Nanomaterials

11 pages, 2864 KB

Open AccessEditor’s ChoiceArticle

Interface Synergistic Effect of NiFe-LDH/3D GA Composites on Efficient Electrocatalytic Water Oxidation

by Jiangcheng Zhang, Qiuhan Cao, Xin Yu, Hu Yao, Baolian Su and Xiaohui Guo

Nanomaterials 2024, 14(20), 1661; https://doi.org/10.3390/nano14201661 - 16 Oct 2024

Cited by 5 | Viewed by 2272

Currently, NiFe-LDH exhibits an excellent oxygen evolution reaction (OER) due to the interaction of the two metal elements on the layered double hydroxide (LDH) platform. However, such interaction is still insufficient to compensate for its poor electrical conductivity, limited number of active sites [...] Read more.

Currently, NiFe-LDH exhibits an excellent oxygen evolution reaction (OER) due to the interaction of the two metal elements on the layered double hydroxide (LDH) platform. However, such interaction is still insufficient to compensate for its poor electrical conductivity, limited number of active sites and sluggish dynamics. Herein, a feasible two-step hydrothermal strategy that involves coupling low-conductivity NiFe-LDH with 3D porous graphene aerogel (GA) is proposed. The optimized NiFe-LDH/GA (1:1) produced possesses a 257 mV (10 mA cm⁻²) overpotential and could operate stably for 56 h in an OER. Our investigation demonstrates that the NiFe-LDH/GA has a three-dimensional mesoporous structure, and that there is synergistic interaction between LDH and GA and interfacial reconstruction of NiOOH. Such an interface synergistic coupling effect promotes fast mass transfer and facilitates OER kinetics, and this work offers new insights into designing efficient and stable GA-based electrocatalysts. Full article

(This article belongs to the Special Issue Nanostructured Electrocatalysts for Hydrogen/Oxygen Evolution Reaction)

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11 pages, 1897 KB

Open AccessEditor’s ChoiceArticle

Electrical Transport Properties of PbS Quantum Dot/Graphene Heterostructures

by Haosong Ying, Binbin Wei, Qing Zang, Jiduo Dong, Hao Zhang, Hao Tian, Chunheng Liu and Yang Liu

Nanomaterials 2024, 14(20), 1656; https://doi.org/10.3390/nano14201656 - 16 Oct 2024

Viewed by 2197

Abstract

The integration of PbS quantum dots (QDs) with graphene represents a notable advancement in enhancing the optoelectronic properties of quantum-dot-based devices. This study investigated the electrical transport properties of PbS quantum dot (QD)/graphene heterostructures, leveraging the high carrier mobility of graphene. We fabricated [...] Read more.

The integration of PbS quantum dots (QDs) with graphene represents a notable advancement in enhancing the optoelectronic properties of quantum-dot-based devices. This study investigated the electrical transport properties of PbS quantum dot (QD)/graphene heterostructures, leveraging the high carrier mobility of graphene. We fabricated QD/graphene/SiO₂/Si heterostructures by synthesizing p-type monolayer graphene via chemical vapor deposition and spin-coating PbS QDs on the surface. Then, we used a low-temperature electrical transport measurement system to study the electrical transport properties of the heterostructure under different temperature, gate voltage, and light conditions and compared them with bare graphene samples. The results indicated that the QD/graphene samples exhibited higher resistance than graphene alone, with both resistances slightly increasing with temperature. The QD/graphene samples exhibited significant hole doping, with conductivity increasing from 0.0002 Ω⁻¹ to 0.0007 Ω⁻¹ under gate voltage modulation. As the temperature increased from 5 K to 300 K, hole mobility decreased from 1200 cm²V⁻¹s⁻¹ to 400 cm²V⁻¹s⁻¹ and electron mobility decreased from 800 cm²V⁻¹s⁻¹ to 200 cm²V⁻¹s⁻¹. Infrared illumination reduced resistance, thereby enhancing conductivity, with a resistance change of about 0.4%/mW at a gate voltage of 125 V, demonstrating the potential of these heterostructures for infrared photodetector applications. These findings offer significant insights into the charge transport mechanisms in low-dimensional materials, paving the way for high-performance optoelectronic devices. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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16 pages, 4116 KB

Open AccessEditor’s ChoiceArticle

Doxorubicin Incorporation into Gold Nanoparticles: An In Vivo Study of Its Effects on Cardiac Tissue in Rats

by Patricia Lorena Dulf, Camelia Alexandra Coadă, Adrian Florea, Remus Moldovan, Ioana Baldea, Daniel Vasile Dulf, Dan Blendea, Luminita David, Bianca Moldovan, Valentina Ioana Morosan, Sergiu Macavei and Gabriela Adriana Filip

Nanomaterials 2024, 14(20), 1647; https://doi.org/10.3390/nano14201647 - 14 Oct 2024

Cited by 1 | Viewed by 2478

Abstract

Gold nanoparticles (Au-NPs) have been explored as potential vectors for enhancing the antitumor efficacy of doxorubicin (DOX) while minimizing its cardiotoxic effects. However, the impacts of DOX Au-NPs on cardiac function and oxidative stress remain inadequately understood. This study aimed to explore the [...] Read more.

Gold nanoparticles (Au-NPs) have been explored as potential vectors for enhancing the antitumor efficacy of doxorubicin (DOX) while minimizing its cardiotoxic effects. However, the impacts of DOX Au-NPs on cardiac function and oxidative stress remain inadequately understood. This study aimed to explore the effects of DOX Au-NPs in comparison to free DOX, focusing on oxidative stress markers, inflammation, ultrastructural changes, and cardiac function. Male rats were divided into the following four groups: control, citrate Au-NPs, DOX, and DOX Au-NPs. Cardiac function was assessed using echocardiography, and oxidative stress was evaluated through Nrf2, malondialdehyde (MDA) and superoxide dismutase (SOD) levels, and the GSH/GSSG ratio. The ultrastructure of cardiac tissue was assessed by transmission electron microscopy (TEM). Rats treated with DOX Au-NPs exhibited significant cardiac dysfunction, as indicated by a reduction in fractional shortening and ejection fraction. Oxidative stress markers, including elevated MDA levels and a reduced GSH/GSSG ratio, were significantly worse in the DOX Au-NP group. SOD levels decreased, indicating compromised antioxidant defenses. Citrate Au-NPs also caused some alterations in cardiac function and ultrastructure but without other molecular alterations. DOX Au-NPs failed to mitigate cardiotoxicity, instead exacerbating oxidative stress and cardiac dysfunction. DOX Au-NPs possess cardiotoxic effects, necessitating further investigation into alternative nanoparticle formulations or therapeutic combinations to ensure both efficacy and safety in cancer treatment. Full article

(This article belongs to the Special Issue Advances in Toxicity of Nanoparticles in Organisms (2nd Edition))

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22 pages, 2514 KB

Open AccessEditor’s ChoiceArticle

Specialized Pro-Resolving Lipid Mediators Distinctly Modulate Silver Nanoparticle-Induced Pulmonary Inflammation in Healthy and Metabolic Syndrome Mouse Models

by Arjun Pitchai, Akshada Shinde, Jenna N. Swihart, Kiley Robison and Jonathan H. Shannahan

Nanomaterials 2024, 14(20), 1642; https://doi.org/10.3390/nano14201642 - 13 Oct 2024

Cited by 2 | Viewed by 1701

Abstract

Individuals with chronic diseases are more vulnerable to environmental inhalation exposures. Although metabolic syndrome (MetS) is increasingly common and is associated with susceptibility to inhalation exposures such as particulate air pollution, the underlying mechanisms remain unclear. In previous studies, we determined that, compared [...] Read more.

Individuals with chronic diseases are more vulnerable to environmental inhalation exposures. Although metabolic syndrome (MetS) is increasingly common and is associated with susceptibility to inhalation exposures such as particulate air pollution, the underlying mechanisms remain unclear. In previous studies, we determined that, compared to a healthy mouse model, a mouse model of MetS exhibited increased pulmonary inflammation 24 h after exposure to AgNPs. This exacerbated response was associated with decreases in pulmonary levels of specific specialized pro-resolving mediators (SPMs). Supplementation with specific SPMs that are known to be dysregulated in MetS may alter particulate-induced inflammatory responses and be useful in treatment strategies. Our current study hypothesized that administration of resolvin E1 (RvE1), protectin D1 (PD1), or maresin (MaR1) following AgNP exposure will differentially regulate inflammatory responses. To examine this hypothesis, healthy and MetS mouse models were exposed to either a vehicle (control) or 50 μg of 20 nm AgNPs via oropharyngeal aspiration. They were then treated 24 h post-exposure with either a vehicle (control) or 400 ng of RvE1, PD1, or MaR1 via oropharyngeal aspiration. Endpoints of pulmonary inflammation and toxicity were evaluated three days following AgNP exposure. MetS mice that were exposed to AgNPs and received PBS treatment exhibited significantly exacerbated pulmonary inflammatory responses compared to healthy mice. In mice exposed to AgNPs and treated with RvE1, neutrophil infiltration was reduced in healthy mice and the exacerbated neutrophil levels were decreased in the MetS model. This decreased neutrophilia was associated with decreases in proinflammatory cytokines’ gene and protein expression. Healthy mice treated with PD1 did not demonstrate alterations in AgNP-induced neutrophil levels compared to mice not receiving treat; however, exacerbated neutrophilia was reduced in the MetS model. These PD1 alterations were associated with decreases in proinflammatory cytokines, as well as elevated interleukin-10 (IL-10). Both mouse models receiving MaR1 treatment demonstrated reductions in AgNP-induced neutrophil influx. MaR1 treatment was associated with decreases in proinflammatory cytokines in both models and increases in the resolution inflammatory cytokine IL-10 in both models, which were enhanced in MetS mice. Inflammatory responses to particulate exposure may be treated using specific SPMs, some of which may benefit susceptible subpopulations. Full article

(This article belongs to the Special Issue Advances in Nanotoxicology: Health and Safety)

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13 pages, 4366 KB

Open AccessEditor’s ChoiceArticle

Nanosized Eu³⁺-Doped NaY₉Si₆O₂₆ Oxyapatite Phosphor: A Comprehensive Insight into Its Hydrothermal Synthesis and Structural, Morphological, Electronic, and Optical Properties

by Madalina Ivanovici, Aleksandar Ćirić, Jovana Periša, Milena Marinović Cincović, Mikhail G. Brik, Abdullah N. Alodhayb, Željka Antić and Miroslav D. Dramićanin

Nanomaterials 2024, 14(20), 1639; https://doi.org/10.3390/nano14201639 - 12 Oct 2024

Cited by 1 | Viewed by 1536

Abstract

Detailed analysis covered the optical and structural properties of Eu³⁺-doped NaY₉Si₆O₂₆ oxyapatite phosphors, which were obtained via hydrothermal synthesis. X-ray diffraction patterns of NaY₉Si₆O₂₆:xEu³⁺ (x = 0, 1, 5, [...] Read more.

Detailed analysis covered the optical and structural properties of Eu³⁺-doped NaY₉Si₆O₂₆ oxyapatite phosphors, which were obtained via hydrothermal synthesis. X-ray diffraction patterns of NaY₉Si₆O₂₆:xEu³⁺ (x = 0, 1, 5, 7, 10 mol% Eu³⁺) samples proved a single-phase hexagonal structure (P63/m (176) space group). Differential thermal analysis showed an exothermic peak at 995 °C attributed to the amorphous to crystalline transformation of NaY₉Si₆O₂₆. Electron microscopy showed agglomerates composed of round-shaped nanoparticles ~53 nm in size. Room temperature photoluminescent emission spectra consisted of emission bands in the visible spectral region corresponding to ⁵D₀ → ⁷F_J (J = 0, 1, 2, 3, 4) f-f transitions of Eu³⁺. Lifetime measurements showed that the Eu³⁺ concentration had no substantial effect on the rather long ⁵D₀-level lifetime. The Eu³⁺ energy levels in the structure were determined using room-temperature excitation/emission spectra. Using the ⁷F₁ manifold, the Nv-crystal field strength parameter was calculated to be 1442.65 cm⁻¹. Structural, electronic, and optical properties were calculated to determine the band gap value, density of states, and index of refraction. The calculated direct band gap value was 4.665 eV (local density approximation) and 3.765 eV (general gradient approximation). Finally, the complete Judd–Ofelt analysis performed on all samples confirmed the experimental findings. Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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15 pages, 4235 KB

Open AccessEditor’s ChoiceArticle

Honeycomb Cell Structures Formed in Drop-Casting CNT Films for Highly Efficient Solar Absorber Applications

by Saiful Islam and Hiroshi Furuta

Nanomaterials 2024, 14(20), 1633; https://doi.org/10.3390/nano14201633 - 11 Oct 2024

Viewed by 2060

Abstract

This study investigates the process of using multi-walled carbon nanotube (MWCNT) coatings to enhance lamp heating temperatures for solar thermal absorption applications. The primary focus is studying the effects of the self-organized honeycomb structures of CNTs formed on silicon substrates on different cell [...] Read more.

