metal is considered the backbone of biomedical nanotechnology. Recently, there has been an exponential increase in nanoscale materials' biomedical applications. These nanomaterials have mainly been employed in drug delivery systems, prosthetic implants, diagnostics, and therapeutics of various diseases, including cancer. Nanoscale materials have two major classes, namely organic and inorganic nanomaterials. Given the merit of excellent biocompatibility, facile synthesis, target recognition, prolonged circulation half-life, and deference to surface functionalization, the inorganic (metallic) nanoparticles hold promising applications in biomedicine. Their biomedical properties may vary based on their type, size, shape, structure, functionalization, and origin. This review will enlighten the recent advances in nanoscale materials applications as nanoscale-knife in cancer theranostics. Moreover, the external assisted technologies and metallic nanoparticle surface decoration will also be highlighted. [ABSTRACT FROM AUTHOR]

Chemotherapy, the cornerstone of cancer treatment, although invaluable, is plagued with unbearable and occasionally life-threatening side effects due to its inability to discriminate between tumorous and healthy cells. Anticancer nanomedicines have gained prominence due to their site-specific delivery of chemotherapeutic agents. In comparison to traditional chemical and physical procedures, which add to the chemical burden of an already ailing body, biosynthesis of nanomaterials by plants and microorganisms has evolved as safer 'green' nano-manufacturing technology. While nanomedicines from plant extracts have been exhaustively researched, the use of microbes as potential nano factories for the production of metal nanoparticles has recently piqued interest. Many bacteria develop defence mechanisms to detoxify hazardous metal ions, which results in formation of nano scaled metals that can be used for numerous therapeutic applications. The intrinsic variability of microbiological systems, however, poses its own set of challenges, necessitating more stringent standardization protocols in order to create nanomaterials with reproducible attributes. In this paper, we review the emerging trends in the green biosynthesis of nanomaterials and their potential applicability in cancer therapeutics. We probe the microbial biosynthetic mechanistic pathways and the efforts taken to control the physicochemical characteristics of nanoparticles. The applications of metallic nanoparticles obtained from microbes as well as polymeric systems obtained from bacteria, fungi and seaweed in oncology are described in detail. The development of these nanomaterials as next-generation green anticancer drugs may result in a revolution in cancer therapeutics. [ABSTRACT FROM AUTHOR]

Carbon supported metallic nanomaterials are of great interest due to their low‐cost, high durability and promising functional performance. Herein, a highly active oxygen evolution reaction (OER) electrocatalyst comprised of defective carbon shell encapsulated metal (Fe, Co, Ni) nanoparticles and their alloys supported on in‐situ formed N‐doped graphene/carbon nanotube hybrid is synthesized from novel single‐source‐precursors (SSP). The precursors are synthesized by a facile one‐pot reaction of tannic acid with polyethylenimine and different metal ions and subsequent pyrolysis of the SSP. Benefiting from the heteroatom doping of carbon and formation of well‐encapsulated metal/alloy nanoparticles, the obtained FeNi@NC‐900 catalyst possesses lowest overpotentials of 310 mV to achieve a current density of 10 mA cm−2 for OER with a small Tafel slope value of 45 mV dec−1, indicating excellent catalytic performance due to the following features: (1) A synergistic electronic effect among metal alloy nanoparticles, nitrogen‐doped carbon, and entangled carbon nanotubes; (2) penetration of electrolyte is promoted towards the active sites through the porous structure of the formed mesoporous carbon clusters; (3) the unique core‐shell nanostructure of the hybrid material effectively curbs the degradation of electrocatalyst by protecting the alloy nanoparticles from harsh electrolyte. This work advances an inexpensive and facile method towards the development of transition metal‐based hybrid material for potential energy storage and conversion. [ABSTRACT FROM AUTHOR]

Automated computational analysis of nanoparticles is the key approach urgently required to achieve further progress in catalysis, the development of new nanoscale materials, and applications. Analysis of nanoscale objects on the surface relies heavily on scanning electron microscopy (SEM) as the experimental analytic method, allowing direct observation of nanoscale structures and morphology. One of the important examples of such objects is palladium on carbon catalysts, allowing access to various chemical reactions in laboratories and industry. SEM images of Pd/C catalysts show a large number of nanoparticles that are usually analyzed manually. Manual analysis of a statistically significant number of nanoparticles is a tedious and highly time-consuming task that is impossible to perform in a reasonable amount of time for practically needed large amounts of samples. This work provides a comprehensive comparison of various computer vision methods for the detection of metal nanoparticles. In addition, multiple new types of data representations were developed, and their applicability in practice was assessed. [ABSTRACT FROM AUTHOR]

