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In this paper, we present the technology of synthesis, characterization and release kinetics of anticancer drug molecules from sandwich-like mesoporous silica nanoflakes. Mesoporous silica nanoflakes are a very attractive material due to their versatility, low cytotoxicity, large surface area, high pore volume and unique feature of containing parallel pores openon both sides. Nanosilica flakes were prepared through the formation of a mesoporous silica layer on a graphene oxide surface. After graphene oxide removal, the silica nanostructures were filled by an anticancer drug—methotrexate. Release kinetics studies were performed in different temperatures, imitating the conditions in living organisms. Release data was analyzed using the zero-order model, first-order model, Higuchi model and Korsmeyer-Peppas model. The optical properties of samples, and the kinetics of drug release from the nanostructure, were examined by UV–vis spectrophotometer. Data obtained from long term studies showed that the system can serve as an anticancer drug carrier system, since a significant amount of methotrexate was loaded to the material and released. The mechanism of MTX release from mesoporous silica nanoflakes appeared to be a parallel processes of diffusion through water-filled mesopores and degradation of the mSiO 2 matrix. Physical and chemical characterization was undertaken by transmission electron microscopy (TEM) and X-ray dispersion spectroscopy (EDX). The specific surface area of the samples was measured through the adsorption of N 2 isotherm, interpreted with the Brunauer–Emmett–Teller model (BET). TGA and UV–vis analyses were conducted in order to estimate the amount of the released drug. [ABSTRACT FROM AUTHOR]

Promoted nanocrystalline iron was carburized in a differential tubular flow reactor with thermogravimetric measurement of mass changes. The carburization process was carried out in the presence of pure methane under atmospheric pressure at 650 °C to obtain different carburization degrees of the sample. The carburized iron samples were characterized by the X-ray diffraction, high-resolution transmission electron microscope in the energy-dispersive X-ray spectroscopy mode, thermoprogrammable oxidation, and Raman spectroscopy. As a result of the methane decomposition on the nanocrystalline iron the following nanocrystalline products were observed: iron carbide FeC, graphite, iron and nanotubes. The crystallinity of the samples increased with the carburization degree. [ABSTRACT FROM AUTHOR]

Carbon nanotubes have unique properties, such as thermal and electrical conductance, which could be useful in the fields of aerospace, microelectronics and biotechnology. However, these properties may vary widely depending on the dimensions, uniformity and purity of the nanotube. Nanotube samples typically contain a significant percentage of more allotropes forms of carbon as well as metal particles left over from catalysts used in manufacturing. Purity characterization of double-walled carbon nanotubes (DWCNTs) is an increasingly popular topic in the field of carbon nanotechnology. In this study, DWCNTs were synthesized in a catalytic reaction, using Fe:MgO as catalyst and methane or methane/ethanol as carbon feedstock for chemical vapor deposition (CVD). The addition of ethanol as carbon feedstock allowed to investigate the influence of oxygen on the sample quality. The purification of the as-produced material from the metallic particles and the catalyst support was performed by sonication in an acid solution. The influence of the duration of the acid treatment using ultrasound on the sample purity was investigated, and the optimal value of this parameter was found. Transmission electron microscopy (TEM) images confirmed the removal of impurities and served to elucidate the morphology of the samples. The purity of carbon nanotubes was analyzed using thermal gravimetric analysis (TGA). The Raman spectra of the samples, as a measure of the concentration of defects, were also reported. [ABSTRACT FROM AUTHOR]

Bacterial infectious diseases are serious health problem which extends to economic and social complications. Moreover, bacterial antibiotic resistance, lack of suitable vaccine or emergence of new mutations is forcing the development of novel antimicrobial agents. The objective of this study is to synthesize and characterize star-like zinc oxide nanoparticles for the application of antibacterial activities in cellulose based hygiene products. ZnO NPs were in situ synthesized via precipitation method on the surface of cellulose fibers. Since bactericidal activity of nanoparticles in part depends on the concentration in the growth medium, various amount of ZnO was incorporated into cellulose matrix ranging from 1 to 3 wt%. Microscopic (TEM, SEM) and spectroscopic (FT-IR, XRD) methods were utilized to investigate the final products. The infrared absorption spectra analysis supported by theoretical finding that during the reaction, ZnO nanoparticles could be bonded with cellulose fibers via hydrogen bonding. The yield of functionalization was determined through thermogravimetric analysis. Collected data proved the successful functionalization of the cellulose fibers with nanoparticles. Static contact angle measurements were carried out showing absorptive character of as prepared fabrics. All the samples were tested for the antibacterial properties and the results were compared to the samples prepared from the pristine cellulose fibers. Moreover, mechanical tests were performed revealing that the addition of only 2 wt% of the nanofiller boosted tensile, tearing and bursting strength by a factor of 1.6, 1.4 and 2.2 in comparison to unfunctionalized paper sample, respectively. Fabricated fabric presenting high hydrophilicity and antibacterial properties have gained increased applications in fabric industry, including hygiene product industry and hence the result of this study would be a welcomed option. [ABSTRACT FROM AUTHOR]

