Nanomaterials

14 pages, 4538 KiB

Open AccessArticle

Investigating the Impact of the Washing Steps of Layered Double Hydroxides (LDH) on the Electrochemical Performance

by Gayi Nyongombe, Guy L. Kabongo, Luyanda L. Noto and Mokhotjwa S. Dhlamini

Nanomaterials 2022, 12(3), 578; https://doi.org/10.3390/nano12030578 - 08 Feb 2022

Cited by 4 | Viewed by 1697

The washing of layered double hydroxides (LDH) material is mostly purposed to discard the unreacted products after the reaction has been completed. However, this study demonstrated that the washing stage can also be targeted to optimise the electrochemical performance of LDH by using [...] Read more.

The washing of layered double hydroxides (LDH) material is mostly purposed to discard the unreacted products after the reaction has been completed. However, this study demonstrated that the washing stage can also be targeted to optimise the electrochemical performance of LDH by using an appropriate solvent. Solvents, namely, ethanol, acetone, and an ethanol–acetone solution (2:1) were used for the washing of LDH and the impacts thereof on the structural, physical, chemical, morphological, and electrochemical properties were investigated. Using Williamson–Hall analysis, we observed modifications on the crystalline domain. The specific surface area and pore parameters for all the samples were also differently affected. The Fourier transform infrared (FTIR) measurements displayed evident changes in the basic sites. The electrochemical performances of samples were analysed. The sample washed with the ethanol–acetone solution exhibited a specific capacitance of 1807.26 Fg⁻¹ at 10 mVs⁻¹, which is higher than that of other samples as well as low internal resistance compared to its counterpart. This demonstrates that the use of an appropriate solvent during the washing stage of LDH affects the electrochemical properties. Full article

(This article belongs to the Special Issue Emerging Nanomaterials for Electrochemical Applications)

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14 pages, 4461 KiB

Open AccessEditor’s ChoiceArticle

Synthesis of Spherical Nanoparticle Hybrids via Aerosol Thiol-Ene Photopolymerization and Their Bioconjugation

by Narmin Suvarli, Max Frentzel, Jürgen Hubbuch, Iris Perner-Nochta and Michael Wörner

Nanomaterials 2022, 12(3), 577; https://doi.org/10.3390/nano12030577 - 08 Feb 2022

Cited by 4 | Viewed by 2080

Abstract

Hybrid nanomaterials possess the properties of both organic and inorganic components and find applications in various fields of research and technology. In this study, aerosol photopolymerization is used in combination with thiol-ene chemistry to produce silver poly(thio-ether) hybrid nanospheres. In aerosol photopolymerization, a [...] Read more.

Hybrid nanomaterials possess the properties of both organic and inorganic components and find applications in various fields of research and technology. In this study, aerosol photopolymerization is used in combination with thiol-ene chemistry to produce silver poly(thio-ether) hybrid nanospheres. In aerosol photopolymerization, a spray solution of monomers is atomized, forming a droplet aerosol, which then polymerizes, producing spherical polymer nanoparticles. To produce silver poly(thio-ether) hybrids, silver nanoparticles were introduced to the spray solution. Diverse methods of stabilization were used to produce stable dispersions of silver nanoparticles to prevent their agglomeration before the photopolymerization process. Successfully stabilized silver nanoparticle dispersion in the spray solution subsequently formed nanocomposites with non-agglomerated silver nanoparticles inside the polymer matrix. Nanocomposite particles were analyzed via scanning and transmission electron microscopy to study the degree of agglomeration of silver nanoparticles and their location inside the polymer spheres. The nanoparticle hybrids were then introduced onto various biofunctionalization reactions. A two-step bioconjugation process was developed involving the hybrid nanoparticles: (1) conjugation of (biotin)-maleimide to thiol-groups on the polymer network of the hybrids, and (2) biotin-streptavidin binding. The biofunctionalization with gold-nanoparticle-conjugates was carried out to confirm the reactivity of -SH groups on each conjugation step. Fluorescence-labeled biomolecules were conjugated to the spherical nanoparticle hybrids (applying the two-step bioconjugation process) verified by Fluorescence Spectroscopy and Fluorescence Microscopy. The presented research offers an effective method of synthesis of smart systems that can further be used in biosensors and various other biomedical applications. Full article

(This article belongs to the Section Nanocomposite Materials)

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27 pages, 5139 KiB

Open AccessReview

Exploring Various Techniques for the Chemical and Biological Synthesis of Polymeric Nanoparticles

by Thiruchelvi Pulingam, Parisa Foroozandeh, Jo-Ann Chuah and Kumar Sudesh

Nanomaterials 2022, 12(3), 576; https://doi.org/10.3390/nano12030576 - 08 Feb 2022

Cited by 43 | Viewed by 10493

Abstract

Nanoparticles (NPs) have remarkable properties for delivering therapeutic drugs to the body’s targeted cells. NPs have shown to be significantly more efficient as drug delivery carriers than micron-sized particles, which are quickly eliminated by the immune system. Biopolymer-based polymeric nanoparticles (PNPs) are colloidal [...] Read more.

Nanoparticles (NPs) have remarkable properties for delivering therapeutic drugs to the body’s targeted cells. NPs have shown to be significantly more efficient as drug delivery carriers than micron-sized particles, which are quickly eliminated by the immune system. Biopolymer-based polymeric nanoparticles (PNPs) are colloidal systems composed of either natural or synthetic polymers and can be synthesized by the direct polymerization of monomers (e.g., emulsion polymerization, surfactant-free emulsion polymerization, mini-emulsion polymerization, micro-emulsion polymerization, and microbial polymerization) or by the dispersion of preformed polymers (e.g., nanoprecipitation, emulsification solvent evaporation, emulsification solvent diffusion, and salting-out). The desired characteristics of NPs and their target applications are determining factors in the choice of method used for their production. This review article aims to shed light on the different methods employed for the production of PNPs and to discuss the effect of experimental parameters on the physicochemical properties of PNPs. Thus, this review highlights specific properties of PNPs that can be tailored to be employed as drug carriers, especially in hospitals for point-of-care diagnostics for targeted therapies. Full article

(This article belongs to the Special Issue Nanomaterials for Advanced Biological Applications)

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9 pages, 21548 KiB

Open AccessArticle

Field Emission of Multi-Walled Carbon Nanotubes from Pt-Assisted Chemical Vapor Deposition

by Hongbin Tang, Ruizi Liu, Weijun Huang, Wei Zhu, Weijin Qian and Changkun Dong

Nanomaterials 2022, 12(3), 575; https://doi.org/10.3390/nano12030575 - 08 Feb 2022

Cited by 4 | Viewed by 1639

Abstract

Multi-walled carbon nanotubes (MWNTs) were grown directly on a metal substrate with the assistance of Pt using a chemical vapor deposition method. In addition, the growth mechanism of Pt-assisted catalytic CNT was discussed. MWNTs were characterized by SEM, TEM, AFM, Raman, and EDS, [...] Read more.

