Nanomaterials

16 pages, 4958 KiB

Open AccessArticle

Disposable and Low-Cost Electrode Based on Graphene Paper-Nafion-Bi Nanostructures for Ultra-Trace Determination of Pb(II) and Cd(II)

by Antonino Scandurra, Francesco Ruffino, Mario Urso, Maria Grazia Grimaldi and Salvo Mirabella

Nanomaterials 2020, 10(8), 1620; https://doi.org/10.3390/nano10081620 - 18 Aug 2020

Cited by 17 | Viewed by 3145

Abstract

There is a huge demand for rapid, reliable and low-cost methods for the analysis of heavy metals in drinking water, particularly in the range of sub-part per billion (ppb). In the present work, we describe the preparation, characterization and analytical performance of the [...] Read more.

There is a huge demand for rapid, reliable and low-cost methods for the analysis of heavy metals in drinking water, particularly in the range of sub-part per billion (ppb). In the present work, we describe the preparation, characterization and analytical performance of the disposable sensor to be employed in Square Wave Anodic Stripping Voltammetry (SWASV) for ultra-trace simultaneous determination of cadmium and lead. The electrode consists of graphene paper-perfluorosulfonic ionomer-bismuth nano-composite material. The electrode preparation implies a key step aimed to enhance the Bi³⁺ adsorption into nafion film, prior to the bismuth electro-deposition. Finely dispersed bismuth nanoparticles embedded in the ionomer film are obtained. The electrode was characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS). The electrode shows a linear response in the 5–100 ppb range, a time-stability tested up to almost three months, and detection limits up to 0.1 ppb for both Pb²⁺ and Cd²⁺. The electrode preparation method is simple and low in cost and the obtained analytical performance is very competitive with the state of art for the SWASV determination of Pb²⁺ and Cd²⁺ in solution. Full article

(This article belongs to the Special Issue Development and Evaluation of Nanostructured Electrochemical Sensors)

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20 pages, 3425 KiB

Open AccessArticle

Foliar Application of Low Concentrations of Titanium Dioxide and Zinc Oxide Nanoparticles to the Common Sunflower under Field Conditions

by Marek Kolenčík, Dávid Ernst, Martin Urík, Ľuba Ďurišová, Marek Bujdoš, Martin Šebesta, Edmud Dobročka, Samuel Kšiňan, Ramakanth Illa, Yu Qian, Huan Feng, Ivan Černý, Veronika Holišová and Gabriela Kratošová

Nanomaterials 2020, 10(8), 1619; https://doi.org/10.3390/nano10081619 - 18 Aug 2020

Cited by 77 | Viewed by 6399

Abstract

Nano-fertilisers have only recently been introduced to intensify plant production, and there still remains inadequate scientific knowledge on their plant-related effects. This paper therefore compares the effects of two nano-fertilisers on common sunflower production under field conditions. The benefits arising from the foliar [...] Read more.

Nano-fertilisers have only recently been introduced to intensify plant production, and there still remains inadequate scientific knowledge on their plant-related effects. This paper therefore compares the effects of two nano-fertilisers on common sunflower production under field conditions. The benefits arising from the foliar application of micronutrient-based zinc oxide fertiliser were compared with those from the titanium dioxide plant-growth enhancer. Both the zinc oxide (ZnO) and titanium dioxide (TiO₂) were delivered by foliar application in nano-size at a concentration of 2.6 mg·L⁻¹. The foliar-applied nanoparticles (NPs) had good crystallinity and a mean size distribution under 30 nm. There were significant differences between these two experimental treatments in the leaf surfaces’ trichomes diversity, ratio, width, and length at the flower-bud development stage. Somewhat surprisingly, our results established that the ZnO-NPs treatment induced generally better sunflower physiological responses, while the TiO₂-NPs primarily affected quantitative and nutritional parameters such as oil content and changed sunflower physiology to early maturation. There were no differences detected in titanium or zinc translocation or accumulation in the fully ripe sunflower seeds compared to the experimental controls, and our positive results therefore encourage further nano-fertiliser research. Full article

(This article belongs to the Section Biology and Medicines)

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12 pages, 2213 KiB

Open AccessArticle

Magnetic Phase Coexistence and Hard–Soft Exchange Coupling in FePt Nanocomposite Magnets

by O. Crisan, I. Dan, P. Palade, A. D. Crisan, A. Leca and A. Pantelica

Nanomaterials 2020, 10(8), 1618; https://doi.org/10.3390/nano10081618 - 18 Aug 2020

Cited by 11 | Viewed by 2670

Abstract

With the aim of demonstrating phase coexistence of two magnetic phases in an intermediate annealing regime and obtaining highly coercive FePt nanocomposite magnets, two alloys of slightly off-equiatomic composition of a binary Fe-Pt system were prepared by dynamic rotation switching and ball milling. [...] Read more.

With the aim of demonstrating phase coexistence of two magnetic phases in an intermediate annealing regime and obtaining highly coercive FePt nanocomposite magnets, two alloys of slightly off-equiatomic composition of a binary Fe-Pt system were prepared by dynamic rotation switching and ball milling. The alloys, with a composition Fe₅₃Pt₄₇ and Fe₅₅Pt₄₅, were subsequently annealed at 400 °C and 550 °C and structurally and magnetically characterized by means of X-ray diffraction, ⁵⁷Fe Mössbauer spectrometry and Superconducting Quantum Interference Device (SQUID) magnetometry measurements. Gradual disorder–order phase transformation and temperature-dependent evolution of the phase structure were monitored using X-ray diffraction of synchrotron radiation. It was shown that for annealing temperatures as low as 400 °C, a predominant, highly ordered L1₀ phase is formed in both alloys, coexisting with a cubic L1₂ soft magnetic FePt phase. The coexistence of the two phases is evidenced through all the investigating techniques that we employed. SQUID magnetometry hysteresis loops of samples annealed at 400 °C exhibit inflection points that witness the coexistence of the soft and hard magnetic phases and high values of coercivity and remanence are obtained. For the samples annealed at 500 °C, the hysteresis loops are continuous, without inflection points, witnessing complete exchange coupling of the hard and soft magnetic phases and further enhancement of the coercive field. Maximum energy products comparable with values of current permanent magnets are found for both samples for annealing temperatures as low as 500 °C. These findings demonstrate an interesting method to obtain rare earth-free permanent nanocomposite magnets with hard–soft exchange-coupled magnetic phases. Full article

(This article belongs to the Special Issue Multifunctional Magnetic Nanocomposites: Innovative Processing and Applications)

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21 pages, 4760 KiB

Open AccessArticle

Toxicity of Carbon Nanomaterials and Their Potential Application as Drug Delivery Systems: In Vitro Studies in Caco-2 and MCF-7 Cell Lines

by Rosa Garriga, Tania Herrero-Continente, Miguel Palos, Vicente L. Cebolla, Jesús Osada, Edgar Muñoz and María Jesús Rodríguez-Yoldi

Nanomaterials 2020, 10(8), 1617; https://doi.org/10.3390/nano10081617 - 18 Aug 2020

Cited by 66 | Viewed by 4954

Abstract

Carbon nanomaterials have attracted increasing attention in biomedicine recently to be used as drug nanocarriers suitable for medical treatments, due to their large surface area, high cellular internalization and preferential tumor accumulation, that enable these nanomaterials to transport chemotherapeutic agents preferentially to tumor [...] Read more.