• Surface properties of ex. g-C 3 N 4 determine photocatalytic AR18 and VOP response. • Positive surface charge promotes AR18 and acetaldehyde decomposition. • Positively charged ex. g-C 3 N 4 exhibits both enhanced activity and high reusability. Two types of exfoliated graphitic carbon nitride (GCN) with similar morphology but different surface properties were fabricated and tested as photocatalysts in acetaldehyde and dyes (Acid Red 18 and Rhodamine B) decomposition processes. Both samples were synthesized via exfoliation of the bulk GCN in the assistance of strong oxidant. Their surface modification was tuned by annealing at different temperature: 250 and 350 °C providing two samples assigned to GCN_250 and GCN_350, respectively. The samples exhibited similar thickness, lateral size, surface area and band gap energy but their photoactivity differed greatly. Exfoliated materials showed different photocatalytic activity depending on the type of dye (anionic or cationic). The Acid Red degradation by GCN_250 with positively charged surface was 1.8-times higher in respect to negatively charged GCN_350, whereas the Rhodamine B decomposition by GCN_350 was 1.4-times higher in comparison to GCN_250. Furthermore, GCN_250 exhibited superior photoactivity towards acetaldehyde decomposition in comparison with GCN_350 under visible light irradiation. This study provides knowledge on GCN surface properties in photocatalytic activity toward both water and volatile pollutant degradation. [ABSTRACT FROM AUTHOR]

Herein, two different photocatalytic composites based on ordered (OCS) and disordered (DCS) mesoporous hollow carbon spheres and graphitic carbon nitride (gCN) have been successfully fabricated through facile acid treatment. The influence of carbon shell morphology of the spheres on gCN loading and photocatalytic H 2 production under simulated solar light irradiation has been revealed. The amount of evolved H 2 was ~6.2 (OCS/gCN) and ~5.3 (DCS/gCN) times higher in comparison to pristine gCN. It was found that graphitic carbon nitride was much more homogenously supported onto ordered mesoporous carbon spheres than disordered ones. The deposition of gCN onto ordered carbon spheres was found to be more efficient to increase carrier concentration, enhance photogenerated charge carrier transport and separation. It is assigned to the formation of the graphitic carbon nitride/carbon heterojunction facilitating the contact surface between the two phases of hybrid. Therefore, via tuning of the morphology of carbon shell being a host for gCN it was possible to find more promising candidate as a photocatalyst in H 2 production under solar light irradiation. Image 1 • Graphitic carbon nitride was deposited onto mesoporous hollow carbon spheres. • Hybrids displayed enhanced H 2 production in respect to the pristine carbon nitride. • The effect of carbon shell morphology on photocatalytic abilities was studied. • The electrochemical behavior of the most efficient catalyst was examined. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • TiO 2 /spheres prepared by calcination of TiO 2 at 800–1000 °C in the benzene vapours. • The core-shell structure of TiO 2 /spheres was found. • Hybrids were the mixture of the uncovered rutile, C-spheres, graphite/graphene flakes. • The core-shell thickness varied 30 and 40 nm (800–900 °C) and to 100 nm (950–1000 °C). Abstract Hybrid carbon-TiO 2 spheres (TiO 2 /C spheres) were prepared via the CVD method in the atmosphere of benzene vapours at 800–1000 °C. Structure and morphology of prepared hybrid composites were examined by means of SEM, TEM, XPS, TG, Raman spectroscopy, XRD and UV–Vis/DRS methods. The SEM and TEM analysis confirmed the presence of uncovered rutile crystallites as well as the different forms of carbon-modified TiO 2 forms: rutile TiO 2 /C spheres and thin flakes of graphite and thin graphene sheets. The average thickness of the typical spheres varied between 30 and 40 nm for samples prepared at lower temperatures (800–900 °C), but the carbon core-shell thickness could be even up to 100 nm for samples obtained at 950–1000 °C. The XPS, TG, Raman spectroscopy and XRD measurements allowed to characterize in detail the carbonaceous nature of carbon layers of the fabricated spheres, indicating the graphitic character of TiO 2 /C hybrids. [ABSTRACT FROM AUTHOR]