Multi-walled carbon nanotubes (MWNTs) were grown directly on a metal substrate with the assistance of Pt using a chemical vapor deposition method. In addition, the growth mechanism of Pt-assisted catalytic CNT was discussed. MWNTs were characterized by SEM, TEM, AFM, Raman, and EDS, and the field emission (FE) properties were investigated, comparing with the direct grown MWNTs. The results showed that CNTs could not been synthesized by Pt particles alone under the experimental condition, but Pt may accelerate the decomposition of the carbon source gas, i.e., assisting MWNT growth with other catalysts. The Pt-assisted MWNTs were longer with larger diameters of around 80 nm and possessed better structural qualities with very few catalyst particles inside. Improved field emission properties were demonstrated for the Pt-assisted MWNTs with lower turn-on fields (for 0.01 mA·cm⁻² current density) of 2.0 V·μm⁻¹ and threshold field (for 10 mA·cm⁻² current density) of 3.5 V·μm⁻¹, as well as better stability under a long-term test of 80 h (started at 3.0 mA for the Pt-assisted emitter and 3.25 mA for the direct grown emitter). This work demonstrated a promising approach to develop high performance CNT field emitters for device applications. Full article

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

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14 pages, 2938 KiB

Open AccessArticle

Fabrication of Bi₂MoO₆ Nanosheets/TiO₂ Nanorod Arrays Heterostructures for Enhanced Photocatalytic Performance under Visible-Light Irradiation

by Di Zhou, Rui Du, Zhenglong Hu, Shu Gao, Yafang Tu, Yunfei Fu, Guang Zheng and Youhua Zhou

Nanomaterials 2022, 12(3), 574; https://doi.org/10.3390/nano12030574 - 08 Feb 2022

Cited by 4 | Viewed by 1903

Abstract

Bi₂MoO₆/TiO₂ heterostructures (HSs) were synthesized in the present study by growing Bi₂MoO₆ nanosheets on vertically aligned TiO₂ nanorod arrays using a two-step solvothermal method. Their morphology and structure were characterized by scanning electron microscopy [...] Read more.

Bi₂MoO₆/TiO₂ heterostructures (HSs) were synthesized in the present study by growing Bi₂MoO₆ nanosheets on vertically aligned TiO₂ nanorod arrays using a two-step solvothermal method. Their morphology and structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Excellent visible-light absorption was observed by UV–Vis absorption spectroscopy, which was attributed to the presence of the Bi₂MoO₆ nanosheets with a narrow-band-gap. The specific surface area and pore volume of the photocatalysts were significantly increased due to the hierarchical structure composed of Bi₂MoO₆ nanosheets and TiO₂ nanorods. The photoluminescence and photoelectrochemical characterizations showed improved separation and collection efficiency of the Bi₂MoO₆/TiO₂ HSs towards the interface charge carrier. The photocatalytic analysis of the Bi₂MoO₆/TiO₂ HSs demonstrated a significantly better methylene blue (MB) degradation efficiency of 95% within 3 h than pristine TiO₂ nanorod arrays under visible-light irradiation. After three photocatalytic cycles, the degradation rate remained at ~90%. The improved performance of the Bi₂MoO₆/TiO₂ HSs was attributed to the synergy among the extended absorption of visible light; the large, specific surface area of the hierarchical structure; and the enhanced separation efficiency of the photogenerated electron-hole pairs. Finally, we also established the Bi₂MoO₆/TiO₂ HSs band structure and described the photocatalytic dye degradation mechanism. The related electrochemical analysis and free-radical trapping experiments indicated that h⁺, ·O₂⁻ and ·OH have significant effects on the degradation process. Full article

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14 pages, 5022 KiB

Open AccessArticle

Bifunctional Metal Oleate as an Alternative Method to Remove Surface Oxide and Passivate Surface Defects of Aminophosphine-Based InP Quantum Dots

by Pin-Ru Chen, Minh-Son Hoang, Kuo-Yang Lai and Hsueh-Shih Chen

Nanomaterials 2022, 12(3), 573; https://doi.org/10.3390/nano12030573 - 08 Feb 2022

Cited by 10 | Viewed by 2718

Abstract

The optical properties of indium phosphide (InP) quantum dots (QDs) are significantly influenced by their surface native oxides, which are generally removed by treating InP cores with hydrofluoric acid (HF). Besides the harmful health effects of HF, its etching may cause over-etching or [...] Read more.

The optical properties of indium phosphide (InP) quantum dots (QDs) are significantly influenced by their surface native oxides, which are generally removed by treating InP cores with hydrofluoric acid (HF). Besides the harmful health effects of HF, its etching may cause over-etching or QD size broadening, and surface oxidation can also reoccur rapidly. In the present study, a safer bifunctional metal oleate treatment was developed to simultaneously remove the surface oxide layer and passivate the surface defects for aminophosphine-based InP QDs. Compared to conventional HF etching, the bifunctional metal oleate was able to more efficiently remove the surface oxide of InP cores and effectively preserve the oxide-free surface, leading to a 20% narrower photoluminescence (PL) bandwidth after growing a ZnSe/ZnS shell. The metal oleate treatment is thus considered a greener and safer post-synthetic method to remove InP surface oxide and provide additional passivation to improve the optical properties of aminophosphine-based InP QDs, which could have potential in industrial mass production. Full article

(This article belongs to the Special Issue Recent Advances in Synthesis, Characterization and Applications of Functional Nanoparticles and Quantum Dots)

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8 pages, 2590 KiB

Open AccessArticle

The Construct CoSe₂ on Carbon Nanosheets as High Sensitivity Catalysts for Electro-Catalytic Oxidation of Glucose

by Di Wang and Ying Chang

Nanomaterials 2022, 12(3), 572; https://doi.org/10.3390/nano12030572 - 07 Feb 2022

Cited by 6 | Viewed by 1680

Abstract

Seeking an efficient, sensitive, and stable catalyst is crucial for no-enzyme glucose sen-sors to detect glucose content accurately. Herein, we constructed a catalyst of selenide cobalt (CoSe₂) on carbon nanomaterials by auxiliary pyrolysis of sodium chloride. The CoSe₂ on carbon [...] Read more.

Seeking an efficient, sensitive, and stable catalyst is crucial for no-enzyme glucose sen-sors to detect glucose content accurately. Herein, we constructed a catalyst of selenide cobalt (CoSe₂) on carbon nanomaterials by auxiliary pyrolysis of sodium chloride. The CoSe₂ on carbon nanosheets possesses good selectivity and a wide linear range up to 5 mM. Based on its good detection per-formance, the CoSe₂ nanomaterial is expected to be an emerging catalyst for no-enzyme sensors. Full article

(This article belongs to the Special Issue Transition Metal Complexes and Nanomaterials for Catalysis Application)

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7 pages, 1846 KiB

Open AccessCommunication

Investigation of SERS and Electron Transport Properties of Oligomer Phenylacetyne-3 Trapped in Gold Junctions

by Ziyu Liu, Tingting Hu, Muwafag Osman Adam Balila, Jihui Zhang, Yujin Zhang and Wei Hu

Nanomaterials 2022, 12(3), 571; https://doi.org/10.3390/nano12030571 - 07 Feb 2022

Cited by 1 | Viewed by 1547

Abstract

Molecular junctions hold great potential for future microelectronics and attract people’s attention. Here, we used density functional theory calculations (DFT) to investigate the surface-enhanced Raman spectroscopy (SERS) and electron transport properties of fully π-conjugated oligomers (phenylacetylene)-3 (OPE-3) trapped in gold junctions. The effects [...] Read more.

