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Volume 11
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Nanomaterials, Volume 11, Issue 11 (November 2021) – 390 articles

Cover Story (view full-size image): The silica frustule of Ctenophora pulchella allows an efficient coupling with photosynthetic active radiation (PAR) in virtue of multiple refractive and diffractive processes induced by its ultrastructure. On the other side, the same material ensures effective protection from detrimental ultraviolet radiation (UVR) due to its absorption spectral features and to UVR-PAR conversion ascribable to photoluminescence. The photonic properties of the nanostructured frustule can thus explain the noticeable tolerance of C. pulchella diatoms versus UVR even in absence of significant amounts of mycosporine-like amino acids and even if they are not able to avoid high UVR exposure by motility.View this paper
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13 pages, 3824 KiB  
Article
Atomistic Simulations on Metal Rod Penetrating Thin Target at Nanoscale Caused by High-Speed Collision
by Yong-Chao Wu, Jin-Ming Liu, Wei Xie, Qing Yin and Jian-Li Shao
Nanomaterials 2021, 11(11), 3160; https://doi.org/10.3390/nano11113160 - 22 Nov 2021
Cited by 1 | Viewed by 1716
Abstract
The penetration process has attracted increasing attention due to its engineering and scientific value. In this work, we investigate the deformation and damage mechanism about the nanoscale penetration of single-crystal aluminum nanorod with atomistic simulations, where distinct draw ratio (∅) and [...] Read more.
The penetration process has attracted increasing attention due to its engineering and scientific value. In this work, we investigate the deformation and damage mechanism about the nanoscale penetration of single-crystal aluminum nanorod with atomistic simulations, where distinct draw ratio (∅) and different incident velocities (up) are considered. The micro deformation processes of no penetration state (within 2 km/s) and complete penetration (above 3 km/s) are both revealed. The high-speed bullet can cause high pressure and temperature at the impacted region, promoting the localized plastic deformation and even solid-liquid phase transformation. It is found that the normalized velocity of nanorod reduces approximately exponentially during penetration (up < 3 km/s), but its residual velocity linearly increased with initial incident velocity. Moreover, the impact crater is also calculated and the corresponding radius is manifested in the linear increase trend with up while inversely proportional to the ∅. Interestingly, the uniform fragmentation is observed instead of the intact spallation, attributed to the relatively thin thickness of the target. It is additionally demonstrated that the number of fragments increases with increasing up and its size distribution shows power law damping nearly. Our findings are expected to provide the atomic insight into the micro penetration phenomena and be helpful to further understand hypervelocity impact related domains. Full article
(This article belongs to the Special Issue Nanomechanics and Plasticity)
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2 pages, 170 KiB  
Editorial
Advances in Plasmonics and Nanophotonics
by Burak Gerislioglu and Arash Ahmadivand
Nanomaterials 2021, 11(11), 3159; https://doi.org/10.3390/nano11113159 - 22 Nov 2021
Cited by 3 | Viewed by 1485
Abstract
Recent developments in subwavelength localization of light have paved the way of novel research directions in the field of optics, plasmonics, and nanophotonics [...] Full article
(This article belongs to the Special Issue Advances in Plasmonics and Nanophotonics)
18 pages, 70372 KiB  
Article
Enhancement of Temperature Fluorescence Brightness of Zn@Si Core-Shell Quantum Dots Produced via a Unified Strategy
by Mohammad S. Almomani, Naser M. Ahmed, Marzaini Rashid, M. K. M. Ali, H. Akhdar, O. Aldaghri and K. H. Ibnaouf
Nanomaterials 2021, 11(11), 3158; https://doi.org/10.3390/nano11113158 - 22 Nov 2021
Cited by 2 | Viewed by 2020
Abstract
Despite many dedicated efforts, the fabrication of high-quality ZnO-incorporated Zinc@Silicon (Zn@Si) core–shell quantum dots (ZnSiQDs) with customized properties remains challenging. In this study, we report a new record for the brightness enhancement of ZnSiQDs prepared via a unified top-down and bottom-up strategy. The [...] Read more.
Despite many dedicated efforts, the fabrication of high-quality ZnO-incorporated Zinc@Silicon (Zn@Si) core–shell quantum dots (ZnSiQDs) with customized properties remains challenging. In this study, we report a new record for the brightness enhancement of ZnSiQDs prepared via a unified top-down and bottom-up strategy. The top-down approach was used to produce ZnSiQDs with uniform sizes and shapes, followed by the bottom-up method for their re-growth. The influence of various NH4OH contents (15 to 25 µL) on the morphology and optical characteristics of ZnSiQDs was investigated. The ZnSiQDs were obtained from the electrochemically etched porous Si (PSi) with Zn inclusion (ZnPSi), followed by the electropolishing and sonication in acetone. EFTEM micrographs of the samples prepared without and with NH4OH revealed the existence of spherical ZnSiQDs with a mean diameter of 1.22 to 7.4 nm, respectively. The emission spectra of the ZnSiQDs (excited by 365 nm) exhibited bright blue, green, orange-yellow, and red luminescence, indicating the uniform morphology related to the strong quantum confinement ZnSiQDs. In addition, the absorption and emission of the ZnSiQDs prepared with NH4OH were enhanced by 198.8% and 132.6%, respectively. The bandgap of the ZnSiQDs conditioned without and with NH4OH was approximately 3.6 and 2.3 eV, respectively. Full article
(This article belongs to the Special Issue Nanomaterials for Advanced Optics and Photonics)
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11 pages, 5963 KiB  
Article
Full 360° Terahertz Dynamic Phase Modulation Based on Doubly Resonant Graphene–Metal Hybrid Metasurfaces
by Binxu Wang, Xiaoqing Luo, Yalin Lu and Guangyuan Li
Nanomaterials 2021, 11(11), 3157; https://doi.org/10.3390/nano11113157 - 22 Nov 2021
Cited by 13 | Viewed by 2303
Abstract
Dynamic phase modulation is vital for tuneable focusing, beaming, polarisation conversion and holography. However, it remains challenging to achieve full 360° dynamic phase modulation while maintaining high reflectance or transmittance based on metamaterials or metasurfaces in the terahertz regime. Here, we propose a [...] Read more.
Dynamic phase modulation is vital for tuneable focusing, beaming, polarisation conversion and holography. However, it remains challenging to achieve full 360° dynamic phase modulation while maintaining high reflectance or transmittance based on metamaterials or metasurfaces in the terahertz regime. Here, we propose a doubly resonant graphene–metal hybrid metasurface to address this challenge. Simulation results show that by varying the graphene Fermi energy, the proposed metasurface with two shifting resonances is capable of providing dynamic phase modulation covering a range of 361° while maintaining relatively high reflectance above 20% at 1.05 THz. Based on the phase profile design, dynamically tuneable beam steering and focusing were numerically demonstrated. We expect that this work will advance the engineering of graphene metasurfaces for the dynamic manipulation of terahertz waves. Full article
(This article belongs to the Section Theory and Simulation of Nanostructures)
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15 pages, 2291 KiB  
Article
Ultra-Low Pt Loading in PtCo Catalysts for the Hydrogen Oxidation Reaction: What Role Do Co Nanoparticles Play?
by Felipe de Jesús Anaya-Castro, Mara Beltrán-Gastélum, Omar Morales Soto, Sergio Pérez-Sicairos, Shui Wai Lin, Balter Trujillo-Navarrete, Francisco Paraguay-Delgado, Luis Javier Salazar-Gastélum, Tatiana Romero-Castañón, Edgar Reynoso-Soto, Rosa María Félix-Navarro and Moisés Israel Salazar-Gastélum
Nanomaterials 2021, 11(11), 3156; https://doi.org/10.3390/nano11113156 - 22 Nov 2021
Cited by 10 | Viewed by 2266
Abstract
The effect of the nature of the catalyst on the performance and mechanism of the hydrogen oxidation reaction (HOR) is discussed for the first time in this work. HOR is an anodic reaction that takes place in anionic exchange membrane fuel cells (AEMFCs) [...] Read more.