This study investigates the process of using multi-walled carbon nanotube (MWCNT) coatings to enhance lamp heating temperatures for solar thermal absorption applications. The primary focus is studying the effects of the self-organized honeycomb structures of CNTs formed on silicon substrates on different cell area ratios (CARs). The drop-casting process was used to develop honeycomb-structured MWCNT-coated absorbers with varying CAR values ranging from ~60% to 17%. The optical properties were investigated within the visible (400–800 nm) and near-infrared (934–1651 nm) wavelength ranges. Although fully coated MWCNT absorbers showed the lowest reflectance, honeycomb structures with a ~17% CAR achieved high-temperature absorption. These structures maintained 8.4% reflectance at 550 nm, but their infrared reflection dramatically increased to 80.5% at 1321 nm. The solar thermal performance was assessed throughout a range of irradiance intensities, from 0.04 W/cm² to 0.39 W/cm². The honeycomb structure with a ~17% CAR value consistently performed better than the other structures by reaching the highest absorption temperatures (ranging from 52.5 °C to 285.5 °C) across all measured intensities. A direct correlation was observed between the reflection ratio (visible: 550 nm/infrared: 1321 nm) and the temperature absorption efficiency, where lower reflection ratios were associated with higher temperature absorption. This study highlights the significant potential for the large-scale production of cost-effective solar thermal absorbers through the application of optimized honeycomb-structured absorbers coated with MWCNTs. These contributions enhance solar energy efficiency for applications in water heating and purification, thereby promoting sustainable development. Full article

(This article belongs to the Special Issue State-of-the-Art Carbon Related and Low-Dimensional Functional Nanomaterials)

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10 pages, 3009 KB

Open AccessEditor’s ChoiceArticle

Unsupervised Learning for the Automatic Counting of Grains in Nanocrystals and Image Segmentation at the Atomic Resolution

by Woonbae Sohn, Taekyung Kim, Cheon Woo Moon, Dongbin Shin, Yeji Park, Haneul Jin and Hionsuck Baik

Nanomaterials 2024, 14(20), 1614; https://doi.org/10.3390/nano14201614 - 10 Oct 2024

Cited by 1 | Viewed by 1438

Abstract

Identifying the grain distribution and grain boundaries of nanoparticles is important for predicting their properties. Experimental methods for identifying the crystallographic distribution, such as precession electron diffraction, are limited by their probe size. In this study, we developed an unsupervised learning method by [...] Read more.

Identifying the grain distribution and grain boundaries of nanoparticles is important for predicting their properties. Experimental methods for identifying the crystallographic distribution, such as precession electron diffraction, are limited by their probe size. In this study, we developed an unsupervised learning method by applying a Gabor filter to HAADF-STEM images at the atomic level for image segmentation and automatic counting of grains in polycrystalline nanoparticles. The methodology comprises a Gabor filter for feature extraction, non-negative matrix factorization for dimension reduction, and K-means clustering. We set the threshold distance and angle between the clusters required for the number of clusters to converge so as to automatically determine the optimal number of grains. This approach can shed new light on the nature of polycrystalline nanoparticles and their structure–property relationships. Full article

(This article belongs to the Special Issue Exploring Nanomaterials through Electron Microscopy and Spectroscopy)

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16 pages, 6579 KB

Open AccessEditor’s ChoiceArticle

Thermo- and Photoresponsive Smart Nanomaterial Based on Poly(diethyl vinyl phosphonate)-Capped Gold Nanoparticles

by Antonio Buonerba, Rosita Lapenta, Francesco Della Monica, Roberto Piacentini, Lucia Baldino, Maria Rosa Scognamiglio, Vito Speranza, Stefano Milione, Carmine Capacchione, Bernhard Rieger and Alfonso Grassi

Nanomaterials 2024, 14(19), 1589; https://doi.org/10.3390/nano14191589 - 1 Oct 2024

Cited by 1 | Viewed by 1703

Abstract

A new nanodevice based on gold nanoparticles (AuNPs) capped with poly(diethylvinylphosphonate) (PDEVP) has been synthesized, showing interesting photophysical and thermoresponsive properties. The synthesis involves a properly designed Yttriocene catalyst coordinating the vinyl-lutidine (VL) initiator active in diethyl vinyl phosphonate polymerization. The unsaturated PDEVP [...] Read more.

A new nanodevice based on gold nanoparticles (AuNPs) capped with poly(diethylvinylphosphonate) (PDEVP) has been synthesized, showing interesting photophysical and thermoresponsive properties. The synthesis involves a properly designed Yttriocene catalyst coordinating the vinyl-lutidine (VL) initiator active in diethyl vinyl phosphonate polymerization. The unsaturated PDEVP chain ending was thioacetylated, deacetylated, and reacted with tetrachloroauric acid and sodium borohydride to form PDEVP-VL-capped AuNPs. The NMR, UV–Vis, and ESI-MS characterization of the metal nanoparticles confirmed the formation of the synthetic intermediates and the expected colloidal systems. AuNPs of subnanometric size were determined by WAXD and UV–Vis analysis. UV–Vis and fluorescence analysis confirmed the effective anchoring of the thiolated PDEVP to AuNPs. The formation of 50–200 nm globular structures was assessed by SEM and AFM microscopy in solid state and confirmed by DLS in aqueous dispersion. Hydrodynamic radius studies showed colloidal contraction with temperature, demonstrating thermoresponsive behavior. These properties suggest potential biomedical applications for the photoablation of malignant cells or controlled drug delivery induced by light or heat for the novel PDEVP-capped AuNP systems. Full article

(This article belongs to the Special Issue Nanosomes in Precision Nanomedicine (Second Edition))

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13 pages, 3754 KB

Open AccessEditor’s ChoiceArticle

Size Effects of Copper(I) Oxide Nanospheres on Their Morphology on Copper Thin Films under Near-Infrared Femtosecond Laser Irradiation

by Mizue Mizoshiri, Thuan Duc Tran and Kien Vu Trung Nguyen

Nanomaterials 2024, 14(19), 1584; https://doi.org/10.3390/nano14191584 - 30 Sep 2024

Viewed by 1679

Abstract

The femtosecond laser direct writing of metals has gained significant attention for micro/nanostructuring. Copper (I) oxide nanospheres (NSs), a promising material for multi-photon metallization, can be reduced to copper (Cu) and sintered through near-infrared femtosecond laser pulse irradiation. In this study, we investigated [...] Read more.

The femtosecond laser direct writing of metals has gained significant attention for micro/nanostructuring. Copper (I) oxide nanospheres (NSs), a promising material for multi-photon metallization, can be reduced to copper (Cu) and sintered through near-infrared femtosecond laser pulse irradiation. In this study, we investigated the size effect of copper (I) oxide nanospheres on their morphology when coated on Cu thin films and irradiated by near-infrared femtosecond laser pulses. Three Cu₂O NS inks were prepared, consisting of small (φ100 nm), large (φ200 nm), and a mixture of φ100 nm and φ200 nm NSs. A unique phenomenon was observed at low laser pulse energy: both sizes of NSs bonded as single layers when the mixed NSs were used. At higher pulse energies, the small NSs melted readily compared to the large NSs. In comparisons between the large and mixed NSs, some large NSs remained intact, suggesting that the morphology of the NSs can be controlled by varying the concentration of different-sized NSs. Considering the simulation results indicating that the electromagnetic fields between large and small NSs are nearly identical, this differential morphology is likely attributed to the differences in the heat capacity of the NSs. Full article

(This article belongs to the Special Issue Laser-Based Nano Fabrication and Nano Lithography: Second Edition)

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18 pages, 5839 KB

Open AccessEditor’s ChoiceArticle

Electrospun Amorphous Solid Dispersions with Lopinavir and Ritonavir for Improved Solubility and Dissolution Rate

by Ewelina Łyszczarz, Oskar Sosna, Justyna Srebro, Aleksandra Rezka, Dorota Majda and Aleksander Mendyk

Nanomaterials 2024, 14(19), 1569; https://doi.org/10.3390/nano14191569 - 28 Sep 2024

Cited by 2 | Viewed by 1872

Abstract

Lopinavir (LPV) and ritonavir (RTV) are two of the essential antiretroviral active pharmaceutical ingredients (APIs) characterized by poor solubility. Hence, attempts have been made to improve both their solubility and dissolution rate. One of the most effective approaches used for this purpose is [...] Read more.

Lopinavir (LPV) and ritonavir (RTV) are two of the essential antiretroviral active pharmaceutical ingredients (APIs) characterized by poor solubility. Hence, attempts have been made to improve both their solubility and dissolution rate. One of the most effective approaches used for this purpose is to prepare amorphous solid dispersions (ASDs). To our best knowledge, this is the first attempt aimed at developing ASDs via the electrospinning technique in the form of fibers containing LPV and RTV. In particular, the impact of the various polymeric carriers, i.e., Kollidon K30 (PVP), Kollidon VA64 (KVA), and Eudragit^® E100 (E100), as well as the drug content as a result of the LPV and RTV amorphization were investigated. The characterization of the electrospun fibers included microscopic, DSC, and XRD analyses, the assessment of their wettability, and equilibrium solubility and dissolution studies. The application of the electrospinning process led to the full amorphization of both the APIs, regardless of the drug content and the type of polymer matrix used. The utilization of E100 as a polymeric carrier for LPV and KVA for RTV, despite the beads-on-string morphology, had a favorable impact on the equilibrium solubility and dissolution rate. The results showed that the electrospinning method can be successfully used to manufacture ASDs with poorly soluble APIs. Full article

(This article belongs to the Special Issue Advances in Micro and Nanofiber: Fabrication, Properties and Applications)

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11 pages, 7311 KB

Open AccessEditor’s ChoiceArticle

Large-Scale High-Accuracy and High-Efficiency Phase Plate Machining

by Guanhua Wang, Zhaoxiang Liu, Lvbin Song, Jianglin Guan, Wei Chen, Jian Liu, Jinming Chen, Min Wang and Ya Cheng

Nanomaterials 2024, 14(19), 1563; https://doi.org/10.3390/nano14191563 - 27 Sep 2024

Cited by 2 | Viewed by 1593

Abstract

In this paper, multifunctional, multilevel phase plates of quartz substrate were efficiently prepared by using a newly developed polygon scanner-based femtosecond laser photolithography system combined with inductively coupled discharge plasma reactive-ion etching (ICP-RIE) technology. The femtosecond laser photolithography system can achieve a scanning [...] Read more.

In this paper, multifunctional, multilevel phase plates of quartz substrate were efficiently prepared by using a newly developed polygon scanner-based femtosecond laser photolithography system combined with inductively coupled discharge plasma reactive-ion etching (ICP-RIE) technology. The femtosecond laser photolithography system can achieve a scanning speed of 5 m/s and a preparation efficiency of 15 cm²/h while ensuring an overlay alignment accuracy of less than 100 nm and a writing resolution of 500 nm. The ICP-RIE technology can control the etching depth error within ±5 nm and the mask-to-mask edge error is less than 1 μm. An 8-level Fresnel lens phase plate with a focal length of 20 mm and an 8-level Fresnel axicon phase plate with a cone angle of 5° were demonstrated. The diffraction efficiency was greater than 93%, and their performance was tested for focusing and glass cutting, respectively. Combined with the high-speed femtosecond laser photolithography system’s infinite field-of-view (IFOV) processing capability, the one-time direct writing preparation of phase plate masks of different sizes was realized on a 6-inch wafer. This is expected to reduce the production cost of quartz substrate diffractive optical elements and promote their customized mass production. Full article

(This article belongs to the Section Nanofabrication and Nanomanufacturing)

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19 pages, 3079 KB

Open AccessEditor’s ChoiceArticle

Enhancement of Triple-Negative Breast Cancer-Specific Induction of Cell Death by Silver Nanoparticles by Combined Treatment with Proteotoxic Stress Response Inhibitors

by Christina M. Snyder, Beatriz Mateo, Khushbu Patel, Cale D. Fahrenholtz, Monica M. Rohde, Richard Carpenter and Ravi N. Singh

Nanomaterials 2024, 14(19), 1564; https://doi.org/10.3390/nano14191564 - 27 Sep 2024

Cited by 3 | Viewed by 2077

Abstract

Metal nanoparticles have been tested for therapeutic and imaging applications in pre-clinical models of cancer, but fears of toxicity have limited their translation. An emerging concept in nanomedicine is to exploit the inherent drug-like properties of unmodified nanomaterials for cancer therapy. To be [...] Read more.