Molecular junctions hold great potential for future microelectronics and attract people’s attention. Here, we used density functional theory calculations (DFT) to investigate the surface-enhanced Raman spectroscopy (SERS) and electron transport properties of fully π-conjugated oligomers (phenylacetylene)-3 (OPE-3) trapped in gold junctions. The effects of charge injection, an applied electric field, and molecular deformation are considered. We found that a new Raman peak located at around 1400 cm⁻¹ appears after the injection of a charge, which agrees well with the experiment. The external electric field and configurational deformation hardly affect the Raman spectra, indicating that the electronic rather than the geometrical structure determines the Raman response. Nonequilibrium Green’s function (NEGF) calculations show that both the rotation of the benzene groups and an increased electrode distance largely reduced the conductivity of the studied molecular junctions. The present investigations provide valuable information on the effect of charging, electric field, and deformation on the SERS and conductivity of molecular junctions, helping the development of molecular devices. Full article

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

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17 pages, 4265 KiB

Open AccessArticle

Electrical and Optical Characterization of CsPbCl₃ Films around the High-Temperature Phase Transitions

by Mara Bruzzi, Matteo Latino, Naomi Falsini, Nicola Calisi and Anna Vinattieri

Nanomaterials 2022, 12(3), 570; https://doi.org/10.3390/nano12030570 - 07 Feb 2022

Cited by 5 | Viewed by 1756

Abstract

Large-area CsPbCl₃ films in the range 0.1–1.5 μm have been grown by radio frequency (RF)-magnetron sputtering on glass substrates by means of a one-step procedure. Three structural phase transitions have been detected, which are associated with hysteresis behavior in the electrical current [...] Read more.

Large-area CsPbCl₃ films in the range 0.1–1.5 μm have been grown by radio frequency (RF)-magnetron sputtering on glass substrates by means of a one-step procedure. Three structural phase transitions have been detected, which are associated with hysteresis behavior in the electrical current when measured as a function of temperature in the range 295–330 K. Similarly, photoluminescence (PL) experiments in the same temperature range bring evidence of a non-monotonic shift of the PL peak. Detailed electrical characterizations evidenced how phase transitions are not influencing detrimentally the electrical transport properties of the films. In particular, the activation energy (0.6–0.8 eV) extracted from the temperature-dependent film resistivity does not appear to be correlated with phase changes. A non-linear trend of the photoconductivity response as a function of a ultra violet (UV) 365 nm light emitting diode (LED) power has been interpreted considering the presence of an exponential tail of intragap defects. Thermally stimulated currents after exposure with the same LED measured from room temperature up to 370 K showed no evidence of trapping effects due to intragap states on the electrical transport properties at room temperature of the films. As a consequence, measured photocurrents at room temperature appear to be well reproducible and stable in time, which are attractive features for possible future applications in photodetection. Full article

(This article belongs to the Special Issue Optoelectronic Properties and Applications of Nanomaterials)

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19 pages, 3617 KiB

Open AccessArticle

Enhancement of Biofunctionalization by Loading Manuka Oil on TiO₂ Nanotubes

by Seo-Young Kim, Yu-Kyoung Kim, Yong-Seok Jang and Min-Ho Lee

Nanomaterials 2022, 12(3), 569; https://doi.org/10.3390/nano12030569 - 07 Feb 2022

Cited by 4 | Viewed by 1845

Abstract

Metallic implants (mesh) for guided bone regeneration can result in foreign body reactions with surrounding tissues, infection, and inflammatory reactions caused by micro-organisms in the oral cavity after implantation. This study aimed to reduce the possibility of surgical failure caused by microbial infection [...] Read more.

Metallic implants (mesh) for guided bone regeneration can result in foreign body reactions with surrounding tissues, infection, and inflammatory reactions caused by micro-organisms in the oral cavity after implantation. This study aimed to reduce the possibility of surgical failure caused by microbial infection by loading antibacterial manuka oil in a biocompatible nanostructure surface on Ti and to induce stable bone regeneration in the bone defect. The manuka oil from New Zealand consisted of a rich β-triketone chemotype, leptospermone, which showed strong inhibitory effects against several bacteria, even at very low oil concentrations. The TiO₂ nanotubular layer formed by anodization effectively enhanced the surface hydrophilicity, bioactivity, and fast initial bone regeneration. A concentration of manuka oil in the range of 0.02% to less than 1% can have a synergistic effect on antibacterial activity and excellent biocompatibility. A manuka oil coating (especially with a concentration of 0.5%) on the TiO₂ nanotube layer can be expected not only to prevent stenosis of the connective tissue around the mesh and inflammation by microbial infection but also to be effective in stable and rapid bone regeneration. Full article

(This article belongs to the Special Issue Antimicrobial Nano Coatings)

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17 pages, 3502 KiB

Open AccessArticle

Synthesis of a Lignin/Zinc Oxide Hybrid Nanoparticles System and Its Application by Nano-Priming in Maize

by Daniele Del Buono, Francesca Luzi, Ciro Tolisano, Debora Puglia and Alessandro Di Michele

Nanomaterials 2022, 12(3), 568; https://doi.org/10.3390/nano12030568 - 07 Feb 2022

Cited by 13 | Viewed by 3018

Abstract

Nanotechnologies are attracting attention in various scientific fields for their technological and application potential, including their use as bio-activators and nanocarriers in agriculture. This work aimed to synthesize a hybrid material (ZnO@LNP) consisting of lignin nanoparticles containing zinc oxide (4 wt %). The [...] Read more.

Nanotechnologies are attracting attention in various scientific fields for their technological and application potential, including their use as bio-activators and nanocarriers in agriculture. This work aimed to synthesize a hybrid material (ZnO@LNP) consisting of lignin nanoparticles containing zinc oxide (4 wt %). The synthesized ZnO hybrid material showed catalytic effect toward thermal degradation, as evidenced by the TGA investigation, while both spectroscopic and contact angle measurements confirmed a modification of surface hydrophilicity for the lignin nanoparticles due to the presence of hydrophobic zinc oxide. In addition, the antioxidant activity of the ZnO@LNP and the zinc release of this material were evaluated. At the application level, this study proposes for the first time the use of such a hybrid system to prime maize seeds by exploiting the release characteristics of this material. Concerning the dosage applied, ZnO@LNP promoted inductive effects on the early stages of seed development and plant growth and biomass development of young seedlings. In particular, the ZnO@LNP stimulated, in the primed seeds, a higher content of chlorophyll, carotenoids, anthocyanins, total phenols, and a better antioxidant activity, as supported by the lower levels of lipid peroxidation found when compared to the control samples. Full article

(This article belongs to the Section Environmental Nanoscience and Nanotechnology)

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17 pages, 1380 KiB

Open AccessFeature PaperArticle

Surface Architecture Influences the Rigidity of Candida albicans Cells

by Phuc H. Le, Duy H. K. Nguyen, Arturo Aburto Medina, Denver P. Linklater, Christian Loebbe, Russell J. Crawford, Shane MacLaughlin and Elena P. Ivanova

Nanomaterials 2022, 12(3), 567; https://doi.org/10.3390/nano12030567 - 07 Feb 2022

Cited by 9 | Viewed by 2272

Abstract

Atomic force microscopy (AFM) was used to investigate the morphology and rigidity of the opportunistic pathogenic yeast, Candida albicans ATCC 10231, during its attachment to surfaces of three levels of nanoscale surface roughness. Non-polished titanium (npTi), polished titanium (pTi), and glass with respective [...] Read more.

