Search

Surface modification, encompassing both chemical and physical features, plays a crucial role in fulfilling the requirements of biomaterial applications and also improves their performance. Due to that, this study focuses on the optimization of morphology and functionalization of hydroxyapatite (HAP). For this purpose, hydrothermal growth of HAP on (fluorine tin oxide) FTO is carried out in the presence of calcium and phosphate precursors with Ca/P molar ratio of 1.67:1 in the solution. Trisodium nitrilotriacetic acid (NTA) is used as a chelating additive for the first time during hydrothermal process at temperature between 120 and 180 °C for 16–24 h. Further studies on the effect of NTA concentration on HAP formation indicate that hierarchical structures are formed in the presence of NTA with NTA/Ca molar ratio of 1:1 at temperature between 150 and 180 °C for 24 h, improving crystallinity as temperature increasing. To facilitate the functionalization of HAP, the layer deposited at 180 °C with NTA/Ca molar ratio of 1:1 is peeled using two different reagents, Fluoromount™ and polyvinyl alcohol (PVA). The HAP peeled with PVA shows no relevant morphological changes in SEM images, indicating a successful peeling process using PVA. After that, the HAP powders are functionalized with alendronate (AL) molecules and studied using ATR-FTIR, XPS and BET techniques. Chemical shift of PO 4 3− vibrations and appearance of the new peaks assigned to the –NH 2 group demonstrate successful AL-functionalization. The AL-HAP hierarchical structures fabricated with the aid of NTA can be introduced as multifunctional biomaterials for future bio-applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Micro/nanostructures of hydroxyapatite (HAP) were electrochemically grown in an optimized electrolytic bath containing Ca(NO 3) 2 and NH 4 H 2 PO 4 with Ca/P molar ratio of 1.67. To increase the local pH around the substrate and conductivity of the solution, H 2 O 2 and NaNO 3 were added to the electrolytic solution. Voltammetric analysis of the reagents disclosed the electroactive working potential range. The potentiostatic technique was selected as a suitable deposition method to obtain homogenous coatings of HAP by applying a potential of around -1.05 V in the presence of peroxide. Surface modification and functionalization of the as-deposited HAP coatings were carried out using alendronate (AL) solution in different concentrations via soaking and drop-casting methods. Successful chemical binding of AL molecules onto the HAP surface was demonstrated by the appearance of new peaks assigned to the -CH 2 vibrations and shift of PO 4 3− vibrations in the Fourier transform infrared (FTIR) spectra. The AL-functionalized HAP coatings treated by fluorescein isothiocyanate (FITC) allowed to confirm the homogeneous distribution of AL molecules on the HAP surface. The surface-activated HAP coatings by AL can be introduced as multifunctional materials for future applications in drug delivery, bone regeneration and electrochemical biosensors. [ABSTRACT FROM AUTHOR]

This work presents solid-state thermal decomposition synthesis of transition metal ferrites (MFe 2 O 4 , M = Zn, Ni, Cd). In this method, binary complexes of [Zn(en) 3 ] 3 [Fe(ox) 3 ] 2 , [Cd(en) 3 ] 3 [Fe(ox) 3 ] 2 and [Ni(en) 3 ] 3 [Fe(ox) 3 ] 2 (where en = ethylenediamine and ox = oxalate) are introduced as new single-source precursors to fabricate ZnFe 2 O 4 , CdFe 2 O 4 and NiFe 2 O 4 micro/nanostructures, respectively. X-ray powder diffraction (XRD) patterns show that pure CdFe 2 O 4 and NiFe 2 O 4 are formed by thermal decomposition of the single-source precursors at 800 °C. When thermal decomposition of [Zn(en) 3 ] 3 [Fe(ox) 3 ] 2 complex is carried out at 700 and 800 °C, the final products are composed of ZnFe 2 O 4 and metal oxides. It is interesting that pure ferrite materials are not formed by using metal salts instead of the binary complexes. Additionally, the particles prepared by using metal salts are highly agglomerated, and it is difficult to measure the individual particle size. The magnetic properties of the products measured by vibrating sample magnetometer (VSM) indicate that the zinc ferrite synthesized at 800 °C is superparamagnetic while the cadmium and nickel ferrites fabricated at 800 °C have ferromagnetic nature. [ABSTRACT FROM AUTHOR]

