Applied Sciences

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15 pages, 32156 KiB

Open AccessArticle

Terminalia ferdinandiana (Kakadu Plum)-Mediated Bio-Synthesized ZnO Nanoparticles for Enhancement of Anti-Lung Cancer and Anti-Inflammatory Activities

by Zelika Mega Ramadhania, Jinnatun Nahar, Jong Chan Ahn, Dong Uk Yang, Jong Hak Kim, Dong Wook Lee, Byoung Man Kong, Ramya Mathiyalagan, Esrat Jahan Rupa, Reshmi Akter, Deok Chun Yang, Se Chan Kang and Gi-Young Kwak

Appl. Sci. 2022, 12(6), 3081; https://doi.org/10.3390/app12063081 - 17 Mar 2022

Cited by 9 | Viewed by 3342

Abstract

Terminalia ferdinandiana (Kakadu plum) is an Australian native plant that has recently gained the attention of researchers due to its highly antioxidant compounds that have substantial health benefits. To raise the value, in this study, it is used for the first time to [...] Read more.

Terminalia ferdinandiana (Kakadu plum) is an Australian native plant that has recently gained the attention of researchers due to its highly antioxidant compounds that have substantial health benefits. To raise the value, in this study, it is used for the first time to synthesize ZnO nanoparticles for anti-lung cancer and anti-inflammatory activities. The formation of KKD-ZnO-NPs (ZnO particles obtained from Kakadu plum) were confirmed using a UV-Visible spectrophotometer. Fourier transform infrared (FTIR) spectroscopy analysis confirmed the functional groups that are responsible for the stabilization and capping of KKD-ZnO-NPs. The flower shape of the synthesized KKD-ZnO-NPs was confirmed by field emission-scanning electron microscopy (FE-SEM) and field emission-transmission electron microscopy (FE-TEM) analyses. The crystallites were highly pure and had an average size of 21.89 nm as measured by X-ray diffraction (XRD). The dynamic light scattering (DLS) revealed size range of polydisperse KKD-ZnO-NPs was 676.65 ± 47.23 nm with a PDI of 0.41 ± 0.0634. Furthermore, the potential cytotoxicity was investigated in vitro against human lung cancer cell lines (A549) and Raw 264.7 Murine macrophages cells as normal cells to ensure safety purposes using MTT assay. Thus, KKD-ZnO-NPs showed prominent cytotoxicity against human lung adenocarcinoma (A549) at 10 μg/mL and increased reactive oxygen species (ROS) production as well, which could promote toxicity to cancer cells. Moreover, upregulation of p53 and downregulation of bcl2 gene expression as apoptosis regulators were confirmed via RT-PCR. In addition, KKD-ZnO-NPs possess a similar capacity of reduction in proinflammatory-nitric oxide (NO) production when compared to the L-NMMA as inflammation’s inhibitor, indicating anti-inflammatory potential. Incorporation of Kakadu plum extract as reducing and stabilizing agents enabled the green synthesis of flower-shaped KKD-ZnO-NPs that could be an initiative development of effective cancer therapy drug. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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13 pages, 4195 KiB

Open AccessArticle

Preparation of Magnetically Driven Nickel Phosphide Nanowires and Their Electrochemical Properties

by Hye-Won Kim and Heon-Cheol Shin

Appl. Sci. 2022, 12(1), 49; https://doi.org/10.3390/app12010049 - 21 Dec 2021

Viewed by 2567

Abstract

In this study, nickel phosphide nanowires with various structures and compositions were fabricated for the first time via magnetically-assisted liquid phase synthesis. The curvature and aspect ratio of the nanowires largely depended on the strength of the magnetic field applied during synthesis. Their [...] Read more.