• A smart methodology to selectively activate NiMOF-based active material in hydrogen and oxygen evolution reactions by designed electrode fabrication. • Hydrogen and oxygen evolution reaction activities and stabilities in alkaline electrolytes demonstrated robustness and efficiency of the prepared composites. • In situ Raman and XRD studies of the electrocatalysts reveal real active species and provide insight into reaction mechanisms. Hydrogen is a promising energy source to replace fossil fuels. Among the methods of generating hydrogen, electrochemical water splitting is distinguished by its ecologically friendly, high efficiency, sustainability, and ability to produce this element without the limitation of geological conditions and scaling devices. However, electrochemical water splitting is thermodynamically unfavorable, especially because its oxidation half-reaction (OER) and commercially available catalysts are expensive and not abundant in natural resources. The efficacy of commonly employed HER catalysts, such as Pt/C, is well-established. However, their high cost and limited natural resources present significant impediments. Given the slow kinetics of OER and the requisite catalyst demand for both HER and OER, it is paramount to pursue alternative solutions that are cost-effective, facile, and more widely accessible. Various new technologies and active materials have recently been developed in electrochemical water splitting for hydrogen production. There are still many knowledge gaps, including how preparation methods, chemical composition, and morphology of electrocatalysts affect both half-reactions of water splitting. Therefore, this work presents a smart approach to selectively activate NiMOF-based active materials in HER and OER. We demonstrate high-performance electrocatalysts based on Nickel/metal-organic frameworks (NiMOF) fabricated via two routes: A - drop cast on pristine Nickel foam with improved activity in OER (flower-like structure), B - Ni foam in situ impregnated by NiMOF during synthesis with improved activity in HER (rectangular-like structure). It allows the demonstration of highly efficient and robust electrocatalysts. Furthermore, in-situ studies on structural changes in the active materials have been conducted to reveal water-splitting half-reaction mechanisms. [Display omitted] [ABSTRACT FROM AUTHOR]

Nitrogen-doped core/shell carbon nanospheres (NHCS are prepared and their capability as an anode material in lithium-ion batteries is investigated. The synthesis methodology is based on a fast template route. The resulting molecular nanostructures are characterized by X-ray diffraction, transmission electron microscopy, thermal analysis, and nitrogen adsorption/desorption measurement as well as by cyclic voltammetry and galvanostatic cycling. The core/shell structure provides a rapid lithium transport pathway and boasts a highly reversible capacity. For undoped HCS the BET specific surface area is 623 m 2 /g which increases up to 1000 m 2 /g upon N-doping. While there is no significant effect of N-doping on the electrochemical performance at small scan rates, the doped NHCS shows better specific capacities than the pristine HCS at elevated rates. For instance, the discharge capacities in the 40th cycle, obtained at 1000 mA/g, amount to 170 mAh/g and 138 mAh/g for NHCS and HCS, respectively. [ABSTRACT FROM AUTHOR]

In this paper a new generation of non-toxic nanoparticles based on the zirconium oxide doped with 0.5%Tb and co-doped by the range of 0–70% with Y was evaluated for the use as a fluorescent biomarker of neuronal trafficking. The ZrO 2 :Tb nanoparticles were created by microwave driven hydrothermal method. Influence of the yttrium content and thermal processing on the Tb 3+ related luminescence emission was discussed. The higher intensities were achieved, when host was cubic and for the nanoparticles with 33 nm. Presence of yttrium was associated with the energy coupling of the host and dopant, wide excitation band is present at 309 and 322 nm before and after calcination respectively. For the experiment on living primary neurons, nanoparticles doped with 0.5%Tb and 7%Y were chosen based on their luminescence emission intensity. Recently transfer of the nanoparticles through the barriers in the organism including blood–brain barrier following their alimentary absorption was confirmed (Godlewski and Godlewski, 2012). This raised the possibility of the nanoparticle application as a tool in the neuroscience, and the question of potential mechanisms of nanoparticle turnover in neurons. Concentration of 0.001 mg/ml of ZrO 2 :0.5%Tb 7%Y in growth medium was added to the primary murine culture medium, and the intracellular trafficking of nanoparticles was observed following 15 min pre-incubation period. ZrO 2 :0.5%Tb 7%Y nanoparticles were dynamically absorbed by the neurons and the dynamic passage of transport vesicles containing ZrO 2 :0.5%Tb 7%Y nanoparticles was observed along the neuronal processes and in between two neighbouring neurons. Reassuming, the ZrO 2 :0.5%Tb 7%Y nanoparticles proved to be biocompatible and a valid tool to assess intracellular trafficking dynamics in the neurobiology. [ABSTRACT FROM AUTHOR]