Metal nanoparticles have been tested for therapeutic and imaging applications in pre-clinical models of cancer, but fears of toxicity have limited their translation. An emerging concept in nanomedicine is to exploit the inherent drug-like properties of unmodified nanomaterials for cancer therapy. To be useful clinically, there must be a window between the toxicity of the nanomaterial to cancer and toxicity to normal cells. This necessitates identification of specific vulnerabilities in cancers that can be targeted using nanomaterials without inducing off-target toxicity. Previous studies point to proteotoxic stress as a driver of silver nanoparticle (AgNPs) toxicity. Two key cell stress responses involved in mitigating proteotoxicity are the heat shock response (HSR) and the integrated stress response (ISR). Here, we examine the role that these stress responses play in AgNP-induced cytotoxicity in triple-negative breast cancer (TNBC) and immortalized mammary epithelial cells. Furthermore, we investigate HSR and ISR inhibitors as potential drug partners to increase the anti-cancer efficacy of AgNPs without increasing off-target toxicity. We showed that AgNPs did not strongly induce the HSR at a transcriptional level, but instead decreased expression of heat shock proteins (HSPs) at the protein level, possibly due to degradation in AgNP-treated TNBC cells. We further showed that the HSR inhibitor, KRIBB11, synergized with AgNPs in TNBC cells, but also increased off-target toxicity in immortalized mammary epithelial cells. In contrast, we found that salubrinal, a drug that can sustain pro-death ISR signaling, enhanced AgNP-induced cell death in TNBC cells without increasing toxicity in immortalized mammary epithelial cells. Subsequent co-culture studies demonstrated that AgNPs in combination with salubrinal selectively eliminated TNBCs without affecting immortalized mammary epithelial cells grown in the same well. Our findings provide additional support for proteotoxic stress as a mechanism by which AgNPs selectively kill TNBCs and will help guide future efforts to identify drug partners that would be beneficial for use with AgNPs for cancer therapy. Full article

(This article belongs to the Special Issue Applications of Nanomaterials in Biomedical Imaging and Cancer Therapy: 3rd Edition)

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12 pages, 1372 KB

Open AccessEditor’s ChoiceArticle

Stable Field Emission from Single-Crystalline Zirconium Carbide Nanowires

by Yimeng Wu, Jie Tang, Shuai Tang, You-Hu Chen, Ta-Wei Chiu, Masaki Takeguchi and Lu-Chang Qin

Nanomaterials 2024, 14(19), 1567; https://doi.org/10.3390/nano14191567 - 27 Sep 2024

Cited by 2 | Viewed by 1293

Abstract

The <100> oriented single-crystalline Zirconium Carbide (ZrC) nanowires were controllably synthesized on a graphite substrate by chemical vapor deposition (CVD) with optimized growth parameters involving Zirconium tetrachloride (ZrCl₄), flow of methane (CH₄), and growth temperature. The length of nanowires [...] Read more.

The <100> oriented single-crystalline Zirconium Carbide (ZrC) nanowires were controllably synthesized on a graphite substrate by chemical vapor deposition (CVD) with optimized growth parameters involving Zirconium tetrachloride (ZrCl₄), flow of methane (CH₄), and growth temperature. The length of nanowires is above 10 µm while the diameter is smaller than 100 nm. A single ZrC nanowire was picked up and fixed on a tungsten tip for field emission measurement. After surface pretreatments, a sharpened and cleaned ZrC nanowire emitter showed a high emission current density of 1.1 × 10¹⁰ A m⁻² at a low turn-on voltage of 440 V. The field emission is stable for 150 min with a fluctuation of 1.77%. This work provides an effective method for synthesizing and stabilizing single-crystalline ZrC nanowire emitters as an electron source for electron-beam applications. Full article

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

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14 pages, 1546 KB

Open AccessEditor’s ChoiceArticle

Mobility Gaps of Hydrogenated Amorphous Silicon Related to Hydrogen Concentration and Its Influence on Electrical Performance

by Francesca Peverini, Saba Aziz, Aishah Bashiri, Marco Bizzarri, Maurizio Boscardin, Lucio Calcagnile, Carlo Calcatelli, Daniela Calvo, Silvia Caponi, Mirco Caprai, Domenico Caputo, Anna Paola Caricato, Roberto Catalano, Roberto Cirro, Giuseppe Antonio Pablo Cirrone, Michele Crivellari, Tommaso Croci, Giacomo Cuttone, Gianpiero de Cesare, Paolo De Remigis, Sylvain Dunand, Michele Fabi, Luca Frontini, Livio Fanò, Benedetta Gianfelici, Catia Grimani, Omar Hammad, Maria Ionica, Keida Kanxheri, Matthew Large, Francesca Lenta, Valentino Liberali, Nicola Lovecchio, Maurizio Martino, Giuseppe Maruccio, Giovanni Mazza, Mauro Menichelli, Anna Grazia Monteduro, Francesco Moscatelli, Arianna Morozzi, Augusto Nascetti, Stefania Pallotta, Andrea Papi, Daniele Passeri, Marco Petasecca, Giada Petringa, Igor Pis, Pisana Placidi, Gianluca Quarta, Silvia Rizzato, Alessandro Rossi, Giulia Rossi, Federico Sabbatini, Andrea Scorzoni, Leonello Servoli, Alberto Stabile, Silvia Tacchi, Cinzia Talamonti, Jonathan Thomet, Luca Tosti, Giovanni Verzellesi, Mattia Villani, Richard James Wheadon, Nicolas Wyrsch, Nicola Zema and Maddalena Pedio Show full author list Hide full author list

Nanomaterials 2024, 14(19), 1551; https://doi.org/10.3390/nano14191551 - 25 Sep 2024

Cited by 1 | Viewed by 2219

Abstract

This paper presents a comprehensive study of hydrogenated amorphous silicon (a-Si)-based detectors, utilizing electrical characterization, Raman spectroscopy, photoemission, and inverse photoemission techniques. The unique properties of a-Si have sparked interest in its application for radiation detection in both physics and medicine. Although amorphous [...] Read more.

This paper presents a comprehensive study of hydrogenated amorphous silicon (a-Si)-based detectors, utilizing electrical characterization, Raman spectroscopy, photoemission, and inverse photoemission techniques. The unique properties of a-Si have sparked interest in its application for radiation detection in both physics and medicine. Although amorphous silicon (a-Si) is inherently a highly defective material, hydrogenation significantly reduces defect density, enabling its use in radiation detector devices. Spectroscopic measurements provide insights into the intricate relationship between the structure and electronic properties of a-Si, enhancing our understanding of how specific configurations, such as the choice of substrate, can markedly influence detector performance. In this study, we compare the performance of a-Si detectors deposited on two different substrates: crystalline silicon (c-Si) and flexible Kapton. Our findings suggest that detectors deposited on Kapton exhibit reduced sensitivity, despite having comparable noise and leakage current levels to those on crystalline silicon. We hypothesize that this discrepancy may be attributed to the substrate material, differences in film morphology, and/or the alignment of energy levels. Further measurements are planned to substantiate these hypotheses. Full article

(This article belongs to the Special Issue Advanced Nanotechnology in Intelligent Flexible Devices)

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17 pages, 9752 KB

Open AccessEditor’s ChoiceArticle

Impact of Silver Incorporation and Flash-Lamp-Annealing on the Photocatalytic Response of Sputtered ZnO Films

by Leo Álvarez-Fraga, Raúl Gago, David G. Calatayud, Slawomir Prucnal and Olga Sánchez

Nanomaterials 2024, 14(18), 1519; https://doi.org/10.3390/nano14181519 - 19 Sep 2024

Cited by 1 | Viewed by 1274

Abstract

Thin films of silver-doped zinc oxide (SZO) were deposited at room temperature using a DC reactive magnetron co-sputtering technique using two independent Zn and Ag targets. The crystallographic structure, chemical composition and surface morphology of SZO films with different silver concentrations were correlated [...] Read more.

Thin films of silver-doped zinc oxide (SZO) were deposited at room temperature using a DC reactive magnetron co-sputtering technique using two independent Zn and Ag targets. The crystallographic structure, chemical composition and surface morphology of SZO films with different silver concentrations were correlated with the photocatalytic (PC) properties. The crystallization of the SZO films was made using millisecond range flash-lamp-annealing (FLA) treatments. FLA induces significant structural ordering of the wurtzite structure and an in-depth redistribution of silver, resulting in the formation of silver agglomerates. The wurtzite ZnO structure is observed for silver contents below 10 at.% where Ag is partially incorporated into the oxide matrix, inducing a decrease in the optical band-gap. Regardless of the silver content, all the as-grown SZO films do not exhibit any significant PC activity. The best PC response is achieved for samples with a relatively low Ag content (2–5 at.%) after FLA treatment. The enhanced PC activity of SZO upon FLA can be attributed to structural ordering and the effective band-gap narrowing through the combination of silver doping and the plasmonic effect caused by the formation of Ag clusters. Full article

(This article belongs to the Special Issue Synthesis and Properties of Metal Oxide Thin Films)

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23 pages, 5179 KB

Open AccessEditor’s ChoiceArticle

Comparison In Vitro Study on the Interface between Skin and Bone Cell Cultures and Microporous Titanium Samples Manufactured with 3D Printing Technology Versus Sintered Samples

by Maxim Shevtsov, Emil Pitkin, Stephanie E. Combs, Greg Van Der Meulen, Chris Preucil and Mark Pitkin

Nanomaterials 2024, 14(18), 1484; https://doi.org/10.3390/nano14181484 - 12 Sep 2024

Cited by 3 | Viewed by 1599

Abstract

Percutaneous implants osseointegrated into the residuum of a person with limb amputation need to provide mechanical stability and protection against infections. Although significant progress has been made in the biointegration of percutaneous implants, the problem of forming a reliable natural barrier at the [...] Read more.

Percutaneous implants osseointegrated into the residuum of a person with limb amputation need to provide mechanical stability and protection against infections. Although significant progress has been made in the biointegration of percutaneous implants, the problem of forming a reliable natural barrier at the level of the surface of the implant and the skin and bone tissues remains unresolved. The use of a microporous implant structure incorporated into the Skin and Bone Integrated Pylon (SBIP) should address the issue by allowing soft and bone tissues to grow directly into the implant structure itself, which, in turn, should form a reliable barrier to infections and support strong osseointegration. To evaluate biological interactions between dermal fibroblasts and MC3T3-E1 osteoblasts in vitro, small titanium discs (with varying pore sizes and volume fractions to achieve deep porosity) were fabricated via 3D printing and sintering. The cell viability MTT assay demonstrated low cytotoxicity for cells co-cultured in the pores of the 3D-printed and sintered Ti samples during the 14-day follow-up period. A subsequent Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) analysis of the relative gene expression of biomarkers that are associated with cell adhesion (α2, α5, αV, and β1 integrins) and extracellular matrix components (fibronectin, vitronectin, type I collagen) demonstrated that micropore sizes ranging from 200 to 500 µm of the 3D printed and sintered Ti discs were favorable for dermal fibroblast adhesion. For example, for representative 3D-printed Ti sample S6 at 72 h the values were 4.71 ± 0.08 (α2 integrin), 4.96 ± 0.08 (α5 integrin), 4.71 ± 0.08 (αV integrin), and 1.87 ± 0.12 (β1 integrin). In contrast, Ti discs with pore sizes ranging from 400 to 800 µm demonstrated the best results (in terms of marker expression related to osteogenic differentiation, including osteopontin, osteonectin, osteocalcin, TGF-β1, and SMAD4) for MC3T3-E1 cells. For example, for the representative 3D sample S4 on day 14, the marker levels were 11.19 ± 0.77 (osteopontin), 7.15 ± 0.29 (osteonectin), and 6.08 ± 0.12 (osteocalcin), while for sintered samples the levels of markers constituted 5.85 ± 0.4 (osteopontin), 4.45 ± 0.36 (osteonectin), and 4.46 ± 0.3 (osteocalcin). In conclusion, the data obtained show the high biointegrative properties of porous titanium structures, while the ability to implement several pore options in one structure using 3D printing makes it possible to create personalized implants for the best one-time integration with both skin and bone tissues. Full article

(This article belongs to the Special Issue Nanomaterials for Biological Applications: Innovative Strategies from Theranostic Approaches to Regenerative Medicine)

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17 pages, 20722 KB

Open AccessEditor’s ChoiceArticle

AFM for Nanomechanical Assessment of Polymer Overcoatings on Nanoparticle-Decorated Biomaterials

by Jonathan Wood, Dennis Palms, Ruvini Dabare, Krasimir Vasilev and Richard Bright

Nanomaterials 2024, 14(18), 1475; https://doi.org/10.3390/nano14181475 - 11 Sep 2024

Viewed by 1620

Abstract

Nanoparticle adhesion to polymer and similar substrates may be prone to low nano-Newton forces, disrupting the surface bonds and patterning, potentially reducing the functionality of complex surface patterns. Testing this, a functionalised surface reported for biological and medical applications, consisting of a thin [...] Read more.

