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Although evolving technology enables the production of sensors with excellent properties, the development of a fast-response, portable, and low-cost sensor is very important for food detection and also for disease diagnosis. Herein, zinc doped manganese oxide nanocomposites (Zn:MnO2 NCs) were designed as smartphone-integrated colorimetric and non-enzymatic electrochemical sensors with high sensitivity and selectivity. According to the Transmission electron microscopy (TEM) results showed that the Zn:MnO2 NCs had a spherical shape with a uniform particle size of less than 10 nm. As one of the most important results, the colorimetric sensing behavior of the Zn:MnO2 NCs was showed excellent fast and selective sensitivity against dopamine, ascorbic acid, gallic acid, and tannic acid among the various bio-analytes such as sugars, amino acids, hormones, and phenolic compounds. The Zn:MnO2 NCs were successfully used as smartphone supported paper based sensor against dopamine, gallic acid, and tannic acid using RGB analysis and with low limit of detection (LOD) values of 2.89, 3.88, and 7.81 μM, respectively. Moreover, Zn:MnO2 exhibited excellent a non-enzymatic electrochemical sensor performance against ascorbic acid with a low LOD of 239 nM and high sensitivity of 44.73 μA/cm2 mM in a concentration range of 0.52–11.35 mM. These findings emphasize that the designed Zn:MnO2 NCs based sensors has a potential as easily applicable and rapid sensor systems against of ascorbic acid, gallic acid, tannic acid and dopamine for real food and blood samples that as a point-of-care detection systems. [ABSTRACT FROM AUTHOR]

Abstract A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially.

This study presents novel nano-mixtures containing zinc oxide (ZnO) nanoparticles (NPs) to enhance the mechanical properties of cement mortars. Different morphological ZnO NPs were synthesised through the green sonochemical method, using tragacanth gum/Kappa carrageenan (TG/κ-C) and tragacanth gum/chitosan (TG/CS) as biopolymer matrices. The ZnO NPs were characterised using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, X-ray diffraction, Zetasizer and Brunauer–Emmett–Teller techniques. The intrinsic viscosities of TG/κ-C-ZnO and TG/CS-ZnO NPs were investigated to determine the miscibility of the polymeric blends in aqueous solution as affected by sonication time and composition ratios. The average diameters for the spherical and prism-like ZnO NPs were around 266 nm and 355 nm, respectively. Seven different cement mortar specimens containing TG/κ-C-ZnO and TG/CS-ZnO NPs were prepared in ratios of 0, 0.1, 0.5 and 1% by weight, and the flexural and compressive strengths of the specimens were determined at the ages of 7 and 28 days. The results indicate that there is a significant improvement in the mechanical performance of different morphological ZnO NP-based cement mortar composites. In comparison, it was observed that specimens containing TG/κ-C-ZnO NPs had much better results than TG/CS-ZnO NPs. Moreover, the workability problem encountered by using only ZnO NPs has been overcome with the presented biopolymers used in this study. [ABSTRACT FROM AUTHOR]

In this study, ethanol detection performance of divanadium pentoxide (V2O5) nanowire array was investigated at various temperatures. The main purpose of this study is to develop a novel V2O5 nanowires-based sensor for the detection of ethanol using an Anodic Aluminum Oxide (AAO) template by direct voltage electrodeposition at room temperature. It was observed that the V2O5 nanowires were approximately 60 nm in diameter in a large area of 6 cm2. X-ray Diffraction (XRD) spectrum indicated the formation of V2O5. The XRD peak was indexed as V2O5 located at 2θ°≅ 20° that is attributed to the (001) lattice plane. The sensitivity of the V2O5 nanowire array was found 0.24 at 200 °C for 50 ppm ethanol. The results reveal that the diffusivity of the V2O5 molecules increases rapidly with increasing temperature, causing an increased sensitivity. The maximum sensor response was obtained at 200 °C. The limit of detection (LOD) of the V2O5 nanowire array sensor was 500 ppb at 200 °C. The response time (t90) of the V2O5 nanowire array sensor was calculated to be 52 s and the recovery time was 26 s at 200 °C. [ABSTRACT FROM AUTHOR]

This study is the first investigation focused on the preparation of novel synthesized borophene nanosheets and their use in cementitious composites. The two-dimensional β borophene was prepared by a facile and low-cost sonication process including ultrasonic cavitations. To understand the effect of the novel synthesized borophene nanosheets, varying ratios of 0, 0.5, 1, 2, 3, and 5 wt% of cement were incorporated in cement composites and improvements on the mechanical strength, workability, and toughness were identified. Also, for the microstructure evaluation, several advanced characterization techniques including SEM, EDS, XRD, and TGA were presented and the relationship between the microstructure and mechanical properties of cementitious composites modified with borophene nanosheets was discussed. As a result of this study, with the incorporation of the borophene nanosheets, clear improvements were achieved for the 28 day compressive and flexural strengths of the specimens within a range of 5–19% and 4–13%, respectively. The findings also indicated that borophene nanosheets contributed to the formation of a denser microstructure of the corresponding cement composites. Thus, within this study, the utility of as-prepared borophene nanosheets in cementitious composites is proved and proposed as a two-dimensional potential nanomaterial candidate to be used in cementitious composites. [ABSTRACT FROM AUTHOR]