The effect of the nature of the catalyst on the performance and mechanism of the hydrogen oxidation reaction (HOR) is discussed for the first time in this work. HOR is an anodic reaction that takes place in anionic exchange membrane fuel cells (AEMFCs) and hydrogen pumps (HPs). Among the investigated catalysts, Pt exhibited the best performance in the HOR. However, the cost and the availability limit the usage. Co is incorporated as a co-catalyst due to its oxophylic nature. Five different PtCo catalysts with different Pt loading values were synthesized in order to decrease Pt loading. The catalytic activities and the reaction mechanism were studied via electrochemical techniques, and it was found that both features are a function of Pt loading; low-Pt-loading catalysts (Pt loading < 2.7%) led to a high half-wave potential in the hydrogen oxidation reaction, which is related to higher activation energy and an intermediate Tafel slope value, related to a mixed HOR mechanism. However, catalysts with moderate Pt loading (Pt loading > 3.1%) exhibited lower E1/2 than the other catalysts and exhibited a mechanism similar to that of commercial Pt catalysts. Our results demonstrate that Co plays an active role in the HOR, facilitating Hads desorption, which is the rate-determining step (RDS) in the mechanism of the HOR. Full article
(This article belongs to the Special Issue Electrocatalysts for Fuel Cell Reactions in Alkaline Media)
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15 pages, 3981 KiB  
Article
EMI Shielding Nanocomposite Laminates with High Temperature Resistance, Hydrophobicity and Anticorrosion Properties
by Shaojun Wu, Zhiyong Zhao, Hongliang Hou and Xiang Xue
Nanomaterials 2021, 11(11), 3155; https://doi.org/10.3390/nano11113155 - 22 Nov 2021
Cited by 8 | Viewed by 1919
Abstract
High-performance multifunctional EMI shielding composite fabricated by low-cost method is increasingly required. Herein, novel EMI shielding nanocomposite laminates, consisting of composite prepreg of carbon fiber/epoxy resin/carbon nanotube film, were manufactured by facile electric heating of carbon nanotube film. The results indicated that composite [...] Read more.
High-performance multifunctional EMI shielding composite fabricated by low-cost method is increasingly required. Herein, novel EMI shielding nanocomposite laminates, consisting of composite prepreg of carbon fiber/epoxy resin/carbon nanotube film, were manufactured by facile electric heating of carbon nanotube film. The results indicated that composite with excellent specific shielding effectiveness of 0.07 dB/μm, 47 dB cm3/g and metamaterial properties can be designed by composite prepreg, and the primary shielding mechanism of it was reflection loss, along with interface polarization loss and conductive loss, which was superior to lots of shielding materials including carbon nanotube-based, carbon black-based, carbon nanofiber-based and graphene-based materials reported previously. Meanwhile, highly required excellent properties, including the thermostability with initial decomposition temperature up to 300 °C, hydrophobicity over contact angle of 115°, corrosion resistance of the composite with metal-free modification, and function as structural laminate compared with previous studies were demonstrated, which suggested tremendous potentials of the multifunctional EMI shielding composites in harsh environment. Full article
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17 pages, 5809 KiB  
Article
Anticancer Potential of L-Histidine-Capped Silver Nanoparticles against Human Cervical Cancer Cells (SiHA)
by Rajmohamed Mohammed Asik, Chidhambaram Manikkaraja, Karuppusamy Tamil Surya, Natarajan Suganthy, Archunan Priya Aarthy, Domokos Mathe, Muthusamy Sivakumar, Govindaraju Archunan, Parasuraman Padmanabhan and Balazs Gulyas
Nanomaterials 2021, 11(11), 3154; https://doi.org/10.3390/nano11113154 - 22 Nov 2021
Cited by 3 | Viewed by 2007
Abstract
This study reports the synthesis of silver nanoparticles using amino acid L-histidine as a reducing and capping agent as an eco-friendly approach. Fabricated L-histidine-capped silver nanoparticles (L-HAgNPs) were characterized by spectroscopic and microscopic studies. Spherical shaped L-HAgNPs were synthesized with a particle size [...] Read more.
This study reports the synthesis of silver nanoparticles using amino acid L-histidine as a reducing and capping agent as an eco-friendly approach. Fabricated L-histidine-capped silver nanoparticles (L-HAgNPs) were characterized by spectroscopic and microscopic studies. Spherical shaped L-HAgNPs were synthesized with a particle size of 47.43 ± 19.83 nm and zeta potential of −20.5 ± 0.95 mV. Results of the anticancer potential of L-HAgNPs showed antiproliferative effect against SiHa cells in a dose-dependent manner with an IC50 value of 18.25 ± 0.36 µg/mL. Fluorescent microscopic analysis revealed L-HAgNPs induced reactive oxygen species (ROS) mediated mitochondrial dysfunction, leading to activation of apoptotic pathway and DNA damage eventually causing cell death. To conclude, L-HAgNPs can act as promising candidates for cervical cancer therapy. Full article
(This article belongs to the Special Issue Nanotechnology-Based Diagnostics)
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25 pages, 16684 KiB  
Article
Melting Enhancement in a Triple-Tube Latent Heat Storage System with Sloped Fins
by Mustafa Z. Mahmoud, Hayder I. Mohammed, Jasim M. Mahdi, Dmitry Olegovich Bokov, Nidhal Ben Khedher, Naif Khalaf Alshammari, Pouyan Talebizadehsardari and Wahiba Yaïci
Nanomaterials 2021, 11(11), 3153; https://doi.org/10.3390/nano11113153 - 22 Nov 2021
Cited by 32 | Viewed by 2114
Abstract
Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction [...] Read more.
Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions through the inner and the outer tubes. Various configurations, dimensions, and orientations of the circular fins at different flow conditions of the heat-transfer fluid were numerically examined and optimized using an experimentally validated computational fluid-dynamic model. The results show that the melting rate, compared with the base case of finless, can be improved by 88% and the heat charging rate by 34%, when the fin orientation is downward–upward along the left side and the right side of the PCM shell. The results also show that there is a benefit if longer fins with smaller thicknesses are adopted in the vertical direction of the storage unit. This benefit helps natural convection to play a greater role, resulting in higher melting rates. Changing the fins’ dimensions from (thickness × length) 2 × 7.071 mm2 to 0.55 × 25.76 mm2 decreases the melting time by 22% and increases the heat charging rate by 9.6%. This study has also confirmed the importance of selecting the suitable values of Reynolds numbers and the inlet temperatures of the heat-transfer fluid for optimizing the melting enhancement potential of circular fins with downward–upward fin orientations. Full article
(This article belongs to the Special Issue Nano-Enhanced Phase Change Materials)
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14 pages, 2422 KiB  
Article
Ciprofloxacin-Loaded Gold Nanoparticles against Antimicrobial Resistance: An In Vivo Assessment
by Afrah Nawaz, Syed Mohsin Ali, Nosheen Fatima Rana, Tahreem Tanweer, Amna Batool, Thomas J. Webster, Farid Menaa, Sundus Riaz, Zahra Rehman, Farhat Batool, Misha Fatima, Tuba Maryam, Iqra Shafique, Abida Saleem and Arfa Iqbal
Nanomaterials 2021, 11(11), 3152; https://doi.org/10.3390/nano11113152 - 22 Nov 2021
Cited by 20 | Viewed by 3455
Abstract
Metallic nanoparticles, such as gold nanoparticles (AuNPs), have been extensively studied as drug delivery systems for various therapeutic applications. However, drug-loaded-AuNPs have been rarely explored in vivo for their effect on bacteria residing inside tissues. Ciprofloxacin (CIP) is a second-generation fluoroquinolone with a [...] Read more.