Nanoparticle adhesion to polymer and similar substrates may be prone to low nano-Newton forces, disrupting the surface bonds and patterning, potentially reducing the functionality of complex surface patterns. Testing this, a functionalised surface reported for biological and medical applications, consisting of a thin plasma-derived oxazoline-based film with 68 nm diameter covalently bound colloidal gold nanoparticles attached within an aqueous solution, underwent nanomechanical analysis. Atomic Force Microscopy nanomechanical analysis was used to quantify the limits of various adaptations to these nanoparticle-featured substrates. Regular and laterally applied forces in the nano-Newton range were shown to de-adhere surface-bound gold nanoparticles. Applying a nanometre-thick overcoating anchored the nanoparticles to the surface and protected the underlying base substrate in a one-step process to improve the overall stability of the functionalised substrate against lower-range forces. The thickness of the oxazoline-based overcoating displayed protection from forces at different rates. Testing overcoating thickness ranging from 5 to 20 nm in 5 nm increments revealed a significant improvement in stability using a 20 nm-thick overcoating. This approach underscores the importance of optimising overcoating thickness to enhance nanoparticle-based surface modifications’ durability and functional integrity. Full article

(This article belongs to the Special Issue Research on Antibacterial Properties of Metal-Based Nanomaterials)

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10 pages, 1916 KB

Open AccessEditor’s ChoiceArticle

Adhesion Strength Enhancement of Butyl Rubber and Aluminum Using Nanoscale Self-Assembled Monolayers of Various Silane Coupling Agents for Vibration Damping Plates

by So Rim Lee, Dang Xuan Nghia, Jin Young Oh and Tae Il Lee

Nanomaterials 2024, 14(18), 1480; https://doi.org/10.3390/nano14181480 - 11 Sep 2024

Cited by 1 | Viewed by 2034

Abstract

In this paper, we enhance the adhesion strength of butyl rubber-based vibrational damping plates using nanoscale self-assembled monolayers of various silane coupling agents. The silane coupling agents used to chemically modify the plate’s aluminum surface include 3-aminopropyltriethoxysilane (APTES), (3-glycidyloxypropyl) triethoxysilane (GPTES), 3-mercaptopropyltrimethoxysilane (MPTMS), [...] Read more.

In this paper, we enhance the adhesion strength of butyl rubber-based vibrational damping plates using nanoscale self-assembled monolayers of various silane coupling agents. The silane coupling agents used to chemically modify the plate’s aluminum surface include 3-aminopropyltriethoxysilane (APTES), (3-glycidyloxypropyl) triethoxysilane (GPTES), 3-mercaptopropyltrimethoxysilane (MPTMS), and 3-(triethoxysilyl)propyl isocyanate (ICPTES). The modified surfaces were analyzed using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the enhancement in adhesion strength between the rubber and aluminum was estimated through T-Peel tests. As a result, MPTMS showed the highest enhancement in adhesion strength, of approximately 220% compared to the untreated sample, while GPTES, ICPTES, and APTES resulted in adhesion strength enhancements of approximately 200%, 150%, and 130%, respectively. Full article

(This article belongs to the Special Issue Mechanical, Thermal and Electrical Properties of Polymer Nanocomposites 2nd Edition)

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13 pages, 4872 KB

Open AccessEditor’s ChoiceArticle

Dual-Mode Sensing of Fe(III) Based on Etching Induced Modulation of Localized Surface Plasmon Resonance and Surface Enhanced Raman Spectroscopy

by Miriam Parmigiani, Benedetta Albini, Pietro Galinetto and Angelo Taglietti

Nanomaterials 2024, 14(18), 1467; https://doi.org/10.3390/nano14181467 - 10 Sep 2024

Viewed by 1346

Abstract

Convenient, rapid, highly sensitive and on-site iron determination is important for environmental safety and human health. We developed a sensing system for the detection of Fe(III) in water based on 7-mercapto-4-methylcoumarine (MMC)-stabilized silver-coated gold nanostars (GNS@Ag@MMC), exploiting a redox reaction between the Fe(III) [...] Read more.

Convenient, rapid, highly sensitive and on-site iron determination is important for environmental safety and human health. We developed a sensing system for the detection of Fe(III) in water based on 7-mercapto-4-methylcoumarine (MMC)-stabilized silver-coated gold nanostars (GNS@Ag@MMC), exploiting a redox reaction between the Fe(III) cation and the silver shell of the nanoparticles, which causes a severe transformation of the nanomaterial structure, reverting it to pristine GNSs. This system works by simultaneously monitoring changes in the Localized Surface Plasmon Resonance (LSPR) and Surface-Enhanced Raman Spectroscopy (SERS) spectra as a function of added Fe(III). The proposed sensing system is able to detect the Fe(III) cation in the 1.0 × 10⁻⁵–1.5 × 10⁻⁴ M range, and its selectivity of the GNS@Ag@MMC sensor toward iron has been verified monitoring the LSPR and the SERS response to other cations with a clear selectivity toward Fe(III). Full article

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22 pages, 9684 KB

Open AccessEditor’s ChoiceArticle

Techniques and Instruments for Assessing and Reducing Risk of Exposure to Nanomaterials in Construction, Focusing on Fire-Resistant Insulation Panels Containing Nanoclay

by Romeo Cristian Ciobanu and Mihaela Aradoaei

Nanomaterials 2024, 14(18), 1470; https://doi.org/10.3390/nano14181470 - 10 Sep 2024

Viewed by 1368

Abstract

The paper explains how nano exposure is assessed in the construction field and focuses on the production of fire-resistant insulation panels with nanoclay. Utilizing the commercial ANSYS CFX^® software, a preliminary theoretical simulation was conducted on nano exposure in the workplace, which [...] Read more.

The paper explains how nano exposure is assessed in the construction field and focuses on the production of fire-resistant insulation panels with nanoclay. Utilizing the commercial ANSYS CFX^® software, a preliminary theoretical simulation was conducted on nano exposure in the workplace, which revealed that particle dispersion is primarily driven by diffusion. Panel post-processing through drilling results in the highest inhalation exposure, followed by mixing and grinding activities. Compared to a state of ‘no activity’, each activity resulted in an exposure increase by a factor of min. 1000. An overall assessment suggests that the use of nanoparticles in construction materials may not significantly heighten workers’ exposure to nanopowders when considering particle concentration alone as opposed to using traditional micro-scale materials. However, the issue persists when it comes to blending powders or performing finishing tasks on panels, with concentration levels being significantly higher for drilling, grinding, and mixing powders at 2.4 times above the standard reference value (40,000 particles/cm³); this is unacceptable, even for brief durations. Examination of dermal contact with gloves and masks worn by workers revealed no nanoparticle penetration. Safety measures were proposed for workers based on decision trees to enhance their safety. Ten categories of protection strategies have been devised to combat the impact of nanoparticles, which are tailored to specific technical situations, but they must be modified for various types of nanoparticles despite potential shared health implications. Full article

(This article belongs to the Special Issue Advances in Toxicity of Nanoparticles in Organisms (2nd Edition))

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12 pages, 4784 KB

Open AccessEditor’s ChoiceArticle

Optimal Computational Modeling and Simulation of QCA Reversible Gates for Information Reliability in Nano-Quantum Circuits

by Jun-Cheol Jeon

Nanomaterials 2024, 14(17), 1460; https://doi.org/10.3390/nano14171460 - 8 Sep 2024

Cited by 1 | Viewed by 1609

Abstract

As the relationship between energy and information loss and reversible gates was revealed, much interest in reversible gate design arose, and as quantum-dot cellular automata (QCA) gained attention as a next-generation nano circuit design technology, various reversible gates based on QCA emerged. The [...] Read more.

As the relationship between energy and information loss and reversible gates was revealed, much interest in reversible gate design arose, and as quantum-dot cellular automata (QCA) gained attention as a next-generation nano circuit design technology, various reversible gates based on QCA emerged. The proposed study optimizes the performance and design costs of existing QCA-based reversible gates including TR, RUG, PQR, and URG. According to most indicators, the proposed circuits showed significant improvement rates and outperformed existing studies. In particular, the proposed optimal TR, RUG, PQR, and URG showed performance improvements of 266%, 265%, 300%, and 144% in Cost_AD, respectively, compared with the best existing circuit. This shows outstanding improvement and superiority in terms of area and delay, which are the most important factors in the performance of nano-scale circuits that are becoming extremely miniaturized. Additionally, the exceptionally high-output polarization of the proposed circuits is an important indicator of the circuit’s expansion and connection and increases the circuit’s reliability. Full article

(This article belongs to the Special Issue Advances in Computational Modeling and Simulation of Nanoscale Materials)

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11 pages, 13353 KB

Open AccessEditor’s ChoiceArticle

In Situ Studies on the Influence of Surface Symmetry on the Growth of MoSe₂ Monolayer on Sapphire Using Reflectance Anisotropy Spectroscopy and Differential Reflectance Spectroscopy

by Yufeng Huang, Mengjiao Li, Zhixin Hu, Chunguang Hu, Wanfu Shen, Yanning Li and Lidong Sun

Nanomaterials 2024, 14(17), 1457; https://doi.org/10.3390/nano14171457 - 7 Sep 2024

Cited by 1 | Viewed by 2161

Abstract

The surface symmetry of the substrate plays an important role in the epitaxial high-quality growth of 2D materials; however, in-depth and in situ studies on these materials during growth are still limited due to the lack of effective in situ monitoring approaches. In [...] Read more.

The surface symmetry of the substrate plays an important role in the epitaxial high-quality growth of 2D materials; however, in-depth and in situ studies on these materials during growth are still limited due to the lack of effective in situ monitoring approaches. In this work, taking the growth of MoSe₂ as an example, the distinct growth processes on Al₂O₃ (

11 \bar{2} 0

) and Al₂O₃ (0001) are revealed by parallel monitoring using in situ reflectance anisotropy spectroscopy (RAS) and differential reflectance spectroscopy (DRS), respectively, highlighting the dominant role of the surface symmetry. In our previous study, we found that the RAS signal of MoSe₂ grown on Al₂O₃ (

11 \bar{2} 0

) initially increased and decreased ultimately to the magnitude of bare Al₂O₃ (

11 \bar{2} 0

) when the first layer of MoSe₂ was fully merged, which is herein verified by the complementary DRS measurement that is directly related to the film coverage. Consequently, the changing rate of reflectance anisotropy (RA) intensity at 2.5 eV is well matched with the dynamic changes in differential reflectance (DR) intensity. Moreover, the surface-dominated uniform orientation of MoSe₂ islands at various stages determined by RAS was further investigated by low-energy electron diffraction (LEED) and atomic force microscopy (AFM). By contrast, the RAS signal of MoSe₂ grown on Al₂O₃ (0001) remains at zero during the whole growth, implying that the discontinuous MoSe₂ islands have no preferential orientations. This work demonstrates that the combination of in situ RAS and DRS can provide valuable insights into the growth of unidirectional aligned islands and help optimize the fabrication process for single-crystal transition metal dichalcogenide (TMDC) monolayers. Full article

(This article belongs to the Special Issue Optical Spectroscopy Characterizations of Low-Dimensional Nanomaterials)

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20 pages, 6599 KB

Open AccessEditor’s ChoiceArticle

Conversion of Ultrasmall Glutathione-Coated Silver Nanoparticles during Dispersion in Water into Ultrasmall Silver Sulfide Nanoparticles

by Natalie Wolff, Oleg Prymak, Nataniel Białas, Torsten Schaller, Kateryna Loza, Felix Niemeyer, Marc Heggen, Claudia Weidenthaler, Cristiano L. P. Oliveira and Matthias Epple

Nanomaterials 2024, 14(17), 1449; https://doi.org/10.3390/nano14171449 - 5 Sep 2024

Cited by 3 | Viewed by 3425

Abstract

Ultrasmall silver nanoparticles (2 nm) were prepared by reduction with sodium borohydride (NaBH₄) and stabilized by the ligand glutathione (a tripeptide: glycine–cysteine–glutamic acid). NMR spectroscopy and optical spectroscopy (UV and fluorescence) revealed that these particles initially consist of silver nanoparticles and [...] Read more.

Ultrasmall silver nanoparticles (2 nm) were prepared by reduction with sodium borohydride (NaBH₄) and stabilized by the ligand glutathione (a tripeptide: glycine–cysteine–glutamic acid). NMR spectroscopy and optical spectroscopy (UV and fluorescence) revealed that these particles initially consist of silver nanoparticles and fluorescing silver nanoclusters, both stabilized by glutathione. Over time, the silver nanoclusters disappear and only the silver nanoparticles remain. Furthermore, the capping ligand glutathione eliminates hydrogen sulfide (H₂S) from the central cysteine and is released from the nanoparticle surface as tripeptide glycine–dehydroalanine–glutamic acid. Hydrogen sulfide reacts with the silver core to form silver sulfide. After four weeks in dispersion at 4 °C, this process is completed. These processes cannot be detected by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), or differential centrifugal sedimentation (DCS) as these methods cannot resolve the mixture of nanoparticles and nanoclusters or the nature of the nanoparticle core. X-ray photoelectron spectroscopy showed the mostly oxidized state of the silver nanoparticle core, Ag(+I), both in freshly prepared and in aged silver nanoparticles. These results demonstrate that ultrasmall nanoparticles can undergo unnoticed changes that considerably affect their chemical, physical, and biological properties. In particular, freshly prepared ultrasmall silver nanoparticles are much more toxic against cells and bacteria than aged particles because of the presence of the silver clusters. Full article

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13 pages, 3601 KB

Open AccessEditor’s ChoiceArticle

Texture-Induced Strain in a WS₂ Single Layer to Monitor Spin–Valley Polarization

by George Kourmoulakis, Antonios Michail, Dimitris Anestopoulos, Joseph A. Christodoulides, Manoj Tripathi, Alan Β. Dalton, John Parthenios, Konstantinos Papagelis, Emmanuel Stratakis and George Kioseoglou

Nanomaterials 2024, 14(17), 1437; https://doi.org/10.3390/nano14171437 - 3 Sep 2024

Cited by 1 | Viewed by 2275

Abstract

Nanoscale-engineered surfaces induce regulated strain in atomic layers of 2D materials that could be useful for unprecedented photonics applications and for storing and processing quantum information. Nevertheless, these strained structures need to be investigated extensively. Here, we present texture-induced strain distribution in single-layer [...] Read more.