Carbon nanomaterials have attracted increasing attention in biomedicine recently to be used as drug nanocarriers suitable for medical treatments, due to their large surface area, high cellular internalization and preferential tumor accumulation, that enable these nanomaterials to transport chemotherapeutic agents preferentially to tumor sites, thereby reducing drug toxic side effects. However, there are widespread concerns on the inherent cytotoxicity of carbon nanomaterials, which remains controversial to this day, with studies demonstrating conflicting results. We investigated here in vitro toxicity of various carbon nanomaterials in human epithelial colorectal adenocarcinoma (Caco-2) cells and human breast adenocarcinoma (MCF-7) cells. Carbon nanohorns (CNH), carbon nanotubes (CNT), carbon nanoplatelets (CNP), graphene oxide (GO), reduced graphene oxide (GO) and nanodiamonds (ND) were systematically compared, using Pluronic F-127 dispersant. Cell viability after carbon nanomaterial treatment followed the order CNP < CNH < RGO < CNT < GO < ND, being the effect more pronounced on the more rapidly dividing Caco-2 cells. CNP produced remarkably high reactive oxygen species (ROS) levels. Furthermore, the potential of these materials as nanocarriers in the field of drug delivery of doxorubicin and camptothecin anticancer drugs was also compared. In all cases the carbon nanomaterial/drug complexes resulted in improved anticancer activity compared to that of the free drug, being the efficiency largely dependent of the carbon nanomaterial hydrophobicity and surface chemistry. These fundamental studies are of paramount importance as screening and risk-to-benefit assessment towards the development of smart carbon nanomaterial-based nanocarriers. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Therapy, Diagnosis, and Biosensing)

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21 pages, 10004 KiB

Open AccessArticle

Microwave-Assisted Rapid Synthesis of Reduced Graphene Oxide-Based Gum Tragacanth Hydrogel Nanocomposite for Heavy Metal Ions Adsorption

by Bhawna Sharma, Sourbh Thakur, Djalal Trache, Hamed Yazdani Nezhad and Vijay Kumar Thakur

Nanomaterials 2020, 10(8), 1616; https://doi.org/10.3390/nano10081616 - 18 Aug 2020

Cited by 42 | Viewed by 5427

Abstract

Reduced graphene oxide (RGO) was synthesized in this research via Tour’s method for the use of filler in the hydrogel matrix. The copolymerization of N,N-dimethylacrylamide (DMA) onto the gum tragacanth (GT) was carried out to develop gum tragacanth-cl-N, [...] Read more.

Reduced graphene oxide (RGO) was synthesized in this research via Tour’s method for the use of filler in the hydrogel matrix. The copolymerization of N,N-dimethylacrylamide (DMA) onto the gum tragacanth (GT) was carried out to develop gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)) hydrogel using N,N’-methylenebisacrylamide (NMBA) and potassium persulfate (KPS) as cross-linker and initiator correspondingly. The various GT-cl-poly(DMA) hydrogel synthesis parameters were optimized to achieve maximum swelling of GT-cl-poly(DMA) hydrogel. The optimized GT-cl-poly(DMA) hydrogel was then filled with RGO to form reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)/RGO) hydrogel composite. The synthesized samples were used for competent adsorption of Hg²⁺ and Cr⁶⁺ ions. Fourier transform infrared, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy were used to characterize the gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. The experiments of adsorption-desorption cycles for Hg²⁺ and Cr⁶⁺ ions were carried out to perform the reusability of gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. From these two samples, reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide exhibited high adsorption ability. The Hg²⁺ and Cr⁶⁺ ions adsorption by gum tragacanth-cl-N,N-dimethylacrylamide and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide were best suited for pseudo-second-order kinetics and Langmuir isotherm. The reported maximum Hg²⁺ and Cr⁶⁺ ions adsorption capacities were 666.6 mg g^-1 and 473.9 mg g^-1 respectively. Full article

(This article belongs to the Special Issue Nanocellulose and Nanocarbons Based Hybrid Materials: Synthesis, Characterization and Applications)

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19 pages, 2889 KiB

Open AccessArticle

Green Synthesis, Characterization and Application of Natural Product Coated Magnetite Nanoparticles for Wastewater Treatment

by Chanchal Das, Subhadeep Sen, Tejinder Singh, Tanmoy Ghosh, Subha Sankar Paul, Tae Wan Kim, Seob Jeon, Dilip K. Maiti, Jungkyun Im and Goutam Biswas

Nanomaterials 2020, 10(8), 1615; https://doi.org/10.3390/nano10081615 - 18 Aug 2020

Cited by 79 | Viewed by 7328

Abstract

Adsorption of organic pollutants, toxic metal ions, and removal of harmful bacteria can give us clean and pure drinkable water from wastewater resources. Respective magnetite nanoparticles (MNPs) were synthesized using a cheaper and greener way in an open-air environment with the use of [...] Read more.

Adsorption of organic pollutants, toxic metal ions, and removal of harmful bacteria can give us clean and pure drinkable water from wastewater resources. Respective magnetite nanoparticles (MNPs) were synthesized using a cheaper and greener way in an open-air environment with the use of crude latex of Jatropha curcas (JC) and leaf extract of Cinnamomum tamala (CT). Characterization of MNPs had been performed by dynamic light scattering (DLS), Ultraviolet-visible (UV-vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, powdered X-ray diffraction (XRD), and field emission scanning electron microscope (FE-SEM). The size ranges of the synthesized MNPs were observed in between 20–42 nm for JC-Fe₃O₄ and within 26–35 nm for CT-Fe₃O₄ by FE-SEM images. The effect of synthesized magnetic nanoparticles in wastewater treatment (bacterial portion), dye adsorption, toxic metal removal as well as antibacterial, antioxidant, and cytotoxic activities were studied. This purification will lead to an increase in the resources of pure drinking water in the future. Full article

(This article belongs to the Special Issue Nanomaterials and Nanotechnology in Wastewater Treatment)

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15 pages, 2201 KiB

Open AccessArticle

Cerium Oxide Nanoparticles and Their Efficient Antibacterial Application In Vitro against Gram-Positive and Gram-Negative Pathogens

by Oana L. Pop, Amalia Mesaros, Dan C. Vodnar, Ramona Suharoschi, Flaviu Tăbăran, Lidia Magerușan, István Sz. Tódor, Zoriţa Diaconeasa, Adriana Balint, Lelia Ciontea and Carmen Socaciu

Nanomaterials 2020, 10(8), 1614; https://doi.org/10.3390/nano10081614 - 18 Aug 2020

Cited by 100 | Viewed by 5977

Abstract

In this study, the antibacterial activity of cerium oxide nanoparticles on two Gram-negative and three Gram-positive foodborne pathogens was investigated. CeO₂ nanoparticles (CeO₂ nps) were synthesized by a Wet Chemical Synthesis route, using the precipitation method and the Simultaneous Addition of [...] Read more.