To control the photocatalytic activity, it is essential to consider several parameters affecting the structure of ordered multicomponent TiO2-based photocatalytic nanotubes. The lack of systematic knowledge about the relationship between structure, property, and preparation parameters may be provided by applying a machine learning (ML) methodology and predictive models based on the quantitative structure-property-condition relationship (QSPCR). In the present study, for the first time, the quantitative mapping of preparation parameters, morphology, and photocatalytic activity of 136 TiO2 NTs doped with metal and non-metal nanoparticles synthesized with the one-step anodization method has been investigated via linear and nonlinear ML methods. Moreover, the developed QSPCR model, for the first time, provides systematic knowledge supporting the design of effective TiO2-based nanotubes by proper structure manipulation. The proposed computer-aided methodology reduces cost and speeds up the process (optimize) of efficient photocatalysts' design at the earliest possible stage (before synthesis) in line with the sustainability-by-design strategy. [ABSTRACT FROM AUTHOR]

Currently, there is tremendous interest in the discovery of efficient and low-cost catalysts for the selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to the biofuel 2,5-dimethylfuran (DMF). In this study, a CoNCx/NiFeO catalyst was synthesized by the adsorption of cobalt (II) phthalocyanine (CoPc) on ultrathin NiFe-layered double hydroxide nanosheets (NiFe-LDH), followed by mild pyrolysis of the resulting CoPc/NiFe-LDH composite at 550 °C under N2 for 5 h. XRD, TEM and XPS showed CoNCx/NiFeO to contain CoOx/Co0 and Ni0 nanoparticles on a NiFe-mixed metal oxide support. CoNCx/NiFeO showed very high initial activity and selectivity for the hydrogenation of HMF to DMF in tetrahydrofuran (THF) under mild reaction conditions (180 °C, 1.0 MPa H2, 6.0 h), evidenced by a 99.8% HMF conversion and 94.3% DMF selectivity. Reaction pathways for the conversion of HMF to DMF over CoNCx/NiFeO were revealed by monitoring the intermediates formed at different stages of the reaction. In this study, a CoNCx/NiFeO catalyst was synthesized by the adsorption of cobalt (II) phthalocyanine (CoPc) on ultrathin NiFe-layered double hydroxide nanosheets (NiFe-LDH), which showed very high initial activity and selectivity for the hydrogenation of HMF to DMF. [ABSTRACT FROM AUTHOR]

As renewable energy is becoming a crucial energy source to meet the global demand, electrochemical energy storage devices become indispensable for efficient energy storage and reliable supply. The electrode material is the key factor determining the energy storage capacity and the power delivery of the devices. Carbon-based materials, specifically graphite, activated carbons etc, are extensively used as electrodes, yet their low energy densities impede the development of advanced energy storage materials. Decoration by nanoparticles of metals, metal oxides, nitrides, carbides, phosphides, chalcogenides and bimetallic components is one of the most promising and easy-to-implement strategies to significantly enhance the structural and electronic properties, pore refinement, charge storage and charge-transfer kinetics of both pristine and doped carbon structures, thereby making their performance promising for next-generation energy storage devices. Structuring the materials at nanoscale is another probable route for better rate performance and charge-transfer kinetics. This review covers the state-of-art nanoparticle decorated nanocarbons (NCs) as materials for battery anode, metal-ion capacitor anode and supercapacitor electrode. A critical analysis of the elemental composition, structure, associated physico-chemical properties and performance relationships of nanoparticle-decorated NC electrodes is provided as well to inform the future development of the next-generation advanced energy storage materials and devices. [ABSTRACT FROM AUTHOR]

Controlling cells using photo-responsive materials is highly indispensable in the current biomedical sector. Considering the potential side effects of nanoparticles, it has become a challenge to control cells with photo-responsive materials. Recent studies have described several methods for controlling cell behavior using nanoparticles subjected to the near-infrared (NIR) laser light operating at the wavelength of 808 nm to 980 nm and at the power densities of 0.33 to 0.72 W·cm−2. The challenge here is the preparation of biocompatible nanoparticles for both in vivo and in vitro studies and understanding cell behavior with an external light source recommended for biological application. Earlier studies have well documented many approaches and associated mechanisms for controlling cell behavior and the interaction between nanoparticles, cells, and appropriate external light sources. In this review, various nanomaterials such as metal nanomaterials and carbon-based nanomaterials are compared systematically regarding the effects of controlling cell behavior and inflammation by studying their mechanisms, route of administration, dose, and adverse effects such as toxicity and the interaction of nanoparticles with a specific wavelength of the light. Future directions should focus on stable and efficient light-responsive materials with minimal cytotoxicity. [ABSTRACT FROM AUTHOR]