[Display omitted] • A magneto-fluorescent contrast agent based on MnFe 2 O 4 and carbon dots is introduced. • MRI studies reveled the efficiency of the nanoparticles as T 2 contrast agent for clinical diagnosis. • In vivo fluorescent imaging indicated that a malignant tumor clearly became distinguishable at 60-min post injection. Bimodal magnetic-fluorescent materials for diagnostic imaging needs surface-engineered nanoparticles with great biosafety, pronounced colloidal stability, high magnetic moments, and strong photoluminescence (PL) emission. This work presents polymer-coated nanoparticles (PCNPs) based on manganese ferrites covered with a thin shell of nitrogen-doped carbon dots for magnetic-resonance and fluorescent dual mode imaging of cancerous tumors in vivo. An in situ thermolysis of metal oxalates and phenylenediamine in diphenyl ether allows for the facile synthesis of hybrid magneto-fluorescent nanoparticles. They possess an average size of 55 ± 5 nm with strong and excitation-independent PL emission at about 600 nm with a saturation magnetization of ∼ 19 emu/g. In vivo dispersion and biosafety of the hybrid nanoparticles are improved by a polymer-coating strategy with the aid of Tween polysorbate. In vitro studies for SK-OV-3 cells reveal that PCNPs are not toxic up to a high concentration of 125 µg/mL. H&E-stained sections of vital organs of animals treated with dosages of 5 mg/kg fail to present any histopathological changes after 24 h post-injection. The fluorescence intensity in the tumor tissue region appears to increases over time and the tumor becomes clearly visible after 60 min. Magnetic resonance imaging (MRI) of phantoms and animal cases also indicates the high efficiency of PCNPs as an T 2 contrast agent in clinical diagnosis. Therefore, the developed PCNPs offer great potential for dual mode imaging of malignant tumors. [ABSTRACT FROM AUTHOR]

Crystalline hydroxyapatite (HAP) nanoparticles and nanorods have been successfully synthesized via a simple precipitation method. To control the shape and particle size of HAP nanocrystals, coordination ligands derived from 2-hydroxy-1-naphthaldehyde were first prepared, characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopies, and finally applied in the synthesis process of HAP. On the other hand, the HAP nanocrystals were also characterized by several techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). According to the FE-SEM and TEM micrographs, it was found that the morphology and crystallinity of the HAP powders depended on the coordination mode of the ligands. [ABSTRACT FROM AUTHOR]

Herein, we report a simple chemical reduction method at low temperature to synthesize different tellurium (Te) nanostructures including nanorods and nanospheres. In addition, the effect of preparation parameters such as solvent, surfactant and reducing agent on the morphology of Te was studied. The as-produced Te nanostructures were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and photoluminescence spectroscopy (PL). Based on the morphological studies, it was found that sphere-like and rod-like nanostructures of Te could be obtained by using potassium borohydride (KBH 4 ) and hydrazine hydrate (N 2 H 4 ·H 2 O) as reducing agents, respectively. On the other hand, very uniform nanoparticles of Te have been formed in the presence of thioglycolic acid (TGA) as surfactant. We have also investigated the photocurrent density–voltage ( J – V ) curve of Te nanorods. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hydroxyapatite nanostructures have been prepared by a simple precipitation method. [•] To control shapes of the products, chelating ligands based on Schiff bases were used. [•] The Schiff bases derived from acetylacetone were applied as novel chelating ligands. [•] Different morphologies of hydroxyapatite nanostructures have been formed. [ABSTRACT FROM AUTHOR]

In this work, crystalline hydroxyapatite (HAP) nanorods were first prepared by a simple precipitation method in the presence of a new capping agent based on Schiff base compounds, and then composite of polyethylene glycol (PEG), graphene oxide (GO), and the HAP nanorods was synthesized by freeze-drying method. X-ray diffraction patterns indicated that poor crystalline HAP powders produced in the absence of Schiff base were highly agglomerated. In addition, in vitro bioactivity of the produced HAP nanorods and PEG/GO/HAP nanocomposite was evaluated by soaking the products in simulated body fluid (SBF). The chemical composition of the SBF solutions was analyzed by inductively coupled plasma-optical emission spectrometry, and it was found that more Ca and P were released from the nanocomposite compared to the pure HAP nanorods, indicating high bioactivity of the nanocomposite. In addition, it was observed that the growth of new apatite on the surface of the nano-sized materials increased after immersion for 14 days in the SBF solution. [ABSTRACT FROM AUTHOR]

New complexing agents based on Schiff base compounds have been employed to fabricate nanocrystalline hydroxyapatite (HAP). The use of the Schiff bases derived from 2-hydroxybenzophenone led to the formation of HAP nanoparticles and nanorods. Moreover, hollow needle-like nanorods of HAP were formed in the presence of the Schiff base derived from 2-aminophenol. In the crystal growth mechanism proposed for HAP crystals, zero-dimensional (0-D) and one-dimensional (1-D) nanostructures were generated by considering tetradentate and bidentate coordination modes of the Schiff bases, respectively. The synthesized products were characterized by several techniques including proton nuclear magnetic resonance (¹H NMR) spectroscopy, transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). [ABSTRACT FROM AUTHOR]