In this study, the antibacterial activity of cerium oxide nanoparticles on two Gram-negative and three Gram-positive foodborne pathogens was investigated. CeO₂ nanoparticles (CeO₂ nps) were synthesized by a Wet Chemical Synthesis route, using the precipitation method and the Simultaneous Addition of reactants (WCS–SimAdd). The as-obtained precursor powders were investigated by thermal analysis (TG–DTA), to study their decomposition process and to understand the CeO₂ nps formation. The composition, structure, and morphology of the thermally treated sample were investigated by FTIR, Raman spectroscopy, X-ray diffraction, TEM, and DLS. The cubic structure and average particle size ranging between 5 and 15 nm were evidenced. Optical absorption measurements (UV–Vis) reveal that the band gap of CeO₂ is 2.61 eV, which is smaller than the band gap of bulk ceria. The antioxidant effect of CeO₂ nps was determined, and the antibacterial test was carried out both in liquid and on solid growth media against five pathogenic microorganisms, namely Escherichia coli, Salmonella typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus. Cerium oxide nanoparticles showed growth inhibition toward all five pathogens tested with notable results. This paper highlights the perspectives for the synthesis of CeO₂ nps with controlled structural and morphological characteristics and enhanced antibacterial properties, using a versatile and low-cost chemical solution method. Full article

(This article belongs to the Special Issue Antibacterial Activity of Nanoparticles)

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15 pages, 1413 KiB

Open AccessReview

pH-Responsive Nanoparticles for Cancer Immunotherapy: A Brief Review

by Yunfeng Yan and Hangwei Ding

Nanomaterials 2020, 10(8), 1613; https://doi.org/10.3390/nano10081613 - 17 Aug 2020

Cited by 62 | Viewed by 5591

Abstract

Immunotherapy has recently become a promising strategy for the treatment of a wide range of cancers. However, the broad implementation of cancer immunotherapy suffers from inadequate efficacy and toxic side effects. Integrating pH-responsive nanoparticles into immunotherapy is a powerful approach to tackle these [...] Read more.

Immunotherapy has recently become a promising strategy for the treatment of a wide range of cancers. However, the broad implementation of cancer immunotherapy suffers from inadequate efficacy and toxic side effects. Integrating pH-responsive nanoparticles into immunotherapy is a powerful approach to tackle these challenges because they are able to target the tumor tissues and organelles of antigen-presenting cells (APCs) which have a characteristic acidic microenvironment. The spatiotemporal control of immunotherapeutic drugs using pH-responsive nanoparticles endows cancer immunotherapy with enhanced antitumor immunity and reduced off-tumor immunity. In this review, we first discuss the cancer-immunity circle and how nanoparticles can modulate the key steps in this circle. Then, we highlight the recent advances in cancer immunotherapy with pH-responsive nanoparticles and discuss the perspective for this emerging area. Full article

(This article belongs to the Special Issue Application of Nanomaterials in Biomedical Imaging and Cancer Therapy)

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10 pages, 2807 KiB

Open AccessArticle

Ultrafine Pd Nanoparticles Supported on Soft Nitriding Porous Carbon for Hydrogen Production from Hydrolytic Dehydrogenation of Dimethyl Amine-Borane

by Zhaoyu Wen, Qiong Fu, Jie Wu and Guangyin Fan

Nanomaterials 2020, 10(8), 1612; https://doi.org/10.3390/nano10081612 - 17 Aug 2020

Cited by 25 | Viewed by 3202

Abstract

Simple and efficient synthesis of a nano-catalyst with an excellent catalytic property for hydrogen generation from hydrolysis of dimethyl amine-borane (DMAB) is a missing piece. Herein, effective and recycled palladium (Pd) nanoparticles (NPs) supported on soft nitriding porous carbon (NPC) are fabricated and [...] Read more.

Simple and efficient synthesis of a nano-catalyst with an excellent catalytic property for hydrogen generation from hydrolysis of dimethyl amine-borane (DMAB) is a missing piece. Herein, effective and recycled palladium (Pd) nanoparticles (NPs) supported on soft nitriding porous carbon (NPC) are fabricated and applied for DMAB hydrolysis. It is discovered that the soft nitriding via a low-temperature urea-pretreatment induces abundant nitrogen-containing species on the NPC support, thus promoting the affinity of the Pd precursor and hindering the agglomeration of formed Pd NPs onto the NPC surface during the preparation process. Surface-clean Pd NPs with a diameter of sub-2.0 nm deposited on the NPC support (Pd/NPC) exhibit an outstanding catalytic performance with a turnover frequency (TOF) of 2758 h⁻¹ toward DMAB hydrolysis, better than many previous reported Pd-based catalysts. It should be emphasized that the Pd/NPC also possesses a good stability without an obvious decrease in catalytic activity for DMAB hydrolysis in five successive recycling runs. This study provides a facile but efficient way for preparing high-performance Pd catalysts for catalytic hydrogen productions. Full article

(This article belongs to the Special Issue Synthesis of Nanocomposites and Catalysis Applications)

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14 pages, 6931 KiB

Open AccessArticle

Enhancement of Electromagnetic Wave Shielding Effectiveness of Carbon Fibers via Chemical Composition Transformation Using H₂ Plasma Treatment

by Hyun-Ji Kim, Gi-Hwan Kang, Sung-Hoon Kim and Sangmoon Park

Nanomaterials 2020, 10(8), 1611; https://doi.org/10.3390/nano10081611 - 17 Aug 2020

Cited by 4 | Viewed by 2800

Abstract

H₂ plasma treatment was performed on carbon-based nonwoven fabrics (c-NFs) in a 900 W microwave plasma-enhanced chemical vapor deposition system at 750 °C and 40 Torr. Consequently, the electromagnetic wave shielding effectiveness (SE) of the c-NFs was significantly enhanced across the operating [...] Read more.

H₂ plasma treatment was performed on carbon-based nonwoven fabrics (c-NFs) in a 900 W microwave plasma-enhanced chemical vapor deposition system at 750 °C and 40 Torr. Consequently, the electromagnetic wave shielding effectiveness (SE) of the c-NFs was significantly enhanced across the operating frequency range of 0.04 to 20.0 GHz. We compared the electromagnetic wave SE of the H₂ plasma-treated c-NFs samples with that of native c-NFs samples coated with nano-sized Ag particles. Despite having a lower surface electrical conductivity, H₂ plasma-treated c-NFs samples exhibited a considerably higher electromagnetic wave SE than the Ag-coated c-NFs samples, across the relatively high operating frequency range of 7.0 to 20.0 GHz. The carbon component of H₂ plasma-treated c-NFs samples increased significantly compared with the oxygen component. The H₂ plasma treatment transformed the alcohol-type (C–O–H) compounds formed by carbon-oxygen bonds on the surface of the native c-NFs samples into ether-type (C–O–C) compounds. On the basis of these results, we proposed a mechanism to explain the electromagnetic wave SE enhancement observed in H₂ plasma-treated c-NFs. Full article

(This article belongs to the Special Issue Surface Chemistry, Catalytic Properties and Applications of Carbons and Carbon Nanomaterials)

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12 pages, 4058 KiB

Open AccessArticle

Upcycling of Wastewater via Effective Photocatalytic Hydrogen Production Using MnO₂ Nanoparticles—Decorated Activated Carbon Nanoflakes

by Sankar Sekar, Sejoon Lee, Preethi Vijayarengan, Kaliyappan Mohan Kalirajan, Thirumavalavan Santhakumar, Saravanan Sekar and Sutha Sadhasivam

Nanomaterials 2020, 10(8), 1610; https://doi.org/10.3390/nano10081610 - 17 Aug 2020

Cited by 32 | Viewed by 4481

Abstract

In the present work, we demonstrated the upcycling technique of effective wastewater treatment via photocatalytic hydrogen production by using the nanocomposites of manganese oxide-decorated activated carbon (MnO₂-AC). The nanocomposites were sonochemically synthesized in pure water by utilizing MnO₂ nanoparticles and [...] Read more.