Atomic force microscopy (AFM) was used to investigate the morphology and rigidity of the opportunistic pathogenic yeast, Candida albicans ATCC 10231, during its attachment to surfaces of three levels of nanoscale surface roughness. Non-polished titanium (npTi), polished titanium (pTi), and glass with respective average surface roughness (S_a) values of 389 nm, 14 nm, and 2 nm, kurtosis (S_kur) values of 4, 16, and 4, and skewness (S_skw) values of 1, 4, and 1 were used as representative examples of each type of nanoarchitecture. Thus, npTi and glass surfaces exhibited similar S_skw and S_kur values but highly disparate S_a. C. albicans cells that had attached to the pTi surfaces exhibited a twofold increase in rigidity of 364 kPa compared to those yeast cells attached to the surfaces of npTi (164 kPa) and glass (185 kPa). The increased rigidity of the C. albicans cells on pTi was accompanied by a distinct round morphology, condensed F-actin distribution, lack of cortical actin patches, and the negligible production of cell-associated polymeric substances; however, an elevated production of loose extracellular polymeric substances (EPS) was observed. The differences in the physical response of C. albicans cells attached to the three surfaces suggested that the surface nanoarchitecture (characterized by skewness and kurtosis), rather than average surface roughness, could directly influence the rigidity of the C. albicans cells. This work contributes to the next-generation design of antifungal surfaces by exploiting surface architecture to control the extent of biofilm formation undertaken by yeast pathogens and highlights the importance of performing a detailed surface roughness characterization in order to identify and discriminate between the surface characteristics that may influence the extent of cell attachment and the subsequent behavior of the attached cells. Full article

(This article belongs to the Special Issue Advances in Antibacterial Nanomaterials and Surface)

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16 pages, 1339 KiB

Open AccessEditor’s ChoiceArticle

Influence of Pre-Dispersion Media on the Batch Reactor Dissolution Behavior of Al₂O₃ Coated TiO₂ (NM-104) and Two ZnO (NM-110 and NM-111) Nanomaterials in Biologically Relevant Test Media

by Else Holmfred, Jens J. Sloth, Katrin Loeschner and Keld Alstrup Jensen

Nanomaterials 2022, 12(3), 566; https://doi.org/10.3390/nano12030566 - 07 Feb 2022

Cited by 2 | Viewed by 1789

Abstract

Dissolution plays an important role on pulmonary toxicity of nanomaterials (NMs). The influence of contextual parameters on the results from dissolution testing needs to be identified to improve the generation of relevant and comparable data. This study investigated how pre-dispersions made in water, [...] Read more.

Dissolution plays an important role on pulmonary toxicity of nanomaterials (NMs). The influence of contextual parameters on the results from dissolution testing needs to be identified to improve the generation of relevant and comparable data. This study investigated how pre-dispersions made in water, low-calcium Gamble’s solution, phagolysosomal simulant fluid (PSF), and 0.05% bovine serum albumin (BSA) affected the dissolution of the Al₂O₃ coating on poorly soluble TiO₂ also coated with glycerine (NM-104) and rapidly dissolving uncoated (NM-110) and triethoxycaprylsilane-coated ZnO (NM-111) NMs. Dissolution tests were undertaken and controlled in a stirred batch reactor using low-calcium Gamble’s solution and phagolysosomal simulant fluid a surrogate for the lung-lining and macrophage phagolysosomal fluid, respectively. Pre-dispersion in 0.05% BSA-water showed a significant delay or decrease in the dissolution of Al₂O₃ after testing in both low-calcium Gamble’s solution and PSF. Furthermore, use of the 0.05% BSA pre-dispersion medium influenced the dissolution of ZnO (NM-110) in PSF and ZnO (NM-111) in low-calcium Gamble’s solution and PSF. We hypothesize that BSA forms a protective coating on the particles, which delays or lowers the short-term dissolution of the materials used in this study. Consequently, the type of pre-dispersion medium can affect the results in short-term dissolution testing. Full article

(This article belongs to the Special Issue Engineered Nanomaterials Exposure and Risk Assessment: Occupational Health and Safety)

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11 pages, 2471 KiB

Open AccessArticle

Band Gap Tuning of Films of Undoped ZnO Nanocrystals by Removal of Surface Groups

by Chengjian Zhang, Qiaomiao Tu, Lorraine F. Francis and Uwe R. Kortshagen

Nanomaterials 2022, 12(3), 565; https://doi.org/10.3390/nano12030565 - 07 Feb 2022

Cited by 8 | Viewed by 2695

Abstract

Transparent conductive oxides (TCOs) are widely used in optoelectronic devices such as flat-panel displays and solar cells. A significant optical property of TCOs is their band gap, which determines the spectral range of the transparency of the material. In this study, a tunable [...] Read more.

Transparent conductive oxides (TCOs) are widely used in optoelectronic devices such as flat-panel displays and solar cells. A significant optical property of TCOs is their band gap, which determines the spectral range of the transparency of the material. In this study, a tunable band gap range from 3.35 eV to 3.53 eV is achieved for zinc oxide (ZnO) nanocrystals (NCs) films synthesized by nonthermal plasmas through the removal of surface groups using atomic layer deposition (ALD) coating of Al₂O₃ and intense pulsed light (IPL) photo-doping. The Al₂O₃ coating is found to be necessary for band gap tuning, as it protects ZnO NCs from interactions with the ambient and prevents the formation of electron traps. With respect to the solar spectrum, the 0.18 eV band gap shift would allow ~4.1% more photons to pass through the transparent layer, for instance, into a CH₃NH₃PbX₃ solar cell beneath. The mechanism of band gap tuning via photo-doping appears to be related to a combination of the Burstein–Moss (BM) and band gap renormalization (BGN) effects due to the significant number of electrons released from trap states after the removal of hydroxyl groups. The BM effect shifts the conduction band edge and enlarges the band gap, while the BGN effect narrows the band gap. Full article

(This article belongs to the Section Nanocomposite Materials)

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11 pages, 3071 KiB

Open AccessArticle

High Power and Large-Energy Pulse Generation in an Erbium-Doped Fiber Laser by a Ferromagnetic Insulator-Cr₂Si₂Te₆ Saturable Absorber

by Zhifeng Hong, Xiwen Jiang, Meixia Zhang, Huanian Zhang and Xiaojuan Liu

Nanomaterials 2022, 12(3), 564; https://doi.org/10.3390/nano12030564 - 07 Feb 2022

Cited by 6 | Viewed by 2064

Abstract

Large-energy mode-locked fiber lasers are extensively studied due to their indispensable use in various fields and applications. Recently, ferromagnetic insulators have attracted tremendous research interest in ultra-fast photonics because of their unique ferromagnetic properties and typical layered structure. In our work, Cr₂ [...] Read more.

Large-energy mode-locked fiber lasers are extensively studied due to their indispensable use in various fields and applications. Recently, ferromagnetic insulators have attracted tremendous research interest in ultra-fast photonics because of their unique ferromagnetic properties and typical layered structure. In our work, Cr₂Si₂Te₆ nanosheets are prepared and utilized as a saturable absorber (SA) in a large-energy mode-locked erbium-doped fiber (EDF) laser. With a total cavity length of 240 m, a stable mode-locked operation characterized by maximum pulse energy as high as 244.76 nJ with a repetition rate of 847.64 kHz is achieved. When the cavity length is extended to 390 m, the output maximum pulse energy is successfully scaled up to 325.50 nJ. To our knowledge, this is the largest pulse energy and highest output power level to be achieved in mode-locked fiber lasers by two-dimensional (2D) material saturable absorbers (SAs) so far. This work not only makes a forward step to the investigation of the generation of large-energy pulses in mode-locked fiber lasers but also fully proves that the ferromagnetic insulator-Cr₂Si₂Te₆ possesses an excellent nonlinear absorption property, antioxidant capacity in ambient conditions, as well as outstanding thermal stability, which enriches our insight into 2D materials. Full article

(This article belongs to the Topic Advances and Applications of 2D Materials)

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16 pages, 3439 KiB

Open AccessArticle

Dual Application of Waste Grape Skin for Photosensitizers and Counter Electrodes of Dye-Sensitized Solar Cells

by Yuan Yuan and Caichao Wan

Nanomaterials 2022, 12(3), 563; https://doi.org/10.3390/nano12030563 - 07 Feb 2022

Cited by 2 | Viewed by 1781

Abstract

Dye-sensitized solar cells (DSSCs), a powerful system to convert solar energy into electrical energy, suffer from the high cost of the Pt counter electrode and photosensitizer. In this study, the dual application of waste grape skin is realized by employing the grape skin [...] Read more.