Nanoscale-engineered surfaces induce regulated strain in atomic layers of 2D materials that could be useful for unprecedented photonics applications and for storing and processing quantum information. Nevertheless, these strained structures need to be investigated extensively. Here, we present texture-induced strain distribution in single-layer WS₂ (1L-WS₂) transferred over Si/SiO₂ (285 nm) substrate. The detailed nanoscale landscapes and their optical detection are carried out through Atomic Force Microscopy, Scanning Electron Microscopy, and optical spectroscopy. Remarkable differences have been observed in the WS₂ sheet localized in the confined well and at the periphery of the cylindrical geometry of the capped engineered surface. Raman spectroscopy independently maps the whole landscape of the samples, and temperature-dependent helicity-resolved photoluminescence (PL) experiments (off-resonance excitation) show that suspended areas sustain circular polarization from 150 K up to 300 K, in contrast to supported (on un-patterned area of Si/SiO₂) and strained 1L-WS₂. Our study highlights the impact of the dielectric environment on the optical properties of two-dimensional (2D) materials, providing valuable insights into the selection of appropriate substrates for implementing atomically thin materials in advanced optoelectronic devices. Full article

(This article belongs to the Special Issue Recent Advances in Optical Spectroscopy of Layered Materials)

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13 pages, 2384 KB

Open AccessEditor’s ChoiceArticle

Potential of Enzymatically Synthesized Hemozoin Analog as Th1 Cell Adjuvant

by Kazuaki Hoshi, Anh Thi Tram Tu, Miwako Shobo, Karin Kettisen, Lei Ye, Leif Bülow, Yoji Hakamata, Tetsuya Furuya, Ryutaro Asano, Wakako Tsugawa, Kazunori Ikebukuro, Koji Sode and Tomohiko Yamazaki

Nanomaterials 2024, 14(17), 1440; https://doi.org/10.3390/nano14171440 - 3 Sep 2024

Viewed by 1864

Abstract

Hemozoin (Hz) is a heme crystal produced during malaria infection that stimulates immune cells, leading to the production of cytokines and chemokines. The immunostimulatory action of Hz has previously been applied in the development of alternative adjuvants. Crystallization of hemin is a chemical [...] Read more.

Hemozoin (Hz) is a heme crystal produced during malaria infection that stimulates immune cells, leading to the production of cytokines and chemokines. The immunostimulatory action of Hz has previously been applied in the development of alternative adjuvants. Crystallization of hemin is a chemical approach for producing Hz. Here, we focused on an enzymatic production method for Hz using the heme detoxification protein (HDP), which catalyzes heme dimer formation from hemin in Plasmodium. We examined the immunostimulatory effects of an enzymatically synthesized analog of Hz (esHz) produced by recombinant Plasmodium falciparum HDP. Enzymatically synthesized Hz stimulates a macrophage cell line and human peripheral mononuclear cells, leading to the production of interleukin (IL)-6 and IL-12p40. In mice, subcutaneous administration of esHz together with an antigen, ovalbumin (OVA), increased the OVA-specific immunoglobulin (Ig) G2c isotype level in the serum, whereas OVA-specific IgG1 was not induced. Our findings suggest that esHz is a useful Th-1 cell adjuvant. Full article

(This article belongs to the Section Biology and Medicines)

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15 pages, 2554 KB

Open AccessEditor’s ChoiceArticle

Ball-Milling Enhanced UV Protection Performance of Ca₂Fe-Sulisobenzone Layered Double Hydroxide Organic Clay

by Márton Szabados, Rebeka Mészáros, Dorina Gabriella Dobó, Zoltán Kónya, Ákos Kukovecz and Pál Sipos

Nanomaterials 2024, 14(17), 1436; https://doi.org/10.3390/nano14171436 - 2 Sep 2024

Cited by 1 | Viewed by 1789

Abstract

Using a co-precipitation technique, the anionic form of sulisobenzone (benzophenone-4) sunscreen ingredient was incorporated into the interlayer space of CaFe-hydrocalumite for the first time. Using detailed post-synthetic millings of the photoprotective nanocomposite obtained, we aimed to study the mechanochemical effects on complex, hybridized [...] Read more.

Using a co-precipitation technique, the anionic form of sulisobenzone (benzophenone-4) sunscreen ingredient was incorporated into the interlayer space of CaFe-hydrocalumite for the first time. Using detailed post-synthetic millings of the photoprotective nanocomposite obtained, we aimed to study the mechanochemical effects on complex, hybridized layered double hydroxides (LDHs). Various physicochemical properties of the ground and the intact LDHs were compared by powder X-ray diffractometry, N₂ adsorption-desorption, UV–Vis diffuse reflectance, infrared and Raman spectroscopy, scanning electron microscopy and thermogravimetric measurements. The data showed significant structural and morphological deformations, surface and textural changes and multifarious thermal behavior. The most interesting development was the change in the optical properties of organic LDHs; the milling significantly improved the UV light blocking ability, especially around 320 nm. Spectroscopic results verified that this could be explained by a modification in interaction between the LDH layers and the sulisobenzone anions, through modulated π–π conjugation and light absorption of benzene rings. In addition to the vibrating mill often used in the laboratory, the photoprotection reinforcement can also be induced by the drum mill grinding system commonly applied in industry. Full article

(This article belongs to the Section Nanocomposite Materials)

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12 pages, 2681 KB

Open AccessEditor’s ChoiceArticle

Interpretable Structural Evaluation of Metal-Oxide Nanostructures in Scanning Transmission Electron Microscopy (STEM) Images via Persistent Homology

by Ryuto Eguchi, Yu Wen, Hideki Abe and Ayako Hashimoto

Nanomaterials 2024, 14(17), 1413; https://doi.org/10.3390/nano14171413 - 29 Aug 2024

Cited by 1 | Viewed by 2096

Abstract

Persistent homology is a powerful tool for quantifying various structures, but it is equally crucial to maintain its interpretability. In this study, we extracted interpretable geometric features from the persistent diagrams (PDs) of scanning transmission electron microscopy (STEM) images of self-assembled Pt-CeO₂ [...] Read more.

Persistent homology is a powerful tool for quantifying various structures, but it is equally crucial to maintain its interpretability. In this study, we extracted interpretable geometric features from the persistent diagrams (PDs) of scanning transmission electron microscopy (STEM) images of self-assembled Pt-CeO₂ nanostructures synthesized under different annealing conditions. We focused on PD quadrants and extracted five interpretable features from the zeroth and first PDs of nanostructures ranging from maze-like to striped patterns. A combination of hierarchical clustering and inverse analysis of PDs reconstructed by principal component analysis through vectorization of the PDs highlighted the importance of the number of arc-like structures of the CeO₂ phase in the first PDs, particularly those that were smaller than a characteristic size. This descriptor enabled us to quantify the degree of disorder, namely the density of bends, in nanostructures formed under different conditions. By using this descriptor along with the width of the CeO₂ phase, we classified 12 Pt-CeO₂ nanostructures in an interpretable way. Full article

(This article belongs to the Special Issue Nanostructured Oxides: Advances in Synthesis, Characterization, and Applications)

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23 pages, 5319 KB

Open AccessEditor’s ChoiceReview

Recent Advances in Chemoresistive Gas Sensors Using Two-Dimensional Materials

by Jae-Kwon Ko, In-Hyeok Park, Kootak Hong and Ki Chang Kwon

Nanomaterials 2024, 14(17), 1397; https://doi.org/10.3390/nano14171397 - 27 Aug 2024

Cited by 13 | Viewed by 3774

Abstract

Two-dimensional (2D) materials have emerged as a promising candidate in the chemoresistive gas sensor field to overcome the disadvantages of conventional metal-oxide semiconductors owing to their strong surface activities and high surface-to-volume ratio. This review summarizes the various approaches to enhance the 2D-material-based [...] Read more.

Two-dimensional (2D) materials have emerged as a promising candidate in the chemoresistive gas sensor field to overcome the disadvantages of conventional metal-oxide semiconductors owing to their strong surface activities and high surface-to-volume ratio. This review summarizes the various approaches to enhance the 2D-material-based gas sensors and provides an overview of their progress. The distinctive attributes of semiconductor gas sensors employing 2D materials will be highlighted with their inherent advantages and associated challenges. The general operating principles of semiconductor gas sensors and the unique characteristics of 2D materials in gas-sensing mechanisms will be explored. The pros and cons of 2D materials in gas-sensing channels are discussed, and a route to overcome the current challenges will be delivered. Finally, the recent advancements to enhance the performance of 2D-material-based gas sensors including photo-activation, heteroatom doping, defect engineering, heterostructures, and nanostructures will be discussed. This review should offer a broad range of readers a new perspective toward the future development of 2D-material-based gas sensors. Full article

(This article belongs to the Special Issue Graphene and Other 2D Layer-Based Nanomaterials for Energy and Sensing Applications)

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18 pages, 6087 KB

Open AccessEditor’s ChoiceArticle

Strain and Substrate-Induced Electronic Properties of Novel Mixed Anion-Based 2D ScHX₂ (X = I/Br) Semiconductors

by Ashima Rawat and Ravindra Pandey

Nanomaterials 2024, 14(17), 1390; https://doi.org/10.3390/nano14171390 - 26 Aug 2024

Viewed by 1478

Abstract

Exploration of compounds featuring multiple anions beyond the single-oxide ion, such as oxyhalides and oxyhydrides, offers an avenue for developing materials with the prospect of novel functionality. In this paper, we present the results for a mixed anion layered material, ScHX₂ (X: [...] Read more.

Exploration of compounds featuring multiple anions beyond the single-oxide ion, such as oxyhalides and oxyhydrides, offers an avenue for developing materials with the prospect of novel functionality. In this paper, we present the results for a mixed anion layered material, ScHX₂ (X: Br, I) based on density functional theory. The result predicted the ScHX₂ (X: Br, I) monolayers to be stable and semiconducting. Notably, the electronic and mechanical properties of the ScHX₂ monolayers are comparable to well-established 2D materials like graphene and MoS₂, rendering them highly suitable for electronic devices. Additionally, these monolayers exhibit an ability to adjust their band gaps and band edges in response to strain and substrate engineering, thereby influencing their photocatalytic applications. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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23 pages, 3531 KB

Open AccessEditor’s ChoiceReview

Metal–Organic Frameworks for Overcoming the Blood–Brain Barrier in the Treatment of Brain Diseases: A Review

by Hafezeh Nabipour and Sohrab Rohani

Nanomaterials 2024, 14(17), 1379; https://doi.org/10.3390/nano14171379 - 23 Aug 2024

Cited by 5 | Viewed by 2871

Abstract

The blood–brain barrier (BBB) plays a vital role in safeguarding the central nervous system by selectively controlling the movement of substances between the bloodstream and the brain, presenting a substantial obstacle for the administration of therapeutic agents to the brain. Recent breakthroughs in [...] Read more.

The blood–brain barrier (BBB) plays a vital role in safeguarding the central nervous system by selectively controlling the movement of substances between the bloodstream and the brain, presenting a substantial obstacle for the administration of therapeutic agents to the brain. Recent breakthroughs in nanoparticle-based delivery systems, particularly metal–organic frameworks (MOFs), provide promising solutions for addressing the BBB. MOFs have become valuable tools in delivering medications to the brain with their ability to efficiently load drugs, release them over time, and modify their surface properties. This review focuses on the recent advancements in molecular-based approaches for treating brain disorders, such as glioblastoma multiforme, stroke, Parkinson’s disease, and Alzheimer’s disease. This paper highlights the significant impact of MOFs in overcoming the shortcomings of conventional brain drug delivery techniques and provides valuable insights for future research in the field of neurotherapeutics. Full article

(This article belongs to the Special Issue Novel Metal–Organic Frameworks and Their Composites: A Journey from Synthesis to Application)

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29 pages, 7083 KB

Open AccessEditor’s ChoiceArticle

Mechanical and Shape Memory Properties of Additively Manufactured Polyurethane (PU)/Halloysite Nanotube (HNT) Nanocomposites

by Wendy Triadji Nugroho, Yu Dong and Alokesh Pramanik

Nanomaterials 2024, 14(16), 1373; https://doi.org/10.3390/nano14161373 - 22 Aug 2024

Cited by 2 | Viewed by 2049

Abstract

This paper investigates the impact of halloysite nanotube (HNT) content on mechanical and shape memory properties of additively manufactured polyurethane (PU)/HNT nanocomposites. The inclusion of 8 wt% HNTs increases their tensile strength by 30.4% when compared with that of virgin PU at 44.75 [...] Read more.