In the present work, we demonstrated the upcycling technique of effective wastewater treatment via photocatalytic hydrogen production by using the nanocomposites of manganese oxide-decorated activated carbon (MnO₂-AC). The nanocomposites were sonochemically synthesized in pure water by utilizing MnO₂ nanoparticles and AC nanoflakes that had been prepared through green routes using the extracts of Brassica oleracea and Azadirachta indica, respectively. MnO₂-AC nanocomposites were confirmed to exist in the form of nanopebbles with a high specific surface area of ~109 m²/g. When using the MnO₂-AC nanocomposites as a photocatalyst for the wastewater treatment, they exhibited highly efficient hydrogen production activity. Namely, the high hydrogen production rate (395 mL/h) was achieved when splitting the synthetic sulphide effluent (S²⁻ = 0.2 M) via the photocatalytic reaction by using MnO₂-AC. The results stand for the excellent energy-conversion capability of the MnO₂-AC nanocomposites, particularly, for photocatalytic splitting of hydrogen from sulphide wastewater. Full article

(This article belongs to the Special Issue Nanomaterials and Nanotechnology in Wastewater Treatment)

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40 pages, 4501 KiB

Open AccessFeature PaperReview

Electrospun Nanofibers for Improved Angiogenesis: Promises for Tissue Engineering Applications

by Simin Nazarnezhad, Francesco Baino, Hae-Won Kim, Thomas J. Webster and Saeid Kargozar

Nanomaterials 2020, 10(8), 1609; https://doi.org/10.3390/nano10081609 - 17 Aug 2020

Cited by 78 | Viewed by 7838

Abstract

Angiogenesis (or the development of new blood vessels) is a key event in tissue engineering and regenerative medicine; thus, a number of biomaterials have been developed and combined with stem cells and/or bioactive molecules to produce three-dimensional (3D) pro-angiogenic constructs. Among the various [...] Read more.

Angiogenesis (or the development of new blood vessels) is a key event in tissue engineering and regenerative medicine; thus, a number of biomaterials have been developed and combined with stem cells and/or bioactive molecules to produce three-dimensional (3D) pro-angiogenic constructs. Among the various biomaterials, electrospun nanofibrous scaffolds offer great opportunities for pro-angiogenic approaches in tissue repair and regeneration. Nanofibers made of natural and synthetic polymers are often used to incorporate bioactive components (e.g., bioactive glasses (BGs)) and load biomolecules (e.g., vascular endothelial growth factor (VEGF)) that exert pro-angiogenic activity. Furthermore, seeding of specific types of stem cells (e.g., endothelial progenitor cells) onto nanofibrous scaffolds is considered as a valuable alternative for inducing angiogenesis. The effectiveness of these strategies has been extensively examined both in vitro and in vivo and the outcomes have shown promise in the reconstruction of hard and soft tissues (mainly bone and skin, respectively). However, the translational of electrospun scaffolds with pro-angiogenic molecules or cells is only at its beginning, requiring more research to prove their usefulness in the repair and regeneration of other highly-vascularized vital tissues and organs. This review will cover the latest progress in designing and developing pro-angiogenic electrospun nanofibers and evaluate their usefulness in a tissue engineering and regenerative medicine setting. Full article

(This article belongs to the Special Issue Nanotechnology and Additive Manufacturing for Hard Tissue Regeneration)

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26 pages, 2583 KiB

Open AccessReview

Synthesis and Technology of Nanoemulsion-Based Pesticide Formulation

by Isshadiba Faikah Mustafa and Mohd Zobir Hussein

Nanomaterials 2020, 10(8), 1608; https://doi.org/10.3390/nano10081608 - 17 Aug 2020

Cited by 140 | Viewed by 16151

Abstract

Declines in crop yield due to pests and diseases require the development of safe, green and eco-friendly pesticide formulations. A major problem faced by the agricultural industry is the use of conventional agrochemicals that contribute broad-spectrum effects towards the environment and organisms. As [...] Read more.

Declines in crop yield due to pests and diseases require the development of safe, green and eco-friendly pesticide formulations. A major problem faced by the agricultural industry is the use of conventional agrochemicals that contribute broad-spectrum effects towards the environment and organisms. As a result of this issue, researchers are currently developing various pesticide formulations using different nanotechnology approaches. The progress and opportunities in developing nanoemulsions as carriers for plant protection or nanodelivery systems for agrochemicals in agricultural practice have been the subject of intense research. New unique chemical and biologic properties have resulted in a promising pesticide nanoformulations for crop protection. These innovations—particularly the nanoemulsion-based agrochemicals—are capable of enhancing the solubility of active ingredients, improving agrochemical bioavailability, and improving stability and wettability properties during the application, thus resulting in better efficacy for pest control and treatment. All of these—together with various preparation methods towards a greener and environmentally friendly agrochemicals—are also discussed and summarized in this review. Full article

(This article belongs to the Special Issue Micro/Nano Emulsions: Smart Colloids for Multiple Applications)

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28 pages, 6066 KiB

Open AccessArticle

Developmental Neurotoxicity Screening for Nanoparticles Using Neuron-Like Cells of Human Umbilical Cord Mesenchymal Stem Cells: Example with Magnetite Nanoparticles

by Teresa Coccini, Patrizia Pignatti, Arsenio Spinillo and Uliana De Simone

Nanomaterials 2020, 10(8), 1607; https://doi.org/10.3390/nano10081607 - 15 Aug 2020

Cited by 14 | Viewed by 3497

Abstract

Metallic nanoparticles (NPs), as iron oxide NPs, accumulate in organs, cross the blood-brain barrier and placenta, and have the potential to elicit developmental neurotoxicity (DNT). Human stem cell-derived in vitro models may provide more realistic platforms to study NPs effects on neural cells, [...] Read more.

Metallic nanoparticles (NPs), as iron oxide NPs, accumulate in organs, cross the blood-brain barrier and placenta, and have the potential to elicit developmental neurotoxicity (DNT). Human stem cell-derived in vitro models may provide more realistic platforms to study NPs effects on neural cells, and to obtain relevant information on the potential for early or late DNT effects in humans. Primary neuronal-like cells (hNLCs) were generated from mesenchymal stem cells derived from human umbilical cord lining and the effects caused by magnetite (Fe₃O₄NPs, 1–50 μg/mL) evaluated. Neuronal differentiation process was divided into stages: undifferentiated, early, mid- and fully-differentiated (from day-2 to 8 of induction) based on different neuronal markers and morphological changes over time. Reduction in neuronal differentiation induction after NP exposure was observed associated with NP uptake: β-tubulin III (β-Tub III), microtubule-associated protein 2 (MAP-2), enolase (NSE) and nestin were downregulated (10–40%), starting from 25 μg/mL at the early stage. Effects were exacerbated at higher concentrations and persisted up to 8 days without cell morphology alterations. Adenosine triphosphate (ATP) and caspase-3/7 activity data indicated Fe₃O₄NPs-induced cell mortality in a concentration-dependent manner and increases of apoptosis: effects appeared early (from day-3), started at low concentrations (≥5 μg/mL) and persisted. This new human cell-based model allows different stages of hNLCs to be cultured, exposed to NPs/chemicals, and analyzed for different endpoints at early or later developmental stage. Full article

(This article belongs to the Special Issue Cytotoxicity and Genotoxicity of Nanomaterials)

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80 pages, 14803 KiB

Open AccessReview

Sulfide and Oxide Inorganic Solid Electrolytes for All-Solid-State Li Batteries: A Review

by Mogalahalli V. Reddy, Christian M. Julien, Alain Mauger and Karim Zaghib

Nanomaterials 2020, 10(8), 1606; https://doi.org/10.3390/nano10081606 - 15 Aug 2020

Cited by 207 | Viewed by 26733

Abstract

Energy storage materials are finding increasing applications in our daily lives, for devices such as mobile phones and electric vehicles. Current commercial batteries use flammable liquid electrolytes, which are unsafe, toxic, and environmentally unfriendly with low chemical stability. Recently, solid electrolytes have been [...] Read more.

