Nanomaterials

10 pages, 1688 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Nanoscale Structure of Langmuir–Blodgett Film of Bent-Core Molecules

by Fabrizio Corrado Adamo, Federica Ciuchi, Maria Penelope De Santo, Paola Astolfi, Isabelle Warner, Eric Scharrer, Michela Pisani, Francesco Vita and Oriano Francescangeli

Nanomaterials 2022, 12(13), 2285; https://doi.org/10.3390/nano12132285 - 2 Jul 2022

Cited by 3 | Viewed by 2173

Abstract

Bent-core mesogens (BCMs) are a class of thermotropic liquid crystals featuring several unconventional properties. However, the interpretation and technological exploitation of their unique behavior have been hampered by the difficulty of controlling their anchoring at surfaces. To tackle this issue, we report the [...] Read more.

Bent-core mesogens (BCMs) are a class of thermotropic liquid crystals featuring several unconventional properties. However, the interpretation and technological exploitation of their unique behavior have been hampered by the difficulty of controlling their anchoring at surfaces. To tackle this issue, we report the nanoscale structural characterization of BCM films prepared using the Langmuir–Blodgett technique. Even though BCMs are quite different from typical amphiphilic molecules, we demonstrate that stable molecular films form over water, which can then be transferred onto silicon substrates. The combination of Brewster angle microscopy, atomic force microscopy, and X-ray reflectivity measurements shows that the molecules, once transferred onto a solid substrate, form a bilayer structure with a bottom layer of flat molecules and an upper layer of upright molecules. These results suggest that Langmuir–Blodgett films of BCMs can provide a useful means to control the alignment of this class of liquid crystals. Full article

(This article belongs to the Special Issue Recent Advances in Nanostructured Liquid Crystals: From Supramolecular Order to Applications)

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13 pages, 3842 KiB

Open AccessEditor’s ChoiceArticle

Far-Field and Non-Intrusive Optical Mapping of Nanoscale Structures

by Guorong Guan, Aiqin Zhang, Xiangsheng Xie, Yan Meng, Weihua Zhang, Jianying Zhou and Haowen Liang

Nanomaterials 2022, 12(13), 2274; https://doi.org/10.3390/nano12132274 - 1 Jul 2022

Cited by 6 | Viewed by 2455

Abstract

Far-field high-density optics storage and readout involve the interaction of a sub-100 nm beam profile laser to store and retrieve data with nanostructure media. Hence, understanding the light–matter interaction responding in the far-field in such a small scale is essential for effective optical [...] Read more.

Far-field high-density optics storage and readout involve the interaction of a sub-100 nm beam profile laser to store and retrieve data with nanostructure media. Hence, understanding the light–matter interaction responding in the far-field in such a small scale is essential for effective optical information processing. We present a theoretical analysis and an experimental study for far-field and non-intrusive optical mapping of nanostructures. By a comprehensive analytical derivation for interaction between the modulated light and the target in a confocal laser scanning microscopy (CLSM) configuration, it is found that the CLSM probes the local density of states (LDOSs) in the far field rather than the sample geometric morphology. With a radially polarized (RP) light for illumination, the far-field mapping of LDOS at the optical resolution down to 74 nm is obtained. In addition, it is experimentally verified that the target morphology is mapped only when the far-field mapping of LDOS coincides with the geometric morphology, while light may be blocked from entering the nanostructures medium with weak or missing LDOS, hence invalidating high-density optical information storage and retrieval. In this scenario, nanosphere gaps as small as 33 nm are clearly observed. We further discuss the characterization for far-field and non-intrusive interaction with nanostructures of different geometric morphology and compare them with those obtainable with the projection of near-field LDOS and scanning electronic microscopic results. Full article

(This article belongs to the Special Issue New Challenges in Nanofilm and Nanowire Characterization)

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18 pages, 5933 KiB

Open AccessEditor’s ChoiceArticle

The Influence of Synthesis Method on the Local Structure and Electrochemical Properties of Li-Rich/Mn-Rich NMC Cathode Materials for Li-Ion Batteries

by Mylène Hendrickx, Andreas Paulus, Maria A. Kirsanova, Marlies K. Van Bael, Artem M. Abakumov, An Hardy and Joke Hadermann

Nanomaterials 2022, 12(13), 2269; https://doi.org/10.3390/nano12132269 - 30 Jun 2022

Cited by 7 | Viewed by 4566

Abstract

Electrochemical energy storage plays a vital role in combating global climate change. Nowadays lithium-ion battery technology remains the most prominent technology for rechargeable batteries. A key performance-limiting factor of lithium-ion batteries is the active material of the positive electrode (cathode). Lithium- and manganese-rich [...] Read more.

Electrochemical energy storage plays a vital role in combating global climate change. Nowadays lithium-ion battery technology remains the most prominent technology for rechargeable batteries. A key performance-limiting factor of lithium-ion batteries is the active material of the positive electrode (cathode). Lithium- and manganese-rich nickel manganese cobalt oxide (LMR-NMC) cathode materials for Li-ion batteries are extensively investigated due to their high specific discharge capacities (>280 mAh/g). However, these materials are prone to severe capacity and voltage fade, which deteriorates the electrochemical performance. Capacity and voltage fade are strongly correlated with the particle morphology and nano- and microstructure of LMR-NMCs. By selecting an adequate synthesis strategy, the particle morphology and structure can be controlled, as such steering the electrochemical properties. In this manuscript we comparatively assessed the morphology and nanostructure of LMR-NMC (Li_1.2Ni_0.13Mn_0.54Co_0.13O₂) prepared via an environmentally friendly aqueous solution-gel and co-precipitation route, respectively. The solution-gel (SG) synthesized material shows a Ni-enriched spinel-type surface layer at the {200} facets, which, based on our post-mortem high-angle annual dark-field scanning transmission electron microscopy and selected-area electron diffraction analysis, could partly explain the retarded voltage fade compared to the co-precipitation (CP) synthesized material. In addition, deviations in voltage fade and capacity fade (the latter being larger for the SG material) could also be correlated with the different particle morphology obtained for both materials. Full article

(This article belongs to the Topic Batteries, Supercapacitors, Fuel Cells and Combined Energy/Power Supply Systems)

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19 pages, 4359 KiB

Open AccessEditor’s ChoiceArticle

Understanding of the Electrochemical Behavior of Lithium at Bilayer-Patched Epitaxial Graphene/4H-SiC

by Ivan Shtepliuk, Mikhail Vagin, Ziyauddin Khan, Alexei A. Zakharov, Tihomir Iakimov, Filippo Giannazzo, Ivan G. Ivanov and Rositsa Yakimova

Nanomaterials 2022, 12(13), 2229; https://doi.org/10.3390/nano12132229 - 29 Jun 2022

Cited by 2 | Viewed by 2643

Abstract

Novel two-dimensional materials (2DMs) with balanced electrical conductivity and lithium (Li) storage capacity are desirable for next-generation rechargeable batteries as they may serve as high-performance anodes, improving output battery characteristics. Gaining an advanced understanding of the electrochemical behavior of lithium at the electrode [...] Read more.

Novel two-dimensional materials (2DMs) with balanced electrical conductivity and lithium (Li) storage capacity are desirable for next-generation rechargeable batteries as they may serve as high-performance anodes, improving output battery characteristics. Gaining an advanced understanding of the electrochemical behavior of lithium at the electrode surface and the changes in interior structure of 2DM-based electrodes caused by lithiation is a key component in the long-term process of the implementation of new electrodes into to a realistic device. Here, we showcase the advantages of bilayer-patched epitaxial graphene on 4H-SiC (0001) as a possible anode material in lithium-ion batteries. The presence of bilayer graphene patches is beneficial for the overall lithiation process because it results in enhanced quantum capacitance of the electrode and provides extra intercalation paths. By performing cyclic voltammetry and chronoamperometry measurements, we shed light on the redox behavior of lithium at the bilayer-patched epitaxial graphene electrode and find that the early-stage growth of lithium is governed by the instantaneous nucleation mechanism. The results also demonstrate the fast lithium-ion transport (~4.7–5.6 × 10⁻⁷ cm²∙s⁻¹) to the bilayer-patched epitaxial graphene electrode. Raman measurements complemented by in-depth statistical analysis and density functional theory calculations enable us to comprehend the lithiation effect on the properties of bilayer-patched epitaxial graphene and ascribe the lithium intercalation-induced Raman G peak splitting to the disparity between graphene layers. The current results are helpful for further advancement of the design of graphene-based electrodes with targeted performance. Full article

(This article belongs to the Special Issue Emerging Two-Dimensional Materials: Inspiring Nanotechnologies for Smart Energy Management)

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12 pages, 17526 KiB

Open AccessEditor’s ChoiceArticle

Performance Enhancement of SPR Biosensor Using Graphene–MoS₂ Hybrid Structure

by Haoyuan Cai, Mengwei Wang, Zhuohui Wu, Jing Liu and Xiaoping Wang

Nanomaterials 2022, 12(13), 2219; https://doi.org/10.3390/nano12132219 - 28 Jun 2022

Cited by 22 | Viewed by 3232

Abstract

We investigate a high-sensitivity surface plasmon resonance (SPR) biosensor consisting of a Au layer, four-layer MoS₂, and monolayer graphene. The numerical simulations, by the transfer matrix method (TMM), demonstrate the sensor has a maximum sensitivity of 282°/RIU, which is approximately 2 [...] Read more.

We investigate a high-sensitivity surface plasmon resonance (SPR) biosensor consisting of a Au layer, four-layer MoS₂, and monolayer graphene. The numerical simulations, by the transfer matrix method (TMM), demonstrate the sensor has a maximum sensitivity of 282°/RIU, which is approximately 2 times greater than the conventional Au-based SPR sensor. The finite difference time domain (FDTD) indicates that the presence of MoS₂ film generates a strong surface electric field and enhances the sensitivity of the proposed SPR sensor. In addition, the influence of the number of MoS₂ layers on the sensitivity of the proposed sensor is investigated by simulations and experiments. In the experiment, MoS₂ and graphene films are transferred on the Au-based substrate by the PMMA-based wet transfer method, and the fabricated samples are characterized by Raman spectroscopy. Furthermore, the fabricated sensors with the Kretschmann configuration are used to detect okadaic acid (OA). The okadaic acid–bovine serum albumin bioconjugate (OA-BSA) is immobilized on the graphene layer of the sensors to develop a competitive inhibition immunoassay. The results show that the sensor has a very low limit of detection (LOD) of 1.18 ng/mL for OA, which is about 22.6 times lower than that of a conventional Au biosensor. We believe that such a high-sensitivity SPR biosensor has potential applications for clinical diagnosis and immunoassays. Full article

(This article belongs to the Special Issue Nanotechnologies and Nanomaterials: Selected Papers from CCMR)

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17 pages, 4886 KiB

Open AccessEditor’s ChoiceArticle

Application of Micro/Nanoporous Fluoropolymers with Reduced Bioadhesion in Digital Microfluidics

by Andreas Goralczyk, Sagar Bhagwat, Fadoua Mayoussi, Niloofar Nekoonam, Kai Sachsenheimer, Peilong Hou, Frederik Kotz-Helmer, Dorothea Helmer and Bastian E. Rapp

Nanomaterials 2022, 12(13), 2201; https://doi.org/10.3390/nano12132201 - 27 Jun 2022

Cited by 6 | Viewed by 3238

Abstract

Digital microfluidics (DMF) is a versatile platform for conducting a variety of biological and chemical assays. The most commonly used set-up for the actuation of microliter droplets is electrowetting on dielectric (EWOD), where the liquid is moved by an electrostatic force on a [...] Read more.