We present the new promising nanostructure- sandwich-like mesoporous silica nanoflakes synthesized on graphene oxide sheets core. In the first step biocompatibility of the nanoflakes with PEG and without functionalization in human fibroblast, melanoma and breast cancer cells was assessed. In order to define the cellular uptake in vitro and biodistribution in vivo the nanostructures were labelled with fluorescent dye. In the next step, the silica nanostructures were filled by the anticancer drug- methotrexate (MTX) and cytotoxicity of the complex in reference to MTX was evaluated. The WST-1 assay shows mild, but concentration dependent, cytotoxicity of the nanoflakes, most significant for the non-functionalized structures. PEG-modified silica nanoflakes didn’t produce a disruption of cell membranes and lactate dehydrogenase (LDH) release. Cell imaging revealed efficient internalization of the silica nanoflakes in cells. Ex vivo organ imaging showed high accumulation of the nanostructures in lungs, bladder and gall bladder, whereas confocal imaging revealed wide nanoflake distribution in all tested tissues, especially at 1 h and 4 h post intravenous injection. Cytotoxicity of the nanoflake-MTX complex in reference to MTX showed similar cytotoxic potential against cancer cells. These findings may provide useful information for designing drug delivery systems, which may improve anticancer efficacy and decrease side effects. [ABSTRACT FROM AUTHOR]

HCS (Hollow carbon spheres) covered with metal oxide nanoparticles (SnO 2 and MnO 2 , respectively) were successfully synthesized and investigated regarding their potential as anode materials for lithium-ion batteries. Raman spectroscopy shows a high degree of graphitization for the HCS host structure. The mesoporous nature of the nanocomposites is confirmed by Brunauer–Emmett–Teller analysis. For both metal oxides under study, the metal oxide functionalization of HCS yields a significant increase of electrochemical performance. The charge capacity of HCS/SnO 2 is 370 mA hg −1 after 45 cycles (266 mA hg −1 in HCS/MnO 2 ) which clearly exceeds the value of 188 mA hg −1 in pristine HCS. Remarkably, the data imply excellent long term cycling stability after 100 cycles in both cases. The results hence show that mesoporous HCS/metal oxide nanocomposites enable exploiting the potential of metal oxide anode materials in Lithium-ion batteries by providing a HCS host structure which is both conductive and stable enough to accommodate big volume change effects. [ABSTRACT FROM AUTHOR]

We report a facile strategy to synthesize carbon nanotubes decorated by mesoporous cobalt oxide (CNT@Co 3 O 4 ). The mesoporous nature of the nanocomposite is confirmed by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The data imply 41 wt% mesoporous Co 3 O 4 spheres in the as-prepared material with mean diameters ∼12 nm. The nanospheres are embedded in an interconnected network of carbon nanotubes. The specific surface area of CNT@Co 3 O 4 amounts to 463 m 2 /g. Cyclic voltammetry studies show a high activity of the Co 2+ /Co 0 and Co 3+ /Co 2+ redox couples. The conversion reaction is observed and full theoretical capacity is found in the 2nd cycle while significant capacity fading appears upon further cycling. Decorating mesoporous metal oxide nanospheres onto the interconnected electrically conducting network of carbon nanotubes therefore provides a first step towards an electrochemically active material promising for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Highlights: [•] Adsorption of methylene blue (MB) on graphene oxide (GO). [•] Characterization of graphene oxide–methylene blue nanocomposite (MB–GO). [•] Examination of MB–GO efficiency in singlet oxygen generation (SOG). [•] MB–GO performs higher SOG efficiency than pristine MB. [ABSTRACT FROM AUTHOR]

Highlights: [•] Covalent graphene oxide functionalization with methotrexate through amide bonding. [•] Detailed characterization of the material. [•] Study on kinetics of the drug release from graphene oxide surface. [•] Study on antineoplastic action against human breast adenocarcinoma cell line MCF7. [Copyright &y& Elsevier]