Energy storage materials are finding increasing applications in our daily lives, for devices such as mobile phones and electric vehicles. Current commercial batteries use flammable liquid electrolytes, which are unsafe, toxic, and environmentally unfriendly with low chemical stability. Recently, solid electrolytes have been extensively studied as alternative electrolytes to address these shortcomings. Herein, we report the early history, synthesis and characterization, mechanical properties, and Li⁺ ion transport mechanisms of inorganic sulfide and oxide electrolytes. Furthermore, we highlight the importance of the fabrication technology and experimental conditions, such as the effects of pressure and operating parameters, on the electrochemical performance of all-solid-state Li batteries. In particular, we emphasize promising electrolyte systems based on sulfides and argyrodites, such as LiPS₅Cl and β-Li₃PS₄, oxide electrolytes, bare and doped Li₇La₃Zr₂O₁₂ garnet, NASICON-type structures, and perovskite electrolyte materials. Moreover, we discuss the present and future challenges that all-solid-state batteries face for large-scale industrial applications. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanomaterials for Energy and Catalysis)

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11 pages, 971 KiB

Open AccessArticle

Reducing Amplified Spontaneous Emission Threshold in CsPbBr₃ Quantum Dot Films by Controlling TiO₂ Compact Layer

by Saif M. H. Qaid, Fahhad H. Alharbi, Idriss Bedja, Mohammad Khaja Nazeeruddin and Abdullah S. Aldwayyan

Nanomaterials 2020, 10(8), 1605; https://doi.org/10.3390/nano10081605 - 15 Aug 2020

Cited by 18 | Viewed by 3554

Abstract

Amplified spontaneous emission (ASE) threshold in

{CsPbBr}_{3}

quantum dot films is systematically reduced by introducing high quality

{TiO}_{2}

compact layer grown by atomic-layer deposition. Uniform and pinhole-free

{TiO}_{2}

films of thickness 10, 20 and 50 nm are used as a [...] Read more.

Amplified spontaneous emission (ASE) threshold in

{CsPbBr}_{3}

quantum dot films is systematically reduced by introducing high quality

{TiO}_{2}

compact layer grown by atomic-layer deposition. Uniform and pinhole-free

{TiO}_{2}

films of thickness 10, 20 and 50 nm are used as a substrates for

{CsPbBr}_{3}

quantum dot films to enhance amplified spontaneous emission performance. The reduction is attributed indirectly to the improved morphology of

{TiO}_{2}

compact layer and subsequently

{CsPbBr}_{3}

active layer as grown on better quality substrates. This is quantified by the reduced roughness of the obtained films to less than 5 nm with 50 nm

{TiO}_{2}

substrate. Considering the used growth method for the quantum dot film, the improved substrate morphology maintains better the structure of the used quantum dots in the precursor solution. This results in better absorption and hence lower threshold of ASE. Besides that, the improved film quality results further in reducing light scattering and hence additional slight optical enhancement. The work demonstrates a potential venue to reduce the amplified spontaneous emission threshold of quantum dot films and therefore enhanced their optical performance. Full article

(This article belongs to the Special Issue Low-Dimensional Nanomaterials for Photonics and Optoelectronics)

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18 pages, 3540 KiB

Open AccessArticle

Removal of As(III) from Water Using the Adsorptive and Photocatalytic Properties of Humic Acid-Coated Magnetite Nanoparticles

by Phuong Pham, Mamun Rashid, Yong Cai, Masafumi Yoshinaga, Dionysios D. Dionysiou and Kevin O’Shea

Nanomaterials 2020, 10(8), 1604; https://doi.org/10.3390/nano10081604 - 15 Aug 2020

Cited by 9 | Viewed by 3389

Abstract

The oxidation of highly toxic arsenite (As(III)) was studied using humic acid-coated magnetite nanoparticles (HA-MNP) as a photosensitizer. Detailed characterization of the HA-MNP was carried out before and after the photoinduced treatment of As(III) species. Upon irradiation of HA-MNP with 350 nm light, [...] Read more.

The oxidation of highly toxic arsenite (As(III)) was studied using humic acid-coated magnetite nanoparticles (HA-MNP) as a photosensitizer. Detailed characterization of the HA-MNP was carried out before and after the photoinduced treatment of As(III) species. Upon irradiation of HA-MNP with 350 nm light, a portion of the As(III) species was oxidized to arsenate (As(V)) and was nearly quantitatively removed from the aqueous solution. The separation of As(III) from the aqueous solution is primarily driven by the strong adsorption of As(III) onto the HA-MNP. As(III) removals of 40–90% were achieved within 60 min depending on the amount of HA-MNP. The generation of reactive oxygen species (•OH and ¹O₂) and the triplet excited state of HA-MNP (³HA-MNP*) was monitored and quantified during HA-MNP photolysis. The results indicate ³HA-MNP* and/or singlet oxygen (¹O₂) depending on the reaction conditions are responsible for converting As(III) to less toxic As(V). The formation of ³HA-MNP* was quantified using the electron transfer probe 2,4,6-trimethylphenol (TMP). The formation rate of ³HA-MNP* was 8.0 ± 0.6 × 10⁻⁹ M s⁻¹ at the TMP concentration of 50 µM and HA-MNP concentration of 1.0 g L⁻¹. The easy preparation, capacity for triplet excited state and singlet oxygen production, and magnetic separation suggest HA-MNP has potential to be a photosensitizer for the remediation of arsenic (As) and other pollutants susceptible to advanced oxidation. Full article

(This article belongs to the Special Issue Nano‐Photocatalytic Materials: Possibilities and Challenges)

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15 pages, 3132 KiB

Open AccessArticle

Synthesis and Cytotoxicity Studies of Wood-Based Cationic Cellulose Nanocrystals as Potential Immunomodulators

by Yusha Imtiaz, Beza Tuga, Christopher W. Smith, Alexander Rabideau, Long Nguyen, Yali Liu, Sabahudin Hrapovic, Karina Ckless and Rajesh Sunasee

Nanomaterials 2020, 10(8), 1603; https://doi.org/10.3390/nano10081603 - 15 Aug 2020

Cited by 20 | Viewed by 3883

Abstract

Polysaccharides have been shown to have immunomodulatory properties. Modulation of the immune system plays a crucial role in physiological processes as well as in the treatment and/or prevention of autoimmune and infectious diseases. Cellulose nanocrystals (CNCs) are derived from cellulose, the most abundant [...] Read more.