Metallic nanoparticles, such as gold nanoparticles (AuNPs), have been extensively studied as drug delivery systems for various therapeutic applications. However, drug-loaded-AuNPs have been rarely explored in vivo for their effect on bacteria residing inside tissues. Ciprofloxacin (CIP) is a second-generation fluoroquinolone with a broad-spectrum of antibiotic properties devoid of developing bacteria resistance. This research is focused on the synthesis and physical characterization of Ciprofloxacin-loaded gold nanoparticles (CIP-AuNPs) and their effect on the colonization of Enterococcus faecalis in the liver and kidneys of mice. The successfully prepared CIP-AuNPs were stable and exerted enhanced in vitro antibacterial activity against E. faecalis compared with free CIP. The optimized CIP-AuNPs were administered (500 µg/Kg) once a day via tail vein to infected mice for eight days and were found to be effective in eradicating E. faecalis from the host tissues. Moreover, unlike CIP, CIP-AuNPs were non-hemolytic. In summary, this study demonstrated that CIP-AuNPs are promising and biocompatible alternative therapeutics for E.-faecalis-induced infections resistant to conventional drugs (e.g., beta-lactams and vancomycin) and should be further investigated. Full article
(This article belongs to the Special Issue Nanomaterials for Biomedical and Biotechnological Applications)
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13 pages, 3083 KiB  
Article
An 8 MeV Electron Beam Modified In:ZnO Thin Films for CO Gas Sensing towards Low Concentration
by Aninamol Ani, P. Poornesh, Albin Antony, K. K. Nagaraja, Ashok Rao, Gopalkrishna Hegde, Evgeny Kolesnikov, Igor V. Shchetinin, Suresh D. Kulkarni, Vikash Chandra Petwal, Vijay Pal Verma and Jishnu Dwivedi
Nanomaterials 2021, 11(11), 3151; https://doi.org/10.3390/nano11113151 - 22 Nov 2021
Cited by 2 | Viewed by 1969
Abstract
In the present investigation, electron beam-influenced modifications on the CO gas sensing properties of indium doped ZnO (IZO) thin films were reported. Dose rates of 5, 10, and 15 kGy were irradiated to the IZO nano films while maintaining the In doping concentration [...] Read more.
In the present investigation, electron beam-influenced modifications on the CO gas sensing properties of indium doped ZnO (IZO) thin films were reported. Dose rates of 5, 10, and 15 kGy were irradiated to the IZO nano films while maintaining the In doping concentration to be 15 wt%. The wurtzite structure of IZO films is observed from XRD studies post electron beam irradiation, confirming structural stability, even in the intense radiation environment. The surface morphological studies by SEM confirms the granular structure with distinct and sharp grain boundaries for 5 kGy and 10 kGy irradiated films whereas the IZO film irradiated at 15 kGy shows the deterioration of defined grains. The presence of defects viz oxygen vacancies, interstitials are recorded from room temperature photoluminescence (RTPL) studies. The CO gas sensing estimations were executed at an optimized operating temperature of 300 °C for 1 ppm, 2 ppm, 3 ppm, 4 ppm, and 5 ppm. The 10 kGy treated IZO film displayed an enhanced sensor response of 2.61 towards low concentrations of 1 ppm and 4.35 towards 5 ppm. The enhancement in sensor response after irradiation is assigned to the growth in oxygen vacancies and well-defined grain boundaries since the former and latter act as vital adsorption locations for the CO gas. Full article
(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)
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14 pages, 4003 KiB  
Article
Novel Pastes Containing Polymeric Nanoparticles for Dentin Hypersensitivity Treatment: An In Vitro Study
by Manuel Toledano-Osorio, Raquel Osorio, Estrella Osorio, Antonio L. Medina-Castillo and Manuel Toledano
Nanomaterials 2021, 11(11), 3150; https://doi.org/10.3390/nano11113150 - 22 Nov 2021
Cited by 4 | Viewed by 2231
Abstract
Tubule occlusion and remineralization are considered the two main goals of dentin hypersensitivity treatment. The objective is to assess the ability of dentifrices containing zinc-doped polymeric nanoparticles (NPs) to enduringly occlude the dentinal tubules, reinforcing dentin’s mechanical properties. Fifteen dentin surfaces were acid-treated [...] Read more.
Tubule occlusion and remineralization are considered the two main goals of dentin hypersensitivity treatment. The objective is to assess the ability of dentifrices containing zinc-doped polymeric nanoparticles (NPs) to enduringly occlude the dentinal tubules, reinforcing dentin’s mechanical properties. Fifteen dentin surfaces were acid-treated for dentinal tubule exposure and brushed with (1) distilled water, or with experimental pastes containing (2) 1% of zinc-doped NPs, (3) 5% of zinc-doped NPs, (4) 10% of zinc-doped NPs or (5) Sensodyne®. Topographical and nanomechanical analyses were performed on treated dentin surfaces and after a citric acid challenge. ANOVA and Student–Newman–Keuls tests were used (p < 0.05). The main results indicate that all pastes produced tubule occlusion (100%) and reinforced mechanical properties of intertubular dentin (complex modulus was above 75 GPa). After the citric acid challenge, only those pastes containing zinc-doped NPs were able to maintain tubular occlusion, as specimens treated with Sensodyne® have around 30% of tubules opened. Mechanical properties were maintained for dentin treated with Zn-doped NPs, but in the case of specimens treated with Sensodyne®, complex modulus values were reduced below 50 GPa. It may be concluded that zinc-doped NPs at the lowest tested concentration produced acid-resistant tubular occlusion and increased the mechanical properties of dentin. Full article
(This article belongs to the Special Issue Nanomaterials in Dentistry)
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17 pages, 4116 KiB  
Article
Study of the Metal–Support Interaction and Electronic Effect Induced by Calcination Temperature Regulation and Their Effect on the Catalytic Performance of Glycerol Steam Reforming for Hydrogen Production
by Songshan Zhu, Yunzhu Wang, Jichang Lu, Huihui Lu, Sufang He, Di Song, Yongming Luo and Jiangping Liu
Nanomaterials 2021, 11(11), 3149; https://doi.org/10.3390/nano11113149 - 22 Nov 2021
Cited by 11 | Viewed by 2037
Abstract
Steam reforming of glycerol to produce hydrogen is considered to be the very promising strategy to generate clean and renewable energy. The incipient-wetness impregnation method was used to load Ni on the reducible carrier TiO2 (P25). In the process of catalyst preparation, [...] Read more.
