The potential therapeutic applications of mesenchymal stem/stromal cells (MSCs) and biomaterials have attracted a great amount of interest in the field of biomedical engineering. MSCs are multipotent adult stem cells characterized as cells with specific features, e.g., high differentiation potential, low immunogenicity, immunomodulatory properties, and efficient in vitro expansion ability. Human umbilical cord Wharton’s jelly-derived MSCs (hUC-MSCs) are a new, important cell type that may be used for therapeutic purposes, i.e., for autologous and allogeneic transplantations. To improve the therapeutic efficiency of hUC-MSCs, novel biomaterials have been considered for use as scaffolds dedicated to the propagation and differentiation of these cells. Nowadays, some of the most promising materials for tissue engineering include graphene and its derivatives such as graphene oxide (GO) and reduced graphene oxide (rGO). Due to their physicochemical properties, they can be easily modified with biomolecules, which enable their interaction with different types of cells, including MSCs. In this study, we demonstrate the impact of graphene-based substrates (GO, rGO) on the biological properties of hUC-MSCs. The size of the GO flakes and the reduction level of GO have been considered as important factors determining the most favorable surface for hUC-MSCs growth. The obtained results revealed that GO and rGO are suitable scaffolds for hUC-MSCs. hUC-MSCs cultured on: (i) a thin layer of GO and (ii) an rGO surface with a low reduction level demonstrated a viability and proliferation rate comparable to those estimated under standard culture conditions. Interestingly, cell culture on a highly reduced GO substrate resulted in a decreased hUC-MSCs proliferation rate and induced cell apoptosis. Moreover, our analysis demonstrated that hUC-MSCs cultured on all the tested GO and rGO scaffolds showed no alterations of their typical mesenchymal phenotype, regardless of the reduction level and size of the GO flakes. Thus, GO scaffolds and rGO scaffolds with a low reduction level exhibit potential applicability as novel, safe, and biocompatible materials for utilization in regenerative medicine.

Cerium-doped yttrium aluminum garnet can be used in white light emitting diodes and lasers. The YAG powders are traditionally formed by the solid state method, but the product particles are large, irregular, and non-homogeneous, which is detrimental for its luminescence properties. We present here a simple and fast method for synthesizing YAG:Ce 3þ nanopowder based on solution combustion synthesis from metal nitrates (Ce content between 0.7 and 35 wt%) and fuel (urea, starch, or glucose) water mixtures. The calcination of the raw product at 900 8C for 2 h yielded crystalline garnet nanopowder with grain size well below 100 nm. The properties of the final product were characterized by XRD, SEM, ATR, TG/DTA, and spectrofluorimetric measurements.

Design and experiment of polymeric nanocomposites (NCs) for photovoltaic applications with outstanding electrical and thermal properties has been investigated with the introduction of SiC nanofibers (NFs) into the poly(trimethylene terephthalate)-blockpoly(tetramethylene oxide) (PTT-PTMO) copolymers. In order to enhance the electrical and thermal conductivity, different concentrations of SiC NFs, ranging from 0.1 to 3.0 wt %, have 2 been selected to mix with PTT-PTMO via in situ polymerization method. This reaction method is an excellent choice for incorporation of high amount of SiC NFs (3 wt %) into the polymer that was confirmed by morphological studies. From dielectric spectroscopy studies a percolating behavior was confirmed at low percolation threshold (less than 2% wt %). Furthermore, the 15 % increment for thermal conductivity appeared with combination of 0.5 wt % SiC NFs with PTT-PTMO copolymers, which can be affected by manufacturing process of NCs, state of nanofillers dispersion and aspect ratio of nanofillers.

In this article, the effect of the addition of graphene oxide (GO) and reduced graphene oxide (rGO) on the mechanical properties, thermal stability, and electrical conductivity of polyvinyl alcohol (PVA) has been investigated. Different weight percentages of nanofillers ranging from 0.5 to 5 wt% have been combined with PVA. The ultrasonic technique has been applied to disperse nanofillers in the PVA solution. The nanocomposite films have been prepared via solution casting technique and the dispersion of nanofillers into the PVA has been studied through optical microscopy. The microstructure, crystallization behavior, and interfacial interaction were characterized through X‐ray diffraction and Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis have been applied to study the thermal properties of the prepared nanocomposites. The DSC results revealed that the crystallization temperature and melting temperature were enhanced in the presence of GO nanofiller. Besides, the tensile strength at break was improved along with the addition of GO; however, elongation at break for PVA/GO and PVA/rGO was diminished. Moreover, all specimens showed insulating behavior and the only sample was electrically conducting, which contain a high amount of rGO (5 wt%).