In this study, nickel phosphide nanowires with various structures and compositions were fabricated for the first time via magnetically-assisted liquid phase synthesis. The curvature and aspect ratio of the nanowires largely depended on the strength of the magnetic field applied during synthesis. Their phosphorus content together with the morphology were significantly modified according to the pH and reducing agent concentration. Nanowires with different structures and phosphorus contents were preliminarily tested for their capabilities to serve in general electrochemical applications. The degree of reaction (i.e., amount of reaction charge) increased with increases in the reaction area and phosphorus content of the nanowires. The rate characteristics of the reaction showed a peculiar increasing trend for a small reaction surface area and low phosphorus content. A change in the ohmic overpotential according to the nanowire curvature (aspect ratio) and porosity was suggested to be the reason for this unusual trend. Electrodes with high phosphorus contents or high reaction surface areas rapidly deteriorated during repetitive redox reactions. Based on the results for the degradation degree, the effect of the reaction surface area dominated that of the phosphorus content in the deterioration of the nickel phosphide nanowires. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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16 pages, 3543 KiB

Open AccessArticle

Synthesis and Characterization of Some Graphene Oxide Powders Used as Additives in Hydraulic Mortars

by Doina Prodan, Marioara Moldovan, Gabriel Furtos, Codruța Saroși, Miuța Filip, Ioana Perhaița, Rahela Carpa, Maria Popa, Stanca Cuc, Simona Varvara and Dorin Popa

Appl. Sci. 2021, 11(23), 11330; https://doi.org/10.3390/app112311330 - 30 Nov 2021

Cited by 30 | Viewed by 2560

Abstract

Various powders of graphene oxide (GO), GO with silver (GO-Ag) and zinc oxide (GO-ZnO) were obtained. The powders were silanized with (3-aminopropyl) triethoxysilane (APTES) aiming to be used, in a future stage, as additives in the hydraulic lime mortars composition. The powders were [...] Read more.

Various powders of graphene oxide (GO), GO with silver (GO-Ag) and zinc oxide (GO-ZnO) were obtained. The powders were silanized with (3-aminopropyl) triethoxysilane (APTES) aiming to be used, in a future stage, as additives in the hydraulic lime mortars composition. The powders were characterized by Fourier Transform Infrared Spectrometry (FTIR) and Scanning Electron Microscopy (SEM) before and after the silanization process. GO, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were also investigated by Thermogravimetric Analysis (TG/DTA) and Ultraviolet–Visible Spectroscopy (UV-Vis). Likewise, the antibacterial effect of powders against five bacterial strains was evaluated. The peaks associated to the functional groups from GO, GO-APTES, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were identified by FTIR analysis. The mass losses of powders, analyzed by TG/DTA were lower than those recorded for GO. By UV-VIS analysis, maxima corresponding to the electronic π-π * and n-π * transitions were recorded. SEM images highlighted the lamellar and layered structure of GO, but also the presence of Ag and Zn nanoparticles on the surface of graphene sheets. All these results confirm the presence of Ag/ZnO/APTES on the GO. The antibacterial effect evaluated by recording the diameter of the inhibition zone ranged between 12–22 mm. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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15 pages, 5125 KiB

Open AccessArticle

Fabrication of Hierarchical Multilayer Poly(Glycerol Sebacate urethane) Scaffolds Based on Ice-Templating

by Andreas Samourides, Andreas Anayiotos, Konstantinos Kapnisis, Zacharoula Xenou, Vanessa Hearnden and Biqiong Chen

Appl. Sci. 2021, 11(11), 5004; https://doi.org/10.3390/app11115004 - 28 May 2021

Cited by 1 | Viewed by 3071

Abstract

In this study, it was demonstrated that ice-templating via freeze drying with custom-made moulds, in combination with air brushing, allows for the fabrication of poly(glycerol sebacate urethane) (PGSU) scaffolds with hierarchical multilayer microstructures to replicate various native soft tissues. The PGSU scaffolds were [...] Read more.

In this study, it was demonstrated that ice-templating via freeze drying with custom-made moulds, in combination with air brushing, allows for the fabrication of poly(glycerol sebacate urethane) (PGSU) scaffolds with hierarchical multilayer microstructures to replicate various native soft tissues. The PGSU scaffolds were either monolayered but exhibited an anisotropic microstructure, or bilayered and trilayered, with each layer showing different microstructures. By using freeze drying with custom-made moulds, the ice crystals of the solvent were grown unidirectionally, and after freeze-drying, the scaffolds had an anisotropic microstructure, mimicking tissues such as tendon and skeletal muscle. The anisotropic PGSU scaffolds were also examined for their tensile strength, and a range of mechanical properties were obtained by altering the reactants’ molar ratio and polymer concentration. This is of importance, since soft tissues exhibit different mechanical properties depending on their native location and functionality. By combining freeze drying with airbrushing, scaffolds were fabricated with a thin, non-porous layer on top of the porous layers to allow three-dimensional cell co-culture for tissues such as skin and oral mucosa. These results show that fabrication techniques can be combined to produce PGSU scaffolds with tailored hierarchical microstructures and mechanical properties for multiple tissue engineering applications. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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12 pages, 2996 KiB