Steam reforming of glycerol to produce hydrogen is considered to be the very promising strategy to generate clean and renewable energy. The incipient-wetness impregnation method was used to load Ni on the reducible carrier TiO2 (P25). In the process of catalyst preparation, the interaction and electronic effect between metal Ni and support TiO2 were adjusted by changing the calcination temperature, and then the activity and hydrogen production of glycerol steam reforming reaction (GSR) was explored. A series of modern characterizations including XRD, UV-vis DRS, BET, XPS, NH3-TPD, H2-TPR, TG, and Raman have been applied to systematically characterize the catalysts. The characterization results showed that the calcination temperature can contribute to varying degrees of influences on the acidity and basicity of the Ni/TiO2 catalyst, the specific surface area, together with the interaction force between Ni and the support. When the Ni/TiO2 catalyst was calcined at 600 °C, the Ni species can be produced in the form of granular NiTiO3 spinel. Consequently, due to the moderate metal–support interaction and electronic activity formed between the Ni species and the reducible support TiO2 in the NiO/Ti-600C catalyst, the granular NiTiO3 spinel can be reduced to a smaller Ni0 at a lower temperature, and thus to exhibit the best catalytic performance. Full article
(This article belongs to the Special Issue Applications of Nanocatalysts in Biomass Conversion)
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13 pages, 1861 KiB  
Article
Treatment with Argovit® Silver Nanoparticles Induces Differentiated Postharvest Biosynthesis of Compounds with Pharmaceutical Interest in Carrot (Daucus carota L.)
by Laura Sofia Santoscoy-Berber, Marilena Antunes-Ricardo, Melissa Zulahi Gallegos-Granados, Juan Carlos García-Ramos, Alexey Pestryakov, Yanis Toledano-Magaña, Nina Bogdanchikova and Rocio Alejandra Chavez-Santoscoy
Nanomaterials 2021, 11(11), 3148; https://doi.org/10.3390/nano11113148 - 22 Nov 2021
Cited by 4 | Viewed by 2637
Abstract
The global market for plant-derived bioactive compounds is growing significantly. The use of plant secondary metabolites has been reported to be used for the prevention of chronic diseases. Silver nanoparticles were used to analyze the content of enhancement phenolic compounds in carrots. Carrot [...] Read more.
The global market for plant-derived bioactive compounds is growing significantly. The use of plant secondary metabolites has been reported to be used for the prevention of chronic diseases. Silver nanoparticles were used to analyze the content of enhancement phenolic compounds in carrots. Carrot samples were immersed in different concentrations (0, 5, 10, 20, or 40 mg/L) of each of five types of silver nanoparticles (AgNPs) for 3 min. Spectrophotometric methods measured the total phenolic compounds and the antioxidant capacity. The individual phenolic compounds were quantified by High Performance Liquid Chromatography (HPLC) and identified by –mass spectrometry (HPLC-MS). The five types of AgNPs could significantly increase the antioxidant capacity of carrots’ tissue in a dose-dependent manner. An amount of 20 mg/L of type 2 and 5 silver nanoparticle formulations increased the antioxidant capacity 3.3-fold and 4.1-fold, respectively. The phenolic compounds that significantly increased their content after the AgNP treatment were chlorogenic acid, 3-O-caffeoylquinic acid, and 5′-caffeoylquinic acid. The increment of each compound depended on the dose and the type of the used AgNPs. The exogenous application of Argovit® AgNPs works like controlled abiotic stress and produces high-value secondary bioactive compounds in carrot. Full article
(This article belongs to the Special Issue Nanotechnologies and Natural Compounds: Current Trends and Applications)
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14 pages, 3332 KiB  
Article
Ultrahigh Sensitivity of a Plasmonic Pressure Sensor with a Compact Size
by Chung-Ting Chou Chao, Yuan-Fong Chou Chau, Sy-Hann Chen, Hung Ji Huang, Chee Ming Lim, Muhammad Raziq Rahimi Kooh, Roshan Thotagamuge and Hai-Pang Chiang
Nanomaterials 2021, 11(11), 3147; https://doi.org/10.3390/nano11113147 - 21 Nov 2021
Cited by 20 | Viewed by 2113
Abstract
This study proposes a compact plasmonic metal-insulator-metal pressure sensor comprising a bus waveguide and a resonator, including one horizontal slot and several stubs. We calculate the transmittance spectrum and the electromagnetic field distribution using the finite element method. When the resonator’s top layer [...] Read more.
This study proposes a compact plasmonic metal-insulator-metal pressure sensor comprising a bus waveguide and a resonator, including one horizontal slot and several stubs. We calculate the transmittance spectrum and the electromagnetic field distribution using the finite element method. When the resonator’s top layer undergoes pressure, the resonance wavelength redshifts with increasing deformation, and their relation is nearly linear. The designed pressure sensor possesses the merits of ultrahigh sensitivity, multiple modes, and a simple structure. The maximum sensitivity and resonance wavelength shift can achieve 592.44 nm/MPa and 364 nm, respectively, which are the highest values to our knowledge. The obtained sensitivity shows 23.32 times compared to the highest one reported in the literature. The modeled design paves a promising path for applications in the nanophotonic field. Full article
(This article belongs to the Special Issue State-of-the-Art Optical Properties and Applications of Metallic Nanostructures in Asia)
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14 pages, 6949 KiB  
Article
Controlled Metal–Support Interactions in Au/CeO2–Mg(OH)2 Catalysts Activating the Direct Oxidative Esterification of Methacrolein with Methanol to Methyl Methacrylate
by Nagyeong Kim, Seulgi Lim, Seungdon Kwon, Yuyeol Choi, Ji-Woong Lee and Kyungsu Na
Nanomaterials 2021, 11(11), 3146; https://doi.org/10.3390/nano11113146 - 21 Nov 2021
Cited by 3 | Viewed by 1974
Abstract
The strong metal–support interaction (SMSI) between the three components in Au/CeO2–Mg(OH)2 can be controlled by the relative composition of CeO2 and Mg(OH)2 and by the calcination temperature for the direct oxidative esterification of methacrolein (MACR) with methanol to [...] Read more.
The strong metal–support interaction (SMSI) between the three components in Au/CeO2–Mg(OH)2 can be controlled by the relative composition of CeO2 and Mg(OH)2 and by the calcination temperature for the direct oxidative esterification of methacrolein (MACR) with methanol to methyl methacrylate (MMA). The composition ratio of CeO2 and Mg(OH)2 in the catalyst affects the catalytic performance dramatically. An Au/CeO2 catalyst without Mg(OH)2 esterified MACR to a hemiacetal species without MMA production, which confirmed that Mg(OH)2 is a prerequisite for successful oxidative esterification. When Au/Mg(OH)2 was used without CeO2, the direct oxidative esterification of MACR was successful and produced MMA, the desired product. However, the MMA selectivity was much lower (72.5%) than that with Au/CeO2–Mg(OH)2 catalysts, which have an MMA selectivity of 93.9–99.8%, depending on the relative composition of CeO2 and Mg(OH)2. In addition, depending on the calcination temperature, the crystallinity of the CeO2–Mg(OH)2 and the surface acidity/basicity can be remarkably changed. Consequently, the Au-nanoparticle-supported catalysts exhibited different MACR conversions and MMA selectivities. The catalytic behavior can be explained by the different metal–support interactions between the three components depending on the composition ratio of CeO2 and Mg(OH)2 and the calcination temperature. These differences were evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and CO2 temperature-programmed desorption. The present study provides new insights into the design of SMSI-induced supported metal catalysts for the development of multifunctional heterogeneous catalysts. Full article
(This article belongs to the Special Issue Design and Synthesis of Nanostructured Materials for Catalytic Applications)
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19 pages, 8135 KiB  
Article
Exendin-4-Conjugated Manganese Magnetism-Engineered Iron Oxide Nanoparticles as a Potential Magnetic Resonance Imaging Contrast Agent for Tracking Transplanted β-Cells
by Jyuhn-Huarng Juang, Chia-Rui Shen, Jiun-Jie Wang, Shu-Ting Wu, Sung-Han Lin, Chen-Yi Chen, Chen-Wei Kao, Chen-Ling Chen, Zei-Tsan Tsai and Yun-Ming Wang
Nanomaterials 2021, 11(11), 3145; https://doi.org/10.3390/nano11113145 - 21 Nov 2021
Cited by 3 | Viewed by 1815
Abstract
To specifically detect and trace transplanted islet β-cells by magnetic resonance imaging (MRI), we conjugated manganese magnetism-engineered iron oxide nanoparticles (MnMEIO NPs) with exendin-4 (Ex4) which specifically binds glucagon-like peptide-1 receptors on the surface of β-cells. The size distribution of MnMEIO and MnMEIO-Ex4 [...] Read more.