Using experimental results and a theoretical model, we establish a relation for the optical response of a mixed nanocolloid. We show that colloids prepared by mixing metal and semiconductor nanocolloids in various ratios result in a mixture composed of a particular metal-semiconductor hybrid nanostructure and unattached original particles. Thus, the properties of hybrid samples prepared by such self-organized growth are decided by the variation in number density of the hybrid and the unattached particles and not due to a continuous change in the interaction between metal nanoparticles and semiconductor quantum dots as was assumed earlier. Using these results, a method to prepare a single type of hybrid nanostructure by measuring only its optical response is presented. [ABSTRACT FROM AUTHOR]

Green synthesis of metal nanoparticles and nanocomposites offers numerous advantages over conventional methods. The present study deals with the synthesis of Ag nanoparticles and Ag@MoS2 nanocomposites by Dracocephalum kotschyi extract as a reductant and a stabilising agent. The influence of extract volume, reaction temperature, contact time and pH on the synthesis of d-AgNPs was investigated. Further, the modified MoS2 using D. kotschyi extract (d-MoS2) could deposit Ag+ ions onto the MoS2 nanosheets surface, reduce the ions to AgNPs, and stabilise the reduced particles effectively. The synthesised nanostructures were characterised by XRD, SEM-EDS, TEM, Zeta potential and FT-IR analysis. Ag nanoparticles are spherical with diameter of 58–75 nm for d-AgNPs and 35–55 nm for Ag@d-MoS2, respectively. The d-AgNPs exhibited high activity in the inhibition of acetylcholinesterase. Also, loading of AgNPs on MoS2 nanosheets resulted in the increase of inhibitory activity against acetylcholinesterase compared to MoS2 nanosheets. [ABSTRACT FROM AUTHOR]

As a promising metal-free photocatalyst, graphitic carbon nitride (g-C3N4) is still limited by insufficient visible light absorption and rapid recombination of photogenerated carriers, resulting in low photocatalytic activity. Here, we adjusted the microstructure of the pristine bulk-g-C3N4 (PCN) and further loaded silver (Ag) nanoparticles. Abundant Ag nanoparticles were grown on the thin-layer g-C3N4 nanosheets (CNNS), and the Ag nanoparticles decorated g-C3N4 nanosheets (Ag@CNNS) were successfully synthesized. The thin-layer nanosheet-like structure was not only beneficial for the loading of Ag nanoparticles but also for the adsorption and activation of reactants via exposing more active sites. Moreover, the surface plasmon resonance (SPR) effect induced by Ag nanoparticles enhanced the absorption of visible light by narrowing the band gap of the substrate. Meanwhile, the composite band structure effectively promoted the separation and transfer of carriers. Benefiting from these merits, the Ag@CNNS reached a superior hydrogen peroxide (H2O2) yield of 120.53 μmol/g/h under visible light irradiation in pure water (about 8.0 times higher than that of PCN), significantly surpassing most previous reports. The design method of manipulating the microstructure of the catalyst combined with the modification of metal nanoparticles provides a new idea for the rational development and application of efficient photocatalysts. [ABSTRACT FROM AUTHOR]

The multifunctional features of noble metal nanoparticles (MNPs) were exploited in various biomedical applications, which eventually demanded the development of a sustainable green synthesis approach. In the present study, Quercetin (Q) was employed as a promising green reductant for the generation of noble metal nanoparticles such as silver (Q-AgNPs), gold (Q-AuNPs), and bimetallic (Q-Ag-AuNPs) towards biomedical perspective. Initially, the NPs were successfully synthesized in a size-controlled manner via optimizing temperature, pH, metal ion concentration, and stoichiometric ratio of the reaction mix. The redox reaction and conversion of metal ions (Ag+ and Au3+) into their respective metal nano-forms were confirmed through their surface plasmonic resonance (SPR) in UV-visible spectroscopy. In addition, different instrumentation like FT-IR, XRD, HR-TE M, and XPS analyses were performed to confirm the size, shape, and chemical composition of fabricated NPs. The bactericidal effect of fabricated NPs was tested against Gram-positive and Gram-negative pathogens. Moreover, the cytotoxic potential was screened against breast (MCF-7) and colorectal (HCT-116) carcinoma cell lines. This work revealed that the flavonoid-functionalized noble metal NPs were associated with good antibacterial and anticancer potential against selected cancer cell lines. [ABSTRACT FROM AUTHOR]