Dye-sensitized solar cells (DSSCs), a powerful system to convert solar energy into electrical energy, suffer from the high cost of the Pt counter electrode and photosensitizer. In this study, the dual application of waste grape skin is realized by employing the grape skin and its extract as the carbon source of the carbon-based counter electrode and photosensitizer, respectively. The ultraviolet–visible absorption and Fourier transform infrared spectroscopy verify the strong binding between the dye molecules (anthocyanins) in the extract and the TiO₂ nanostructure on the photoanode, contributing to a high open-circuit voltage (V_OC) value of 0.48 V for the assembled DSSC device. Moreover, the waste grape skin was subjected to pyrolysis and KOH activation and the resultant KOH-activated grape skin-derived carbon (KA-GSDC) possesses a large surface area (620.79 m² g⁻¹) and hierarchical porous structure, leading to a high short circuit current density (J_SC) value of 1.52 mA cm⁻². Additionally, the electrochemical impedance spectroscopy reveals the efficient electron transfer between the electrocatalyst and the redox couples and the slow recombination of electrolytic cations and the photo-induced electrons in the conduction band of TiO₂. These merits endow the DSSC with a high photovoltaic efficiency of 0.48%, which is 33% higher than that of a common Pt-based DSSC (0.36%). The efficiency is also competitive, compared with some congeneric DSSCs based on other natural dyes and Pt counter electrode. The result confirms the feasibility of achieving the high-value application of waste grape skin in DSSCs. Full article

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23 pages, 2860 KiB

Open AccessArticle

Biomimetic Citrate-Coated Luminescent Apatite Nanoplatforms for Diclofenac Delivery in Inflammatory Environments

by Sandra Maria Cano Plá, Annarita D’Urso, Jorge Fernando Fernández-Sánchez, Donato Colangelo, Duane Choquesillo-Lazarte, Riccardo Ferracini, Michela Bosetti, Maria Prat and Jaime Gómez-Morales

Nanomaterials 2022, 12(3), 562; https://doi.org/10.3390/nano12030562 - 06 Feb 2022

Cited by 3 | Viewed by 2047

Abstract

Luminescent nanoparticles are innovative tools for medicine, allowing the imaging of cells and tissues, and, at the same time, carrying and releasing different types of molecules. We explored and compared the loading/release ability of diclofenac (COX-2 antagonist), in both undoped- and luminescent Terbium [...] Read more.

Luminescent nanoparticles are innovative tools for medicine, allowing the imaging of cells and tissues, and, at the same time, carrying and releasing different types of molecules. We explored and compared the loading/release ability of diclofenac (COX-2 antagonist), in both undoped- and luminescent Terbium³⁺ (Tb³⁺)-doped citrate-coated carbonated apatite nanoparticles at different temperatures (25, 37, 40 °C) and pHs (7.4, 5.2). The cytocompatibility was evaluated on two osteosarcoma cell lines and primary human osteoblasts. Biological effects of diclofenac-loaded-nanoparticles were monitored in an in vitro osteoblast’s cytokine–induced inflammation model by evaluating COX-2 mRNA expression and production of PGE₂. Adsorption isotherms fitted the multilayer Langmuir-Freundlich model. The maximum adsorbed amounts at 37 °C were higher than at 25 °C, and particularly when using the Tb³⁺ -doped particles. Diclofenac-release efficiencies were higher at pH 5.2, a condition simulating a local inflammation. The luminescence properties of diclofenac-loaded Tb³⁺ -doped particles were affected by pH, being the relative luminescence intensity higher at pH 5.2 and the luminescence lifetime higher at pH 7.4, but not influenced either by the temperature or by the diclofenac-loaded amount. Both undoped and Tb³⁺-doped nanoparticles were cytocompatible. In addition, diclofenac release increased COX-2 mRNA expression and decreased PGE₂ production in an in vitro inflammation model. These findings evidence the potential of these nanoparticles for osteo-localized delivery of anti-inflammatory drugs and the possibility to localize the inflammation, characterized by a decrease in pH, by changes in luminescence. Full article

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14 pages, 2436 KiB

Open AccessArticle

Boosting CdS Photocatalytic Activity for Hydrogen Evolution in Formic Acid Solution by P Doping and MoS₂ Photodeposition

by Junchen Liu, Haoran Huang, Chunyu Ge, Zhenghui Wang, Xunfu Zhou and Yueping Fang

Nanomaterials 2022, 12(3), 561; https://doi.org/10.3390/nano12030561 - 06 Feb 2022

Cited by 7 | Viewed by 2344

Abstract

Formic acid is an appealing hydrogen storage material. In order to rapidly produce hydrogen from formic acid under relatively mild conditions, high-efficiency and stable photocatalytic systems are of great significance to prompt hydrogen (H₂) evolution from formic acid. In this paper, [...] Read more.

Formic acid is an appealing hydrogen storage material. In order to rapidly produce hydrogen from formic acid under relatively mild conditions, high-efficiency and stable photocatalytic systems are of great significance to prompt hydrogen (H₂) evolution from formic acid. In this paper, an efficient and stable photocatalytic system (CdS/P/MoS₂) for H₂ production from formic acid is successfully constructed by elemental P doping of CdS nanorods combining with in situ photodeposition of MoS₂. In this system, P doping reduces the band gap of CdS for enhanced light absorption, as well as promoting the separation of photogenerated charge carriers. More importantly, MoS₂ nanoparticles decorated on P-doped CdS nanorods can play as noble-metal-free cocatalysts, which increase the light adsorption, facilitate the charge transfer and effectively accelerate the hydrogen evolution reaction. Consequently, the apparent quantum efficiency (AQE) of the designed CdS/P/MoS₂ is up to 6.39% at 420 nm, while the H₂ evolution rate is boosted to 68.89 mmol·g⁻¹·h⁻¹, which is 10 times higher than that of pristine CdS. This study could provide an alternative strategy for the development of competitive CdS-based photocatalysts as well as noble-metal-free photocatalytic systems toward efficient hydrogen production. Full article

(This article belongs to the Section Energy and Catalysis)

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10 pages, 2542 KiB

Open AccessArticle

Preparation of Bimodal Silver Nanoparticle Ink Based on Liquid Phase Reduction Method

by Zhiheng Yu, Tiancheng Zhang, Kaifeng Li, Fengli Huang and Chengli Tang

Nanomaterials 2022, 12(3), 560; https://doi.org/10.3390/nano12030560 - 06 Feb 2022

Cited by 16 | Viewed by 2127

Abstract

Improving the conductivity of metal particle inks is a hot topic of scientific research. In this paper, a method for preparing metal-filled particles was proposed. By adding filled particles to the ink, the size distribution of particles could be changed to form a [...] Read more.