In this study, the effects of zero-valent iron (ZVI) nanoparticles (NPs) on the mechanical performance of cementitious composites were investigated. For this purpose, the use of a novel nanomaterial containing ZVI NPs blended with carboxymethyl cellulose (CMC) and SiO2 was introduced. CMC/SiO2-ZVI NPs were prepared by a green and low-cost sonochemical method at room temperature and characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy, thermal gravimetry analysis, Brunauer–Emmett–Teller, and X-ray diffraction techniques. The values of intrinsic viscosities of CMC/SiO2-ZVI NPs were examined to determine the optimal miscible condition as affected by the different mass ratios of CMC/SiO2 and sonication time. Then, eight different cement mortar specimens containing CMC/SiO2 and CMC/SiO2-ZVI NPs were prepared in ratios of 0.2%, 0.5%, 1%, and 2% by weight, and flexural and compressive strengths of the specimens were determined at the ages of 7 and 28 days. The microstructure of the specimens was also evaluated. Comprehensive results proving the improvement in the mechanical properties have been obtained in the specimens containing 1% and 2% CMC/SiO2-ZVI NPs. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the hydrogen sensing properties of nanoporous Pd–Ag and Pd–Cu alloy films based on anodic aluminum oxide (AAO) templates were investigated at various temperatures (25–100°C) and hydrogen with concentrations in the range between 250 and 5000ppm in high purity nitrogen to determine the temperature–sensitivity relationship. A hexagonally shaped AAO template of approximately 50nm in diameter and 10μm in length was fabricated as a substrate for supporting a nanoporous Pd alloy film with an approximate thickness of 80nm. The morphologies of the AAO template and the Pd alloy films were studied by scanning electron microscopy (SEM). The hydrogen sensing properties of the nanoporous Pd–Ag and Pd–Cu alloy films were measured using a transient resistance method. The sensor responses of the nanoporous Pd–Ag and Pd–Cu films on the AAO template were better than the traditional Pd–Ag and Pd–Cu thin film sensors; the sensitivities of the sensors were approximately 1.6% and 1.2%, respectively, for 1000ppm H2, and the detection limit was 250ppm at room temperature. The highest sensitivity was measured at room temperature for all alloy nanoporous sensors, and the sensitivity of the Pd–Ag nanoporous alloy was higher than that of the Pd–Cu nanoporous alloy. [Copyright &y& Elsevier]

Abstract: In this study, vertically oriented Pd0.86Fe0.14 nanowires have been fabricated using an anodized aluminum oxide (AAO) template by direct voltage electrodeposition at room temperature. AAO template-assisted electrodeposition of Pd–Fe was carried out in Pd(NH3)2Cl2:FeSO4·7H2O solution. The AAO template and the Pd0.86Fe0.14 nanowires were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) methods and X-ray diffraction (XRD). It was observed that the Pd0.86Fe0.14 nanowires were approximately 65nm in diameter and 10μm in length with an aspect ratio of 153 in a relatively large area of about 4cm2. The nucleation rate and the number of atoms in the critical nucleus are determined from the analysis of current transients. [Copyright &y& Elsevier]

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially. [ABSTRACT FROM AUTHOR]

In this study, thin anodic aluminum oxide (AAO) templates both on silicon substrates (AAO template/SiO2/Si) and Ti-coated silicon substrates (AAO template/Ti/SiO2/Si) were developed for design of magnetic, electronic and optoelectronic devices, chemical sensors and chip-scale lithium-ion rechargeable microbatteries. Two types of AAO template were prepared by using a two-step anodization procedure. The templates were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The obtained thin AAO templates were approximately 50 nm in diameter and 700 nm in length with 80-nm interpore distances in a relatively large area of 6 cm2. A barrier layer of the AAO templates was removed by a cathodic polarization method in KCl solution for several seconds. The current–time transient during removing the alumina barrier layer of the thin AAO template and the mechanism of electrochemical dissolution of the barrier layer are given in detail. [ABSTRACT FROM AUTHOR]