Digital microfluidics (DMF) is a versatile platform for conducting a variety of biological and chemical assays. The most commonly used set-up for the actuation of microliter droplets is electrowetting on dielectric (EWOD), where the liquid is moved by an electrostatic force on a dielectric layer. Superhydrophobic materials are promising materials for dielectric layers, especially since the minimum contact between droplet and surface is key for low adhesion of biomolecules, as it causes droplet pinning and cross contamination. However, superhydrophobic surfaces show limitations, such as full wetting transition between Cassie and Wenzel under applied voltage, expensive and complex fabrication and difficult integration into already existing devices. Here we present Fluoropor, a superhydrophobic fluorinated polymer foam with pores on the micro/nanoscale as a dielectric layer in DMF. Fluoropor shows stable wetting properties with no significant changes in the wetting behavior, or full wetting transition, until potentials of 400 V. Furthermore, Fluoropor shows low attachment of biomolecules to the surface upon droplet movement. Due to its simple fabrication process, its resistance to adhesion of biomolecules and the fact it is capable of being integrated and exchanged as thin films into commercial DMF devices, Fluoropor is a promising material for wide application in DMF. Full article

(This article belongs to the Special Issue Functional Nanostructured Materials—from Synthesis to Applications)

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20 pages, 4191 KiB

Open AccessEditor’s ChoiceArticle

Efficient Removal of Methylene Blue and Ciprofloxacin from Aqueous Solution Using Flower-like, Nanostructured ZnO Coating under UV Irradiation

by Vasile Tiron, Mihai Alexandru Ciolan, Georgiana Bulai, Gabriela Mihalache, Florin Daniel Lipsa and Roxana Jijie

Nanomaterials 2022, 12(13), 2193; https://doi.org/10.3390/nano12132193 - 26 Jun 2022

Cited by 12 | Viewed by 2907

Abstract

Flower-like ZnO architectures assembled with many nanorods were successfully synthesized through Thermionic Vacuum Arc, operated both in direct current (DC-TVA) and a pulsed mode (PTVA), and coupled with annealing in an oxygen atmosphere. The prepared coatings were analysed by scanning-electron microscopy with energy-dispersive [...] Read more.

Flower-like ZnO architectures assembled with many nanorods were successfully synthesized through Thermionic Vacuum Arc, operated both in direct current (DC-TVA) and a pulsed mode (PTVA), and coupled with annealing in an oxygen atmosphere. The prepared coatings were analysed by scanning-electron microscopy with energy-dispersive X-ray-spectroscopy (SEM-EDX), X-ray-diffraction (XRD), and photoluminescence (PL) measurements. By simply modifying the TVA operation mode, the morphology and uniformity of ZnO nanorods can be tuned. The photocatalytic performance of synthesized nanostructured ZnO coatings was measured by the degradation of methylene-blue (MB) dye and ciprofloxacin (Cipro) antibiotic. The ZnO (PTVA) showed enhancing results regarding the photodegradation of target contaminants. About 96% of MB molecules were removed within 60 min of UV irradiation, with a rate constant of 0.058 min⁻¹, which is almost nine times higher than the value of ZnO (DC-TVA). As well, ZnO (PTVA) presented superior photocatalytic activity towards the decomposition of Cipro, after 240 min of irradiation, yielding 96% degradation efficiency. Moreover, the agar-well diffusion assay performance against both Gram-positive and Gram-negative bacteria confirms the degradation of antibiotic molecules by the UV/ZnO (PTVA) approach, without the formation of secondary hazardous products during the photocatalysis process. Repeated cyclic usage of coatings revealed excellent reusability and operational stability. Full article

(This article belongs to the Special Issue Nanostructured and Functional Nanomaterials for Energy Storage and Removal of Pollutants)

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18 pages, 14678 KiB

Open AccessEditor’s ChoiceArticle

In Vivo Evaluation of the Effects of Sintering Temperature on the Optical Properties of Dental Glass-Ceramics

by Kuo-Cheng Fan, Yu-Ling Lin, Hao-Wei Tsao, Hsuan Chen, Sheng-Yang Lee, Yu-Chen Cheng, Hsiao-Ping Huang and Wei-Chun Lin

Nanomaterials 2022, 12(13), 2187; https://doi.org/10.3390/nano12132187 - 25 Jun 2022

Cited by 12 | Viewed by 3236

Abstract

In prosthodontics, the ability of glass-ceramics to express the optical properties of natural teeth is an important goal of esthetic restorations. Dental restorations do not merely need to be similar in color to natural teeth; proper optical properties, such as opalescence, transparency, etc., [...] Read more.

In prosthodontics, the ability of glass-ceramics to express the optical properties of natural teeth is an important goal of esthetic restorations. Dental restorations do not merely need to be similar in color to natural teeth; proper optical properties, such as opalescence, transparency, etc., must be combined in order to achieve excellent esthetic effects. The optical properties of ceramic materials are mainly distinguished by different hues (e.g., A, B, C, and D) combined with translucency (e.g., high translucency (HT), medium translucency (MT), low translucency (LT), and medium opacity (MO)). However, there are many varieties of tooth color. Therefore, it is expected that glass-ceramics can change their nanocrystal size and porosity through different heat-treatment temperatures and times and, thereby, present different transparency effects. This study mainly analyzed the influence of changes in sintering temperature on the optical properties of glass-ceramics. The optical properties of glass-ceramics in the oral cavity were evaluated with human trials. We hypothesized that (1) the transparency of glass-ceramics can be changed by controlling the sintering temperature and (2) glass-ceramics modified by the sintering temperature can be suitable for clinical applications. Results showed that the transparency decreased, the nanoparticle size increased, the crystallinity increased, and the surface hardness decreased as the sintering temperature increased. High-brightness glass-ceramics have more-sensitive optical properties. Results of clinical trials showed that glass-ceramics whose transparency was changed by controlling the sintering temperature can be candidates for clinical applications. Based on the above results, the hypotheses of this study were supported. In the future, we will continue to explore the esthetic field of dental restorations. Full article

(This article belongs to the Special Issue Biocompatible Dental Nanomaterials: State of the Art and Perspectives)

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17 pages, 3724 KiB

Open AccessEditor’s ChoiceArticle

Microstructure and Electrical Conductivity of Electrospun Titanium Oxynitride Carbon Composite Nanofibers

by Gorazd Koderman Podboršek, Špela Zupančič, Rok Kaufman, Angelja Kjara Surca, Aleš Marsel, Andraž Pavlišič, Nejc Hodnik, Goran Dražić and Marjan Bele

Nanomaterials 2022, 12(13), 2177; https://doi.org/10.3390/nano12132177 - 24 Jun 2022

Cited by 3 | Viewed by 4273

Abstract

Titanium oxynitride carbon composite nanofibers (TiON/C-CNFs) were synthesised with electrospinning and subsequent heat treatment in ammonia gas. In situ four-probe electrical conductivity measurements of individual TiON/C-CNFs were performed. Additionally, the TiON/C-CNFs were thoroughly analysed with various techniques, such as X-ray and electron diffractions, [...] Read more.

Titanium oxynitride carbon composite nanofibers (TiON/C-CNFs) were synthesised with electrospinning and subsequent heat treatment in ammonia gas. In situ four-probe electrical conductivity measurements of individual TiON/C-CNFs were performed. Additionally, the TiON/C-CNFs were thoroughly analysed with various techniques, such as X-ray and electron diffractions, electron microscopies and spectroscopies, thermogravimetric analysis and chemical analysis to determine the crystal structure, morphology, chemical composition, and N/O at. ratio. It was found that nanofibers were composed of 2–5 nm sized titanium oxynitride (TiON) nanoparticles embedded in an amorphous carbon matrix with a small degree of porosity. The average electrical conductivity of a single TiON/C-CNF was 1.2 kS/m and the bulk electrical conductivity of the TiON/C-CNF fabric was 0.053 kS/m. From the available data, the mesh density of the TiON/C-CNF fabric was estimated to have a characteristic length of 1.0 µm and electrical conductivity of a single TiON/C-CNF was estimated to be from 0.45 kS/m to 19 kS/m. The electrical conductivity of the measured TiON/C-CNFs is better than that of amorphous carbon nanofibers and has ohmic behaviour, which indicates that it can effectively serve as a new type of support material for electrocatalysts, batteries, sensors or supercapacitors. Full article

(This article belongs to the Section Energy and Catalysis)

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11 pages, 1830 KiB

Open AccessEditor’s ChoiceArticle

The Design of Aluminum-Matrix Composites Reinforced with AlCoCrFeNi High-Entropy Alloy Nanoparticles by First-Principles Studies on the Properties of Interfaces

by Yu Liu and Guangping Zheng

Nanomaterials 2022, 12(13), 2157; https://doi.org/10.3390/nano12132157 - 23 Jun 2022

Cited by 6 | Viewed by 2413

Abstract

The present work reports the interfacial behaviors and mechanical properties of AlCoCrFeNi high-entropy alloy (HEA) reinforced aluminum matrix composites (AMCs) based on first-principles calculations. It is found the stability of HEA-reinforced AMCs is strongly dependent on the local chemical compositions in the interfacial [...] Read more.

The present work reports the interfacial behaviors and mechanical properties of AlCoCrFeNi high-entropy alloy (HEA) reinforced aluminum matrix composites (AMCs) based on first-principles calculations. It is found the stability of HEA-reinforced AMCs is strongly dependent on the local chemical compositions in the interfacial regions, i.e., those regions containing more Ni atoms (>25%) or fewer Al atoms (<20%) render more stable interfaces in the HEA-reinforced AMCs. It is calculated that the interfacial energy of Al(001)/Al₂₀Co₁₉Cr₁₉Fe₁₉Ni₁₉(001) interfaces varies from −0.242 eV/Å² to −0.192 eV/Å², suggesting that the formation of interfaces at (100) atomic plane is energetically favorable. For those constituent alloy elements presented at the interfaces, Ni could stabilize the interface whereas Al tends to deteriorate the stability of interface. It is determined that although the HEA-reinforced AMCs have less yield strength compared to aluminum, their Young’s modulus is enhanced from 69 GPa for pure Al to 134 GPa. Meanwhile, the meaningful plasticity under tension could also be improved, which are related to the chemical compositions at the interfaces. The results presented in this work could facilitate the designs of compositions and interfacial behaviors of HEA-reinforced AMCs for structural applications. Full article

(This article belongs to the Special Issue Design of Nanomaterials by Computer Simulation and Artificial Intelligence Approaches)

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13 pages, 6465 KiB

Open AccessEditor’s ChoiceArticle

Formamidinium Lead Halide Perovskite Nanocomposite Scintillators

by Isabel H. B. Braddock, Maya Al Sid Cheikh, Joydip Ghosh, Roma E. Mulholland, Joseph G. O’Neill, Vlad Stolojan, Carol Crean, Stephen J. Sweeney and Paul J. Sellin

Nanomaterials 2022, 12(13), 2141; https://doi.org/10.3390/nano12132141 - 22 Jun 2022

Cited by 19 | Viewed by 3952

Abstract

While there is great demand for effective, affordable radiation detectors in various applications, many commonly used scintillators have major drawbacks. Conventional inorganic scintillators have a fixed emission wavelength and require expensive, high-temperature synthesis; plastic scintillators, while fast, inexpensive, and robust, have low atomic [...] Read more.

While there is great demand for effective, affordable radiation detectors in various applications, many commonly used scintillators have major drawbacks. Conventional inorganic scintillators have a fixed emission wavelength and require expensive, high-temperature synthesis; plastic scintillators, while fast, inexpensive, and robust, have low atomic numbers, limiting their X-ray stopping power. Formamidinium lead halide perovskite nanocrystals show promise as scintillators due to their high X-ray attenuation coefficient and bright luminescence. Here, we used a room-temperature, solution-growth method to produce mixed-halide FAPbX

_{3}

(X = Cl, Br) nanocrystals with emission wavelengths that can be varied between 403 and 531 nm via adjustments to the halide ratio. The substitution of bromine for increasing amounts of chlorine resulted in violet emission with faster lifetimes, while larger proportions of bromine resulted in green emission with increased luminescence intensity. By loading FAPbBr

_{3}

nanocrystals into a PVT-based plastic scintillator matrix, we produced 1 mm-thick nanocomposite scintillators, which have brighter luminescence than the PVT-based plastic scintillator alone. While nanocomposites such as these are often opaque due to optical scattering from aggregates of the nanoparticles, we used a surface modification technique to improve transmission through the composites. A composite of FAPbBr

_{3}

nanocrystals encapsulated in inert PMMA produced even stronger luminescence, with intensity 3.8× greater than a comparative FAPbBr

_{3}

/plastic scintillator composite. However, the luminescence decay time of the FAPbBr

_{3}

/PMMA composite was more than 3× slower than that of the FAPbBr

_{3}

/plastic scintillator composite. We also demonstrate the potential of these lead halide perovskite nanocomposite scintillators for low-cost X-ray imaging applications. Full article

(This article belongs to the Special Issue New Advances for Halide Perovskite Materials and Applications)

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15 pages, 1550 KiB

Open AccessEditor’s ChoiceArticle

Towards Perfect Ultra-Broadband Absorbers, Ultra-Narrow Waveguides, and Ultra-Small Cavities at Optical Frequencies

by Kiyanoush Goudarzi and Moonjoo Lee

Nanomaterials 2022, 12(13), 2132; https://doi.org/10.3390/nano12132132 - 21 Jun 2022

Viewed by 2114

Abstract

In this study, we design ultra-broadband optical absorbers, ultra-narrow optical waveguides, and ultra-small optical cavities comprising two-dimensional metallic photonic crystals that tolerate fabrication imperfections such as position and radius disorderings. The absorbers containing gold rods show an absorption amplitude of more than 90% [...] Read more.