To specifically detect and trace transplanted islet β-cells by magnetic resonance imaging (MRI), we conjugated manganese magnetism-engineered iron oxide nanoparticles (MnMEIO NPs) with exendin-4 (Ex4) which specifically binds glucagon-like peptide-1 receptors on the surface of β-cells. The size distribution of MnMEIO and MnMEIO-Ex4 NPs were 67.8 ± 1.3 and 70.2 ± 2.3 nm and zeta potential 33.3 ± 0.5 and 0.6 ± 0.1 mV, respectively. MnMEIO and MnMEIO-Ex4 NPs with iron content ≤ 40 μg/mL did not affect MIN6 β-cell viability and insulin secretion. Positive iron staining was found in MIN6 β-cells loaded with MnMEIO-Ex4 NPs but not in those with MnMEIO NPs. A transmission electron microscope confirmed MnMEIO-Ex4 NPs were distributed in the cytoplasm of MIN6. In vitro MR images revealed a loss of signal intensity in MIN6 β-cells labeled with MnMEIO-Ex4 NPs but not with MnMEIO NPs. After transplantation of islets labeled with MnMEIO-Ex4, the graft under kidney capsule could be visualized on MRI as persistent hypointense areas up to 17 weeks. Moreover, histology of the islet graft showed positive staining for insulin, glucagon and iron. Our results indicate MnMEIO-Ex4 NPs are safe and effective for the detection and long-term monitoring of transplanted β-cells by MRI. Full article
(This article belongs to the Special Issue Nanomaterials for Magnetic Resonance Imaging)
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12 pages, 3076 KiB  
Article
Carbon Nano-Fiber/PDMS Composite Used as Corrosion-Resistant Coating for Copper Anodes in Microbial Fuel Cells
by Fatma Bensalah, Julien Pézard, Naoufel Haddour, Mohsen Erouel, François Buret and Kamel Khirouni
Nanomaterials 2021, 11(11), 3144; https://doi.org/10.3390/nano11113144 - 21 Nov 2021
Cited by 16 | Viewed by 2116
Abstract
The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an [...] Read more.
The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an unsuitable anode material, in raw state, for MFC application due to its corrosion and its toxicity to microorganisms. In this paper, we report the development of a Cu anode material coated with a corrosion-resistant composite made of Polydimethylsiloxane (PDMS) doped with carbon nanofiber (CNF). The surface modification method was optimized for improving the interfacial electron transfer of Cu anodes for use in MFCs. Characterization of CNF-PDMS composites doped at different weight ratios demonstrated that the best electrical conductivity and electrochemical properties are obtained at 8% weight ratio of CNF/PDMS mixture. Electrochemical characterization showed that the corrosion rate of Cu electrode in acidified solution decreased from (17 ± 6) × 103 μm y−1 to 93 ± 23 μm y−1 after CNF-PDMS coating. The performance of Cu anodes coated with different layer thicknesses of CNF-PDMS (250 µm, 500 µm, and 1000 µm), was evaluated in MFC. The highest power density of 70 ± 8 mW m−2 obtained with 500 µm CNF-PDMS was about 8-times higher and more stable than that obtained through galvanic corrosion of unmodified Cu. Consequently, the followed process improves the performance of Cu anode for MFC applications. Full article
(This article belongs to the Special Issue Applications of Nanomaterials and Nanotechnology in Energy Storage Device)
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12 pages, 3178 KiB  
Article
Simultaneous Ultrasound-Assisted Hybrid Polyzwitterion/Antimicrobial Peptide Nanoparticles Synthesis and Deposition on Silicone Urinary Catheters for Prevention of Biofilm-Associated Infections
by Aleksandra Ivanova, Kristina Ivanova and Tzanko Tzanov
Nanomaterials 2021, 11(11), 3143; https://doi.org/10.3390/nano11113143 - 21 Nov 2021
Cited by 6 | Viewed by 2456
Abstract
Nosocomial infections caused by antibiotic-resistant bacteria are constantly growing healthcare threats, as they are the reason for the increased mortality, morbidity, and considerable financial burden due to the poor infection outcomes. Indwelling medical devices, such as urinary catheters, are frequently colonized by bacteria [...] Read more.
Nosocomial infections caused by antibiotic-resistant bacteria are constantly growing healthcare threats, as they are the reason for the increased mortality, morbidity, and considerable financial burden due to the poor infection outcomes. Indwelling medical devices, such as urinary catheters, are frequently colonized by bacteria in the form of biofilms that cause dysfunction of the device and severe chronic infections. The current treatment strategies of such device-associated infections are impaired by the resistant pathogens but also by a risk of prompting the appearance of new antibiotic-resistant bacterial mechanisms. Herein, the one-step sonochemical synthesis of hybrid poly(sulfobetaine) methacrylate/Polymyxin B nanoparticles (pSBMA@PM NPs) coating was employed to engineer novel nanoenabled silicone catheters with improved antifouling, antibacterial, and antibiofilm efficiencies. The synergistic mode of action of nanohybridized zwitterionic polymer and antimicrobial peptide led to complete inhibition of the nonspecific protein adsorption and up to 97% reduction in Pseudomonas aeruginosa biofilm formation, in comparison with the pristine silicone. Additionally, the bactericidal activity in the hybrid coating reduced the free-floating and surface-attached bacterial growth by 8 logs, minimizing the probability for further P. aeruginosa spreading and host invasion. This coating was stable for up to 7 days under conditions simulating the real scenario of catheter usage and inhibited by 80% P. aeruginosa biofilms. For the same time of use, the pSBMA@PM NPs coating did not affect the metabolic activity and morphology of mammalian cells, demonstrating their capacity to control antibiotic-resistant biofilm-associated bacterial infections. Full article
(This article belongs to the Special Issue Antimicrobial Nano Coatings)
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12 pages, 2724 KiB  
Article
Sunlight-Driven AO7 Degradation with Perovskites (La,Ba)(Fe,Ti)O3 as Heterogeneous Photocatalysts
by Ana Sofia Rodrigues, Lurdes Ciríaco, Maria José Pacheco, Annabel Fernandes, Sandra Mogo and Ana Lopes
Nanomaterials 2021, 11(11), 3142; https://doi.org/10.3390/nano11113142 - 21 Nov 2021
Cited by 4 | Viewed by 1551
Abstract
Perovskites of the (La,Ba)(Fe,Ti)O3 family were prepared, characterized, and utilized as heterogeneous photocatalysts, activated by natural sunlight, for environmental remediation of Acid Orange 7 (AO7) aqueous solutions. Catalysts were prepared by the ceramic (CM) and the complex polymerization (CP) methods and characterized [...] Read more.