[Display omitted] • β-rhombohedral crystalline structured borophene nanosheets were prepared by physical exfoliation. • The antimicrobial property of β borophene nanosheets was investigated against microorganisms. • β borophene nanosheets exhibited inhibitory activity against medically serious bacterial and fungal pathogenic microorganisms. Antimicrobial resistance toward antibiotics has been a serious clinical problem to current bacterial infections therapy. In this context, current research and development have been focused on developing new perspectives on two-dimensional (2D) materials based antimicrobial agents. With the rapid development of 2D borophene, it has been regarded as a promising agent for sensor, energy, and biomedical applications. Herein, we have reported the fabrication of the multifunctional antibacterial and antifungal agent, β-rhombohedral crystalline structured borophene nanosheets, which were prepared using a top-down synthesis approach. The antibacterial and antifungal activities of β borophene nanosheets were investigated to determine using different pathogenic microorganisms such as Staphylococcus aureus (NCTC 10788/Lot 0350520029), Pseudomonas aureginosa (ATCC 9027/Lot 3270513), Escherichia coli (ATCC 8739/Lot 4835151), Candida albicans (NCPF 3179/Lot040920020), and Aspergillus brasilliensis (NCPF 2275/Lot 020620065) using the total aerobic mesophilic microorganism (lSO 21149) and mold-yeast (lSO 16212) guidelines. According to the experimental results, we showed that the borophene nanosheets had an effectively inhibitory activity against several medically serious bacterial and fungal pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Current density–voltage curves of Cu core shell nanospheres coated electrochemical transducers with Tin / Gold 3-electrodes against to glucose in PBS. • 100 nm sized Cu/CuO/SiO2 nanospheres were synthesized via ultrasonic-assisted method. • Cu core shell nanosphere showed high electrochemical performance for sensing glucose. • Benefiting from electrochemical performance of the nanospheres, a sensitive electrochemical non-enzymatic glucose sensor was realized. In this study, we prepared Copper (Cu) metal-based core shell nanosphere (spherical Cu/CuO/SiO 2 nanostructures with approximately 100 nm size) using a green ultrasound method for investigation the electrochemical sensing of glucose, fructose, lactose, and maltose. In the non-enzymatic glucose Cu-core shell nanosphere sensor based on electrode surfaces, we proved that the morphology of the electrode material has a large impact on the performance of the sensor. The Cu core shell nanospheres were prepared by using nontoxic, biodegradable, and biocompatible biopolymer chitosan, which were modified by an inorganic phase SiO 2. Electrochemical properties of Cu core shell nanospheres were compared against glucose, fructose, lactose, and maltose in PBS. The electrochemical measurement results indicate that prepared Cu core shell nanosphere based electrochemical sensor has a higher sensitivity and selectivity against to glucose. Prepared Cu core shell nanosphere based electrochemical sensor detected [3–12] mM glucose with sensitivity of 8 μA. mM−1. cm−2 during 1 min cyclic voltammetry measurement. Lower limit of detection of the prepared glucose sensor was found to be 1.45 mM. This study reveals new high potential novel Cu core shell nanosphere based sensing material for selective detection of glucose with high sensitivity. The innovation of non-enzymatic glucose sensors with synthesized Cu core shell nanosphere in this study was proposed and was shown from a promising perspective in this period. [ABSTRACT FROM AUTHOR]

We report an integrated optical sensor of hydrogen (H 2 ) gas employing an SU-8 polymer microdisk resonator coated with a palladium (Pd) layer and coupled to a single-mode optical waveguide. The sensing mechanism relies on the expansion in the Pd lattice due to palladium hydride formation in the presence of H 2 . Strain induced in the microresonator then causes a red shift of the spectral positions of the resonator whispering gallery modes (WGMs) which is monitored using a tunable laser coupled to the waveguide. H 2 concentrations below the flammable limit (4%) down to 0.3% could be detected in nitrogen atmosphere at room temperature. For H 2 concentrations between 0.3 and 1%, WGM spectral positions shifted linearly with H 2 concentration at a rate of 32 pm/% H 2 . Average response time of the devices was measured to be 50 s for 1% H 2 . The proposed device concept can also be used to detect different chemical gases by using appropriate sensing layers. [ABSTRACT FROM AUTHOR]

[Display omitted] • An ultra-sensitive smartphone-integrated digital colorimetric CuO nanoparticles-based biosensor was developed. • CuO nanoparticles-based biosensor was used for nanomolar determination of ammonia. • The colorant biosensor was used for monitoring of food spoilage. • The colorimetric PPS-CuO NPs-based biosensor showed a high selectivity of ammonia. With advancement trends in recent studies, it has drawn considerable attention towards the development of smartphone-integrated colorimetric biosensors with a high performance, stability, and selectivity for specific detection of analytes in food safety. Herein, camellia sinensis polyphenols encapsulated CuO nanoparticles (PPS-CuO NPs) based biosensors were developed as an ultra-sensitive smartphone-integrated digital colorimetric ammonia indicator for monitoring of food spoilage. The PPS-CuO NPs were characterized using different techniques such as SEM, HRTEM, FTIR, and XRD techniques. The colorimetric and electrochemical PPS-CuO NPs-based biosensor showed a high selectivity of ammonia with a high coefficient of correlation (R2 = 0.960), a wide concentration range of 12.5–100 µM, and a low limit of detection (LOD) of 40.6 nM. The developed smartphone-integrated colorimetric system exhibited high chemical selectivity for ammonia. Consequently, the sensing performance of PPS-CuO NPs based biosensors showed that it is a promising material for the determination of ammonia for food safety. [ABSTRACT FROM AUTHOR]