In this study, we design ultra-broadband optical absorbers, ultra-narrow optical waveguides, and ultra-small optical cavities comprising two-dimensional metallic photonic crystals that tolerate fabrication imperfections such as position and radius disorderings. The absorbers containing gold rods show an absorption amplitude of more than 90% under 54% position disordering at

200 < λ < 530

nm. The absorbers containing silver rods show an absorptance of more than 90% under 54% position disordering at

200 < λ < 400

nm. B-type straight waveguides that contain four rows of silver rods exposed to air reveal normalized transmittances of 75% and 76% under 32% position and 60% radius disorderings, respectively. B-type L-shaped waveguides containing four rows of silver rods show 76% and 90% normalized transmittances under 32% position and 40% radius disorderings, respectively. B-type cavities containing two rings of silver rods reveal 70% and 80% normalized quality factors under 32% position and 60% radius disorderings, respectively. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

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18 pages, 3252 KiB

Open AccessEditor’s ChoiceArticle

Microwave-Assisted Synthesis of Zn₂SnO₄ Nanostructures for Photodegradation of Rhodamine B under UV and Sunlight

by Ana Rovisco, Maria Morais, Rita Branquinho, Elvira Fortunato, Rodrigo Martins and Pedro Barquinha

Nanomaterials 2022, 12(12), 2119; https://doi.org/10.3390/nano12122119 - 20 Jun 2022

Cited by 10 | Viewed by 3212

Abstract

The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications [...] Read more.

The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications since they present wide band gaps and high surface areas. Among the photocatalytic oxide nanostructures, zinc tin oxide (ZTO) presents itself as an eco-friendly alternative since its composition includes abundant and non-toxic zinc and tin, instead of critical elements. Moreover, ZTO nanostructures have a multiplicity of structures and morphologies possible to be obtained through low-cost solution-based syntheses. In this context, the current work presents an optimization of ZTO nanostructures (polyhedrons, nanoplates, and nanoparticles) obtained by microwave irradiation-assisted hydrothermal synthesis, toward photocatalytic applications. The nanostructures’ photocatalytic activity in the degradation of rhodamine B under both ultraviolet (UV) irradiation and natural sunlight was evaluated. Among the various morphologies, ZTO nanoparticles revealed the best performance, with degradation > 90% being achieved in 60 min under UV irradiation and in 90 min under natural sunlight. The eco-friendly production process and the demonstrated ability of these nanostructures to be used in various water decontamination processes reinforces their sustainability and the role they can play in a circular economy. Full article

(This article belongs to the Special Issue Selected Papers from the 2nd International Online Conference on Nanomaterials)

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12 pages, 2802 KiB

Open AccessEditor’s ChoiceArticle

Artificial Synapse Consisted of TiSbTe/SiC_x:H Memristor with Ultra-high Uniformity for Neuromorphic Computing

by Liangliang Chen, Zhongyuan Ma, Kangmin Leng, Tong Chen, Hongsheng Hu, Yang Yang, Wei Li, Jun Xu, Ling Xu and Kunji Chen

Nanomaterials 2022, 12(12), 2110; https://doi.org/10.3390/nano12122110 - 19 Jun 2022

Cited by 3 | Viewed by 2601

Abstract

To enable a-SiC_x:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC_0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into [...] Read more.

To enable a-SiC_x:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC_0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into an a-SiC_0.11:H memristor, and successfully observed the ultra-high uniformity of the TiSbTe/a-SiC_0.11:H memristor device. Compared with the a-SiC_0.11:H memristor, the cycle-to-cycle coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC_0.11:H memristors was reduced by 92.5% and 66.4%, respectively. Moreover, the device-to-device coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC_0.11:H memristors decreased by 93.6% and 86.3%, respectively. A high-resolution transmission electron microscope revealed that a permanent TiSbTe nanocrystalline conductive nanofilament was formed in the TiSbTe layer during the DC sweeping process. The localized electric field of the TiSbTe nanocrystalline was beneficial for confining the position of the conductive filaments in the a-SiC_0.11:H film, which contributed to improving the uniformity of the device. The temperature-dependent I-V characteristic further confirmed that the bridge and rupture of the Si dangling bond nanopathway was responsible for the resistive switching of the TiSbTe/a-SiC_0.11:H device. The ultra-high uniformity of the TiSbTe/a-SiC_0.11:H device ensured the successful implementation of biosynaptic functions such as spike-duration-dependent plasticity, long-term potentiation, long-term depression, and spike-timing-dependent plasticity. Furthermore, visual learning capability could be simulated through changing the conductance of the TiSbTe/a-SiC_0.11:H device. Our discovery of the ultra-high uniformity of TiSbTe/a-SiC_0.11:H memristor devices provides an avenue for their integration into the next generation of AI chips. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 3632 KiB

Open AccessEditor’s ChoiceArticle

Zn and Zn-Fe Nanostructures with Multifunctional Properties as Components for Food Packaging Materials

by Hafsae Lamsaf, Lina F. Ballesteros, Miguel A. Cerqueira, José A. Teixeira, Lorenzo M. Pastrana, Luís Rebouta, Sandra Carvalho and Sebastian Calderon

Nanomaterials 2022, 12(12), 2104; https://doi.org/10.3390/nano12122104 - 18 Jun 2022

Viewed by 2881

Abstract

Metallic and bimetallic nanostructures have shown interesting chromatic and antibacterial properties, and they can be used in various applications. In this work, zinc (Zn) and iron (Fe) nanostructures were produced with different morphologies: (i) pure Zn; (ii) Zn-Fe nanoalloys; (iii) Zn-Fe nanolayers (Zn-Fe [...] Read more.

Metallic and bimetallic nanostructures have shown interesting chromatic and antibacterial properties, and they can be used in various applications. In this work, zinc (Zn) and iron (Fe) nanostructures were produced with different morphologies: (i) pure Zn; (ii) Zn-Fe nanoalloys; (iii) Zn-Fe nanolayers (Zn-Fe NLs); and (iv) Zn nanolayers combined with Fe nanoparticles (Zn NLs + Fe NPs). The aim was to produce components for food packaging materials with active and intelligent properties, including oxygen absorption capacity, chromatic properties, and antibacterial properties. Thus, the morphology, structure, and chemical composition of the samples were characterized and correlated with their oxidation, chromatic, and antibacterial properties. The results revealed a relevant reduction in the coating’s opacity after oxidation varying from 100 to 10% depending on the morphology of the system. All coatings exhibited significant antibacterial activity against S. aureus, revealing a direct correlation with Zn content. The incorporation of Fe for all atomic arrangements showed a negative impact on the antibacterial effect against E. coli, decreasing to less than half the zone of inhibition for Zn-Fe NLs and Zn NLs + Fe NPs and suppressing the antibacterial effect for Zn-Fe alloy when compared with the pure Zn system. Full article

(This article belongs to the Section Nanocomposite Materials)

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19 pages, 3362 KiB

Open AccessEditor’s ChoiceArticle

Structural-Functional Changes in a Ti₅₀Ni₄₅Cu₅ Alloy Caused by Training Procedures Based on Free-Recovery and Work-Generating Shape Memory Effect

by Mihai Popa, Nicoleta-Monica Lohan, Bogdan Pricop, Nicanor Cimpoeșu, Marieta Porcescu, Radu Ioachim Comăneci, Maria Cazacu, Firuța Borza and Leandru-Gheorghe Bujoreanu

Nanomaterials 2022, 12(12), 2088; https://doi.org/10.3390/nano12122088 - 17 Jun 2022

Cited by 6 | Viewed by 2703

Abstract

Active elements made of Ti₅₀Ni₄₅Cu₅ shape memory alloy (SMA) were martensitic at room temperature (RT) after hot rolling with instant water quenching. These pristine specimens were subjected to two thermomechanical training procedures consisting of (i) free recovery shape [...] Read more.

Active elements made of Ti₅₀Ni₄₅Cu₅ shape memory alloy (SMA) were martensitic at room temperature (RT) after hot rolling with instant water quenching. These pristine specimens were subjected to two thermomechanical training procedures consisting of (i) free recovery shape memory effect (FR-SME) and (ii) work generating shape memory effect (WG-SME) under constant stress as well as dynamic bending and RT static tensile testing (TENS). The structural-functional changes, caused by the two training procedures as well as TENS were investigated by various experimental techniques, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X-ray diffraction (XRD), and atomic force microscopy (AFM). Fragments cut from the active regions of trained specimens or from the elongated gauges of TENS specimens were analyzed by DSC, XRD, and AFM. The DSC thermograms revealed the shift in critical transformation temperatures and a diminution in specific absorbed enthalpy as an effect of training cycles. The DMA thermograms of pristine specimens emphasized a change of storage modulus variation during heating after the application of isothermal dynamical bending at RT. The XRD patterns and AMF micrographs disclosed the different evolution of martensite plate variants as an effect of FR-SME cycling and of being elongated upon convex surfaces or compressed upon concave surfaces of bent specimens. For illustrative reasons, the evolution of unit cell parameters of B19′ martensite, as a function of the number of cycles of FR-SME training, upon concave regions was discussed. AFM micrographs emphasized wider and shallower martensite plates on the convex region as compared to the concave one. With increasing the number of FR-SME training cycles, plates’ heights decreased by 84–87%. The results suggest that FR-SME training caused marked decreases in martensite plate dimensions, which engendered a decrease in specific absorbed enthalpy during martensite reversion. Full article

(This article belongs to the Special Issue Nanostructural Processing Effects in Shape Memory Alloys)

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11 pages, 2158 KiB

Open AccessEditor’s ChoiceArticle

Chain Formation during Hydrogen Loss and Reconstruction in Carbon Nanobelts

by Yuri Tanuma, Paul Dunk, Toru Maekawa and Chris P. Ewels

Nanomaterials 2022, 12(12), 2073; https://doi.org/10.3390/nano12122073 - 16 Jun 2022

Cited by 5 | Viewed by 2070

Abstract

Using laser-induced vaporisation to evaporate and ionise a source of curved polyaromatic hydrocarbons (carbon nanobelts), we show collision impacts between species cause mass loss and the resultant ions are catalogued via mass-spectrometry. These data are interpreted via a series of “in-silico”-simulated systematic hydrogen-loss [...] Read more.

Using laser-induced vaporisation to evaporate and ionise a source of curved polyaromatic hydrocarbons (carbon nanobelts), we show collision impacts between species cause mass loss and the resultant ions are catalogued via mass-spectrometry. These data are interpreted via a series of “in-silico”-simulated systematic hydrogen-loss studies using density functional theory modelling, sequentially removing hydrogen atoms using thermodynamic stability as a selection for subsequent dehydrogenation. Initial hydrogen loss results in the formation of carbyne chains and pentagon-chains while the nanobelt rings are maintained, giving rise to new circular strained dehydrobenzoannulene species. The chains subsequently break, releasing CH and C₂. Alternative routes towards the formation of closed-cages (fullerenes) are identified but shown to be less stable than chain formation, and are not observed experimentally. The results provide important information on collision degradation routes of curved molecular carbon species, and notably serve as a useful guide to high-energy impact conditions observed in some astrochemical environments. Full article

(This article belongs to the Special Issue State-of-the-Art 2D and Carbon Nanomaterials in France)

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20 pages, 5665 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Controlling the Deposition Process of Nanoarchitectonic Nanocomposites Based on {Nb_6−xTa_xXⁱ₁₂}ⁿ⁺ Octahedral Cluster-Based Building Blocks (Xⁱ = Cl, Br; 0 ≤ x ≤ 6, n = 2, 3, 4) for UV-NIR Blockers Coating Applications

by Clément Lebastard, Maxence Wilmet, Stéphane Cordier, Clothilde Comby-Zerbino, Luke MacAleese, Philippe Dugourd, Toru Hara, Naoki Ohashi, Tetsuo Uchikoshi and Fabien Grasset

Nanomaterials 2022, 12(12), 2052; https://doi.org/10.3390/nano12122052 - 15 Jun 2022

Cited by 6 | Viewed by 2556

Abstract

The antagonism between global energy needs and the obligation to slow global warming is a current challenge. In order to ensure sufficient thermal comfort, the automotive, housing and agricultural building sectors are major energy consumers. Solar control materials and more particularly, selective glazing [...] Read more.