Improving the conductivity of metal particle inks is a hot topic of scientific research. In this paper, a method for preparing metal-filled particles was proposed. By adding filled particles to the ink, the size distribution of particles could be changed to form a bimodal distribution structure in accordance with Horsfield’s stacking model. The filling particles had small volume and good fluidity, which could fill the gaps between the particles after printing and improve its electrical conductivity without significantly changing the metal solid content in the ink. Experimental results show that the silver content of the ink slightly increased from 15 wt% to 16.5 wt% after adding filled particles. However, the conductivity of the ink was significantly improved, and after sintering, the resistivity of the ink decreased from 70.2 μΩ∙cm to 31.2 μΩ∙cm. In addition, the filling particles prepared by this method is simple and has a high material utilization rate, which could be applied to the preparation of other kinds of metal particle inks. Full article

(This article belongs to the Special Issue State-of-the-Art Nanophotonic and Optical Nanomaterials in China)

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11 pages, 6538 KiB

Open AccessArticle

Light Absorption Enhancement and Laser-Induced Damage Ability Improvement of Aluminum Alloy 6061 with Non-Porous Alumina/CdSe@Al₂O₃/SiO₂ Functional Gradient Films

by Jiaheng Yin, Lihua Lu, Yaowen Cui, Yongzhi Cao and Yunlong Du

Nanomaterials 2022, 12(3), 559; https://doi.org/10.3390/nano12030559 - 06 Feb 2022

Viewed by 1665

Abstract

Numerical calculations of ultraviolet to near-infrared absorption spectra by cadmium selenide quantum dots (CdSe QDs) doped in anodic aluminum oxide pores were performed using a finite-difference time-domain model. The height, diameter, and periodic spacing of the pores were optimized. Light absorption by the [...] Read more.

Numerical calculations of ultraviolet to near-infrared absorption spectra by cadmium selenide quantum dots (CdSe QDs) doped in anodic aluminum oxide pores were performed using a finite-difference time-domain model. The height, diameter, and periodic spacing of the pores were optimized. Light absorption by the dots was enhanced by increasing the height and decreasing the diameter of the pores. When the height was less than 1 μm, visible light absorption was enhanced as the spacing was reduced from 400 nm to 100 nm. No enhancement was observed for heights greater than 6 μm. Finally, the optical mode coupling of the aluminum oxide and the quantum dots was enhanced by decreasing the pore diameter and periodic spacing and increasing the height. Laser ablation verified light absorption enhancement by the CdSe QDs. The experiments verified the improvement in the laser-induced damage ability with a nanosecond laser at a wavelength of 355 nm after aluminum alloy 6061 was coated with functional films and fabricated based on numerical calculations. Full article

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11 pages, 3766 KiB

Open AccessFeature PaperArticle

Efficient Hydrogen Evolution Reaction with Bulk and Nanostructured Mitrofanovite Pt₃Te₄

by Gianluca D’Olimpio, Lixue Zhang, Chia-Nung Kuo, Daniel Farias, Luca Ottaviano, Chin Shan Lue, Jun Fujii, Ivana Vobornik, Amit Agarwal, Piero Torelli, Danil W. Boukhvalov and Antonio Politano

Nanomaterials 2022, 12(3), 558; https://doi.org/10.3390/nano12030558 - 06 Feb 2022

Cited by 3 | Viewed by 2578

Abstract

Here, we discuss the key features of electrocatalysis with mitrofanovite (Pt₃Te₄), a recently discovered mineral with superb performances in hydrogen evolution reaction. Mitrofanovite is a layered topological metal with spin-polarized topological surface states with potential applications for spintronics. However, [...] Read more.

Here, we discuss the key features of electrocatalysis with mitrofanovite (Pt₃Te₄), a recently discovered mineral with superb performances in hydrogen evolution reaction. Mitrofanovite is a layered topological metal with spin-polarized topological surface states with potential applications for spintronics. However, mitrofanovite is also an exceptional platform for electrocatalysis, with costs of the electrodes suppressed by 47% owing to the partial replacement of Pt with Te. Remarkably, the Tafel slope in nanostructured mitrofanovite is just 33 mV/dec, while reduced mitrofanovite has the same Tafel slope (36 mV/dec) as state-of-the-art electrodes of pure Pt. Mitrofanovite also affords surface stability and robustness to CO poisoning. Accordingly, these findings pave the way for the advent of mitrofanovite for large-scale hydrogen production. Full article

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

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17 pages, 5041 KiB

Open AccessArticle

Enhancement of Bacterial Anti-Adhesion Properties on Robust PDMS Micro-Structure Using a Simple Flame Treatment Method

by Nongluck Houngkamhang, Ploymanee Chaisawat, Waisaree Joksathit, Sutichai Samart, Sutee Chutipaijit, Suphichaya Radomyos, Pawasuth Saengdee and Nithi Atthi

Nanomaterials 2022, 12(3), 557; https://doi.org/10.3390/nano12030557 - 06 Feb 2022

Cited by 4 | Viewed by 2516

Abstract

Biofilm-associated infections caused by an accumulation of micro-organisms and pathogens significantly impact the environment, health risks, and the global economy. Currently, a non-biocide-releasing superhydrophobic surface is a potential solution for antibacterial purposes. This research demonstrated a well-designed robust polydimethylsiloxane (PDMS) micro-structure and a [...] Read more.

Biofilm-associated infections caused by an accumulation of micro-organisms and pathogens significantly impact the environment, health risks, and the global economy. Currently, a non-biocide-releasing superhydrophobic surface is a potential solution for antibacterial purposes. This research demonstrated a well-designed robust polydimethylsiloxane (PDMS) micro-structure and a flame treatment process with improved hydrophobicity and bacterial anti-adhesion properties. After the flame treatment at 700 ± 20 °C for 15 s, unique flower-petal re-entrant nano-structures were formed on pillars (PIL-F, width: 1.87 ± 0.30 μm, height: 7.76 ± 0.13 μm, aspect ratio (A.R.): 4.14) and circular rings with eight stripe supporters (C-RESS-F, width: 0.50 ± 0.04 μm, height: 3.55 ± 0.11 μm, A.R.: 7.10) PDMS micro-patterns. The water contact angle (WCA) and ethylene glycol contact angle (EGCA) of flame-treated flat-PDMS (FLT-F), PIL–F, and C–RESS-F patterns were (133.9 ± 3.8°, 128.6 ± 5.3°), (156.1 ± 1.5°, 151.5 ± 2.1°), and (146.3 ± 3.5°, 150.7 ± 1.8°), respectively. The Escherichia coli adhesion on the C-RESS-F micro-pattern with hydrophobicity and superoleophobicity was 42.6%, 31.8%, and 2.9% less than FLT-F, PIL-F, and Teflon surfaces. Therefore, the flame-treated C-RESS-F pattern is one of the promising bacterial anti-adhesion micro-structures in practical utilization for various applications. Full article

(This article belongs to the Special Issue Advance in Nanoimprint Technology)

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12 pages, 3065 KiB

Open AccessArticle

Theoretical Study on the Electronic Structure and Magnetic Properties Regulation of Janus Structure of M’MCO₂ 2D MXenes

by Panpan Gao, Minhui Song, Xiaoxu Wang, Qing Liu, Shizhen He, Ye Su and Ping Qian

Nanomaterials 2022, 12(3), 556; https://doi.org/10.3390/nano12030556 - 06 Feb 2022

Cited by 7 | Viewed by 2205

Abstract

Motivated by the recent successful synthesis of Janus monolayer of transition metal (TM) dichalcogenides, MXenes with Janus structures are worthy of further study, concerning its electronic structure and magnetic properties. Here, we study the effect of different transition metal atoms on the structure [...] Read more.