Open AccessArticle

The Use of the ROS Scavenger Cysteine as a Surface Ligand of Metal Nanoclusters and Its Bactericidal Elimination Effect

by Dyah Ika Krisnawati, Po-Hsuan Hsu, Yu-Hsiang Lin, Moh Alimansur, Didik Susetiyanto Atmojo, Elfi Quyumi Rahmawati, Dwi Rahayu, Muhamad Khafid, Ssu-Chiao Lu and Tsung-Rong Kuo

Appl. Sci. 2021, 11(9), 4095; https://doi.org/10.3390/app11094095 - 30 Apr 2021

Cited by 6 | Viewed by 2550

Abstract

The bactericidal effects of fluorescent metal nanoclusters have impeded their bacterial bioimaging applications due to the reactive oxygen species (ROS) generation that is induced by the nanoclusters in bacteria to cause bacterial death. Herein, an ROS scavenger of cysteine was exploited as a [...] Read more.

The bactericidal effects of fluorescent metal nanoclusters have impeded their bacterial bioimaging applications due to the reactive oxygen species (ROS) generation that is induced by the nanoclusters in bacteria to cause bacterial death. Herein, an ROS scavenger of cysteine was exploited as a surface ligand to prepare cysteine-conjugated gold nanoclusters (Cys–AuNCs) and cysteine-conjugated silver nanoclusters (Cys–AgNCs) using a facile hydrothermal approach. The structural and optical characterizations demonstrated successful syntheses of Cys–AuNCs and Cys–AgNCs. With the same weight concentration, the bactericidal effect increased in the order of Cys–AuNCs, Cys–AgNCs, and silver nanoparticles (AgNPs), according to the results of the bacterial growth curves. Furthermore, based on the results of the standard colony-counting method, the Cys–AuNCs revealed the best biocompatibility compared to those of the Cys–AgNCs and AgNPs in Escherichia coli (E. coli). The superior biocompatibility of the Cys–AuNCs can be attributed to the use of the ligand of cysteine as an ROS scavenger to reduce ROS in E. coli. Electron paramagnetic resonance (EPR) analyses indicated that the use of the ROS scavenger cysteine as the surface ligand of the Cys–AuNCs eliminated the ROS production induced by the Cys–AuNCs in E. coli. The biocompatible Cys–AuNCs were also confirmed as a fluorescent probe using confocal microscopy. Highly biocompatible Cys–AuNCs could be a potential fluorescent probe in the application of bacterial bioimaging. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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13 pages, 1679 KiB

Open AccessFeature PaperArticle

Bacteria-Mediated Synthesis of Silver and Silver Chloride Nanoparticles and Their Antimicrobial Activity

by Ioana Ghiuta, Catalin Croitoru, Joseph Kost, Rodica Wenkert and Daniel Munteanu

Appl. Sci. 2021, 11(7), 3134; https://doi.org/10.3390/app11073134 - 1 Apr 2021

Cited by 18 | Viewed by 3088

Abstract

Within the frame of this work, the synthesis of silver nanoparticles (Ag NPs) and silver chloride nanoparticles (AgCl NPs) as mediated by microbes has been investigated. The nanoparticles were reduced from a silver nitrate precursor by the presence of bacteria, like Raoultella planticola [...] Read more.