The antagonism between global energy needs and the obligation to slow global warming is a current challenge. In order to ensure sufficient thermal comfort, the automotive, housing and agricultural building sectors are major energy consumers. Solar control materials and more particularly, selective glazing are part of the solutions proposed to reduce global energy consumption and tackle global warming. In this context, these works are focused on developing new highly ultraviolet (UV) and near-infrared (NIR) absorbent nanocomposite coatings based on K₄[{Nb_6-xTa_xXⁱ₁₂}X^a₆]. (X = Cl, Br, 0 ≤ x ≤ 6) transition metal cluster compounds. These compounds contain cluster-based active species that are characterized by their strong absorption of UV and NIR radiations as well as their good transparency in the visible range, which makes them particularly attractive for window applications. Their integration, by solution processes, into a silica-polyethylene glycol or polyvinylpyrrolidone matrices is discussed. Of particular interest is the control and the tuning of their optical properties during the integration and shaping processes. The properties of the solutions and films were investigated by complementary techniques (UV-Vis-NIR spectrometry, ESI-MS, SEM, HRTEM, etc.). Results of these works have led to the development of versatile solar control coatings whose optical properties are competitive with commercialized material. Full article

(This article belongs to the Special Issue Functional Nanocomposite Material Based on Metal Atom Clusters)

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17 pages, 4813 KiB

Open AccessEditor’s ChoiceArticle

Magnetic Nanoclusters Increase the Sensitivity of Lateral Flow Immunoassays for Protein Detection: Application to Pneumolysin as a Biomarker for Streptococcus pneumoniae

by María Salvador, José Luis Marqués-Fernández, Alexander Bunge, José Carlos Martínez-García, Rodica Turcu, Davide Peddis, María del Mar García-Suárez, María Dolores Cima-Cabal and Montserrat Rivas

Nanomaterials 2022, 12(12), 2044; https://doi.org/10.3390/nano12122044 - 14 Jun 2022

Cited by 14 | Viewed by 3600

Abstract

Lateral flow immunoassays for detecting biomarkers in body fluids are simple, quick, inexpensive point-of-care tests widely used in disease surveillance, such as during the coronavirus disease 2019 (COVID-19) pandemic. Improvements in sensitivity would increase their utility in healthcare, food safety, and environmental control. [...] Read more.

Lateral flow immunoassays for detecting biomarkers in body fluids are simple, quick, inexpensive point-of-care tests widely used in disease surveillance, such as during the coronavirus disease 2019 (COVID-19) pandemic. Improvements in sensitivity would increase their utility in healthcare, food safety, and environmental control. Recently, biofunctional magnetic nanoclusters have been used to selectively label target proteins, which allows their detection and quantification with a magneto-inductive sensor. This type of detector is easily integrated with the lateral flow immunoassay format. Pneumolysin is a cholesterol-dependent cytolysin and one of the most important protein virulence factors of pneumonia produced by Streptococcus pneumoniae. It is recognized as an important biomarker for diagnosis in urine samples. Pneumonia is the infectious disease that causes the most deaths globally, especially among children under five years and adults over 65 years, most of them in low- and middle-income countries. There especially, a rapid diagnostic urine test for pneumococcal pneumonia with high sensitivity and specificity would be helpful in primary care. In this work, a lateral flow immunoassay with magnetic nanoclusters conjugated to anti-pneumolysin antibodies was combined with two strategies to increase the technique’s performance. First, magnetic concentration of the protein before the immunoassay was followed by quantification by means of a mobile telephone camera, and the inductive sensor resulted in detection limits as low as 0.57 ng (telephone camera) and 0.24 ng (inductive sensor) of pneumolysin per milliliter. Second, magnetic relocation of the particles within the test strip after the immunoassay was completed increased the detected signal by 20%. Such results obtained with portable devices are promising when compared to non-portable conventional pneumolysin detection techniques such as enzyme-linked immunosorbent assays. The combination and optimization of these approaches would have excellent application in point-of-care biodetection to reduce antibiotic misuse, hospitalizations, and deaths from community-acquired pneumonia. Full article

(This article belongs to the Special Issue Functional Nanomaterials for Biosensing Applications)

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16 pages, 7405 KiB

Open AccessEditor’s ChoiceArticle

Characterization of ENM Dynamic Dose-Dependent MOA in Lung with Respect to Immune Cells Infiltration

by Angela Serra, Giusy del Giudice, Pia Anneli Sofia Kinaret, Laura Aliisa Saarimäki, Sarah Søs Poulsen, Vittorio Fortino, Sabina Halappanavar, Ulla Vogel and Dario Greco

Nanomaterials 2022, 12(12), 2031; https://doi.org/10.3390/nano12122031 - 13 Jun 2022

Cited by 8 | Viewed by 3138

Abstract

The molecular effects of exposures to engineered nanomaterials (ENMs) are still largely unknown. In classical inhalation toxicology, cell composition of bronchoalveolar lavage (BAL) is a toxicity indicator at the lung tissue level that can aid in interpreting pulmonary histological changes. Toxicogenomic approaches help [...] Read more.

The molecular effects of exposures to engineered nanomaterials (ENMs) are still largely unknown. In classical inhalation toxicology, cell composition of bronchoalveolar lavage (BAL) is a toxicity indicator at the lung tissue level that can aid in interpreting pulmonary histological changes. Toxicogenomic approaches help characterize the mechanism of action (MOA) of ENMs by investigating the differentially expressed genes (DEG). However, dissecting which molecular mechanisms and events are directly induced by the exposure is not straightforward. It is now generally accepted that direct effects follow a monotonic dose-dependent pattern. Here, we applied an integrated modeling approach to study the MOA of four ENMs by retrieving the DEGs that also show a dynamic dose-dependent profile (dddtMOA). We further combined the information of the dddtMOA with the dose dependency of four immune cell populations derived from BAL counts. The dddtMOA analysis highlighted the specific adaptation pattern to each ENM. Furthermore, it revealed the distinct effect of the ENM physicochemical properties on the induced immune response. Finally, we report three genes dose-dependent in all the exposures and correlated with immune deregulation in the lung. The characterization of dddtMOA for ENM exposures, both for apical endpoints and molecular responses, can further promote toxicogenomic approaches in a regulatory context. Full article

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24 pages, 5227 KiB

Open AccessEditor’s ChoiceArticle

Modulation of Pulmonary Toxicity in Metabolic Syndrome Due to Variations in Iron Oxide Nanoparticle-Biocorona Composition

by Li Xia, Saeed Alqahtani, Christina R. Ferreira, Uma K. Aryal, Katelyn Biggs and Jonathan H. Shannahan

Nanomaterials 2022, 12(12), 2022; https://doi.org/10.3390/nano12122022 - 11 Jun 2022

Cited by 5 | Viewed by 3743

Abstract

Nanoparticles (NPs) interact with biomolecules by forming a biocorona (BC) on their surface after introduction into the body and alter cell interactions and toxicity. Metabolic syndrome (MetS) is a prevalent condition and enhances susceptibility to inhaled exposures. We hypothesize that distinct NP-biomolecule interactions [...] Read more.

Nanoparticles (NPs) interact with biomolecules by forming a biocorona (BC) on their surface after introduction into the body and alter cell interactions and toxicity. Metabolic syndrome (MetS) is a prevalent condition and enhances susceptibility to inhaled exposures. We hypothesize that distinct NP-biomolecule interactions occur in the lungs due to MetS resulting in the formation of unique NP-BCs contributing to enhanced toxicity. Bronchoalveolar lavage fluid (BALF) was collected from healthy and MetS mouse models and used to evaluate variations in the BC formation on 20 nm iron oxide (Fe₃O₄) NPs. Fe₃O₄ NPs without or with BCs were characterized for hydrodynamic size and zeta potential. Unique and differentially associated proteins and lipids with the Fe₃O₄ NPs were identified through proteomic and lipidomic analyses to evaluate BC alterations based on disease state. A mouse macrophage cell line was utilized to examine alterations in cell interactions and toxicity due to BCs. Exposures to 6.25, 12.5, 25, and 50 μg/mL of Fe₃O₄ NPs with BCs for 1 h or 24 h did not demonstrate overt cytotoxicity. Macrophages increasingly associated Fe₃O₄ NPs following addition of the MetS BC compared to the healthy BC. Macrophages exposed to Fe₃O₄ NPs with a MetS-BC for 1 h or 24 h at a concentration of 25 μg/mL demonstrated enhanced gene expression of inflammatory markers: CCL2, IL-6, and TNF-α compared to Fe₃O₄ NPs with a healthy BC. Western blot analysis revealed activation of STAT3, NF-κB, and ERK pathways due to the MetS-BC. Specifically, the Jak/Stat pathway was the most upregulated inflammatory pathway following exposure to NPs with a MetS BC. Overall, our study suggests the formation of distinct BCs due to NP exposure in MetS, which may contribute to exacerbated inflammatory effects and susceptibility. Full article

(This article belongs to the Special Issue Advances in Nano-Bio Interactions: Nanosafety and Nanotoxicology)

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11 pages, 2886 KiB

Open AccessEditor’s ChoiceArticle

Hansen Solubility Parameter Analysis on Dispersion of Oleylamine-Capped Silver Nanoinks and their Sintered Film Morphology

by Satoshi Saita, Shin-ichi Takeda and Hideya Kawasaki

Nanomaterials 2022, 12(12), 2004; https://doi.org/10.3390/nano12122004 - 10 Jun 2022

Cited by 10 | Viewed by 4563

Abstract

Optimizing stabilizers and solvents is crucial for obtaining highly dispersed nanoparticle inks. Generally, nonpolar (hydrophobic) ligand-stabilized nanoparticles show superior dispersibility in nonpolar solvents, whereas polar ligand (hydrophilic)-stabilized nanoparticles exhibit high dispersibility in polar solvents. However, these properties are too qualitative to select optimum [...] Read more.

Optimizing stabilizers and solvents is crucial for obtaining highly dispersed nanoparticle inks. Generally, nonpolar (hydrophobic) ligand-stabilized nanoparticles show superior dispersibility in nonpolar solvents, whereas polar ligand (hydrophilic)-stabilized nanoparticles exhibit high dispersibility in polar solvents. However, these properties are too qualitative to select optimum stabilizers and solvents for stable nanoparticle inks, and researchers often rely on their experiences. This study presents a Hansen solubility parameter (HSP)-based analysis of the dispersibility of oleylamine-capped silver nanoparticle (OAm-Ag NP) inks for optimizing ink preparation. We determined the HSP sphere of the OAm-Ag NPs, defined as the center coordinate, and the interaction radius in 3D HSP space. The solvent’s HSP inside the HSP sphere causes high dispersibility of the OAm-Ag NPs in the solvent. In contrast, the HSPs outside the sphere resulted in low dispersibility in the solvent. Thus, we can quantitatively predict the dispersibility of the OAm-Ag NPs in a given solvent using the HSP approach. Moreover, the HSP sphere method can establish a correlation between the dispersibility of the particles in inks and the sintered film morphology, facilitating electronic application of the nanoparticle inks. The HSP method is also helpful for optimizing stabilizers and solvents for stable nanoparticle inks in printed electronics. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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17 pages, 3920 KiB

Open AccessEditor’s ChoiceArticle

Automated Quantum Dots Purification via Solid Phase Extraction

by Malín G. Lüdicke, Jana Hildebrandt, Christoph Schindler, Ralph A. Sperling and Michael Maskos

Nanomaterials 2022, 12(12), 1983; https://doi.org/10.3390/nano12121983 - 9 Jun 2022

Cited by 5 | Viewed by 2407

Abstract

The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, [...] Read more.