Perovskites of the (La,Ba)(Fe,Ti)O3 family were prepared, characterized, and utilized as heterogeneous photocatalysts, activated by natural sunlight, for environmental remediation of Acid Orange 7 (AO7) aqueous solutions. Catalysts were prepared by the ceramic (CM) and the complex polymerization (CP) methods and characterized by XRD, SEM, EDS, and band gap energy. It was found that catalytic properties depend on the synthesis method and annealing conditions. In the photocatalytic assays with sunlight, different AO7 initial concentrations and perovskite amounts were tested. During photocatalytic assays, AO7 and degradation products concentrations were followed by HPLC. Only photocatalysis with BaFeO3-CM and BaTiO3-CP presented AO7 removals higher than that observed for photolysis. However, photolysis leads to the formation of almost exclusively amino-naphthol and sulfanilic acid, whereas some of the perovskites utilized form less-toxic compounds as degradation products, such as carboxylic acids (CA). Partial substitution of Ba by La in BaTiO3-CM does not produce any change in the photocatalytic properties, but the replacement of Ti by Fe in the La0.1Ba0.9TiO3 leads to reduced AO7 removal rate, but with the formation of CAs. The best AO7 removal (92%) was obtained with BaFeO3-CM (750 mg L−1), after 4 h of photocatalytic degradation with solar radiation. Full article
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10 pages, 32853 KiB  
Article
Permeability of a Zinc-Methacrylate-Based Self-Polishing Copolymer for Use in Antifouling Coating Materials by Molecular Dynamics Simulations
by Sung Hyun Kwon, Inwon Lee, Hyun Park and Seung Geol Lee
Nanomaterials 2021, 11(11), 3141; https://doi.org/10.3390/nano11113141 - 21 Nov 2021
Cited by 3 | Viewed by 1555
Abstract
Molecular dynamics simulations were used to investigate the solubility and permeability of H2O in a self-polishing copolymer (SPC) with two zinc methacrylate (ZMA) contents (Z2: 2 mol% ZMA; Z16: 16 mol% ZMA) and ethyl acrylate, methyl methacrylate, 2-methoxyethyl acrylate, and butyl [...] Read more.
Molecular dynamics simulations were used to investigate the solubility and permeability of H2O in a self-polishing copolymer (SPC) with two zinc methacrylate (ZMA) contents (Z2: 2 mol% ZMA; Z16: 16 mol% ZMA) and ethyl acrylate, methyl methacrylate, 2-methoxyethyl acrylate, and butyl acrylate as antifouling agents. Water was found to be more soluble in hydrated Z16 than Z2 because ZMA interacts strongly with H2O. In contrast, the diffusion coefficient of H2O in Z16 is lower than that of Z2 because H2O molecules are more constrained in the former due to strong ZMA/H2O interactions. Z16 was found to be significantly more permeable than Z2 over time. The SPC hydrated region in Z2 tends to expand toward the SPC region, while the analogous region in Z16 swelled toward both the SPC and H2O regions to leach SPC owing to the higher permeation of H2O into the SPC. These results reveal that H2O permeability can be controlled by adjusting the ZMA content, which provides insight into antifouling performance. Full article
(This article belongs to the Special Issue Advances in Computational Materials Science on Functional Interfaces and Surfaces)
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20 pages, 2013 KiB  
Review
Surface Modified Activated Carbons: Sustainable Bio-Based Materials for Environmental Remediation
by Manoj Kumar Jha, Sahira Joshi, Ram Kumar Sharma, Allison A Kim, Bishweshwar Pant, Mira Park and Hem Raj Pant
Nanomaterials 2021, 11(11), 3140; https://doi.org/10.3390/nano11113140 - 21 Nov 2021
Cited by 31 | Viewed by 3749
Abstract
Global warming and water/air contamination caused by human activities are major challenges in environmental pollution and climate change. The improper discharge of a large amount of agro-forest byproduct is accelerating these issues mainly in developing countries. The burning of agricultural byproducts causes global [...] Read more.
Global warming and water/air contamination caused by human activities are major challenges in environmental pollution and climate change. The improper discharge of a large amount of agro-forest byproduct is accelerating these issues mainly in developing countries. The burning of agricultural byproducts causes global warming, whereas their improper waste management causes water/air pollution. The conversion of these waste materials into effective smart materials can be considered as a promising strategy in waste management and environmental remediation. Over the past decades, activated carbons (ACs) have been prepared from various agricultural wastes and extensively used as adsorbents. The adsorption capacity of ACs is linked to a well-developed porous structure, large specific surface area, and rich surface functional moieties. Activated carbon needs to increase their adsorption capacity, especially for specific adsorbates, making them suitable for specific applications, and this is possible by surface modifications of their surface chemistry. The modifications of surface chemistry involve the introduction of surface functional groups which can be carried out by various methods such as acid treatment, alkaline treatment, impregnation, ozone treatment, plasma treatment, and so on. Depending on the treatment methods, surface modification mainly affects surface chemistry. In this review, we summarized several modification methods for agricultural-waste-based ACs. In addition, the applications of AC for the adsorption of various pollutants are highlighted. Full article
(This article belongs to the Section Environmental Nanoscience and Nanotechnology)
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10 pages, 2769 KiB  
Article
Plasmonic Gold Nanoisland Film for Bacterial Theranostics
by Shih-Hua Tan, Sibidou Yougbaré, Hsuan-Ya Tao, Che-Chang Chang and Tsung-Rong Kuo
Nanomaterials 2021, 11(11), 3139; https://doi.org/10.3390/nano11113139 - 21 Nov 2021
Cited by 11 | Viewed by 1699
Abstract
Plasmonic nanomaterials have been intensively explored for applications in biomedical detection and therapy for human sustainability. Herein, plasmonic gold nanoisland (NI) film (AuNIF) was fabricated onto a glass substrate by a facile seed-mediated growth approach. The structure of the tortuous gold NIs of [...] Read more.
Plasmonic nanomaterials have been intensively explored for applications in biomedical detection and therapy for human sustainability. Herein, plasmonic gold nanoisland (NI) film (AuNIF) was fabricated onto a glass substrate by a facile seed-mediated growth approach. The structure of the tortuous gold NIs of the AuNIF was demonstrated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Based on the ultraviolet-visible spectrum, the AuNIF revealed plasmonic absorption with maximum intensity at 624 nm. With the change to the surface topography created by the NIs, the capture efficiency of Escherichia coli (E. coli) by the AuNIF was significantly increased compared to that of the glass substrate. The AuNIF was applied as a surface-enhanced Raman scattering (SERS) substrate to enhance the Raman signal of E. coli. Moreover, the plasmonic AuNIF exhibited a superior photothermal effect under irradiation with simulated AM1.5 sunlight. For photothermal therapy, the AuNIF also displayed outstanding efficiency in the photothermal killing of E. coli. Using a combination of SERS detection and photothermal therapy, the AuNIF could be a promising platform for bacterial theranostics. Full article
(This article belongs to the Special Issue Antibacterial Applications of Nanomaterials)
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11 pages, 3285 KiB  
Article
One-Step Synthesis of SnO2/Carbon Nanotube Nanonests Composites by Direct Current Arc-Discharge Plasma and Its Application in Lithium-Ion Batteries
by Da Zhang, Yuanzheng Tang, Chuanqi Zhang, Qianpeng Dong, Wenming Song and Yan He
Nanomaterials 2021, 11(11), 3138; https://doi.org/10.3390/nano11113138 - 21 Nov 2021
Cited by 10 | Viewed by 2414
Abstract
Tin dioxide (SnO2)-based materials, as anode materials for lithium-ion batteries (LIBs), have been attracting growing research attention due to the high theoretical specific capacity. However, the complex synthesis process of chemical methods and the pollution of chemical reagents limit its commercialization. [...] Read more.