Motivated by the recent successful synthesis of Janus monolayer of transition metal (TM) dichalcogenides, MXenes with Janus structures are worthy of further study, concerning its electronic structure and magnetic properties. Here, we study the effect of different transition metal atoms on the structure stability and magnetic and electronic properties of M’MCO₂ (M’ and M = V, Cr and Mn). The result shows the output magnetic moment is contributed mainly by the d orbitals of the V, Cr, and Mn atoms. The total magnetic moments of ferromagnetic (FM) configuration and antiferromagnetic (AFM) configuration are affected by coupling types. FM has a large magnetic moment output, while the total magnetic moments of AFM2’s (intralayer AFM/interlayer FM) configuration and AFM3’s (interlayer AFM/intralayer AFM) configuration are close to 0. The band gap widths of VCrCO₂, VMnCO₂, CrMnCO₂, V₂CO₂, and Cr₂CO₂ are no more than 0.02 eV, showing metallic properties, while Mn₂CO₂ is a semiconductor with a 0.7071 eV band gap width. Janus MXenes can regulate the size of band gap, magnetic ground state, and output net magnetic moment. This work achieves the control of the magnetic properties of the available 2D materials, and provides theoretical guidance for the extensive design of novel Janus MXene materials. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Electrochemical Energy Conversion and Storage)

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11 pages, 4384 KiB

Open AccessArticle

Enhancement of Self-Collimation Effect in Photonic Crystal Membranes Using Hyperbolic Metamaterials

by Yaoxian Zheng, Qiong Wang, Mi Lin and Zhengbiao Ouyang

Nanomaterials 2022, 12(3), 555; https://doi.org/10.3390/nano12030555 - 06 Feb 2022

Cited by 6 | Viewed by 1694

Abstract

Hyperbolic metamaterials (HMMs) exhibit high tunability in photonic devices. This study numerically investigates light propagation in photonic crystal (PhC) membranes containing HMMs. The proposed HMM PhC membranes contain square HMM rods, which comprise dielectric (Si) and metallic (Ag) layers. Owing to their property [...] Read more.

Hyperbolic metamaterials (HMMs) exhibit high tunability in photonic devices. This study numerically investigates light propagation in photonic crystal (PhC) membranes containing HMMs. The proposed HMM PhC membranes contain square HMM rods, which comprise dielectric (Si) and metallic (Ag) layers. Owing to their property of subwavelength field localization, HMMs can be applied to PhCs to improve tunability and thus enhance the self-collimation (SC) effect of PhCs. The SC points were obtained in the second HMM PhC band, wherein the nearby dispersion curves change significantly. In addition, the effect of the HMM filling factor (i.e., the ratio of the metal-layer to unit-cell thicknesses) on the SC point frequency is studied. Finally, we demonstrate the efficient control of beam behaviors using HMM PhC membranes while considering the nonlinearity of Ag. The findings of this study confirm that high-performance HMM PhC membranes can be employed in nonlinear all-optical switches, filters, tunable lenses, and other integrated optical devices. Full article

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

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17 pages, 3305 KiB

Open AccessArticle

Numerical Simulation of Temperature Variations during the Application of Safety Protocols in Magnetic Particle Hyperthermia

by Gerasimos Pefanis, Nikolaos Maniotis, Aikaterini-Rafailia Tsiapla, Antonios Makridis, Theodoros Samaras and Mavroeidis Angelakeris

Nanomaterials 2022, 12(3), 554; https://doi.org/10.3390/nano12030554 - 06 Feb 2022

Cited by 6 | Viewed by 1809

Abstract

Unavoidably, magnetic particle hyperthermia is limited by the unwanted heating of the neighboring healthy tissues, due to the generation of eddy currents. Eddy currents naturally occur, due to the applied alternating magnetic field, which is used to excite the nanoparticles in the tumor [...] Read more.

Unavoidably, magnetic particle hyperthermia is limited by the unwanted heating of the neighboring healthy tissues, due to the generation of eddy currents. Eddy currents naturally occur, due to the applied alternating magnetic field, which is used to excite the nanoparticles in the tumor and, therefore, restrict treatment efficiency in clinical application. In this work, we present two simply applicable methods for reducing the heating of healthy tissues by simultaneously keeping the heating of cancer tissue, due to magnetic nanoparticles, at an adequate level. The first method involves moving the induction coil relative to the phantom tissue during the exposure. More specifically, the coil is moving symmetrically—left and right relative to the specimen—in a bidirectional fashion. In this case, the impact of the maximum distance (2–8 cm) between the coil and the phantom is investigated. In the second method, the magnetic field is applied intermittently (in an ON/OFF pulsed mode), instead of the continuous field mode usually employed. The parameters of the intermittent field mode, such as the time intervals (ON time and OFF time) and field amplitude, are optimized based on the numerical assessment of temperature increase in healthy tissue and cancer tissue phantoms. Different ON and OFF times were tested in the range of 25–100 s and 50–200 s, respectively, and under variable field amplitudes (45–70 mT). In all the protocols studied here, the main goal is to generate inside the cancer tissue phantom the maximum temperature increase, possible (preferably within the magnetic hyperthermia window of 4–8 °C), while restricting the temperature increase in the healthy tissue phantom to below 4 °C, signifying eddy current mitigation. Full article

(This article belongs to the Special Issue Biomedical Applications of Anisotropic Magnetic Nanoparticles)

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18 pages, 4864 KiB

Open AccessArticle

Enhanced Li-Ion Rate Capability and Stable Efficiency Enabled by MoSe₂ Nanosheets in Polymer-Derived Silicon Oxycarbide Fiber Electrodes

by Sonjoy Dey, Shakir Bin Mujib and Gurpreet Singh

Nanomaterials 2022, 12(3), 553; https://doi.org/10.3390/nano12030553 - 06 Feb 2022

Cited by 12 | Viewed by 2667

Abstract

Transition metal dichalcogenides (TMDs) such as MoSe₂ have continued to generate interest in the engineering community because of their unique layered morphology—the strong in-plane chemical bonding between transition metal atoms sandwiched between two chalcogen atoms and the weak physical attraction between adjacent [...] Read more.

Transition metal dichalcogenides (TMDs) such as MoSe₂ have continued to generate interest in the engineering community because of their unique layered morphology—the strong in-plane chemical bonding between transition metal atoms sandwiched between two chalcogen atoms and the weak physical attraction between adjacent TMD layers provides them with not only chemical versatility but also a range of electronic, optical, and chemical properties that can be unlocked upon exfoliation into individual TMD layers. Such a layered morphology is particularly suitable for ion intercalation as well as for conversion chemistry with alkali metal ions for electrochemical energy storage applications. Nonetheless, host of issues including fast capacity decay arising due to volume changes and from TMD’s degradation reaction with electrolyte at low discharge potentials have restricted use in commercial batteries. One approach to overcome barriers associated with TMDs’ chemical stability functionalization of TMD surfaces by chemically robust precursor-derived ceramics or PDC materials, such as silicon oxycarbide (SiOC). SiOC-functionalized TMDs have shown to curb capacity degradation in TMD and improve long term cycling as Li-ion battery (LIBs) electrodes. Herein, we report synthesis of such a composite in which MoSe₂ nanosheets are in SiOC matrix in a self-standing fiber mat configuration. This was achieved via electrospinning of TMD nanosheets suspended in pre-ceramic polymer followed by high temperature pyrolysis. Morphology and chemical composition of synthesized material was established by use of electron microscopy and spectroscopic technique. When tested as LIB electrode, the SiOC/MoSe₂ fiber mats showed improved cycling stability over neat MoSe₂ and neat SiOC electrodes. The freestanding composite electrode delivered a high charge capacity of 586 mAh g⁻¹_electrode with an initial coulombic efficiency of 58%. The composite electrode also showed good cycling stability over SiOC fiber mat electrode for over 100 cycles. Full article

(This article belongs to the Special Issue Electrochemical Properties and Applications of Ceramic Nanomaterials)

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47 pages, 6869 KiB

Open AccessReview

How the Physicochemical Properties of Manufactured Nanomaterials Affect Their Performance in Dispersion and Their Applications in Biomedicine: A Review

by Spiros H. Anastasiadis, Kiriaki Chrissopoulou, Emmanuel Stratakis, Paraskevi Kavatzikidou, Georgia Kaklamani and Anthi Ranella

Nanomaterials 2022, 12(3), 552; https://doi.org/10.3390/nano12030552 - 06 Feb 2022

Cited by 31 | Viewed by 4120

Abstract

The growth in novel synthesis methods and in the range of possible applications has led to the development of a large variety of manufactured nanomaterials (MNMs), which can, in principle, come into close contact with humans and be dispersed in the environment. The [...] Read more.