The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types. Full article

(This article belongs to the Topic Synthesis, Properties and Applications of Fluorescent Nanomaterials)

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17 pages, 1651 KiB

Open AccessEditor’s ChoiceArticle

Change in Magnetic Anisotropy at the Surface and in the Bulk of FINEMET Induced by Swift Heavy Ion Irradiation

by Ernő Kuzmann, Sándor Stichleutner, Libor Machala, Jiří Pechoušek, René Vondrášek, David Smrčka, Lukáš Kouřil, Zoltán Homonnay, Michael I. Oshtrakh, András Mozzolai, Vladimir A. Skuratov, Mátyás Kudor, Bence Herczeg and Lajos Károly Varga

Nanomaterials 2022, 12(12), 1962; https://doi.org/10.3390/nano12121962 - 8 Jun 2022

Cited by 6 | Viewed by 2395

Abstract

⁵⁷Fe transmission and conversion electron Mössbauer spectroscopy as well as XRD were used to study the effect of swift heavy ion irradiation on stress-annealed FINEMET samples with a composition of Fe_73.5Si_13.5Nb₃B₉Cu₁. The [...] Read more.

⁵⁷Fe transmission and conversion electron Mössbauer spectroscopy as well as XRD were used to study the effect of swift heavy ion irradiation on stress-annealed FINEMET samples with a composition of Fe_73.5Si_13.5Nb₃B₉Cu₁. The XRD of the samples indicated changes neither in the crystal structure nor in the texture of irradiated ribbons as compared to those of non-irradiated ones. However, changes in the magnetic anisotropy both in the bulk as well as at the surface of the FINEMET alloy ribbons irradiated by 160 MeV ¹³²Xe ions with a fluence of 10¹³ ion cm⁻² were revealed via the decrease in relative areas of the second and fifth lines of the magnetic sextets in the corresponding Mössbauer spectra. The irradiation-induced change in the magnetic anisotropy in the bulk was found to be similar or somewhat higher than that at the surface. The results are discussed in terms of the defects produced by irradiation and corresponding changes in the orientation of spins depending on the direction of the stress generated around these defects. Full article

(This article belongs to the Special Issue Novel RE-free Nanocomposite Magnets)

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15 pages, 1652 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Antibacterial Activity through Silver Nanoparticles Deposited onto Carboxylated Graphene Oxide Surface

by Arturo Barjola, María Ángeles Tormo-Mas, Oscar Sahuquillo, Patricia Bernabé-Quispe, José Manuel Pérez and Enrique Giménez

Nanomaterials 2022, 12(12), 1949; https://doi.org/10.3390/nano12121949 - 7 Jun 2022

Cited by 13 | Viewed by 3139

Abstract

The strong bactericidal action of silver nanoparticles (AgNPs) is usually limited by their degree of aggregation. Deposition of AgNPs onto a graphene oxide (GO) surface to generate GO-Ag hybrids has been shown to be an effective method of controlling these aggregation problems. In [...] Read more.

The strong bactericidal action of silver nanoparticles (AgNPs) is usually limited by their degree of aggregation. Deposition of AgNPs onto a graphene oxide (GO) surface to generate GO-Ag hybrids has been shown to be an effective method of controlling these aggregation problems. In this sense, a novel carboxylated graphene oxide–silver nanoparticle (GOCOOH-Ag) material has been synthesized, and their antibacterial and biofilm formation inhibitions have been studied. AgNPs decorating the GOCOOH surface achieved an average size of 6.74 ± 0.25 nm, which was smaller than that of AgNPs deposited onto the GO surface. In addition, better distribution of AgNPs was achieved using carboxylated material. It is important to highlight the main role of the carboxylic groups in the nucleation and growth of the AgNPs that decorate the GO-based material surface. In vitro antibacterial activity and antibiofilm-forming action were tested against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). Both GO-Ag and GOCOOH-Ag reduced bacterial growth, analyzed by time–kill curves. However, the minimum inhibitory concentration and the minimum bactericidal concentration of GOCOOH-Ag were lower than those of GO-Ag for all strains studied, indicating that GOCOOH-Ag has better antibacterial activity. In addition, both nanomaterials prevent biofilm formation, with a higher reduction of biofilm mass and cell viability in the presence of GOCOOH-Ag. The carboxylation functionalization in GO-based materials can be applied to improve the bactericidal and antibiofilm-forming action of the AgNPs. Full article

(This article belongs to the Topic Application of Graphene-Based Materials)

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11 pages, 2751 KiB

Open AccessEditor’s ChoiceArticle

Circular Optical Phased Arrays with Radial Nano-Antennas

by Qiankun Liu, Daniel Benedikovic, Tom Smy, Ahmad Atieh, Pavel Cheben and Winnie N. Ye

Nanomaterials 2022, 12(11), 1938; https://doi.org/10.3390/nano12111938 - 6 Jun 2022

Cited by 15 | Viewed by 3888

Abstract

On-chip optical phased arrays (OPAs) are the enabling technology for diverse applications, ranging from optical interconnects to metrology and light detection and ranging (LIDAR). To meet the required performance demands, OPAs need to achieve a narrow beam width and wide-angle steering, along with [...] Read more.

On-chip optical phased arrays (OPAs) are the enabling technology for diverse applications, ranging from optical interconnects to metrology and light detection and ranging (LIDAR). To meet the required performance demands, OPAs need to achieve a narrow beam width and wide-angle steering, along with efficient sidelobe suppression. A typical OPA configuration consists of either one-dimensional (1D) linear or two-dimensional (2D) rectangular arrays. However, the presence of grating sidelobes from these array configurations in the far-field pattern limits the aliasing-free beam steering, when the antenna element spacing is larger than half of a wavelength. In this work, we provide numerical analysis for 2D circular OPAs with radially arranged nano-antennas. The circular array geometry is shown to effectively suppress the grating lobes, expand the range for beam steering and obtain narrower beamwidths, while increasing element spacing to about 10 μm. To allow for high coupling efficiency, we propose the use of a central circular grating coupler to feed the designed circular OPA. Leveraging radially positioned nano-antennas and an efficient central grating coupler, our design can yield an aliasing-free azimuthal field of view (FOV) of 360°, while the elevation angle FOV is limited by the far-field beamwidth of the nano-antenna element and its array arrangement. With a main-to-sidelobe contrast ratio of 10 dB, a 110-element OPA offers an elevation FOV of 5° and an angular beamwidth of 1.14°, while an 870-element array provides an elevation FOV up to 20° with an angular beamwidth of 0.35°. Our analysis suggests that the performance of the circular OPAs can be further improved by integrating more elements, achieving larger aliasing-free FOV and narrower beamwidths. Our proposed design paves a new way for the development of on-chip OPAs with large 2D beam steering and high resolutions in communications and LIDAR systems. Full article

(This article belongs to the Special Issue Nanophotonics and Integrated Optics Devices)

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31 pages, 13873 KiB

Open AccessEditor’s ChoiceArticle

One A₃B Porphyrin Structure—Three Successful Applications

by Ion Fratilescu, Anca Lascu, Bogdan Ovidiu Taranu, Camelia Epuran, Mihaela Birdeanu, Ana-Maria Macsim, Eugenia Tanasa, Eugeniu Vasile and Eugenia Fagadar-Cosma

Nanomaterials 2022, 12(11), 1930; https://doi.org/10.3390/nano12111930 - 5 Jun 2022

Cited by 13 | Viewed by 3864

Abstract

Porphyrins are versatile structures capable of acting in multiple ways. A mixed substituted A₃B porphyrin, 5-(3-hydroxy-phenyl)-10,15,20-tris-(3-methoxy-phenyl)-porphyrin and its Pt(II) complex, were synthesised and fully characterised by ¹H- and ¹³C-NMR, TLC, UV-Vis, FT-IR, fluorescence, AFM, TEM and SEM with EDX [...] Read more.

Porphyrins are versatile structures capable of acting in multiple ways. A mixed substituted A₃B porphyrin, 5-(3-hydroxy-phenyl)-10,15,20-tris-(3-methoxy-phenyl)-porphyrin and its Pt(II) complex, were synthesised and fully characterised by ¹H- and ¹³C-NMR, TLC, UV-Vis, FT-IR, fluorescence, AFM, TEM and SEM with EDX microscopy, both in organic solvents and in acidic mediums. The pure compounds were used, firstly, as sensitive materials for sensitive and selective optical and fluorescence detection of hydroquinone with the best results in the range 0.039–6.71 µM and a detection limit of 0.013 µM and, secondly, as corrosion inhibitors for carbon–steel (OL) in an acid medium giving a best performance of 88% in the case of coverings with Pt-porphyrin. Finally, the electrocatalytic activity for the hydrogen and oxygen evolution reactions (HER and OER) of the free-base and Pt-metalated A₃B porphyrins was evaluated in strong alkaline and acidic electrolyte solutions. The best results were obtained for the electrode modified with the metalated porphyrin, drop-casted on a graphite substrate from an N,N-dimethylformamide solution. In the strong acidic medium, the electrode displayed an HER overpotential of 108 mV, at i = −10 mA/cm² and a Tafel slope value of 205 mV/dec. Full article

(This article belongs to the Special Issue Multifunctional Nanomaterials and Hybrid Structures for Sensors, Actuators and Smart Technologies)

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24 pages, 3088 KiB

Open AccessEditor’s ChoiceReview

Reactive Oxygen Species Formed by Metal and Metal Oxide Nanoparticles in Physiological Media—A Review of Reactions of Importance to Nanotoxicity and Proposal for Categorization

by Amanda Kessler, Jonas Hedberg, Eva Blomberg and Inger Odnevall

Nanomaterials 2022, 12(11), 1922; https://doi.org/10.3390/nano12111922 - 4 Jun 2022

Cited by 124 | Viewed by 10073

Abstract

Diffusely dispersed metal and metal oxide nanoparticles (NPs) can adversely affect living organisms through various mechanisms and exposure routes. One mechanism behind their toxic potency is their ability to generate reactive oxygen species (ROS) directly or indirectly to an extent that depends on [...] Read more.

Diffusely dispersed metal and metal oxide nanoparticles (NPs) can adversely affect living organisms through various mechanisms and exposure routes. One mechanism behind their toxic potency is their ability to generate reactive oxygen species (ROS) directly or indirectly to an extent that depends on the dose, metal speciation, and exposure route. This review provides an overview of the mechanisms of ROS formation associated with metal and metal oxide NPs and proposes a possible way forward for their future categorization. Metal and metal oxide NPs can form ROS via processes related to corrosion, photochemistry, and surface defects, as well as via Fenton, Fenton-like, and Haber–Weiss reactions. Regular ligands such as biomolecules can interact with metallic NP surfaces and influence their properties and thus their capabilities of generating ROS by changing characteristics such as surface charge, surface composition, dissolution behavior, and colloidal stability. Interactions between metallic NPs and cells and their organelles can indirectly induce ROS formation via different biological responses. H₂O₂ can also be generated by a cell due to inflammation, induced by interactions with metallic NPs or released metal species that can initiate Fenton(-like) and Haber–Weiss reactions forming various radicals. This review discusses these different pathways and, in addition, nano-specific aspects such as shifts in the band gaps of metal oxides and how these shifts at biologically relevant energies (similar to activation energies of biological reactions) can be linked to ROS production and indicate which radical species forms. The influences of kinetic aspects, interactions with biomolecules, solution chemistry (e.g., Cl⁻ and pH), and NP characteristics (e.g., size and surface defects) on ROS mechanisms and formation are discussed. Categorization via four tiers is suggested as a way forward to group metal and metal oxide NPs based on the ROS reaction pathways that they may undergo, an approach that does not include kinetics or environmental variations. The criteria for the four tiers are based on the ability of the metallic NPs to induce Fenton(-like) and Haber–Weiss reactions, corrode, and interact with biomolecules and their surface catalytic properties. The importance of considering kinetic data to improve the proposed categorization is highlighted. Full article

(This article belongs to the Special Issue Advances in Nano-Bio Interactions: Nanosafety and Nanotoxicology)

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11 pages, 4405 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improving the Stability of Lithium Aluminum Germanium Phosphate with Lithium Metal by Interface Engineering

by Yue Zhang, Hanshuo Liu, Zhong Xie, Wei Qu and Jian Liu

Nanomaterials 2022, 12(11), 1912; https://doi.org/10.3390/nano12111912 - 3 Jun 2022

Cited by 3 | Viewed by 2778

Abstract

Lithium aluminum germanium phosphate (LAGP) solid electrolyte is receiving increasing attention due to its high ionic conductivity and low air sensitivity. However, the poor interface compatibility between lithium (Li) metal and LAGP remains the main challenge in developing all-solid-state lithium batteries (ASSLB) with [...] Read more.