Tin dioxide (SnO2)-based materials, as anode materials for lithium-ion batteries (LIBs), have been attracting growing research attention due to the high theoretical specific capacity. However, the complex synthesis process of chemical methods and the pollution of chemical reagents limit its commercialization. The new material synthesis method is of great significance for expanding the application of SnO2-based materials. In this study, the SnO2/carbon nanotube nanonests (SnO2/CNT NNs) composites are synthesized in one step by direct current (DC) arc-discharge plasma; compared with conventional methods, the plasma synthesis achieves a uniform load of SnO2 nanoparticles on the surfaces of CNTs while constructing the CNTs conductive network. The SnO2/CNT NNs composites are applied in LIBs, it can be found that the nanonest-like CNT conductive structure provides adequate room for the volume expansion and also helps to transfer the electrons. Electrochemical measurements suggests that the SnO2/CNT NNscomposites achieve high capacity, and still have high electrochemical stability and coulombic efficiency under high current density, which proves the reliability of the synthesis method. This method is expected to be industrialized and also provides new ideas for the preparation of other nanocomposites. Full article
(This article belongs to the Topic Advances and Applications of Carbon Nanotubes)
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13 pages, 2186 KiB  
Article
Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries
by Andika Pandu Nugroho, Naufal Hanif Hawari, Bagas Prakoso, Andam Deatama Refino, Nursidik Yulianto, Ferry Iskandar, Evvy Kartini, Erwin Peiner, Hutomo Suryo Wasisto and Afriyanti Sumboja
Nanomaterials 2021, 11(11), 3137; https://doi.org/10.3390/nano11113137 - 20 Nov 2021
Cited by 22 | Viewed by 4067
Abstract
Due to its high theoretical specific capacity, a silicon anode is one of the candidates for realizing high energy density lithium-ion batteries (LIBs). However, problems related to bulk silicon (e.g., low intrinsic conductivity and massive volume expansion) limit the performance of silicon anodes. [...] Read more.
Due to its high theoretical specific capacity, a silicon anode is one of the candidates for realizing high energy density lithium-ion batteries (LIBs). However, problems related to bulk silicon (e.g., low intrinsic conductivity and massive volume expansion) limit the performance of silicon anodes. In this work, to improve the performance of silicon anodes, a vertically aligned n-type silicon nanowire array (n-SiNW) was fabricated using a well-controlled, top-down nano-machining technique by combining photolithography and inductively coupled plasma reactive ion etching (ICP-RIE) at a cryogenic temperature. The array of nanowires ~1 µm in diameter and with the aspect ratio of ~10 was successfully prepared from commercial n-type silicon wafer. The half-cell LIB with free-standing n-SiNW electrode exhibited an initial Coulombic efficiency of 91.1%, which was higher than the battery with a blank n-silicon wafer electrode (i.e., 67.5%). Upon 100 cycles of stability testing at 0.06 mA cm−2, the battery with the n-SiNW electrode retained 85.9% of its 0.50 mAh cm−2 capacity after the pre-lithiation step, whereas its counterpart, the blank n-silicon wafer electrode, only maintained 61.4% of 0.21 mAh cm−2 capacity. Furthermore, 76.7% capacity retention can be obtained at a current density of 0.2 mA cm−2, showing the potential of n-SiNW anodes for high current density applications. This work presents an alternative method for facile, high precision, and high throughput patterning on a wafer-scale to obtain a high aspect ratio n-SiNW, and its application in LIBs. Full article
(This article belongs to the Special Issue Silica and Silicon Based Nanostructures)
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23 pages, 4203 KiB  
Article
Sea Bass Primary Cultures versus RTgill-W1 Cell Line: Influence of Cell Model on the Sensitivity to Nanoparticles
by Alba Jimeno-Romero, Frederik Gwinner, Michelle Müller, Espen Mariussen, Manu Soto and Yvonne Kohl
Nanomaterials 2021, 11(11), 3136; https://doi.org/10.3390/nano11113136 - 20 Nov 2021
Cited by 4 | Viewed by 2468
Abstract
Determination of acute toxicity to vertebrates in aquatic environments is mainly performed following OECD test guideline 203, requiring the use of a large number of fish and with mortality as endpoint. This test is also used to determine toxicity of nanomaterials in aquatic [...] Read more.
Determination of acute toxicity to vertebrates in aquatic environments is mainly performed following OECD test guideline 203, requiring the use of a large number of fish and with mortality as endpoint. This test is also used to determine toxicity of nanomaterials in aquatic environments. Since a replacement method for animal testing in nanotoxicity studies is desirable, the feasibility of fish primary cultures or cell lines as a model for nanotoxicity screenings is investigated here. Dicentrarchus labrax primary cultures and RTgill-W1 cell line were exposed to several concentrations (0.1 to 200 ug/mL) of different nanoparticles (TiO2, polystyrene and silver), and cytotoxicity, metabolic activity and reactive oxygen species formation were investigated after 24 and 48 h of exposure. Protein corona as amount of protein bound, as well as the influence of surface modification (-COOH, -NH2), exposure media (Leibovitz’s L15 or seawater), weathering and cell type were the experimental variables included to test their influence on the results of the assays. Data from all scenarios was split based on the significance each experimental variable had in the result of the cytotoxicity tests, in an exploratory approach that allows for better understanding of the determining factors affecting toxicity. Data shows that more variables significantly influenced the outcome of toxicity tests when the primary cultures were exposed to the different nanoparticles. Toxicity tests performed in RTgill-W1 were influenced only by exposure time and nanoparticle concentration. The whole data set was integrated in a biological response index to show the overall impact of nanoparticle exposures. Full article
(This article belongs to the Special Issue Ecotoxicology and Risk Assessment of Engineered Nanomaterials)
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16 pages, 4996 KiB  
Article
Solution Blow Spun Silica Nanofibers: Influence of Polymeric Additives on the Physical Properties and Dye Adsorption Capacity
by Rosiane Maria da Costa Farias, Lucas Leite Severo, Artur P. Klamczynski, Eliton Souto de Medeiros, Lisiane Navarro de Lima Santana, Gelmires de Araújo Neves, Gregory Melvin Glenn and Romualdo Rodrigues Menezes
Nanomaterials 2021, 11(11), 3135; https://doi.org/10.3390/nano11113135 - 20 Nov 2021
Cited by 4 | Viewed by 2012
Abstract
The physical properties of porous silica nanofibers are an important factor that impacts their performance in various applications. In this study, porous silica nanofibers were produced via solution blow spinning (SBS) from a silica precursor/polymer solution. Two polyvinylpyrrolidone (PVP, Mw = 360,000 [...] Read more.