Polysaccharides have been shown to have immunomodulatory properties. Modulation of the immune system plays a crucial role in physiological processes as well as in the treatment and/or prevention of autoimmune and infectious diseases. Cellulose nanocrystals (CNCs) are derived from cellulose, the most abundant polysaccharide on the earth. CNCs are an emerging class of crystalline nanomaterials with exceptional physico-chemical properties for high-end applications and commercialization prospects. The aim of this study was to design, synthesize, and evaluate the cytotoxicity of a series of biocompatible, wood-based, cationic CNCs as potential immunomodulators. The anionic CNCs were rendered cationic by grafting with cationic polymers having pendant ⁺NMe₃ and ⁺NH₃ moieties. The success of the synthesis of the cationic CNCs was evidenced by Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, and elemental analysis. No modification in the nanocrystals rod-like shape was observed in transmission electron microscopy and atomic force microscopy analyses. Cytotoxicity studies using three different cell-based assays (MTT, Neutral Red, and LIVE/DEAD^®) and three relevant mouse and human immune cells indicated very low cytotoxicity of the cationic CNCs in all tested experimental conditions. Overall, our results showed that cationic CNCs are suitable to be further investigated as immunomodulators and potential vaccine nanoadjuvants. Full article

(This article belongs to the Special Issue Nanocellulose and Nanocarbons Based Hybrid Materials: Synthesis, Characterization and Applications)

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14 pages, 1916 KiB

Open AccessArticle

Partial Reversibility of the Cytotoxic Effect Induced by Graphene-Based Materials in Skin Keratinocytes

by Marco Pelin, Hazel Lin, Arianna Gazzi, Silvio Sosa, Cristina Ponti, Amaya Ortega, Amaia Zurutuza, Ester Vázquez, Maurizio Prato, Aurelia Tubaro and Alberto Bianco

Nanomaterials 2020, 10(8), 1602; https://doi.org/10.3390/nano10081602 - 15 Aug 2020

Cited by 12 | Viewed by 3063

Abstract

In the frame of graphene-based material (GBM) hazard characterization, particular attention should be given to the cutaneous effects. Hence, this study investigates if HaCaT skin keratinocytes exposed to high concentrations of few-layer graphene (FLG) or partially dehydrated graphene oxide (d-GO) for a short [...] Read more.

In the frame of graphene-based material (GBM) hazard characterization, particular attention should be given to the cutaneous effects. Hence, this study investigates if HaCaT skin keratinocytes exposed to high concentrations of few-layer graphene (FLG) or partially dehydrated graphene oxide (d-GO) for a short time can recover from the cytotoxic insult, measured by means of cell viability, mitochondrial damage and oxidative stress, after GBM removal from the cell medium. When compared to 24 or 72 h continuous exposure, recovery experiments suggest that the cytotoxicity induced by 24 h exposure to GBM is only partially recovered after 48 h culture in GBM-free medium. This partial recovery, higher for FLG as compared to GO, is not mediated by autophagy and could be the consequence of GBM internalization into cells. The ability of GBMs to be internalized inside keratinocytes together with the partial reversibility of the cellular damage is important in assessing the risk associated with skin exposure to GBM-containing devices. Full article

(This article belongs to the Special Issue Safety Assessment of Graphene-Based Materials: Human Health and Environment)

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18 pages, 3889 KiB

Open AccessArticle

Nanocomposites of NiO/CuO Based MOF with rGO: An Efficient and Robust Electrocatalyst for Methanol Oxidation Reaction in DMFC

by Tayyaba Noor, Sadaf Pervaiz, Naseem Iqbal, Habib Nasir, Neelam Zaman, Muhammad Sharif and Erum Pervaiz

Nanomaterials 2020, 10(8), 1601; https://doi.org/10.3390/nano10081601 - 15 Aug 2020

Cited by 76 | Viewed by 5927

Abstract

In this work a novel bimetallic nickel oxide/copper oxide metal–organic framework (NiO/CuO MOF) has been developed by using two linkers: Benzene Dicarboxylic acid (BDC) and Pyrazine. The composites of NiO/CuO MOF with different amounts of reduced graphene oxide (rGO) were synthesized through a [...] Read more.

In this work a novel bimetallic nickel oxide/copper oxide metal–organic framework (NiO/CuO MOF) has been developed by using two linkers: Benzene Dicarboxylic acid (BDC) and Pyrazine. The composites of NiO/CuO MOF with different amounts of reduced graphene oxide (rGO) were synthesized through a hydrothermal method and subsequently characterized by multiple significant techniques like XRD, SEM, EDX, FTIR and Raman IR for an investigation of their structural and morphological properties. The prepared series of material was later employed for electrochemical oxidation of methanol, tested by cyclic voltammetry (CV) in basic medium on a modified glassy carbon electrode (GCE). The electrochemical response depicts that increasing concentration of rGO enhances the electrocatalytic activity of the catalyst for methanol oxidation reaction (MOR). The catalyzed oxidation reaction of methanol by NiO/CuO MOF and rGO-NiO/CuO MOF composites give a superlative current density of 437. 28 mA/cm² at 0.9 V potential at 50 mV/s scan rate. This activity makes it a promising catalytic material for electrolysis of methanol in direct methanol fuel cell (DMFC). Full article

(This article belongs to the Special Issue Nanomaterial for Energy Conversion and Storage)

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10 pages, 2262 KiB

Open AccessArticle

A Cost-Effective Approach for Non-Persistent Gold Nano-Architectures Production

by Giulia Giannone, Melissa Santi, Maria Laura Ermini, Domenico Cassano and Valerio Voliani

Nanomaterials 2020, 10(8), 1600; https://doi.org/10.3390/nano10081600 - 14 Aug 2020

Cited by 13 | Viewed by 4164

Abstract

The effective exploitation of the intriguing theranostic features of noble metal nanoparticles for therapeutic applications is far from being a routine practice due to the persistence issue. In this regard, passion fruit-like nano-architectures (NAs), biodegradable and excretable all-in-one, nature-inspired platforms which jointly combine [...] Read more.

The effective exploitation of the intriguing theranostic features of noble metal nanoparticles for therapeutic applications is far from being a routine practice due to the persistence issue. In this regard, passion fruit-like nano-architectures (NAs), biodegradable and excretable all-in-one, nature-inspired platforms which jointly combine these characteristics with the appealing optical behaviors of noble metal nanoparticles, can offer a new alternative for theranostic applications. Besides the need for efficacious and innovative systems, the reliable and cost-effective production of nanomaterials is a pivotal subject for their translation to the clinical setting. Here, we demonstrate the production of a new cheaper class of degradable, ultrasmall-in-nano-architectures (dragon fruit NAs, dNAs) using polyethyleneimine (PEI) as a cationic polymer without affecting either their compositions or their physiological behaviors, compared to the previous NAs. In particular, the standardized protocol characterized in this work ensures the preparation of high gold-loading capacity nanoparticles, a peculiar characteristic that, synergically with the interesting properties of PEI, may unlock new possible applications previously precluded to the first version of NAs while reducing the hand-made production cost by three orders of magnitude. Full article

(This article belongs to the Special Issue Biodegradable Inorganic Nano-Architectures)

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22 pages, 3973 KiB

Open AccessReview

Hollow Silica Particles: Recent Progress and Future Perspectives

by Jaswinder Sharma and Georgios Polizos

Nanomaterials 2020, 10(8), 1599; https://doi.org/10.3390/nano10081599 - 14 Aug 2020

Cited by 55 | Viewed by 8853

Abstract

Hollow silica particles (or mesoporous hollow silica particles) are sought after for applications across several fields, including drug delivery, battery anodes, catalysis, thermal insulation, and functional coatings. Significant progress has been made in hollow silica particle synthesis and several new methods are being [...] Read more.

Hollow silica particles (or mesoporous hollow silica particles) are sought after for applications across several fields, including drug delivery, battery anodes, catalysis, thermal insulation, and functional coatings. Significant progress has been made in hollow silica particle synthesis and several new methods are being explored to use these particles in real-world applications. This review article presents a brief and critical discussion of synthesis strategies, characterization techniques, and current and possible future applications of these particles. Full article

(This article belongs to the Special Issue Applications of Mesoporous Silica Nanostructures)

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9 pages, 2095 KiB

Open AccessArticle

Titanium Dioxide-Coated Zinc Oxide Nanorods as an Efficient Photoelectrode in Dye-Sensitized Solar Cells

by Qiang Zhang, Shengwen Hou and Chaoyang Li

Nanomaterials 2020, 10(8), 1598; https://doi.org/10.3390/nano10081598 - 14 Aug 2020

Cited by 28 | Viewed by 4898

Abstract

Well-arrayed zinc oxide nanorods applied as photoelectrodes for dye-sensitized solar cells were synthesized on an aluminum-doped zinc oxide substrate by the multi-annealing method. In order to improve the chemical stability and surface-to-volume ratio of photoanodes in dye-sensitized solar cells, the synthesized zinc oxide [...] Read more.