Lithium aluminum germanium phosphate (LAGP) solid electrolyte is receiving increasing attention due to its high ionic conductivity and low air sensitivity. However, the poor interface compatibility between lithium (Li) metal and LAGP remains the main challenge in developing all-solid-state lithium batteries (ASSLB) with a long cycle life. Herein, this work introduces a thin aluminum oxide (Al₂O₃) film on the surface of the LAGP pellet as a physical barrier to Li/LAGP interface by the atomic layer deposition technique. It is found that this layer induces the formation of stable solid electrolyte interphase, which significantly improves the structural and electrochemical stability of LAGP toward metallic Li. As a result, the optimized symmetrical cell exhibits a long lifetime of 360 h with an areal capacity of 0.2 mAh cm⁻² and a current density of 0.2 mA cm⁻². This strategy provides new insights into the stabilization of the solid electrolyte/Li interface to boost the development of ASSLB. Full article

(This article belongs to the Topic Electromaterials for Environment & Energy)

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14 pages, 5632 KiB

Open AccessEditor’s ChoiceArticle

Effectiveness of Oxygen during Sintering of Silver Thin Films Derived by Nanoparticle Ink

by Feng Feng, Haofeng Hong, Xing Gao, Tian Ren, Yuan Ma and Pingfa Feng

Nanomaterials 2022, 12(11), 1908; https://doi.org/10.3390/nano12111908 - 2 Jun 2022

Cited by 6 | Viewed by 3277

Abstract

Silver nanoparticle (NP) inks have been widely used in the ink-jet printing field because of their excellent properties during low-temperature sintering. However, the organic dispersant used to prevent the aggregation and sedimentation of NPs can hinder the sintering process and result in the [...] Read more.

Silver nanoparticle (NP) inks have been widely used in the ink-jet printing field because of their excellent properties during low-temperature sintering. However, the organic dispersant used to prevent the aggregation and sedimentation of NPs can hinder the sintering process and result in the high resistivity of sintered films. In this study, silver thin films derived from silver NP ink with polyvinylpyrrolidone (PVP) dispersant were sintered in different atmospheres of pure nitrogen, air, and pure oxygen. The effect of the oxygen content in the sintering atmosphere on the thermal properties of the ink, the electrical resistivity and microstructure of the sintered films, and the amount of organic residue were studied by using differential scanning calorimetry, the four-point probe method, scanning electron microscopy, Fourier transform infrared spectroscopy, etc. The mechanism of optimizing the film resistivity by influencing the decomposition of the PVP dispersant and the microstructure evolution of the silver thin films through the sintering atmosphere was discussed. The results demonstrated that an oxygen-containing atmosphere could be effective for silver NPs in two ways. First, the oxygen content could enhance the diffusion ability of silver atoms, thus accelerating the stage transition of microstructural evolution at low temperatures. Second, the oxygen content could enable the PVP to decompose at a temperature much lower than in conditions of pure nitrogen, thus helping to finalize the densification of a silver film with a low resistivity of 2.47 μΩ·cm, which is approximately 1.5-fold that of bulk silver. Our findings could serve as a foundation for the subsequent establishment of ink-jet printing equipment and the optimization of the sintering process for printing silver patterns on flexible substrates. Full article

(This article belongs to the Special Issue Nanotechnologies and Nanomaterials: Selected Papers from CCMR)

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13 pages, 1710 KiB

Open AccessEditor’s ChoiceArticle

MPTHub: An Open-Source Software for Characterizing the Transport of Particles in Biorelevant Media

by Leandro Gabriel, Helena Almeida, Marta Avelar, Bruno Sarmento and José das Neves

Nanomaterials 2022, 12(11), 1899; https://doi.org/10.3390/nano12111899 - 1 Jun 2022

Cited by 4 | Viewed by 3702

Abstract

The study of particle transport in different environments plays an essential role in understanding interactions with humans and other living organisms. Importantly, obtained data can be directly used for multiple applications in fields such as fundamental biology, toxicology, or medicine. Particle movement in [...] Read more.

The study of particle transport in different environments plays an essential role in understanding interactions with humans and other living organisms. Importantly, obtained data can be directly used for multiple applications in fields such as fundamental biology, toxicology, or medicine. Particle movement in biorelevant media can be readily monitored using microscopy and converted into time-resolved trajectories using freely available tracking software. However, translation into tangible and meaningful parameters is time consuming and not always intuitive. We developed new software—MPTHub—as an open-access, standalone, user-friendly tool for the rapid and reliable analysis of particle trajectories extracted from video microscopy. The software was programmed using Python and allowed to import and analyze trajectory data, as well as to export relevant data such as individual and ensemble time-averaged mean square displacements and effective diffusivity, and anomalous transport exponent. Data processing was reliable, fast (total processing time of less than 10 s), and required minimal memory resources (up to a maximum of around 150 MB in random access memory). Demonstration of software applicability was conducted by studying the transport of different polystyrene nanoparticles (100–200 nm) in mucus surrogates. Overall, MPTHub represents a freely available software tool that can be used even by inexperienced users for studying the transport of particles in biorelevant media. Full article

(This article belongs to the Special Issue Advances in Nanomaterials for Drug Delivery and Controlled Drug Release)

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10 pages, 4675 KiB

Open AccessEditor’s ChoiceArticle

Achieving High Current Stability of Gated Carbon Nanotube Cold Cathode Electron Source Using IGBT Modulation for X-ray Source Application

by Yajie Guo, Junfan Wang, Baohong Li, Yu Zhang, Shaozhi Deng and Jun Chen

Nanomaterials 2022, 12(11), 1882; https://doi.org/10.3390/nano12111882 - 31 May 2022

Cited by 9 | Viewed by 3042

Abstract

The cold cathode X-ray source has potential application in the field of radiotherapy, which requires a stable dose. In this study, a gated carbon nanotube cold cathode electron gun with high current stability was developed by using Insulated Gate Bipolar Transistor (IGBT) modulation, [...] Read more.

The cold cathode X-ray source has potential application in the field of radiotherapy, which requires a stable dose. In this study, a gated carbon nanotube cold cathode electron gun with high current stability was developed by using Insulated Gate Bipolar Transistor (IGBT) modulation, and its application in X-ray source was explored. Carbon nanotube (CNTs) films were prepared directly on stainless steel substrate by chemical vapor deposition and assembled with control gate and focus electrodes to form an electron gun. A maximum cathode current of 200 μA and approximately 53% transmission rate was achieved. An IGBT was used to modulate and stabilize the cathode current. High stable cathode current with fluctuation less than 0.5% has been obtained for 50 min continuous operation. The electron gun was used in a transmission target X-ray source and a stable X-ray dose rate was obtained. Our study demonstrates the feasibility of achieving high current stability from a gated carbon nanotube cold cathode electron source using IGBT modulation for X-ray source application. Full article

(This article belongs to the Special Issue The Research Related to Nanomaterial Cold Cathode)

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14 pages, 6154 KiB

Open AccessEditor’s ChoiceArticle

Bactericidal and Antiviral Bionic Metalized Nanocoatings

by Mikhail Kryuchkov, Jozef Adamcik and Vladimir L. Katanaev

Nanomaterials 2022, 12(11), 1868; https://doi.org/10.3390/nano12111868 - 30 May 2022

Cited by 10 | Viewed by 3120

Abstract

In diverse living organisms, bionanocoatings provide multiple functionalities, to the surfaces they cover. We have, previously, identified the molecular mechanisms of Turing-based self-assembly of insect corneal nanocoatings and developed forward-engineering approaches to construct multifunctional soft bionic nanocoatings, encompassing the Drosophila protein Retinin. Here, [...] Read more.

In diverse living organisms, bionanocoatings provide multiple functionalities, to the surfaces they cover. We have, previously, identified the molecular mechanisms of Turing-based self-assembly of insect corneal nanocoatings and developed forward-engineering approaches to construct multifunctional soft bionic nanocoatings, encompassing the Drosophila protein Retinin. Here, we expand the versatility of the bionic nanocoatings, by identifying and using diverse Retinin-like proteins and different methods of their metallization, using nickel, silver, and copper ions. Comparative assessment, of the resulting bactericidal, antiviral, and cytotoxic properties, identifies the best protocols, to construct safe and anti-infective metalized bionic nanocoatings. Upscaled application of these protocols, to various public surfaces, may represent a safe and economic approach to limit hazardous infections. Full article

(This article belongs to the Special Issue Prospects of Bioinspired and Biomimetic Materials)

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16 pages, 4496 KiB

Open AccessEditor’s ChoiceArticle

Antibacterial Activity and Mechanism of GO/Cu₂O/ZnO Coating on Ultrafine Glass Fiber

by Manna Li, Zhaofeng Chen, Lixia Yang, Jiayu Li, Jiang Xu, Chao Chen, Qiong Wu, Mengmeng Yang and Tianlong Liu

Nanomaterials 2022, 12(11), 1857; https://doi.org/10.3390/nano12111857 - 29 May 2022

Cited by 13 | Viewed by 3203

Abstract

A GO (graphene oxide)/ZnO/Cu₂O antibacterial coating was successfully sprayed on the ultrafine glass fibers using room temperature hydrothermal synthesis and air spraying techniques. The microstructures of the antibacterial coating were characterized, and the results showed that the Cu₂ONPs (nano [...] Read more.

A GO (graphene oxide)/ZnO/Cu₂O antibacterial coating was successfully sprayed on the ultrafine glass fibers using room temperature hydrothermal synthesis and air spraying techniques. The microstructures of the antibacterial coating were characterized, and the results showed that the Cu₂ONPs (nano particles)/ZnONPs were uniformly dispersed on the surface of GO. Then, the antibacterial properties of the GO/ZnO/Cu₂O (GZC) antibacterial coating were evaluated using the disc diffusion test. It was found that the coating exhibits excellent antibacterial properties and stability against E. coli and S. aureus, and the antibacterial rate of each group of antibacterial powder against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was 100%. To explore the antibacterial mechanism of the GZC antibacterial powder on the ultrafine glass fibers based on the photocatalysis/oxidative stress method, the photoelectric coupling synergistic effect between GZC antibacterial coating was analyzed deeply. The results all showed that the photochemical activity of GZC antibacterial powder was significantly improved compared with pure component materials. The enhancement of its photochemical activity is beneficial to the generation of ROS (including hydroxyl radicals, superoxide anion radicals, etc.), which further confirms the speculation of the photocatalytic/oxidative stress mechanism. Full article

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31 pages, 4680 KiB

Open AccessEditor’s ChoiceArticle

Disclosing the Potential of Fluorinated Ionic Liquids as Interferon-Alpha 2b Delivery Systems

by Margarida L. Ferreira, Nicole S. M. Vieira, Ana L. S. Oliveira, João M. M. Araújo and Ana B. Pereiro

Nanomaterials 2022, 12(11), 1851; https://doi.org/10.3390/nano12111851 - 28 May 2022

Cited by 3 | Viewed by 2154

Abstract

Interferon-alpha 2b (IFN-α 2b) is a therapeutic protein used for the treatment of cancer, viral infections, and auto-immune diseases. Its application is hindered by a low bioavailability and instability in the bloodstream, and the search for new strategies for a target delivery and [...] Read more.