The physical properties of porous silica nanofibers are an important factor that impacts their performance in various applications. In this study, porous silica nanofibers were produced via solution blow spinning (SBS) from a silica precursor/polymer solution. Two polyvinylpyrrolidone (PVP, Mw = 360,000 and 1,300,000) were chosen as spinning aids in order to create different pore properties. The effect of their physical properties on the adsorption of methylene blue (MB) in an aqueous solution was explored. After forming, the nanofibers were calcined to remove the organic phase and create pores. The calcined nanofibers had a large amount of micro and mesopores without the use of additional surfactants. The molecular weight of the PVP impacted the growth of silica particles and consequently the pore size. High Mw PVP inhibited the growth of silica particles, resulting in a large volume of micropores. On the other hand, silica nanofibers with a high fraction of mesopores were obtained using the lower Mw PVP. These results demonstrate a simple method of producing blow spun silica nanofibers with defined variations of pore sizes by varying only the molecular weight of the PVP. In the adsorption process, the accessible mesopores improved the adsorption performance of large MB molecules. Full article
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9 pages, 2211 KiB  
Article
Optical Properties of GaN-Based Green Light-Emitting Diodes Influenced by Low-Temperature p-GaN Layer
by Jianfei Li, Duo Chen, Kuilong Li, Qiang Wang, Mengyao Shi, Dejie Diao, Chen Cheng, Changfu Li and Jiancai Leng
Nanomaterials 2021, 11(11), 3134; https://doi.org/10.3390/nano11113134 - 20 Nov 2021
Cited by 2 | Viewed by 1954
Abstract
GaN-based green light-emitting diodes (LEDs) with different thicknesses of the low-temperature (LT) p-GaN layer between the last GaN barriers and p-AlGaN electron blocking layer were characterized by photoluminescence (PL) and electroluminescence (EL) spectroscopic methods in the temperature range of 6–300 K and injection [...] Read more.
GaN-based green light-emitting diodes (LEDs) with different thicknesses of the low-temperature (LT) p-GaN layer between the last GaN barriers and p-AlGaN electron blocking layer were characterized by photoluminescence (PL) and electroluminescence (EL) spectroscopic methods in the temperature range of 6–300 K and injection current range of 0.01–350 mA. Based on the results, we suggest that a 20 nm-thick LT p-GaN layer can effectively prevent indium (In) re-evaporation, improve the quantum-confined Stark effect in the last quantum well (QW) of the active region, and finally reduce the efficiency droop by about 7%. Full article
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15 pages, 4141 KiB  
Article
Functionalized Activated Carbon Derived from Palm Kernel Shells for the Treatment of Simulated Heavy Metal-Contaminated Water
by Rabia Baby, Mohd Zobir Hussein, Zulkarnain Zainal and Abdul Halim Abdullah
Nanomaterials 2021, 11(11), 3133; https://doi.org/10.3390/nano11113133 - 20 Nov 2021
Cited by 12 | Viewed by 2280
Abstract
Heavy metal contamination in water poses a great risk to human health as well as to the lives of other creatures. Activated carbon is a useful material to be applied for the treatment of heavy metal-contaminated water. In this study, functionalized activated carbon [...] Read more.
Heavy metal contamination in water poses a great risk to human health as well as to the lives of other creatures. Activated carbon is a useful material to be applied for the treatment of heavy metal-contaminated water. In this study, functionalized activated carbon (FAC) was produced by the induction of nitro groups onto activated carbon using nitric acid. The resulting material was characterized in detail using the XRD, Raman, BET, FTIR, and FESEM techniques. The FAC was used for the treatment of heavy metal-contaminated water using different adsorption parameters, i.e., solution pH, contact time, adsorbent dosage and heavy metal ion concentrations, and these parameters were systematically optimized. It was found that FAC requires 90 min for the maximum adsorption of the heavy metal ions; Cr6+, Pb2+, Zn2+ and Cd2+. The kinetic study revealed that the metal ion adsorption follows the pseudo-second-order. The Freundlich and Langmuir isotherms were applied to determine the best fitting adsorption isotherm models. The adsorption capacities were also determined for each metal ion. Full article
(This article belongs to the Special Issue Carbon Nanostructures as Promising Future Materials)
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37 pages, 3518 KiB  
Review
Nanoparticle Systems for Cancer Phototherapy: An Overview
by Thais P. Pivetta, Caroline E. A. Botteon, Paulo A. Ribeiro, Priscyla D. Marcato and Maria Raposo
Nanomaterials 2021, 11(11), 3132; https://doi.org/10.3390/nano11113132 - 20 Nov 2021
Cited by 37 | Viewed by 4262
Abstract
Photodynamic therapy (PDT) and photothermal therapy (PTT) are photo-mediated treatments with different mechanisms of action that can be addressed for cancer treatment. Both phototherapies are highly successful and barely or non-invasive types of treatment that have gained attention in the past few years. [...] Read more.
Photodynamic therapy (PDT) and photothermal therapy (PTT) are photo-mediated treatments with different mechanisms of action that can be addressed for cancer treatment. Both phototherapies are highly successful and barely or non-invasive types of treatment that have gained attention in the past few years. The death of cancer cells because of the application of these therapies is caused by the formation of reactive oxygen species, that leads to oxidative stress for the case of photodynamic therapy and the generation of heat for the case of photothermal therapies. The advancement of nanotechnology allowed significant benefit to these therapies using nanoparticles, allowing both tuning of the process and an increase of effectiveness. The encapsulation of drugs, development of the most different organic and inorganic nanoparticles as well as the possibility of surfaces’ functionalization are some strategies used to combine phototherapy and nanotechnology, with the aim of an effective treatment with minimal side effects. This article presents an overview on the use of nanostructures in association with phototherapy, in the view of cancer treatment. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Biomedical Imaging and Cancer Therapy)
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28 pages, 14866 KiB  
Article
Evaluation of Optical and Acoustical Properties of Ba1−xSrxTiO3 Thin Film Material Library via Conjugation of Picosecond Laser Ultrasonics with X-ray Diffraction, Energy Dispersive Spectroscopy, Electron Probe Micro Analysis, Scanning Electron and Atomic Force Microscopies
by Sathyan Sandeep, Samuel Raetz, Jerome Wolfman, Beatrice Negulescu, Guozhen Liu, Jean-Louis Longuet, Théo Thréard and Vitalyi E. Gusev
Nanomaterials 2021, 11(11), 3131; https://doi.org/10.3390/nano11113131 - 20 Nov 2021
Cited by 4 | Viewed by 2028
Abstract
Wide-range continuous spatial variation of the film composition in lateral compositionally graded epitaxial films requires the development of high throughput measurement techniques for their local and non-destructive characterization with the highest possible spatial resolution. Here we report on the first application of the [...] Read more.
Wide-range continuous spatial variation of the film composition in lateral compositionally graded epitaxial films requires the development of high throughput measurement techniques for their local and non-destructive characterization with the highest possible spatial resolution. Here we report on the first application of the picosecond laser ultrasonics (PLU) technique for the evaluation of acoustical and optical parameters of lateral compositionally graded film, the Ba1−xSrxTiO3 (0 ≤ x ≤ 1) material library. The film was not dedicatedly prepared for its opto-acousto-optic evaluation by PLU, exhibiting significant lateral variations in thickness and surface roughness. Therefore, the achieved measurements of the sound velocity and of the optical refractive index, and characterization of the surface roughness confirm the robustness of the PLU technique for thin film evaluation. We hope that the first measurements of the acoustical and optical properties of epitaxial grown Ba1−xSrxTiO3 (0 ≤ x ≤ 1) by PLU technique accomplished here provide the parameters required for more extended predictive design of the phononic, photonic and phoxonic mirrors and cavities with superior properties/functionalities for novel multifunctional nanodevices. Full article
(This article belongs to the Special Issue Thermal and Mechanical Dynamics in Nanosystems)
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