Well-arrayed zinc oxide nanorods applied as photoelectrodes for dye-sensitized solar cells were synthesized on an aluminum-doped zinc oxide substrate by the multi-annealing method. In order to improve the chemical stability and surface-to-volume ratio of photoanodes in dye-sensitized solar cells, the synthesized zinc oxide nanorods were coated with pure anatase phase titanium dioxide film using a novel mist chemical vapor deposition method. The effects of the titanium dioxide film on the morphological, structural, optical, and photovoltaic properties of zinc oxide–titanium dioxide core–shell nanorods were investigated. It was found that the diameter and surface-to-volume ratio of zinc oxide nanorods were significantly increased by coating them with titanium dioxide thin film. The power conversion efficiency of dye-sensitized solar cells was improved from 1.31% to 2.68% by coating titanium dioxide film onto the surface of zinc oxide nanorods. Full article

(This article belongs to the Special Issue Nanostructured Materials for Solar Cell Applications)

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17 pages, 5865 KiB

Open AccessArticle

One-Pot Synthesis of W₂C/WS₂ Hybrid Nanostructures for Improved Hydrogen Evolution Reactions and Supercapacitors

by Sajjad Hussain, Iqra Rabani, Dhanasekaran Vikraman, Asad Feroze, Muhammad Ali, Young-Soo Seo, Hyun-Seok Kim, Seung-Hyun Chun and Jongwan Jung

Nanomaterials 2020, 10(8), 1597; https://doi.org/10.3390/nano10081597 - 14 Aug 2020

Cited by 47 | Viewed by 5153

Abstract

Tungsten sulfide (WS₂) and tungsten carbide (W₂C) are materialized as the auspicious candidates for various electrochemical applications, owing to their plentiful active edge sites and better conductivity. In this work, the integration of W₂C and WS₂ [...] Read more.

Tungsten sulfide (WS₂) and tungsten carbide (W₂C) are materialized as the auspicious candidates for various electrochemical applications, owing to their plentiful active edge sites and better conductivity. In this work, the integration of W₂C and WS₂ was performed by using a simple chemical reaction to form W₂C/WS₂ hybrid as a proficient electrode for hydrogen evolution and supercapacitors. For the first time, a W₂C/WS₂ hybrid was engaged as a supercapacitor electrode and explored an incredible specific capacitance of ~1018 F g⁻¹ at 1 A g⁻¹ with the outstanding robustness. Furthermore, the constructed symmetric supercapacitor using W₂C/WS₂ possessed an energy density of 45.5 Wh kg⁻¹ at 0.5 kW kg⁻¹ power density. For hydrogen evolution, the W₂C/WS₂ hybrid produced the low overpotentials of 133 and 105 mV at 10 mA cm⁻² with the small Tafel slopes of 70 and 84 mV dec⁻¹ in acidic and alkaline media, respectively, proving their outstanding interfaced electrocatalytic characteristics. The engineered W₂C/WS₂-based electrode offered the high-performance for electrochemical energy applications. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanocomposite Thin Films and 2D Materials)

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56 pages, 6435 KiB

Open AccessReview

A Review about the Recent Advances in Selected NonThermal Plasma Assisted Solid–Gas Phase Chemical Processes

by Vincenzo Palma, Marta Cortese, Simona Renda, Concetta Ruocco, Marco Martino and Eugenio Meloni

Nanomaterials 2020, 10(8), 1596; https://doi.org/10.3390/nano10081596 - 14 Aug 2020

Cited by 45 | Viewed by 6303

Abstract

Plasma science has attracted the interest of researchers in various disciplines since the 1990s. This continuously evolving field has spawned investigations into several applications, including industrial sterilization, pollution control, polymer science, food safety and biomedicine. nonthermal plasma (NTP) can promote the occurrence of [...] Read more.

Plasma science has attracted the interest of researchers in various disciplines since the 1990s. This continuously evolving field has spawned investigations into several applications, including industrial sterilization, pollution control, polymer science, food safety and biomedicine. nonthermal plasma (NTP) can promote the occurrence of chemical reactions in a lower operating temperature range, condition in which, in a conventional process, a catalyst is generally not active. The aim, when using NTP, is to selectively transfer electrical energy to the electrons, generating free radicals through collisions and promoting the desired chemical changes without spending energy in heating the system. Therefore, NTP can be used in various fields, such as NO_x removal from exhaust gases, soot removal from diesel engine exhaust, volatile organic compound (VOC) decomposition, industrial applications, such as ammonia production or methanation reaction (Sabatier reaction). The combination of NTP technology with catalysts is a promising option to improve selectivity and efficiency in some chemical processes. In this review, recent advances in selected nonthermal plasma assisted solid–gas processes are introduced, and the attention was mainly focused on the use of the dielectric barrier discharge (DBD) reactors. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanomaterials for Energy and Catalysis)

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11 pages, 5037 KiB

Open AccessArticle

Investigation of Early Stage of Carbon Nanotube Growth on Plasma-Pretreated Inconel Plates and Comparison with Other Superalloys as Substrates

by Eui-Chul Shin, Byeong-Joo Lee, Sung-Il Jo and Goo-Hwan Jeong

Nanomaterials 2020, 10(8), 1595; https://doi.org/10.3390/nano10081595 - 14 Aug 2020

Cited by 2 | Viewed by 2844

Abstract

We investigate the early stage of carbon nanotube (CNTs) growth on Inconel 600 to address the effect of pretreatments such as annealing and plasma pretreatment on growth behavior. In addition, we compare the growth results to other Ni-based superalloys including Invar 42 and [...] Read more.

We investigate the early stage of carbon nanotube (CNTs) growth on Inconel 600 to address the effect of pretreatments such as annealing and plasma pretreatment on growth behavior. In addition, we compare the growth results to other Ni-based superalloys including Invar 42 and Hastelloy C276. The growth substrates were prepared using mechanical polish, thermal annealing and plasma pretreatment. The air annealing was performed at 725 °C for 10 min and plasma pretreatment was subsequently undergone with 10.5 W at 500 °C for 30 min. The annealed and plasma-pretreated substrates exhibited different surface morphologies on the surface and enhanced growth behavior of CNT was observed from the region of particulate surface. The optimized growth temperature, which produces the highest CNT height, was determined at 525 °C for Ni and Inconel 600 and 625 °C for Invar 42 and Hastelloy C276 substrates. The difference of optimal growth temperature is expected to the existence of high temperature elements such as Mn or Mo in the alloys. X-ray diffraction spectroscopy revealed that the formation of roughened oxide layers caused by the pretreatments would promote the nucleation and growth of the CNTs. Full article

(This article belongs to the Special Issue Carbon Nanotube: Synthesis, Characteristics and Applications)

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16 pages, 2966 KiB

Open AccessArticle

Tailor-Made Fluorinated Ionic Liquids for Protein Delivery

by N. S. M. Vieira, P. J. Castro, D. F. Marques, J. M. M. Araújo and A. B. Pereiro

Nanomaterials 2020, 10(8), 1594; https://doi.org/10.3390/nano10081594 - 14 Aug 2020

Cited by 13 | Viewed by 2735

Abstract

Nowadays, pharmaceutical companies are facing several challenges with the development and approval of new biological products. The unique properties of several fluorinated ionic liquids (FILs), such as their high surfactant power in aqueous solutions, their chemical and biological stability, and low toxicity, favor [...] Read more.