Interferon-alpha 2b (IFN-α 2b) is a therapeutic protein used for the treatment of cancer, viral infections, and auto-immune diseases. Its application is hindered by a low bioavailability and instability in the bloodstream, and the search for new strategies for a target delivery and stabilization of IFN-α 2b to improve its therapeutic efficacy is crucial. Fluorinated ionic liquids (FILs) are promising biomaterials that: (i) can form self-assembled structures; (ii) have complete miscibility in water; and (iii) can be designed to have reduced toxicity. The influence of IFN-α 2b in the aggregation behaviour of FILs and the interactions between them were investigated through conductivity and surface tension measurements, and using electron microscopic and spectroscopy techniques to study FILs feasibility as an interferon-alpha 2b delivery system. The results show that the presence of IFN-α 2b influences the aggregation behaviour of FILs and that strong interaction between the two compounds occurs. The protein might not be fully encapsulated by FILs. However, the FIL can be tailored in the future to carry IFN-α 2b by the formation of a conjugate, which prevents the aggregation of this protein. This work constitutes a first step toward the design and development of FIL-based IFN-α 2b delivery systems. Full article

(This article belongs to the Special Issue Ionic Liquids as Task-Specific Materials)

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15 pages, 2929 KiB

Open AccessEditor’s ChoiceArticle

Disordered Rock-Salt Type Li₂TiS₃ as Novel Cathode for LIBs: A Computational Point of View

by Riccardo Rocca, Mauro Francesco Sgroi, Bruno Camino, Maddalena D’Amore and Anna Maria Ferrari

Nanomaterials 2022, 12(11), 1832; https://doi.org/10.3390/nano12111832 - 27 May 2022

Cited by 7 | Viewed by 2685

Abstract

The development of high-energy cathode materials for lithium-ion batteries with low content of critical raw materials, such as cobalt and nickel, plays a key role in the progress of lithium-ion batteries technology. In recent works, a novel and promising family of lithium-rich sulfides [...] Read more.

The development of high-energy cathode materials for lithium-ion batteries with low content of critical raw materials, such as cobalt and nickel, plays a key role in the progress of lithium-ion batteries technology. In recent works, a novel and promising family of lithium-rich sulfides has received attention. Among the possible structures and arrangement, cubic disordered Li₂TiS₃ has shown interesting properties, also for the formulation of new cell for all-solid-state batteries. In this work, a computational approach based on DFT hybrid Hamiltonian, localized basis functions and the use of the periodic CRYSTAL code, has been set up. The main goal of the present study is to determine accurate structural, electronic, and spectroscopic properties for this class of materials. Li₂TiS₃ precursors as Li₂S, TiS₂, and TiS₃ alongside other formulations and structures such as LiTiS₂ and monoclinic Li₂TiS₃ have been selected as benchmark systems and used to build up a consistent and robust predictive scheme. Raman spectra, XRD patterns, electronic band structures, and density of states have been simulated and compared to available literature data. Disordered rock-salt type Li₂TiS₃ structures have been derived via a solid solution method as implemented into the CRYSTAL code. Representative structures were extensively characterized through the calculations of their electronic and vibrational properties. Furthermore, the correlation between structure and Raman fingerprint was established. Full article

(This article belongs to the Special Issue Computational Study of Nanomaterials)

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16 pages, 1056 KiB

Open AccessEditor’s ChoiceArticle

Physical Characterization and Cellular Toxicity Studies of Commercial NiO Nanoparticles

by Filip Kunc, Michael Bushell, Xiaomei Du, Andre Zborowski, Linda J. Johnston and David C. Kennedy

Nanomaterials 2022, 12(11), 1822; https://doi.org/10.3390/nano12111822 - 26 May 2022

Cited by 12 | Viewed by 1987

Abstract

Nickel oxide (NiO) nanoparticles from several manufacturers with different reported sizes and surface coatings were characterized prior to assessing their cellular toxicity. The physical characterization of these particles revealed that sizes often varied from those reported by the supplier, and that particles were [...] Read more.

Nickel oxide (NiO) nanoparticles from several manufacturers with different reported sizes and surface coatings were characterized prior to assessing their cellular toxicity. The physical characterization of these particles revealed that sizes often varied from those reported by the supplier, and that particles were heavily agglomerated when dispersed in water, resulting in a smaller surface area and larger hydrodynamic diameter upon dispersion. Cytotoxicity testing of these materials showed differences between samples; however, correlation of these differences with the physical properties of the materials was not conclusive. Generally, particles with higher surface area and smaller hydrodynamic diameter were more cytotoxic. While all samples produced an increase in reactive oxygen species (ROS), there was no correlation between the magnitude of the increase in ROS and the difference in cytotoxicity between different materials. Full article

(This article belongs to the Special Issue Effects, Analysis and Applications of Nanomaterials in Biological Systems)

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37 pages, 3379 KiB

Open AccessEditor’s ChoiceReview

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

by Filipa Lebre, Nivedita Chatterjee, Samantha Costa, Eli Fernández-de-Gortari, Carla Lopes, João Meneses, Luís Ortiz, Ana R. Ribeiro, Vânia Vilas-Boas and Ernesto Alfaro-Moreno

Nanomaterials 2022, 12(11), 1810; https://doi.org/10.3390/nano12111810 - 25 May 2022

Cited by 25 | Viewed by 6114

Abstract

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and [...] Read more.

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety. Full article

(This article belongs to the Special Issue Health, Environment and Nanosafety)

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13 pages, 16844 KiB

Open AccessEditor’s ChoiceArticle

Revisiting the van der Waals Epitaxy in the Case of (Bi_0.4Sb_0.6)₂Te₃ Thin Films on Dissimilar Substrates

by Liesbeth Mulder, Daan H. Wielens, Yorick A. Birkhölzer, Alexander Brinkman and Omar Concepción

Nanomaterials 2022, 12(11), 1790; https://doi.org/10.3390/nano12111790 - 24 May 2022

Cited by 2 | Viewed by 2567

Abstract

Ultrathin films of the ternary topological insulator (Bi

_{0.4}

Sb

_{0.6}

)

_{2}

Te

_{3}

are fabricated by molecular beam epitaxy. Although it is generally assumed that the ternary topological insulator tellurides grow by van der Waals epitaxy, our results show that the [...] Read more.

Ultrathin films of the ternary topological insulator (Bi

_{0.4}

Sb

_{0.6}

)

_{2}

Te

_{3}

are fabricated by molecular beam epitaxy. Although it is generally assumed that the ternary topological insulator tellurides grow by van der Waals epitaxy, our results show that the influence of the substrate is substantial and governs the formation of defects, mosaicity, and twin domains. For this comparative study, InP (111)A, Al

_{2}

O

_{3}

(001), and SrTiO

_{3}

(111) substrates were selected. While the films deposited on lattice-matched InP (111)A show van der Waals epitaxial relations, our results point to a quasi-van der Waals epitaxy for the films grown on substrates with a larger lattice mismatch. Full article

(This article belongs to the Special Issue Advances in Topological Materials: Fundamentals, Challenges and Outlook)

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17 pages, 1369 KiB

Open AccessEditor’s ChoiceArticle

Diffraction from Nanocrystal Superlattices

by Antonio Cervellino and Ruggero Frison

Nanomaterials 2022, 12(10), 1781; https://doi.org/10.3390/nano12101781 - 23 May 2022

Viewed by 2096

Abstract

Diffraction from a lattice of periodically spaced crystals is a topic of current interest because of the great development of self-organised superlattices (SL) of nanocrystals (NC). The self-organisation of NC into SL has theoretical interest, but especially a rich application prospect, as the [...] Read more.

Diffraction from a lattice of periodically spaced crystals is a topic of current interest because of the great development of self-organised superlattices (SL) of nanocrystals (NC). The self-organisation of NC into SL has theoretical interest, but especially a rich application prospect, as the coherent organisation has large effects on a wide range of material properties. Diffraction is a key method to understand the type and quality of SL ordering. Hereby, the characteristic diffraction signature of an SL of NC—together with the characteristic types of disorder—are theoretically explored. Full article

(This article belongs to the Special Issue Total Scattering Based Characterization Techniques for Nanostructures)

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17 pages, 55035 KiB

Open AccessEditor’s ChoiceArticle

Machine Learning Approach for Application-Tailored Nanolubricants’ Design

by Jarosław Kałużny, Aleksandra Świetlicka, Łukasz Wojciechowski, Sławomir Boncel, Grzegorz Kinal, Tomasz Runka, Marek Nowicki, Oleksandr Stepanenko, Bartosz Gapiński, Joanna Leśniewicz, Paulina Błaszkiewicz and Krzysztof Kempa

Nanomaterials 2022, 12(10), 1765; https://doi.org/10.3390/nano12101765 - 22 May 2022

Cited by 10 | Viewed by 3050

Abstract

The fascinating tribological phenomenon of carbon nanotubes (CNTs) observed at the nanoscale was confirmed in our numerous macroscale experiments. We designed and employed CNT-containing nanolubricants strictly for polymer lubrication. In this paper, we present the experiment characterising how the CNT structure determines its [...] Read more.

The fascinating tribological phenomenon of carbon nanotubes (CNTs) observed at the nanoscale was confirmed in our numerous macroscale experiments. We designed and employed CNT-containing nanolubricants strictly for polymer lubrication. In this paper, we present the experiment characterising how the CNT structure determines its lubricity on various types of polymers. There is a complex correlation between the microscopic and spectral properties of CNTs and the tribological parameters of the resulting lubricants. This confirms indirectly that the nature of the tribological mechanisms driven by the variety of CNT–polymer interactions might be far more complex than ever described before. We propose plasmonic interactions as an extension for existing models describing the tribological roles of nanomaterials. In the absence of quantitative microscopic calculations of tribological parameters, phenomenological strategies must be employed. One of the most powerful emerging numerical methods is machine learning (ML). Here, we propose to use this technique, in combination with molecular and supramolecular recognition, to understand the morphology and macro-assembly processing strategies for the targeted design of superlubricants. Full article

(This article belongs to the Special Issue Functional Carbon-Based Nanocomposite and Applications)

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11 pages, 1845 KiB

Open AccessEditor’s ChoiceArticle

Gold Ion Beam Milled Gold Zero-Mode Waveguides

by Troy C. Messina, Bernadeta R. Srijanto, Charles Patrick Collier, Ivan I. Kravchenko and Christopher I. Richards

Nanomaterials 2022, 12(10), 1755; https://doi.org/10.3390/nano12101755 - 21 May 2022

Cited by 2 | Viewed by 2745

Abstract

Zero-mode waveguides (ZMWs) are widely used in single molecule fluorescence microscopy for their enhancement of emitted light and the ability to study samples at physiological concentrations. ZMWs are typically produced using photo or electron beam lithography. We report a new method of ZMW [...] Read more.

Zero-mode waveguides (ZMWs) are widely used in single molecule fluorescence microscopy for their enhancement of emitted light and the ability to study samples at physiological concentrations. ZMWs are typically produced using photo or electron beam lithography. We report a new method of ZMW production using focused ion beam (FIB) milling with gold ions. We demonstrate that ion-milled gold ZMWs with 200 nm apertures exhibit similar plasmon-enhanced fluorescence seen with ZMWs fabricated with traditional techniques such as electron beam lithography. Full article

(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)

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10 pages, 2897 KiB

Open AccessEditor’s ChoiceArticle

3D Polymer-Based 1 × 4 MMI Splitter

by Tomas Mizera, Peter Gaso, Dusan Pudis, Martin Ziman, Anton Kuzma and Matej Goraus

Nanomaterials 2022, 12(10), 1749; https://doi.org/10.3390/nano12101749 - 20 May 2022

Cited by 12 | Viewed by 2515

Abstract

Due to the increasing trend of photonic device miniaturisation, there is also an increased need for optical splitting in a small volume. We propose a smart solution to split light in three dimensions (3D). A 3D optical splitter based on multimode interference (MMI) [...] Read more.

Due to the increasing trend of photonic device miniaturisation, there is also an increased need for optical splitting in a small volume. We propose a smart solution to split light in three dimensions (3D). A 3D optical splitter based on multimode interference (MMI) for the wavelength of 1550 nm is here designed, simulated, fabricated and optimised for splitting at 1550 nm. We focus also on the possibility of its direct integration on an optical fibre. The design is focused on the use of 3D laser lithography based on the direct laser writing (DLW) process. The output characteristics are investigated by near-field measurement, where we confirm the successful 1 × 4 splitting on a 158 µm long MMI splitter. Full article

(This article belongs to the Special Issue Nanostructures for Advanced Photonic Devices)

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26 pages, 8054 KiB

Open AccessEditor’s ChoiceReview

Dynamics of Spin Crossover Molecular Complexes

by Thilini K. Ekanayaka, Krishna Prasad Maity, Bernard Doudin and Peter A. Dowben

Nanomaterials 2022, 12(10), 1742; https://doi.org/10.3390/nano12101742 - 19 May 2022

Cited by 18 | Viewed by 4778

Abstract

We review the current understanding of the time scale and mechanisms associated with the change in spin state in transition metal-based spin crossover (SCO) molecular complexes. Most time resolved experiments, performed by optical techniques, rely on the intrinsic light-induced switching properties of this [...] Read more.