In this paper, we present a study on enhanced photocatalytic performance of TiO nanospheres deposited on graphene (n-TiO-G) in a process of coumarin oxidation. The enhancement of the photoactivity has been observed in respect to commercial TiO P25. The presented material was prepared in two steps: (i) hydrolysis of titanium (IV) butoxide (TBT) in ethanol solution with simultaneous deposition on graphene oxide (GO) and (ii) calcination of TiO-GO to form anatase-TiO and reduce GO to graphene. The nanomaterial was characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier-Transformed Infrared spectroscopy and Raman spectroscopy. In the presented photocatalytic process the fluorescence was used to detect OH formed on a photo-illuminated n-TiO-G surface using coumarin which readily reacted with OH to produce highly fluorescent 7-hydroxycoumarin. [ABSTRACT FROM AUTHOR]

The growth of iron filled multiwalled carbon nanotubes (Fe-MWCNT) using chemical vapour deposition (CVD) has been widely studied. Considering the remarkable magnetic and structural properties of Fe-MWCNT, these materials have been applied in numerous areas. In particular their biomedical application has been explored, where Fe-MWCNT can be used in hyperthermia, acting as a local nano-heater at cellular level. Regarding this aim, the reproducible and highly purified ferromagnetically filled samples of carbon nanotubes are still required. There are several parameters during the synthesis process that influence the properties of the nanotubes. The most favourable temperature of the CNT growth is probably one of the most important issues and its optimisation is crucial. In the current study, the Fe-MWCNT were grown at different temperatures ranging from 650 °C to 1050 °C. Additionally, a comparison between two different CVD systems and two carbon sources are also here presented. The Fe-MWCNT were characterised using diverse techniques regarding the evaluation of their morphology, filling ratio, and purity. Observations showed a strong influence of the growth temperature on the morphology and properties of the Fe-MWCNT. The samples characterisation was performed using Raman spectroscopy, thermogravimetric analysis (TGA), X ray diffraction (XRD), and transmission electron microscopy analysis (TEM). [ABSTRACT FROM AUTHOR]

In this study, hexagonal boron nitride nanosheets enriched with hydroxyl groups (h-BN-OH) were successfully grafted on the surface of cellulose fibers after the simple and effective exfoliation and oxidation of bulk h-BN. OH groups of h-BN-OH and the ones presented on the surface of cellulose fibers interacted via hydrogen bonding. Both spectroscopic (FT-IR, XRD) and microscopic (TEM, SEM, and atomic force microscopy (AFM)) methods results proved the successful functionalization of the cellulose fibers with the nanomaterial. Modified cellulose fibers were used to prepare paper sheets samples with different concentrations of the nanomaterial (1 wt %, 2 wt %, and 3 wt %). All the samples were tested for the antibacterial properties via the colony forming unit method and exhibited good performance against both Gram-negative (E. coli) and Gram-positive (S. epidermidis) model bacteria. Additionally, the influence of the volume of working bacterial suspension on the antibacterial efficiency of the obtained materials was examined. The results showed significantly better antibacterial performance when the volume of bacterial suspension was reduced. Mechanical properties of the paper samples with and without nanofiller were also characterized. Tensile strength, tearing strength, and bursting strength of the paper samples containing only 2 wt % of the nanofiller were improved by 60%, 61%, and 118% in comparison to the control paper samples, respectively. Furthermore, the nanofiller improved the thermal properties of the composite paper—the heat release rate decreased by up to 11.6%. Therefore, the composite paper can be further explored in a wide range of antibacterial materials, such as packaging or paper coatings [ABSTRACT FROM AUTHOR]

• A new preparation method of WS2 rod-like structure is developed. • The mechanism of growth WS2 rodes is proposed. • Different shape of WS2 improve its catalytic activity. • This structure used as highly efficient electrocatalyst for oxygen evolution. Oxygen evolution reaction (OER) via electrocatalytic water splitting is crucial for efficient electrochemical energy storage and conversion. Herein, we describe the preparation of the rod-like structure of tungsten disulphide (WS 2) as efficient catalysts for OER. Exfoliated tungsten disulphide was used as a source of the rods. The reshaping process required high-temperature treatment with the assistance of hydrogen and ethylene. We propose a structure with novel morphology and promising performance as an electrocatalyst. The rod-like structure was manifested by high-resolution transmission electron microscopy measurements including HAADF intensity line profile. Further structural insights were obtained in X-ray diffraction and Raman spectroscopy. The structures exhibited apparent electrocatalytic activity toward OER overpotential =351 mV at 10 mA/cm2 which is superior in respect to exfoliated tungsten disulphide (overpotential =564 mV at 10 mA/cm2). [ABSTRACT FROM AUTHOR]