Within the frame of this work, the synthesis of silver nanoparticles (Ag NPs) and silver chloride nanoparticles (AgCl NPs) as mediated by microbes has been investigated. The nanoparticles were reduced from a silver nitrate precursor by the presence of bacteria, like Raoultella planticola and Pantoea agglomerans. The results show that the characteristic surface plasmon resonance absorption band occurs at about 440 nm. Nanoparticles were also characterized with the help of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD), which showed the formation of spherical Ag/AgCl NPs with a centered cubic crystal structure and a mean particle size of around 10–50 nm. Assays for antimicrobial activity of the biosynthesized nanoparticles demonstrated meaningful results against microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Salmonella, and Bacillus amyloliquefaciens. Furthermore, this study shows that the combination of the obtained nanoparticles with standard antibiotics may be useful in the fight against emerging microbial drug resistance. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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11 pages, 7601 KiB

Open AccessArticle

Effects of Carbon Doping and Annealing Temperature on Magnetic MnAl Powders and MnAl Polymeric Composites

by Wannisa Thongsamrit, Thanida Charoensuk, Panissa Saetang, Pongsakorn Jantaratana, Chesta Ruttanapun and Chitnarong Sirisathitkul

Appl. Sci. 2021, 11(5), 2067; https://doi.org/10.3390/app11052067 - 26 Feb 2021

Cited by 6 | Viewed by 1963

Abstract

Process parameters leading to magnetic polymer composites, an essential ingredient in the additive manufacturing of rare-earth-free magnets, are investigated. The induction melting of manganese (Mn) and aluminum (Al), and subsequent annealing at 450, 500, or 550 °C for 20 min, gave rise to [...] Read more.

Process parameters leading to magnetic polymer composites, an essential ingredient in the additive manufacturing of rare-earth-free magnets, are investigated. The induction melting of manganese (Mn) and aluminum (Al), and subsequent annealing at 450, 500, or 550 °C for 20 min, gave rise to ferromagnetic τ–MnAl phase, as well as other phases. The nonmagnetic Al₄C₃ and oxide phases were then removed by the magnetic separation. Magnetic powders from the magnetic separation were incorporated in polylactic acid (PLA) matrix via a solution route. The remanent magnetization as high as 4.3 emu/g in the powder form was reduced to 2.3–2.6 emu/g in the composites. The reduction in coercivity was minimal, and the largest value of 814 Oe was obtained when the powder annealed at 450 °C was loaded in the composite. The phase composition and hence magnetic properties were even more sensitive to the carbon (C) doping. Interestingly, the addition of 3% C led to coercivity as high as 1445 Oe in MnAl–C powders without further annealing. The enhanced coercivity was attributed to the domain wall pinning by the AlMn₃C phase, and magnetizations are likely increased by this phase. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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14 pages, 4702 KiB

Open AccessFeature PaperArticle

Characterization of Aluminum Alloy–Silicon Carbide Functionally Graded Materials Developed by Centrifugal Casting Process

by Ioan Milosan, Tibor Bedő, Camelia Gabor, Daniel Munteanu, Mihai Alin Pop, Dorin Catana, Mihaela Cosnita and Béla Varga

Appl. Sci. 2021, 11(4), 1625; https://doi.org/10.3390/app11041625 - 11 Feb 2021

Cited by 10 | Viewed by 2634

Abstract

The continuous development of modern industries rises the necessity for functionally graded materials. This research starts from the consideration that the incorporation of SiC particles in the molten aluminum alloy can be difficult due to the very low wettability of SiC particles. In [...] Read more.

The continuous development of modern industries rises the necessity for functionally graded materials. This research starts from the consideration that the incorporation of SiC particles in the molten aluminum alloy can be difficult due to the very low wettability of SiC particles. In order to increase their wettability, SiC particles were covered with a layer of metallic copper. The incorporation of SiC particles into the aluminum alloy mass was performed by centrifugal casting. The secondary hypoeutectic Al-Si alloy used in this study was elaborated within the crucible of a resistors heated furnace. The metallic coating of SiC particles, in addition to the effect of increasing their wettability by molten metal, also has a role in preventing the formation of aluminum carbide in case of heating above 700 °C. A great amount of attention was paid to the parameters used during the centrifugal casting process. The results showed that adjusting the proportion of SiC particles within the composite allows us to obtain values of the thermal expansion coefficient within previously established limits. The present work demonstrates that the coating of SiC particles covered with a thin layer of metallic Cu creates the conditions to easily incorporate them into the molten Al mass, thus obtaining FGMs with controlled properties. Full article

(This article belongs to the Special Issue Nanostructured and Functionalized Materials: Characterization and Applications)

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