We review the current understanding of the time scale and mechanisms associated with the change in spin state in transition metal-based spin crossover (SCO) molecular complexes. Most time resolved experiments, performed by optical techniques, rely on the intrinsic light-induced switching properties of this class of materials. The optically driven spin state transition can be mediated by a rich interplay of complexities including intermediate states in the spin state transition process, as well as intermolecular interactions, temperature, and strain. We emphasize here that the size reduction down to the nanoscale is essential for designing SCO systems that switch quickly as well as possibly retaining the memory of the light-driven state. We argue that SCO nano-sized systems are the key to device applications where the “write” speed is an important criterion. Full article

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14 pages, 4832 KiB

Open AccessEditor’s ChoiceCommunication

Design, Analysis, and Optimization of a Plasmonic Slot Waveguide for Mid-Infrared Gas Sensing

by Parviz Saeidi, Bernhard Jakoby, Gerald Pühringer, Andreas Tortschanoff, Gerald Stocker, Jasmin Spettel, Florian Dubois, Thomas Grille and Reyhaneh Jannesari

Nanomaterials 2022, 12(10), 1732; https://doi.org/10.3390/nano12101732 - 18 May 2022

Cited by 3 | Viewed by 2159

Abstract

In this work, we investigated the optimization of a plasmonic slot waveguide (PSWG) in the mid-IR region particularly for a representative wavelength of 4.26 µm, which is the absorption line of CO₂ and thus particularly relevant for applications. We analysed the mode [...] Read more.

In this work, we investigated the optimization of a plasmonic slot waveguide (PSWG) in the mid-IR region particularly for a representative wavelength of 4.26 µm, which is the absorption line of CO₂ and thus particularly relevant for applications. We analysed the mode features associated with metal-dielectric-metal (MDM), dielectric-metal-dielectric (DMD), and truncated metal film (TMF) structures with respect to the considered PSWG. Subsequently, the mode features of the PSWG were considered based on what we outlined for MDM, DMD, and TMF structures. Furthermore, as confinement factor and propagation length are two crucial parameters for absorption sensing applications, we optimized the PSWG based on a figure of merit (FOM) defined as the product of the aforementioned quantities. To characterize the propagation length, the imaginary part of the effective mode index of a guided mode was considered, leading to a dimensionless FOM. Finally, we investigated the PSWG also for other wavelengths and identified particularly attractive wavelengths and geometries maximizing the FOM. Full article

(This article belongs to the Special Issue Functional Plasmonic Nanostructures)

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13 pages, 3862 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

One-Chip Isolation of Drug-Resistant Acute Myeloid Leukemia Cells with CXCR4-Targeted Magnetic Fluorescent Nanoprobes

by Fan Wang, Yuqi Jiang, Luhai Wang, Yi Chen, Yu Zhang and Ming Ma

Nanomaterials 2022, 12(10), 1711; https://doi.org/10.3390/nano12101711 - 17 May 2022

Cited by 3 | Viewed by 2121

Abstract

Drug resistance and relapse lead to high mortality in acute myeloid leukemia, and studies have shown that CXCR4 overexpression is highly correlated with poor prognosis and drug resistance in leukemia cells. Isolation and detection of AML cells with CXCR4 overexpression will be crucial [...] Read more.

Drug resistance and relapse lead to high mortality in acute myeloid leukemia, and studies have shown that CXCR4 overexpression is highly correlated with poor prognosis and drug resistance in leukemia cells. Isolation and detection of AML cells with CXCR4 overexpression will be crucial to the treatment of AML. In this paper, magnetic nanoparticles were firstly prepared successfully by high-temperature thermal decomposition method, and then characterized by TEM, VSM and DLS. Subsequently CXCR4-targeted magnetic fluorescent nanoprobes conjugated with antibody 12G5 were constructed by stepwise coupling. In cell experiments, the obtained probes demonstrated excellent targeting efficacy to CXCR4 overexpressed AML cells HL-60. In addition, HL-60 cells labelled with the magnetic probes can be magnetic isolated successfully in one microfluidics chip, with efficiency of 82.92 ± 7.03%. Overall, this method utilizes the superiority of superparamagnetic nanomaterials and microfluidic technology to achieve the enrichment and capture of drug-resistant cells in a microfluidic chip, providing a new idea for the isolation and detective of drug-resistant acute myeloid leukemia cells. Full article

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6 pages, 1683 KiB

Open AccessEditor’s ChoiceCommunication

Fast Filling of Microvia by Pre-Settling Particles and Following Cu Electroplating

by Ganglong Li, Zhiyi Li, Junjie Li and Houya Wu

Nanomaterials 2022, 12(10), 1699; https://doi.org/10.3390/nano12101699 - 16 May 2022

Viewed by 2302

Abstract

Microvia interconnectors are a critical element of 3D packaging technology, as they provide the shortest interconnection path between stacked chips. However, low efficiency of microvia filling is a long-standing problem. This study proposed a two-step method to enhance the electroplating filling efficiency by [...] Read more.

Microvia interconnectors are a critical element of 3D packaging technology, as they provide the shortest interconnection path between stacked chips. However, low efficiency of microvia filling is a long-standing problem. This study proposed a two-step method to enhance the electroplating filling efficiency by pre-setting metal particles in microvias and later electroplating the Cu to fill the gaps among the pre-settled particles. Since these particles occupy a certain volume in the microvia, less electroplating Cu is needed for microvia filling, leading to a shorter electroplating period. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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21 pages, 5462 KiB

Open AccessEditor’s ChoiceArticle

Electron-Induced Decomposition of Different Silver(I) Complexes: Implications for the Design of Precursors for Focused Electron Beam Induced Deposition

by Petra Martinović, Markus Rohdenburg, Aleksandra Butrymowicz, Selma Sarigül, Paula Huth, Reinhard Denecke, Iwona B. Szymańska and Petra Swiderek

Nanomaterials 2022, 12(10), 1687; https://doi.org/10.3390/nano12101687 - 15 May 2022

Cited by 9 | Viewed by 2827

Abstract

Focused electron beam induced deposition (FEBID) is a versatile tool to produce nanostructures through electron-induced decomposition of metal-containing precursor molecules. However, the metal content of the resulting materials is often low. Using different Ag(I) complexes, this study shows that the precursor performance depends [...] Read more.

Focused electron beam induced deposition (FEBID) is a versatile tool to produce nanostructures through electron-induced decomposition of metal-containing precursor molecules. However, the metal content of the resulting materials is often low. Using different Ag(I) complexes, this study shows that the precursor performance depends critically on the molecular structure. This includes Ag(I) 2,2-dimethylbutanoate, which yields high Ag contents in FEBID, as well as similar aliphatic Ag(I) carboxylates, aromatic Ag(I) benzoate, and the acetylide Ag(I) 3,3-dimethylbutynyl. The compounds were sublimated on inert surfaces and their electron-induced decomposition was monitored by electron-stimulated desorption (ESD) experiments in ultrahigh vacuum and by reflection−absorption infrared spectroscopy (RAIRS). The results reveal that Ag(I) carboxylates with aliphatic side chains are particularly favourable for FEBID. Following electron impact ionization, they fragment by loss of volatile CO₂. The remaining alkyl radical converts to a stable and equally volatile alkene. The lower decomposition efficiency of Ag(I) benzoate and Ag(I) 3,3-dimethylbutynyl is explained by calculated average local ionization energies (ALIE) which reveal that ionization from the unsaturated carbon units competes with ionization from the coordinate bond to Ag. This can stabilise the ionized complex with respect to fragmentation. This insight provides guidance with respect to the design of novel FEBID precursors. Full article

(This article belongs to the Special Issue Nanomaterials Fabricated by Electron-Beam-Induced Deposition and Related Processes)

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40 pages, 5745 KiB

Open AccessEditor’s ChoiceReview

Carbon-Based Nanocatalysts (CnCs) for Biomass Valorization and Hazardous Organics Remediation

by Dimitrios A. Giannakoudakis, Foteini F. Zormpa, Antigoni G. Margellou, Abdul Qayyum, Ramón Fernando Colmenares-Quintero, Christophe Len, Juan Carlos Colmenares and Konstantinos S. Triantafyllidis

Nanomaterials 2022, 12(10), 1679; https://doi.org/10.3390/nano12101679 - 14 May 2022

Cited by 21 | Viewed by 5286

Abstract

The continuous increase of the demand in merchandise and fuels augments the need of modern approaches for the mass-production of renewable chemicals derived from abundant feedstocks, like biomass, as well as for the water and soil remediation pollution resulting from the anthropogenic discharge [...] Read more.

The continuous increase of the demand in merchandise and fuels augments the need of modern approaches for the mass-production of renewable chemicals derived from abundant feedstocks, like biomass, as well as for the water and soil remediation pollution resulting from the anthropogenic discharge of organic compounds. Towards these directions and within the concept of circular (bio)economy, the development of efficient and sustainable catalytic processes is of paramount importance. Within this context, the design of novel catalysts play a key role, with carbon-based nanocatalysts (CnCs) representing one of the most promising class of materials. In this review, a wide range of CnCs utilized for biomass valorization towards valuable chemicals production, and for environmental remediation applications are summarized and discussed. Emphasis is given in particular on the catalytic production of 5-hydroxymethylfurfural (5-HMF) from cellulose or starch-rich food waste, the hydrogenolysis of lignin towards high bio-oil yields enriched predominately in alkyl and oxygenated phenolic monomers, the photocatalytic, sonocatalytic or sonophotocatalytic selective partial oxidation of 5-HMF to 2,5-diformylfuran (DFF) and the decomposition of organic pollutants in aqueous matrixes. The carbonaceous materials were utilized as stand-alone catalysts or as supports of (nano)metals are various types of activated micro/mesoporous carbons, graphene/graphite and the chemically modified counterparts like graphite oxide and reduced graphite oxide, carbon nanotubes, carbon quantum dots, graphitic carbon nitride, and fullerenes. Full article

(This article belongs to the Special Issue Nanoscale Materials for Water Purification and Catalysis)

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17 pages, 3709 KiB

Open AccessEditor’s ChoiceArticle

Food-Grade Titanium Dioxide Induces Toxicity in the Nematode Caenorhabditis elegans and Acute Hepatic and Pulmonary Responses in Mice

by Giovanni Sitia, Fabio Fiordaliso, Martina B. Violatto, Jennifer Fernandez Alarcon, Laura Talamini, Alessandro Corbelli, Lorena Maria Ferreira, Ngoc Lan Tran, Indranath Chakraborty, Mario Salmona, Wolfgang J. Parak, Luisa Diomede and Paolo Bigini

Nanomaterials 2022, 12(10), 1669; https://doi.org/10.3390/nano12101669 - 13 May 2022

Cited by 14 | Viewed by 2860

Abstract

Food-grade titanium dioxide (E171) contains variable percentages of titanium dioxide (TiO₂) nanoparticles (NPs), posing concerns for its potential effects on human and animal health. Despite many studies, the actual relationship between the physicochemical properties of E171 NPs and their interaction with [...] Read more.

Food-grade titanium dioxide (E171) contains variable percentages of titanium dioxide (TiO₂) nanoparticles (NPs), posing concerns for its potential effects on human and animal health. Despite many studies, the actual relationship between the physicochemical properties of E171 NPs and their interaction with biological targets is still far from clear. We evaluated the impact of acute E171 administration on invertebrate and vertebrate animals. In the nematode, Caenorhabditis elegans, the administration of up to 1.0 mg/mL of E171 did not affect the worm’s viability and lifespan, but significantly impaired its pharyngeal function, reproduction, and development. We also investigated whether the intravenous administration of E171 in mice (at the dose of 6 mg/kg/body weight) could result in an acute over-absorption of filter organs. A significant increase of hepatic titanium concentration and the formation of microgranulomas were observed. Interstitial inflammation and parenchymal modification were found in the lungs, coupled with titanium accumulation. This was probably due to the propensity of TiO₂ NPs to agglomerate, as demonstrated by transmission electron microscopy experiments showing that the incubation of E171 with serum promoted the formation of compact clusters. Overall, these data emphasize the actual risk for human and animal exposure to E171. Full article

(This article belongs to the Special Issue Biological Interactions of Nanomaterials)

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