Phone: þ48 22 55 26 416, Fax: þ48 22 822 59 96Combustion synthesis is known as a cost-effective technique to produce many novel ceramic nanomaterials such as nitrides, carbides, and intermetallic compounds. Herein, we report an extremely fast chemical transformation of magnesium-magnesium oxalate (Mg/MgC 2 O 4 ) mixtures into solid products containing different nanocarbons and MgO. Despite a wide range of molar ratios of reactants all combustions, carried out in Ar at 1 MPa, were successful. The solid products were chemically purified (leaching of unreacted Mg and MgO) and characterized by XRD, SEM/EDX, TEM, DSC, and Raman spectroscopy. The residue contained mostly layered (circa several nm thick) carbon petal-like nanostructures and carbon-coated MgO.

We demonstrate a novel and simple protocol for the fast and autothermal synthesis of layered graphene-related nanomaterial via the self-sustaining combustion synthesis. Various initial composition of starting reactants (Mg/CaC 2 O 4 and Mg/MgC 2 O 4 ) were tested and the effects of the operational parameters were systemically investigated in terms of the efficiency of product formation and its characteristics. The obtained products were analyzed using X-ray diffraction, electron microscopy, Raman spectroscopy and thermogravimetric analysis. The as-produced 3D graphene-related material has interesting properties and can be used in supercapacitors and as adsorbent for the removal of organic compounds. Graphene, a unique two-dimensional (2D) array of monolayer carbon atoms packed into a dense honeycomb crystal, has attracted much attention because of its diverse and extraordinary properties, i.e. electronic, magnetic, thermal, lubricant, chemical, optical, and mechanical.1 Graphene-related materials are also postulated to be used in energy conversion and storage.2 Thus, graphene and graphene-related materials have shown many applications in nanoelectronics, 3 sensors, 4 composite materials, 5 and in an environmental engineering.6 Carbon and graphitic materials have also been for decades a workhorse material in electrochemistry.7 Graphene was first produced by Novoselov et al. by mechanical exfoliation of graphite in 2004. 8 Since then many techniques have been proposed to obtain graphene with a main approach via energy-and timeconsuming wet chemistry route of graphite exfoliation. Jankovsky et al. 9 presented recently in details the thermal exfoliation/reduction of graphite oxide.The focus of this work is to obtain hierarchical layered carbons. Such few-layered graphene is also called 3D graphene 10 which, in fact, has many potential applications including energy storage (capacitors, electrodes), gas sensing, catalysis, biomedicine (biocompatible scaffolds), adsorption, hydrogels, and composites. As for example, Zhang et al. reported recently the synthesis of porous 3D graphene-based material with excellent properties for such applications. 11Herein we apply a self-propagating high-temperature synthesis (SHS), also called combustion synthesis (thermolysis) which has been widely used for years for fabrication of many compounds with large negative heat of formation.12,13 Such fast process usually progresses in a self-sustaining and energy self-efficient regime.7 In fact, we have shown elsewhere that SiC nanowires can be efficiently synthesized from simple starting reactants (Si/Teflon).14,15 Zhao et al. presented recently 16 an approach for synthesizing graphene through a magnesiothermic reduction of calcium carbonate, while Poh et al. 17 synthesized graphenes for electrochemical applications via reduction of CO 2 by lithium.The aim of this work was to test such a synthetic strategy for converting carbon-containing Ca/Mg oxalates into 3D graphene-related materials. The electrochemical measurements were performed to e...

We present the results of exploratory research on the fast synthesis of few‐layered graphite via a self‐propagating high‐temperature synthesis (SHS). We reported previously that different solid carbonates and gaseous carbon oxides could be directly converted into novel nanocarbons using strong reducers and SHS approach. In the current work, such combustion synthesis (CS) is extended toward the direct and efficient reduction and exfoliation of graphite oxide (GO) or fluorinated graphite (CFx) using different reducers (Si, Mg, NaN3, Li3N) into few‐layered graphene (FLG).

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