This paper investigates the impact of halloysite nanotube (HNT) content on mechanical and shape memory properties of additively manufactured polyurethane (PU)/HNT nanocomposites. The inclusion of 8 wt% HNTs increases their tensile strength by 30.4% when compared with that of virgin PU at 44.75 MPa. Furthermore, consistently significant increases in tensile modulus, compressive strength and modulus, as well as specific energy absorption are also manifested by 47.2%, 34.0%, 125% and 72.7% relative to neat PU at 2.29 GPa, 3.88 MPa, 0.28 GPa and 0.44 kJ/kg respectively. However, increasing HNT content reduces lateral strain due to the restricted mobility of polymeric chains, leading to a decrease in negative Poisson’s ratio (NPR). As such, shape recovery ratio and time of PU/HNT nanocomposites are reduced by 9 and 45% with the inclusion of 10 wt% HNTs despite an increasing shape fixity ratio up to 12% relative to those of neat PU. Full article

(This article belongs to the Section Nanocomposite Materials)

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14 pages, 5143 KB

Open AccessEditor’s ChoiceArticle

A Self-Powered, Skin Adhesive, and Flexible Human–Machine Interface Based on Triboelectric Nanogenerator

by Xujie Wu, Ziyi Yang, Yu Dong, Lijing Teng, Dan Li, Hang Han, Simian Zhu, Xiaomin Sun, Zhu Zeng, Xiangyu Zeng and Qiang Zheng

Nanomaterials 2024, 14(16), 1365; https://doi.org/10.3390/nano14161365 - 20 Aug 2024

Cited by 6 | Viewed by 2340

Abstract

Human–machine interactions (HMIs) have penetrated into various academic and industrial fields, such as robotics, virtual reality, and wearable electronics. However, the practical application of most human–machine interfaces faces notable obstacles due to their complex structure and materials, high power consumption, limited effective skin [...] Read more.

Human–machine interactions (HMIs) have penetrated into various academic and industrial fields, such as robotics, virtual reality, and wearable electronics. However, the practical application of most human–machine interfaces faces notable obstacles due to their complex structure and materials, high power consumption, limited effective skin adhesion, and high cost. Herein, we report a self-powered, skin adhesive, and flexible human–machine interface based on a triboelectric nanogenerator (SSFHMI). Characterized by its simple structure and low cost, the SSFHMI can easily convert touch stimuli into a stable electrical signal at the trigger pressure from a finger touch, without requiring an external power supply. A skeleton spacer has been specially designed in order to increase the stability and homogeneity of the output signals of each TENG unit and prevent crosstalk between them. Moreover, we constructed a hydrogel adhesive interface with skin-adhesive properties to adapt to easy wear on complex human body surfaces. By integrating the SSFHMI with a microcontroller, a programmable touch operation platform has been constructed that is capable of multiple interactions. These include medical calling, music media playback, security unlocking, and electronic piano playing. This self-powered, cost-effective SSFHMI holds potential relevance for the next generation of highly integrated and sustainable portable smart electronic products and applications. Full article

(This article belongs to the Special Issue Self-Powered Flexible Sensors Based on Triboelectric Nanogenerators)

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23 pages, 31708 KB

Open AccessEditor’s ChoiceArticle

Development of In Situ Methods for Preparing La-Mn-Co-Based Compounds over Carbon Xerogel for Oxygen Reduction Reaction in an Alkaline Medium

by Jhony Xavier Flores-Lasluisa, Bryan Carré, Joachim Caucheteux, Philippe Compère, Alexandre F. Léonard and Nathalie Job

Nanomaterials 2024, 14(16), 1362; https://doi.org/10.3390/nano14161362 - 19 Aug 2024

Cited by 3 | Viewed by 1596

Abstract

Metal oxides containing La, Mn, and Co cations can catalyze oxygen reduction reactions (ORRs) in electrochemical processes. However, these materials require carbon support and optimal interactions between both compounds to be active. In this work, two approaches to prepare composites of La-Mn-Co-based compounds [...] Read more.

Metal oxides containing La, Mn, and Co cations can catalyze oxygen reduction reactions (ORRs) in electrochemical processes. However, these materials require carbon support and optimal interactions between both compounds to be active. In this work, two approaches to prepare composites of La-Mn-Co-based compounds over carbon xerogel were developed. Using sol-gel methods, either the metal-based material was deposited on the existing carbon xerogel or vice versa. The metal oxide selected was the LaMn_0.7Co_0.3O₃ perovskite, which has good catalytic behavior and selectivity towards direct ORRs. All the as-prepared composites were tested for ORRs in alkaline liquid electrolytes and characterized by diverse physicochemical techniques such as XRD, XPS, SEM, or N₂ adsorption. Although the perovskite structure either decomposed or failed to form using those in situ methods, the materials exhibited great catalytic activity, which can be ascribed to the strengthening of the interactions between oxides and the carbon support via C-O-M covalent bonds and to the formation of new active sites such as the MnO/Co heterointerfaces. Moreover, Co-N_x-C species are formed during the synthesis of the metal compounds over the carbon xerogel. These species possess a strong catalytic activity towards ORR. Therefore, the composites formed by synthesizing metal compounds over the carbon xerogel exhibit the best performance in the ORR, which can be ascribed to the presence of the MnO/Co heterointerfaces and Co-N_x-C species and the strong interactions between both compounds. Moreover, the small nanoparticle size leads to a higher number of active sites available for the reaction. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Electrocatalytic Application)

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10 pages, 1994 KB

Open AccessEditor’s ChoiceArticle

Enhanced Thermal Stability of Conductive Mercury Telluride Colloidal Quantum Dot Thin Films Using Atomic Layer Deposition

by Edward W. Malachosky, Matthew M. Ackerman and Liliana Stan

Nanomaterials 2024, 14(16), 1354; https://doi.org/10.3390/nano14161354 - 16 Aug 2024

Cited by 2 | Viewed by 1688

Abstract

Colloidal quantum dots (CQDs) are valuable for their potential applications in optoelectronic devices. However, they are susceptible to thermal degradation during processing and while in use. Mitigating thermally induced sintering, which leads to absorption spectrum broadening and undesirable changes to thin film electrical [...] Read more.

Colloidal quantum dots (CQDs) are valuable for their potential applications in optoelectronic devices. However, they are susceptible to thermal degradation during processing and while in use. Mitigating thermally induced sintering, which leads to absorption spectrum broadening and undesirable changes to thin film electrical properties, is necessary for the reliable design and manufacture of CQD-based optoelectronics. Here, low-temperature metal–oxide atomic layer deposition (ALD) was investigated as a method for mitigating sintering while preserving the optoelectronic properties of mercury telluride (HgTe) CQD films. ALD-coated films are subjected to temperatures up to 160 °C for up to 5 h and alumina (Al₂O₃) is found to be most effective at preserving the optical properties, demonstrating the feasibility of metal–oxide in-filling to protect against sintering. HgTe CQD film electrical properties were investigated before and after alumina ALD in-filling, which was found to increase the p-type doping and hole mobility of the films. The magnitude of these effects depended on the conditions used to prepare the HgTe CQDs. With further investigation into the interaction effects of CQD and ALD process factors, these results may be used to guide the design of CQD–ALD materials for their practical integration into useful optoelectronic devices. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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31 pages, 4738 KB

Open AccessEditor’s ChoiceArticle

Synthesized Bis-Triphenyl Phosphonium-Based Nano Vesicles Have Potent and Selective Antibacterial Effects on Several Clinically Relevant Superbugs

by Silvana Alfei, Guendalina Zuccari, Francesca Bacchetti, Carola Torazza, Marco Milanese, Carlo Siciliano, Constantinos M. Athanassopoulos, Gabriella Piatti and Anna Maria Schito

Nanomaterials 2024, 14(16), 1351; https://doi.org/10.3390/nano14161351 - 15 Aug 2024

Cited by 9 | Viewed by 2117

Abstract

The increasing emergence of multidrug-resistant (MDR) pathogens due to antibiotic misuse translates into obstinate infections with high morbidity and high-cost hospitalizations. To oppose these MDR superbugs, new antimicrobial options are necessary. Although both quaternary ammonium salts (QASs) and phosphonium salts (QPSs) possess antimicrobial [...] Read more.

The increasing emergence of multidrug-resistant (MDR) pathogens due to antibiotic misuse translates into obstinate infections with high morbidity and high-cost hospitalizations. To oppose these MDR superbugs, new antimicrobial options are necessary. Although both quaternary ammonium salts (QASs) and phosphonium salts (QPSs) possess antimicrobial effects, QPSs have been studied to a lesser extent. Recently, we successfully reported the bacteriostatic and cytotoxic effects of a triphenyl phosphonium salt against MDR isolates of the Enterococcus and Staphylococcus genera. Here, aiming at finding new antibacterial devices possibly active toward a broader spectrum of clinically relevant bacteria responsible for severe human infections, we synthesized a water-soluble, sterically hindered quaternary phosphonium salt (BPPB). It encompasses two triphenyl phosphonium groups linked by a C12 alkyl chain, thus embodying the characteristics of molecules known as bola-amphiphiles. BPPB was characterized by ATR-FTIR, NMR, and UV spectroscopy, FIA-MS (ESI), elemental analysis, and potentiometric titrations. Optical and DLS analyses evidenced BPPB tendency to self-forming spherical vesicles of 45 nm (DLS) in dilute solution, tending to form larger aggregates in concentrate solution (DLS and optical microscope), having a positive zeta potential (+18 mV). The antibacterial effects of BPPB were, for the first time, assessed against fifty clinical isolates of both Gram-positive and Gram-negative species. Excellent antibacterial effects were observed for all strains tested, involving all the most concerning species included in ESKAPE bacteria. The lowest MICs were 0.250 µg/mL, while the highest ones (32 µg/mL) were observed for MDR Gram-negative metallo-β-lactamase-producing bacteria and/or species resistant also to colistin, carbapenems, cefiderocol, and therefore intractable with currently available antibiotics. Moreover, when administered to HepG2 human hepatic and Cos-7 monkey kidney cell lines, BPPB showed selectivity indices > 10 for all Gram-positive isolates and for clinically relevant Gram-negative superbugs such as those of E. coli species, thus being very promising for clinical development. Full article

(This article belongs to the Section Biology and Medicines)

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15 pages, 1723 KB

Open AccessEditor’s ChoiceArticle

Human Serum Albumin Protein Corona in Prussian Blue Nanoparticles

by Chiara Colombi, Giacomo Dacarro, Yuri Antonio Diaz Fernandez, Angelo Taglietti, Piersandro Pallavicini and Lavinia Doveri

Nanomaterials 2024, 14(16), 1336; https://doi.org/10.3390/nano14161336 - 11 Aug 2024

Cited by 3 | Viewed by 1777

Abstract

Prussian Blue nanoparticles (PBnps) are now popular in nanomedicine thanks to the FDA approval of PB. Despite the numerous papers suggesting or describing the in vivo use of PBnps, no studies have been carried out on the formation of a protein corona on [...] Read more.

Prussian Blue nanoparticles (PBnps) are now popular in nanomedicine thanks to the FDA approval of PB. Despite the numerous papers suggesting or describing the in vivo use of PBnps, no studies have been carried out on the formation of a protein corona on the PBnp surface and its stabilizing role. In this paper, we studied qualitatively and quantitatively the corona formed by the most abundant protein of blood, human serum albumin (HSA). Cubic PBnps (41 nm side), prepared in citric acid solution at PB concentration 5 × 10⁻⁴ M, readily form a protein corona by redissolving ultracentrifuged PBnp pellets in HSA solutions, with C_HSA ranging from 0.025 to 7.0 mg/mL. The basic decomposition of PBnp@HSA was studied in phosphate buffer at the physiological pH value of 7.4. Increased stability with respect to uncoated PBnps was observed at all concentrations, but a minimum C_HSA value of 3.0 mg/mL was determined to obtain stability identical to that observed at serum-like HSA concentrations (35–50 mg/mL). Using a modified Lowry protocol, the quantity of firmly bound HSA in the protein corona (hard corona) was determined for all the C_HSA used in the PBnp@HSA synthesis, finding increasing quantities with increasing C_HSA. In particular, an HSA/PBnp number in the 1500–2300 range was found for C_HSA 3.0–7.0 mg/mL, largely exceeding the 180 HSA/PBnp value calculated for an HSA monolayer on a PBnp. Finally, the stabilization brought by the HSA corona allowed us to carry out pH-spectrophotometric titrations on PBnp@HSA in the 3.5-9-0 pH range, revealing a pKa value of 6.68 for the water molecules bound to the Fe³⁺ centers on the PBnp surface, whose deprotonation is responsible for the blue-shift of the PBnp band from 706 nm (acidic solution) to 685 nm (basic solution). Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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10 pages, 3536 KB

Open AccessEditor’s ChoiceArticle

Gamma-Irradiation-Induced Electrical Characteristic Variations in MoS₂ Field-Effect Transistors with Buried Local Back-Gate Structure

by Su Jin Kim, Seungkwon Hwang, Jung-Dae Kwon, Jongwon Yoon, Jeong Min Park, Yongsu Lee, Yonghun Kim and Chang Goo Kang

Nanomaterials 2024, 14(16), 1324; https://doi.org/10.3390/nano14161324 - 7 Aug 2024

Cited by 1 | Viewed by 2851

Abstract

The impact of radiation on MoS₂-based devices is an important factor in the utilization of two-dimensional semiconductor-based technology in radiation-sensitive environments. In this study, the effects of gamma irradiation on the electrical variations in MoS₂ field-effect transistors with buried local [...] Read more.