g-C 3 N 4 has shown great potentials in photocatalytic water splitting to produce hydrogen. Herein, we successfully synthesized g-C 3 N 4 nanosheets via exfoliating bulk g-C 3 N 4. And different metal nanoparticles were photo-deposited onto the surface of g-C 3 N 4 nanosheets. The photocatalytic H 2 production activity of g-C 3 N 4 nanosheets increased from 0 to 11.2 μmol/h/g cat. The Pt loaded g-C 3 N 4 nanosheets manifested the highest H 2 production activity with a rate of 589.4 μmol/h/g cat. In addition, the hydrogen evolution rate was further enhanced with addition of external bias to fabricate a photoelectrocatalytic (PEC) system. And the maximum hydrogen production rate (23.1 mmol/h/m2) was obtained at a voltage of 0.6 V (vs. Ag/AgCl). The enhancement in H 2 production may be due to the following reasons: (1) Two-dimensional atomic flakes is beneficial to increase the specific surface area of g-C 3 N 4 , enhance the mobility of carriers, and improve the energy band structure, (2) Pt nanoparticles play an important role in g-C 3 N 4 electron transport, (3) the g-C 3 N 4 nanosheets loaded with Pt nanoparticles exhibited significant enhancement in photoelectrocatalytic performance, which may be attributed to its enhanced electronic conductivity and photoelectrochemical surface area, (4) Pt inhibited the recombination of photogenerated carriers and significantly improved the photocatalytic performance. The enhancement mechanism was deeply discussed and explained in this work. [Display omitted] • The Pt-loaded C 3 N 4 nanosheets was synthesized. • Pt 0.3 -C 3 N 4 –N exhibited good photocatalytic activity for H 2 production, with a rate of 589.4 μmol/h/g cat. • Pt 0.3 -C 3 N 4 –N showed good photoelectrocatalytic activity for H 2 production, reaching 23.1 mmol/h/m2. • Pt acts as a reservoir of photogenerated charge carriers, inhibiting its recombination. [ABSTRACT FROM AUTHOR]

The use of microbial adsorption for metal ions to prepare novel carbon-supported metal nanomaterials has attracted growing research attention. However, the relationship between the adsorbed metal content and catalytic performance of the resulting nanomaterials is unclear. In this work, Pichia pastoris residues was utilized to adsorb Ce(â...˘) at different metal ion concentrations, and then CeO2@C nanomaterials were prepared by pyrolysis. The effects of solution pH and adsorption behavior were investigated. The prepared nanostructures were characterized using electron microscopy and different spectroscopy methods, and their catalytic performances in the removal of salicylic acid from solution by catalytic ozonation were invested. The microbial residue had a metal uptake of 172.00 ± 2.82 mg· gâˆ'1 at pH 6. In addition, the efficiency of total organic carbon (TOC) removal increased from 21.54% to 34.10% with an increase in metal content in the catalysts from 0 mg· gâˆ'1 to 170.05 mg· gâˆ'1. After pyrolysis, the absorbed Ce(â...˘) metal transformed to CeO2 metal nanoparticles embedded in a carbon matrix and had a coreâ€"shell CeO2@C structure. Therefore, this work not only reveals a relationship between metal content and catalytic performance, but also provides an approach for studying performance of materials with different metal contents loaded on various carriers. [ABSTRACT FROM AUTHOR]

The development of new approaches to treat the growing antibiotic resistance of pathogenic bacterial species is an important task to ensure the future safety of society. Utilization of irradiation of different wavelengths together with nanostructured materials based on metal containing nanoparticles may result in synergetic antibacterial effects. In this paper we aim to show the main conceptions of light-assisted bacteria deactivation techniques and prospects of application of natural clay nanotubes as a carrier for scalable photoactive antibacterial nanomaterials. Halloysite aluminosilicate nanotubes (ca 50 nm diameter, ca. 1.0 μm length) are safe and biocompatible natural materials produced in tons. Their application as a template or a carrier for metal nanoparticles, QDs and organic compounds has already found application in biomedical research, cosmetics, polymers, coatings, catalysis and related applications. Here, we show the toxicity of halloysite decorated with photoactive nanoparticles on prokaryotic and eukaryotic cells. The formation of light active nanostructured materials with this clay as the base is a promising tool for solving the problem of the antibiotic resistance of microorganisms. [ABSTRACT FROM AUTHOR]

Heavy crude oil is one of the most potential fossil fuels at present and in the future. However, its high viscosity severely hinders its recovery from reservoir conditions. Heavy oil viscosity reduction is rather essential for its exploitation and transportation. Applying nanomaterials as viscosity reducer for heavy crude oil is an emerging research topic in petroleum industry. In this review, the recent progress about different nanomaterials that have been used in heavy oil viscosity reduction was summarized. These nanomaterials were roughly divided into four kinds: silicon oxide nanoparticles, metal oxide nanoparticles, carbon nanotubes, modified nanoparticles and nanocomposites. The properties of the nanomaterials, including chemical property, concentration and injection form, size and the operational conditions such as temperature, different heavy oil and field application were discussed. At the same time, the possible oil viscosity reduction mechanisms including asphaltenes adsorption, disruption of asphaltene aggregates and heavy oil viscoelastic network, recombination of hydrogen bonds for different nanoparticles were summarized. The challenges and future work for this technology are proposed at the end. Nanomaterials for heavy oil viscosity reduction are expected to make a huge impact on petroleum industry. [ABSTRACT FROM AUTHOR]