Nowadays, pharmaceutical companies are facing several challenges with the development and approval of new biological products. The unique properties of several fluorinated ionic liquids (FILs), such as their high surfactant power in aqueous solutions, their chemical and biological stability, and low toxicity, favor their application in the pharmaceutical industry. Furthermore, the numerous combinations between cations and anions, in the FILs design, enlarge the possibilities to construct a successful delivery system. Several FILs also proved to not affect the activity, stability, and secondary structure of the therapeutic protein lysozyme. This work aims to study the aggregation behavior of distinct FILs in the protein suitable medium, in the presence or absence of lysozyme. Besides, different incubation conditions were tested to guarantee the optimal enzymatic activity of the protein at more stable delivery systems. Following the optimization of the incubation conditions, the quantification of the encapsulated lysozyme was performed to evaluate the encapsulation efficiency of each FIL-based system. The release of the protein was tested applying variables such as time, temperature, and ultrasound frequency. The experimental results suggest that the aggregation behavior of FILs is not significantly influenced by the protein and/or protein buffer and supports their application for the design of delivery systems with high encapsulation efficiencies, maintaining the biological activity of either encapsulated and released protein. Full article

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

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24 pages, 2980 KiB

Open AccessReview

High Sensitivity Resists for EUV Lithography: A Review of Material Design Strategies and Performance Results

by Theodore Manouras and Panagiotis Argitis

Nanomaterials 2020, 10(8), 1593; https://doi.org/10.3390/nano10081593 - 14 Aug 2020

Cited by 111 | Viewed by 21197

Abstract

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad [...] Read more.

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad consensus on this direction has triggered a dramatic increase of interest on resist materials of high sensitivity especially designed for use in the EUV spectral region in order to meet the strict requirements needed for overcoming the source brightness issues and securing the cost efficiency of the technology. To this direction both fundamental studies on the radiation induced chemistry in this spectral area and a plethora of new ideas targeting at the design of new highly sensitive and top performing resists have been proposed. Besides the traditional areas of acid-catalyzed chemically amplified resists and the resists based on polymer backbone breaking new unconventional ideas have been proposed based on the insertion of metal compounds or compounds of other highly absorbing at EUV atoms in the resist formulations. These last developments are reviewed here. Since the effort targets to a new understanding of electron-induced chemical reactions that dominate the resist performance in this region these last developments may lead to unprecedented changes in lithographic technology but can also strongly affect other scientific areas where electron-induced chemistry plays a critical role. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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12 pages, 1093 KiB

Open AccessCommunication

Gated Resonance Energy Transfer (gRET) Controlled by Programmed Death Protein Ligand 1

by Hubert Grel, Katarzyna Ratajczak, Slawomir Jakiela and Magdalena Stobiecka

Nanomaterials 2020, 10(8), 1592; https://doi.org/10.3390/nano10081592 - 13 Aug 2020

Cited by 20 | Viewed by 2932

Abstract

The resonance energy transfer (RET) between an excited fluorescent probe molecule and a plasmonic nanoparticle (AuNP) has been investigated to evaluate the effect of protein molecules on the RET efficiency. We have found that the energy transfer to a functionalized AuNP can be [...] Read more.

The resonance energy transfer (RET) between an excited fluorescent probe molecule and a plasmonic nanoparticle (AuNP) has been investigated to evaluate the effect of protein molecules on the RET efficiency. We have found that the energy transfer to a functionalized AuNP can be modulated by a sub-monolayer film of programmed death-ligand 1 (PD-L1) protein. The interactions of PD-L1 with AuNP@Cit involve incorporation of the protein in AuNP shell and formation of a submonolayer adsorption film with voids enabling gated surface plasmon resonance energy transfer (SPRET). A model of the gated-RET system based on the protein size, estimated using Fisher–Polikarpov–Craievich density approximation, has been developed and can be utilized for other proteins, with minimum data requirement, as well. The value of the equilibrium constant K_L determined for the Langmuir isotherm is high: K_L = 1.27 × 10⁸ M⁻¹, enabling highly sensitive control of the gated-RET by PD-L1. Thus, with the gated-RET technique, one can determine PD-L1 within the dynamic range, extending from 1.2 to 50 nM. Moreover, we have found that the Gibbs free energy for PD-L1 binding to AuNP@Cit is −46.26 kJ/mol (−11.05 kcal/mol), indicating a strong adsorption with supramolecular interactions. The proposed gated-RET system, with the fluorescence intensity of the fluorophore probe molecule modulated by plasmonic quenching with AuNP and shielding of energy transfer by the adsorbed PD-L1 can be further developed for determination of PD-L1 in pharmaceutical formulations for immune checkpoint control in cancer therapy. Full article

(This article belongs to the Special Issue Gold Nanoparticle-Based Biosensors)

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15 pages, 3971 KiB

Open AccessArticle

Potential of TiO₂ with Various Au Nanoparticles for Catalyzing Mesotrione Removal from Wastewaters under Sunlight

by Daniela Šojić Merkulov, Marina Lazarević, Aleksandar Djordjevic, Máté Náfrádi, Tünde Alapi, Predrag Putnik, Zlatko Rakočević, Mirjana Novaković, Bojan Miljević, Szabolcs Bognár and Biljana Abramović

Nanomaterials 2020, 10(8), 1591; https://doi.org/10.3390/nano10081591 - 13 Aug 2020

Cited by 7 | Viewed by 3768

Abstract

Nowadays, great focus is given to the contamination of surface and groundwater because of the extensive usage of pesticides in agriculture. The improvements of commercial catalyst TiO₂ activity using different Au nanoparticles were investigated for mesotrione photocatalytic degradation under simulated sunlight. The [...] Read more.

Nowadays, great focus is given to the contamination of surface and groundwater because of the extensive usage of pesticides in agriculture. The improvements of commercial catalyst TiO₂ activity using different Au nanoparticles were investigated for mesotrione photocatalytic degradation under simulated sunlight. The selected system was 2.43 × 10⁻³% Au–S–CH₂–CH₂–OH/TiO₂ (0.5 g/L) that was studied by transmission electron microscopy and ultraviolet-visible (UV-Vis) spectroscopy. It was found that TiO₂ particles size was ~20 nm and ~50 nm, respectively. The Au nanoparticles were below 10 nm and were well distributed within the framework of TiO₂. For 2.43 × 10⁻³% Au–S–CH₂–CH₂–OH/TiO₂ (0.5 g/L), band gap energy was 2.45 eV. In comparison to the pure TiO₂, addition of Au nanoparticles generally enhanced photocatalytic removal of mesotrione. By examining the degree of mineralization, it was found that 2.43 × 10⁻³% Au–S–CH₂–CH₂–OH/TiO₂ (0.5 g/L) system was the most efficient for the removal of the mesotrione and intermediates. The effect of tert-butanol, NaF and ethylenediaminetetraacetic acid disodium salt on the transformation rate suggested that the relative contribution of various reactive species changed in following order: h⁺ > ^●OH_ads > ^●OH_bulk. Finally, several intermediates that were formed during the photocatalytic treatment of mesotrione were identified. Full article

(This article belongs to the Special Issue Nanostructured Catalysts for Sustainable Applications)

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