The impact of radiation on MoS₂-based devices is an important factor in the utilization of two-dimensional semiconductor-based technology in radiation-sensitive environments. In this study, the effects of gamma irradiation on the electrical variations in MoS₂ field-effect transistors with buried local back-gate structures were investigated, and their related effects on Al₂O₃ gate dielectrics and MoS₂/Al₂O₃ interfaces were also analyzed. The transfer and output characteristics were analyzed before and after irradiation. The current levels decreased by 15.7% under an exposure of 3 kGy. Additionally, positive shifts in the threshold voltages of 0.50, 0.99, and 1.15 V were observed under irradiations of 1, 2, and 3 kGy, respectively, compared to the non-irradiated devices. This behavior is attributable to the comprehensive effects of hole accumulation in the Al₂O₃ dielectric interface near the MoS₂ side and the formation of electron trapping sites at the interface, which increased the electron tunneling at the MoS₂ channel/dielectric interface. Full article

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

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18 pages, 3895 KB

Open AccessEditor’s ChoiceArticle

Core–Shell Interface Engineering Strategies for Modulating Energy Transfer in Rare Earth-Doped Nanoparticles

by Zhaoxi Zhou, Yuan Liu, Lichao Guo, Tian Wang, Xinrong Yan, Shijiong Wei, Dehui Qiu, Desheng Chen, Xiaobo Zhang and Huangxian Ju

Nanomaterials 2024, 14(16), 1326; https://doi.org/10.3390/nano14161326 - 7 Aug 2024

Cited by 1 | Viewed by 2285

Abstract

Rare earth-doped nanoparticles (RENPs) are promising biomaterials with substantial potential in biomedical applications. Their multilayered core–shell structure design allows for more diverse uses, such as orthogonal excitation. However, the typical synthesis strategies—one-pot successive layer-by-layer (LBL) method and seed-assisted (SA) method—for creating multilayered RENPs [...] Read more.

Rare earth-doped nanoparticles (RENPs) are promising biomaterials with substantial potential in biomedical applications. Their multilayered core–shell structure design allows for more diverse uses, such as orthogonal excitation. However, the typical synthesis strategies—one-pot successive layer-by-layer (LBL) method and seed-assisted (SA) method—for creating multilayered RENPs show notable differences in spectral performance. To clarify this issue, a thorough comparative analysis of the elemental distribution and spectral characteristics of RENPs synthesized by these two strategies was conducted. The SA strategy, which avoids the partial mixing stage of shell and core precursors inherent in the LBL strategy, produces RENPs with a distinct interface in elemental distribution. This unique elemental distribution reduces unnecessary energy loss via energy transfer between heterogeneous elements in different shell layers. Consequently, the synthesis method choice can effectively modulate the spectral properties of RENPs. This discovery has been applied to the design of orthogonal RENP biomedical probes with appropriate dimensions, where the SA strategy introduces a refined inert interface to prevent unnecessary energy loss. Notably, this strategy has exhibited a 4.3-fold enhancement in NIR-II in vivo imaging and a 2.1-fold increase in reactive oxygen species (ROS)-related photodynamic therapy (PDT) orthogonal applications. Full article

(This article belongs to the Special Issue Lanthanide-Doped Luminescent Nanomaterials: Design, Synthesis, Optical Properties and Applications)

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23 pages, 4546 KB

Open AccessEditor’s ChoiceArticle

Enhanced Dye Adsorption on Cold Plasma-Oxidized Multi-Walled Carbon Nanotubes: A Comparative Study

by Anastasia Skourti, Stefania Giannoulia, Maria K. Daletou and Christos A. Aggelopoulos

Nanomaterials 2024, 14(15), 1298; https://doi.org/10.3390/nano14151298 - 1 Aug 2024

Cited by 3 | Viewed by 2170

Abstract

The oxidation of multi-walled carbon nanotubes (MWCNTs) using cold plasma was investigated for their subsequent use as adsorbents for the removal of dyes from aqueous solutions. The properties of MWCNTs after plasma modification and their adsorption capacities were compared with pristine and chemically [...] Read more.

The oxidation of multi-walled carbon nanotubes (MWCNTs) using cold plasma was investigated for their subsequent use as adsorbents for the removal of dyes from aqueous solutions. The properties of MWCNTs after plasma modification and their adsorption capacities were compared with pristine and chemically oxidized nanotubes. The modification process employed a reactor where plasma was generated through dielectric barrier discharges (DBD) powered by high-voltage nanosecond pulses. Various modification conditions were examined, such as processing time and pulse voltage amplitude. The degree of oxidation and the impact on the chemistry and structure of the nanotubes was investigated through various physicochemical and morphological characterization techniques (XPS, BET, TEM, etc.). Maximum oxidation (O/C = 0.09 from O/C = 0.02 for pristine MWCNTs) was achieved after 60 min of nanopulsed-DBD plasma treatment. Subsequently, the modified nanotubes were used as adsorbents for the removal of the dye methylene blue (MB) from water. The adsorption experiments examined the effects of contact time between the adsorbent and MB, as well as the initial dye concentration in water. The plasma-modified nanotubes exhibited high MB removal efficiency, with adsorption capacity proportional to the degree of oxidation. Notably, their adsorption capacity significantly increased compared to both pristine and chemically oxidized MWCNTs (~54% and ~9%, respectively). Finally, the kinetics and mechanism of the adsorption process were studied, with experimental data fitting well to the pseudo-second-order kinetic model and the Langmuir isotherm model. This study underscores the potential of plasma technology as a low-cost and environmentally friendly approach for material modification and water purification. Full article

(This article belongs to the Special Issue Novel Nanostructured Materials and Their Applications in Wastewater Treatment)

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11 pages, 1818 KB

Open AccessEditor’s ChoiceArticle

How Well Can Quantum Embedding Method Predict the Reaction Profiles for Hydrogenation of Small Li Clusters?

by Dominic Alfonso, Benjamin Avramidis, Hari P. Paudel and Yuhua Duan

Nanomaterials 2024, 14(15), 1267; https://doi.org/10.3390/nano14151267 - 29 Jul 2024

Cited by 1 | Viewed by 2203

Abstract

Quantum computing leverages the principles of quantum mechanics in novel ways to tackle complex chemistry problems that cannot be accurately addressed using traditional quantum chemistry methods. However, the high computational cost and available number of physical qubits with high fidelity limit its application [...] Read more.

Quantum computing leverages the principles of quantum mechanics in novel ways to tackle complex chemistry problems that cannot be accurately addressed using traditional quantum chemistry methods. However, the high computational cost and available number of physical qubits with high fidelity limit its application to small chemical systems. This work employed a quantum-classical framework which features a quantum active space-embedding approach to perform simulations of chemical reactions that require up to 14 qubits. This framework was applied to prototypical example metal hydrogenation reactions: the coupling between hydrogen and Li₂, Li₃, and Li₄ clusters. Particular attention was paid to the computation of barriers and reaction energies. The predicted reaction profiles compare well with advanced classical quantum chemistry methods, demonstrating the potential of the quantum embedding algorithm to map out reaction profiles of realistic gas-phase chemical reactions to ascertain qualitative energetic trends. Additionally, the predicted potential energy curves provide a benchmark to compare against both current and future quantum embedding approaches. Full article

(This article belongs to the Special Issue Theoretical Calculation Study of Nanomaterials: 2nd Edition)

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26 pages, 8570 KB

Open AccessEditor’s ChoiceReview

Polymeric Nanocomposites of Boron Nitride Nanosheets for Enhanced Directional or Isotropic Thermal Transport Performance

by Buta Singh, Jinchen Han, Mohammed J. Meziani, Li Cao, Subhadra Yerra, Jordan Collins, Simran Dumra and Ya-Ping Sun

Nanomaterials 2024, 14(15), 1259; https://doi.org/10.3390/nano14151259 - 27 Jul 2024

Cited by 2 | Viewed by 3117

Abstract

Polymeric composites with boron nitride nanosheets (BNNs), which are thermally conductive yet electrically insulating, have been pursued for a variety of technological applications, especially those for thermal management in electronic devices and systems. Highlighted in this review are recent advances in the effort [...] Read more.

Polymeric composites with boron nitride nanosheets (BNNs), which are thermally conductive yet electrically insulating, have been pursued for a variety of technological applications, especially those for thermal management in electronic devices and systems. Highlighted in this review are recent advances in the effort to improve in-plane thermal transport performance in polymer/BNNs composites and also the growing research activities aimed at composites of enhanced cross-plane or isotropic thermal conductivity, for which various filler alignment strategies during composite fabrication have been explored. Also highlighted and discussed are some significant challenges and major opportunities for further advances in the development of thermally conductive composite materials and their mechanistic understandings. Full article

(This article belongs to the Special Issue Functional Nanocomposites: From Strategic Design to Applications)

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24 pages, 2408 KB

Open AccessEditor’s ChoiceReview

Carbon Dots in Photodynamic/Photothermal Antimicrobial Therapy

by Siqi Wang, Colin P. McCoy, Peifeng Li, Yining Li, Yinghan Zhao, Gavin P. Andrews, Matthew P. Wylie and Yi Ge

Nanomaterials 2024, 14(15), 1250; https://doi.org/10.3390/nano14151250 - 25 Jul 2024

Cited by 15 | Viewed by 5266

Abstract

Antimicrobial resistance (AMR) presents an escalating global challenge as conventional antibiotic treatments become less effective. In response, photodynamic therapy (PDT) and photothermal therapy (PTT) have emerged as promising alternatives. While rooted in ancient practices, these methods have evolved with modern innovations, particularly through [...] Read more.

Antimicrobial resistance (AMR) presents an escalating global challenge as conventional antibiotic treatments become less effective. In response, photodynamic therapy (PDT) and photothermal therapy (PTT) have emerged as promising alternatives. While rooted in ancient practices, these methods have evolved with modern innovations, particularly through the integration of lasers, refining their efficacy. PDT harnesses photosensitizers to generate reactive oxygen species (ROS), which are detrimental to microbial cells, whereas PTT relies on heat to induce cellular damage. The key to their effectiveness lies in the utilization of photosensitizers, especially when integrated into nano- or micron-scale supports, which amplify ROS production and enhance antimicrobial activity. Over the last decade, carbon dots (CDs) have emerged as a highly promising nanomaterial, attracting increasing attention owing to their distinctive properties and versatile applications, including PDT and PTT. They can not only function as photosensitizers, but also synergistically combine with other photosensitizers to enhance overall efficacy. This review explores the recent advancements in CDs, underscoring their significance and potential in reshaping advanced antimicrobial therapeutics. Full article

(This article belongs to the Special Issue Carbon Nanostructures as Promising Future Materials: 2nd Edition)

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17 pages, 2591 KB

Open AccessEditor’s ChoiceArticle

High Magnetic Performance in MnGa Nanocomposite Magnets

by Ovidiu Crisan and Alina Daniela Crisan

Nanomaterials 2024, 14(15), 1245; https://doi.org/10.3390/nano14151245 - 24 Jul 2024

Cited by 1 | Viewed by 1725

Abstract

In view of their potential applicability in technology fields where magnets are required to operate at higher temperatures, the class of nanocomposite magnets with little or no rare earth (RE) content has been widely researched in the last two decades. Among these nanocomposite [...] Read more.

In view of their potential applicability in technology fields where magnets are required to operate at higher temperatures, the class of nanocomposite magnets with little or no rare earth (RE) content has been widely researched in the last two decades. Among these nanocomposite magnets, the subclass of magnetic binary systems exhibiting the formation of L1₀ tetragonal phases is the most illustrious. Some of the most interesting systems are represented by the Mn-based alloys, with addition of Al, Bi, Ga, Ge. Such alloys are interesting as they are less costly than RE magnets and they show promising magnetic properties. The paper tackles the case of MnGa binary alloys with various compositions around the Mn₃Ga stoichiometry. Four MnGa magnetic alloys, with Mn content ranging from 70 at% to 75 at% were produced using rapid solidification to form the melt. By combining structural information arising from X-ray diffractometry and transmission electron microscopy with magnetic properties determined by vibrating sample magnetometry, we are able to document the nature and properties of the structural phases formed in the alloys in their as-cast state and upon annealing, the evolution of the phase structure after annealing and its influence on the magnetic behavior of the MnGa alloys. After annealing at 400 °C and 500 °C, MnGa alloys are showing a multiple-phase microstructure, consisting of co-existing crystallites of L1₀ and D0₂₂ tetragonal phase. As a consequence of these structurally and magnetically different phases, co-existing within the microstructure, promising magnetic features are obtained, with both coercive fields and saturation magnetization exceeding values previously reported for both alloys and layers of MnGa. Full article

(This article belongs to the Special Issue Advanced Nanocomposite Magnets with the L10 Phase)

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15 pages, 4439 KB

Open AccessEditor’s ChoiceArticle

Photocatalytic CO₂ Reduction Using Zinc Indium Sulfide Aggregated Nanostructures Fabricated under Four Anionic Conditions

by I-Hua Tsai and Eric Wei-Guang Diau

Nanomaterials 2024, 14(14), 1231; https://doi.org/10.3390/nano14141231 - 20 Jul 2024

Viewed by 1560

Abstract

Zinc indihuhium sulfide (ZIS), among various semiconductor materials, shows considerable potential due to its simplicity, low cost, and environmental compatibility. However, the influence of precursor anions on ZIS properties remains unclear. In this study, we synthesized ZIS via a hydrothermal method using four [...] Read more.