The growth in novel synthesis methods and in the range of possible applications has led to the development of a large variety of manufactured nanomaterials (MNMs), which can, in principle, come into close contact with humans and be dispersed in the environment. The nanomaterials interact with the surrounding environment, this being either the proteins and/or cells in a biological medium or the matrix constituent in a dispersion or composite, and an interface is formed whose properties depend on the physicochemical interactions and on colloidal forces. The development of predictive relationships between the characteristics of individual MNMs and their potential practical use critically depends on how the key parameters of MNMs, such as the size, shape, surface chemistry, surface charge, surface coating, etc., affect the behavior in a test medium. This relationship between the biophysicochemical properties of the MNMs and their practical use is defined as their functionality; understanding this relationship is very important for the safe use of these nanomaterials. In this mini review, we attempt to identify the key parameters of nanomaterials and establish a relationship between these and the main MNM functionalities, which would play an important role in the safe design of MNMs; thus, reducing the possible health and environmental risks early on in the innovation process, when the functionality of a nanomaterial and its toxicity/safety will be taken into account in an integrated way. This review aims to contribute to a decision tree strategy for the optimum design of safe nanomaterials, by going beyond the compromise between functionality and safety. Full article

(This article belongs to the Special Issue Tuning the Physicochemical Properties of Nanostructured Materials through Advanced Preparation Methods)

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19 pages, 6317 KiB

Open AccessArticle

Influence of Cryomilling on Crystallite Size of Aluminum Powder and Spark Plasma Sintered Component

by Amanendra K. Kushwaha, Raven Maccione, Merbin John, Sridhar Lanka, Manoranjan Misra and Pradeep L. Menezes

Nanomaterials 2022, 12(3), 551; https://doi.org/10.3390/nano12030551 - 06 Feb 2022

Cited by 11 | Viewed by 2172

Abstract

The present investigation aims to develop nanocrystalline (NC) pure aluminum powders using cryomilling technique and manufacture bulk components using spark plasma sintering (SPS). The cryomilling was performed on pure Al powders for 2, 6, and 8 h. The cryomilled powders were then consolidated [...] Read more.

The present investigation aims to develop nanocrystalline (NC) pure aluminum powders using cryomilling technique and manufacture bulk components using spark plasma sintering (SPS). The cryomilling was performed on pure Al powders for 2, 6, and 8 h. The cryomilled powders were then consolidated using SPS to produce bulk components. The particle morphology and crystallite size of the powders and the bulk SPS components were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that the crystallite size of pure Al powders decreases with increased cryomilling time. The results also showed that the SPS at elevated temperatures resulted in a slight increase in crystallite size, however, the changes were insignificant. The mechanical properties of the bulk components were determined using a Vickers microhardness tester. The hardness of the cryomilled SPS component was determined to be three times higher than that of the unmilled SPS component. The mechanism for the reduction in crystallite size with increasing cryomilling time is discussed. This fundamental study provides an insight into the development of bulk nanomaterials with superior mechanical properties for automotive, aerospace, marine, and nuclear applications. Full article

(This article belongs to the Special Issue Crystallization and Assembly-Driven Nanostructures for Energy, Electronics, Environment and Emerging Applications)

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20 pages, 5637 KiB

Open AccessEditor’s ChoiceArticle

New Epoxy Thermosets Organic-Inorganic Hybrid Nanomaterials Derived from Imidazolium Ionic Liquid Monomers and POSS^®Ph

by Houssém Chabane, Sébastien Livi, Jannick Duchet-Rumeau and Jean-François Gérard

Nanomaterials 2022, 12(3), 550; https://doi.org/10.3390/nano12030550 - 06 Feb 2022

Cited by 1 | Viewed by 2018

Abstract

New epoxy-amine networks issue from epoxydized imidazolium ionic liquid monomers (ILMs) and isophorone diamine (IPD) were modified for the first time by incorporating unmodified trisilanol phenyl POSS^® (POSS^®Ph-triol) and two ionic liquid-modified POSS^®Ph (IL-g-POSS^®Ph) having chloride (Cl [...] Read more.

New epoxy-amine networks issue from epoxydized imidazolium ionic liquid monomers (ILMs) and isophorone diamine (IPD) were modified for the first time by incorporating unmodified trisilanol phenyl POSS^® (POSS^®Ph-triol) and two ionic liquid-modified POSS^®Ph (IL-g-POSS^®Ph) having chloride (Cl⁻) and bis-trifluoromethanesulfonimidate (NTf₂⁻) counter anions. Then, 5 wt.% of unmodified and IL-modified POSS^®Ph were introduced in order to develop new solid electrolytes. First, a homogeneous dispersion of the POSS^®Ph aggregates (diameters from 80 to 400 nm) into epoxy networks was observed. As a consequence, ILM/IPD networks with glass transition temperatures between 45 and 71 °C combined with an enhancement of the thermal stability (>380 °C) were prepared. Moreover, a significant increase of the hydrophobic character and high oil repellency of the network surfaces were obtained by using IL-g-POSS^®Ph (19–20 mJ.m⁻²), opening up promising prospects for surface coating applications. Finally, these new epoxy networks exhibited outstanding high ionic conductivities (from 3.4 × 10⁻⁸ to 6.8 × 10⁻² S.m⁻¹) combined with an increase in permitivity. Full article

(This article belongs to the Special Issue Ionic Interfaces in Smart Polymer Materials)

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10 pages, 1823 KiB

Open AccessArticle

Preparation, Characterization, and Evaluation of Pyraclostrobin Nanocapsules by In Situ Polymerization

by Bingna Huang, Feifei Chen, Yue Shen, Changcheng An, Ningjun Li, Jiajun Jiang, Chong Wang, Changjiao Sun, Xiang Zhao, Bo Cui, Zhanghua Zeng, Haixin Cui and Yan Wang

Nanomaterials 2022, 12(3), 549; https://doi.org/10.3390/nano12030549 - 05 Feb 2022

Cited by 5 | Viewed by 2125

Abstract

In this study, pyraclostrobin nanocapsules were prepared by in situ polymerization with urea–formaldehyde resin as a wall material. The effects of different emulsifiers, emulsifier concentrations, and solvents on the physicochemical properties of pyraclostrobin nanocapsules were investigated. Solvesso™ 100 was selected as the solvent, [...] Read more.

In this study, pyraclostrobin nanocapsules were prepared by in situ polymerization with urea–formaldehyde resin as a wall material. The effects of different emulsifiers, emulsifier concentrations, and solvents on the physicochemical properties of pyraclostrobin nanocapsules were investigated. Solvesso™ 100 was selected as the solvent, and Emulsifier 600# was used as the emulsifier, which accounted for 5% of the aqueous phase system, to prepare pyraclostrobin nanocapsules with excellent physical and chemical properties. The particle size, ζ potential, and morphology of the nanocapsules were characterized by a particle size analyzer and transmission electron microscope. The nanocapsules were analyzed by Fourier-transform infrared spectroscopy, and the loading content and sustained release properties of the nanocapsules were measured. The results show that the size of the prepared nanocapsules was 261.87 nm, and the polydispersity index (PDI) was 0.12, presenting a uniform spherical appearance. The loading content of the pyraclostrobin nanocapsules was 14.3%, and their cumulative release rate was 70.99% at 250 h, providing better efficacy and sustainability compared with the pyraclostrobin commercial formulation. Full article

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