Zinc indihuhium sulfide (ZIS), among various semiconductor materials, shows considerable potential due to its simplicity, low cost, and environmental compatibility. However, the influence of precursor anions on ZIS properties remains unclear. In this study, we synthesized ZIS via a hydrothermal method using four different anionic precursors (ZnCl₂/InCl₃, Zn(NO₃)₂/In(NO₃)₃, Zn(CH₃CO₂)₂/In(CH₃CO₂)₃, and Zn(CH₃CO₂)₂/In₂(SO₄)₃), resulting in distinct morphologies and crystal structures. Our findings reveal that ZIS produced from Zn(CH₃CO₂)₂/In₂(SO₄)₃ (ZIS-AceSO₄) exhibited the highest photocatalytic CO₂ reduction efficiency, achieving a CO production yield of 134 μmol g⁻¹h⁻¹. This enhanced performance is attributed to the formation of more zinc and indium vacancy defects, as confirmed by EDS analysis. Additionally, we determined the energy levels of the valence band maximum (VBM) and the conduction band minimum (CBM) via UPS and absorption spectra, providing insights into the band alignment essential for photocatalytic processes. These findings not only deepen our understanding of the anionic precursor’s impact on ZIS properties but also offer new avenues for optimizing photocatalytic CO₂ reduction, marking a significant advancement over previous studies. Full article

(This article belongs to the Section Energy and Catalysis)

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23 pages, 22654 KB

Open AccessEditor’s ChoiceReview

Ligand Engineering of Inorganic Lead Halide Perovskite Quantum Dots toward High and Stable Photoluminescence

by Changbo Deng, Qiuping Huang, Zhengping Fu and Yalin Lu

Nanomaterials 2024, 14(14), 1201; https://doi.org/10.3390/nano14141201 - 15 Jul 2024

Cited by 6 | Viewed by 4203

Abstract

The ligand engineering of inorganic lead halide perovskite quantum dots (PQDs) is an indispensable strategy to boost their photoluminescence stability, which is pivotal for optoelectronics applications. CsPbX₃ (X = Cl, Br, I) PQDs exhibit exceptional optical properties, including high color purity and [...] Read more.

The ligand engineering of inorganic lead halide perovskite quantum dots (PQDs) is an indispensable strategy to boost their photoluminescence stability, which is pivotal for optoelectronics applications. CsPbX₃ (X = Cl, Br, I) PQDs exhibit exceptional optical properties, including high color purity and tunable bandgaps. Despite their promising characteristics, environmental sensitivity poses a challenge to their stability. This article reviews the solution-based synthesis methods with ligand engineering. It introduces the impact of factors like humidity, temperature, and light exposure on PQD’s instability, as well as in situ and post-synthesis ligand engineering strategies. The use of various ligands, including X- and L-type ligands, is reviewed for their effectiveness in enhancing stability and luminescence performance. Finally, the significant potential of ligand engineering for the broader application of PQDs in optoelectronic devices is also discussed. Full article

(This article belongs to the Special Issue Metal Halide Perovskite Nanomaterials for Optoelectronics, Photovoltaics and Beyond)

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12 pages, 8570 KB

Open AccessEditor’s ChoiceArticle

Quantized Microcavity Polariton Lasing Based on InGaN Localized Excitons

by Huying Zheng, Runchen Wang, Xuebing Gong, Junxing Dong, Lisheng Wang, Jingzhuo Wang, Yifan Zhang, Yan Shen, Huanjun Chen, Baijun Zhang and Hai Zhu

Nanomaterials 2024, 14(14), 1197; https://doi.org/10.3390/nano14141197 - 14 Jul 2024

Viewed by 1697

Abstract

Exciton–polaritons, which are bosonic quasiparticles with an extremely low mass, play a key role in understanding macroscopic quantum effects related to Bose–Einstein condensation (BEC) in solid-state systems. The study of trapped polaritons in a potential well provides an ideal platform for manipulating polariton [...] Read more.

Exciton–polaritons, which are bosonic quasiparticles with an extremely low mass, play a key role in understanding macroscopic quantum effects related to Bose–Einstein condensation (BEC) in solid-state systems. The study of trapped polaritons in a potential well provides an ideal platform for manipulating polariton condensates, enabling polariton lasing with specific formation in k-space. Here, we realize quantized microcavity polariton lasing in simple harmonic oscillator (SHO) states based on spatial localized excitons in InGaN/GaN quantum wells (QWs). Benefiting from the high exciton binding energy (90 meV) and large oscillator strength of the localized exciton, room-temperature (RT) polaritons with large Rabi splitting (61 meV) are obtained in a strongly coupled microcavity. The manipulation of polariton condensates is performed through a parabolic potential well created by optical pump control. Under the confinement situation, trapped polaritons are controlled to be distributed in the selected quantized energy sublevels of the SHO state. The maximum energy spacing of 11.3 meV is observed in the SHO sublevels, indicating the robust polariton trapping of the parabolic potential well. Coherent quantized polariton lasing is achieved in the ground state of the SHO state and the coherence property of the lasing is analyzed through the measurements of spatial interference patterns and g⁽²⁾(τ). Our results offer a feasible route to explore the manipulation of macroscopic quantum coherent states and to fabricate novel polariton devices towards room-temperature operations. Full article

(This article belongs to the Special Issue Nanoscale Materials and Their Photonic Devices)

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39 pages, 3752 KB

Open AccessEditor’s ChoiceReview

Harnessing Magnetic Nanoparticles for the Effective Removal of Micro- and Nanoplastics: A Critical Review

by Sabina Vohl, Matjaž Kristl and Janja Stergar

Nanomaterials 2024, 14(14), 1179; https://doi.org/10.3390/nano14141179 - 11 Jul 2024

Cited by 26 | Viewed by 5971

Abstract

The spread of micro- (MPs) and nanoplastics (NPs) in the environment has become a significant environmental concern, necessitating effective removal strategies. In this comprehensive scientific review, we examine the use of magnetic nanoparticles (MNPs) as a promising technology for the removal of MPs [...] Read more.

The spread of micro- (MPs) and nanoplastics (NPs) in the environment has become a significant environmental concern, necessitating effective removal strategies. In this comprehensive scientific review, we examine the use of magnetic nanoparticles (MNPs) as a promising technology for the removal of MPs and NPs from water. We first describe the issues of MPs and NPs and their impact on the environment and human health. Then, the fundamental principles of using MNPs for the removal of these pollutants will be presented, emphasizing that MNPs enable the selective binding and separation of MPs and NPs from water sources. Furthermore, we provide a short summary of various types of MNPs that have proven effective in the removal of MPs and NPs. These include ferromagnetic nanoparticles and MNPs coated with organic polymers, as well as nanocomposites and magnetic nanostructures. We also review their properties, such as magnetic saturation, size, shape, surface functionalization, and stability, and their influence on removal efficiency. Next, we describe different methods of utilizing MNPs for the removal of MPs and NPs. We discuss their advantages, limitations, and potential for further development in detail. In the final part of the review, we provide an overview of the existing studies and results demonstrating the effectiveness of using MNPs for the removal of MPs and NPs from water. We also address the challenges that need to be overcome, such as nanoparticle optimization, process scalability, and the removal and recycling of nanoparticles after the completion of the process. This comprehensive scientific review offers extensive insights into the use of MNPs for the removal of MPs and NPs from water. With improved understanding and the development of advanced materials and methods, this technology can play a crucial role in addressing the issues of MPs and NPs and preserving a clean and healthy environment. The novelty of this review article is the emphasis on MNPs for the removal of MPs and NPs from water and a detailed review of the advantages and disadvantages of various MNPs for the mentioned application. Additionally, a review of a large number of publications in this field is provided. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for a Cleaner Environment and Environmental Health)

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23 pages, 7475 KB

Open AccessEditor’s ChoiceReview

Design Strategies of Hydrogen Evolution Reaction Nano Electrocatalysts for High Current Density Water Splitting

by Bao Zang, Xianya Liu, Chen Gu, Jianmei Chen, Longlu Wang and Weihao Zheng

Nanomaterials 2024, 14(14), 1172; https://doi.org/10.3390/nano14141172 - 9 Jul 2024

Cited by 6 | Viewed by 2924

Abstract

Hydrogen is now recognized as the primary alternative to fossil fuels due to its renewable, safe, high-energy density and environmentally friendly properties. Efficient hydrogen production through water splitting has laid the foundation for sustainable energy technologies. However, when hydrogen production is scaled up [...] Read more.

Hydrogen is now recognized as the primary alternative to fossil fuels due to its renewable, safe, high-energy density and environmentally friendly properties. Efficient hydrogen production through water splitting has laid the foundation for sustainable energy technologies. However, when hydrogen production is scaled up to industrial levels, operating at high current densities introduces unique challenges. It is necessary to design advanced electrocatalysts for hydrogen evolution reactions (HERs) under high current densities. This review will briefly introduce the challenges posed by high current densities on electrocatalysts, including catalytic activity, mass diffusion, and catalyst stability. In an attempt to address these issues, various electrocatalyst design strategies are summarized in detail. In the end, our insights into future challenges for efficient large-scale industrial hydrogen production from water splitting are presented. This review is expected to guide the rational design of efficient high-current density water electrolysis electrocatalysts and promote the research progress of sustainable energy. Full article

(This article belongs to the Special Issue Functional Nanocatalysts for Energy Conversion and Environmental Applications)

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14 pages, 3765 KB

Open AccessEditor’s ChoiceArticle

Optimization of Thermoelectric Nanoantenna for Massive High-Output-Voltage Arrays

by Mohamad Khoirul Anam, Yudhistira Yudhistira and Sangjo Choi

Nanomaterials 2024, 14(13), 1159; https://doi.org/10.3390/nano14131159 - 7 Jul 2024

Cited by 2 | Viewed by 2071

Abstract

Thermoelectric nanoantennas have been extensively investigated due to their ability to directly convert infrared (IR) radiation into direct current without an additional rectification device. In this study, we introduce a thermoelectric nanoantenna geometry for maximum output voltage (V_oc) and propose [...] Read more.

Thermoelectric nanoantennas have been extensively investigated due to their ability to directly convert infrared (IR) radiation into direct current without an additional rectification device. In this study, we introduce a thermoelectric nanoantenna geometry for maximum output voltage (V_oc) and propose an optimal series array configuration with a finite number of antennas to enhance the V_oc. A finite and open-ended SiO₂ substrate, with a thickness of a quarter-effective wavelength at a frequency of 28.3 THz, is used to generate standing waves within the substrate. An array of antennas is then positioned optimally on the substrate to maximize the temperature difference (

∆ T

) between hot and cold areas, thereby increasing the average V_oc per antenna element. In numerical simulations, a linearly polarized incident wave with a power density of 1.42 W/cm² is applied to the structure. The results show that a single antenna with the optimum geometry on a substrate measuring 35 µm × 35 µm generates a

∆

T of 64.89 mK, corresponding to a V_oc of 1.75 µV. Finally, a series array of 5 × 6 thermoelectric nanoantennas on a 150 µm × 75 µm substrate including measurement pads achieves an average

∆

T of 49.60 mK with a total V_oc of 40.18 µV, resulting in an average V_oc of 1.34 µV per antenna element and a voltage responsivity (β_v) of 0.77 V/W. This value, achieved solely by optimizing the antenna geometry and open-ended substrate, matches or exceeds the V_oc and β_v of approximately 1 µV and 0.66 V/W, respectively, from suspended thermoelectric antenna arrays over air cavities. Therefore, the proposed thermoelectric nanoantenna array device, characterized by high stability and ease of fabrication, is suitable for manufacturing massive nanoantenna arrays for high-output IR-DC energy harvesters. Full article

(This article belongs to the Special Issue Harvesting Electromagnetic Fields with Nanomaterials from Microwaves to Ultraviolet)

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15 pages, 2843 KB

Open AccessEditor’s ChoiceArticle

p-Type Schottky Contacts for Graphene Adjustable-Barrier Phototransistors

by Carsten Strobel, Carlos Alvarado Chavarin, Martin Knaut, Matthias Albert, André Heinzig, Likhith Gummadi, Christian Wenger and Thomas Mikolajick

Nanomaterials 2024, 14(13), 1140; https://doi.org/10.3390/nano14131140 - 2 Jul 2024

Cited by 3 | Viewed by 2394

Abstract

The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device, graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required [...] Read more.

The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device, graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required for this device. While n-type Schottky contacts are widely investigated, reports about p-type Schottky contacts between graphene and the two involved semiconductors are scarce. In this study, we demonstrate a p-type Schottky contact between graphene and p-germanium. A clear rectification with on–off ratios of close to 10³ (±5 V) and a distinct photoresponse at telecommunication wavelengths in the infrared are achieved. Further, p-type silicon is transferred to or deposited on graphene, and we also observe rectification and photoresponse in the visible range for some of these p-type Schottky junctions. These results are an important step toward the realization of functional graphene adjustable-barrier phototransistors. Full article

(This article belongs to the Special Issue 2D Layered Nanomaterials and Heterostructures for Electronics, Optoelectronics and Sensing)

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