Abstract: In this work, hydroxyapatite (HAP), Ca10(PO4)6(OH)2, nanostructures including nanorods, nanobundles and nanoparticles have been prepared via a simple precipitation method. In the present method, Ca(NO3)2·4H2O and (NH4)2HPO4 were used as calcium and phosphorus precursors, respectively. Besides, the Schiff bases derived from 2-hydroxyacetophenone and different diamines were used as complexing agents for the in situ formation of Ca2+ complexes. The formation mechanism of 0-D and 1-D nanostructures of HAP was also considered. When the complexing agents could coordinate to the Ca2+ ions through N and O atoms to form the [CaN2O2]2+ complexes, HAP nanoparticles were generated. On the other hand, nanorods and nanobundles of HAP were obtained by forming the [CaN2]2+ as well as [CaO2]2+ complexes in the reaction solution. This work is the first successful synthesis of pure HAP nanostructures in the presence of Schiff bases instead of using the common surfactants. [Copyright &y& Elsevier]

Highlights: [•] Silver salicylate as a new precursor was applied to fabricate γ-AgI nanoparticles. [•] To further decrease the particle size of AgI, SDS was used as surfactant. [•] The effect of preparation parameters on the particle size of AgI was investigated. [Copyright &y& Elsevier]

Abstract: In this work, Ag2CrO4 and Ag2Cr2O7 nanostructures have been produced via a sonochemical method using silver salicylate as precursor. Besides silver salicylate, Na2CrO4 and (NH4)2Cr2O7 as starting reagents were applied. To investigate the effect of preparation parameters on the morphology and particle size of Ag2CrO4 and Ag2Cr2O7, sonication time, type of surfactant and its concentration were changed. The as-produced nanostructures were characterized by techniques like powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The scanning electron micrographs showed that particle-like and rod-like nanostructures of Ag2CrO4 and Ag2Cr2O7 were produced using different surfactants. To investigate the catalytic properties of Ag2CrO4 nanoparticles, photooxidation of methyl orange (MO) was performed. According to the obtained results, it was found that the methyl orange degradation was about 87.3% after 280min irradiation of visible light. [Copyright &y& Elsevier]

Abstract: In this investigation, a facile sonochemical route has been developed for the preparation of silver vanadium oxide (SVO) micro/nanorods by using silver salicylate and ammonium metavanadate as silver and vanadate precursor, respectively. Here, silver salicylate, [Ag(HSal)], is introduced as a new silver precursor to fabricate AgVO3 nanorods. The effect of numerous solvents and surfactants on the morphology and sonochemical formation mechanism of AgVO3 nanorods was studied. AgVO3 nanorods were characterized by SEM and TEM images, XRD patterns, FT-IR, XPS, and EDS spectroscopy. SEM, TEM, and XRD results showed that AgO nanoparticles were formed onto AgVO3 nanorods in the presence of ethanol, cyclohexanol, dimethylsulfoxide (DMSO), and acetone. By using polyethylene glycol (PEG-6000) and N,N-dimethylformamide (DMF) as organic additives, the thickness of AgVO3 nanorods decreased. [Copyright &y& Elsevier]

Abstract: In this work, CuInS2 (CIS) nanoparticles have been synthesized with the aid of (1,8-diamino-3,6-dioxaoctan)copper(II) sulfate ([Cu(DADO)]SO4) and bis(propylenediamine)copper(II) sulfate ([Cu(pn)2]SO4) complexes as copper precursor in the presence of microwave irradiation. Besides, l-cystine, InCl3, and sodium dodecyl sulfate (SDS) were applied as sulfur source, indium precursor, and capping agent, respectively. To investigate the effect of preparation parameters like microwave power and irradiation time on the morphology and particle size of CuInS2, the experiment was carried out at different conditions. The as-synthesized CuInS2 nanoparticles were characterized by XRD, FT-IR, PL, SEM, TEM, and EDS. The XRD results showed that pure tetragonal CuInS2 could be only obtained after annealing at 400°C for 2h. The SEM images indicated that with decreasing the microwave power and irradiation time, particle size of CuInS2 nanoparticles decreased. To fabricate a solar cell, CdS film was directly deposited on top of the CIS film prepared by Doctor''s blade method through chemical bath deposition. The as-deposited CdS/CuInS2 films were used for the photovoltaic measurements. [Copyright &y& Elsevier]

Abstract: The present work reports the synthesis of magnesium oxide (MgO) nanocrystals via a thermal decomposition route and the study of physicochemical properties of products. The MgO nanocrystals were prepared from magnesium oxalate powders as precursor. Transmission electron microscopy (TEM) analysis demonstrated MgO nanocrystals with an average diameter of about 20−25nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electronic diffraction (SAED), and Fourier transform infrared (FT-IR) spectroscopy. Optical absorption and photoluminescence emission properties of MgO nanocrystals were investigated. [ABSTRACT FROM AUTHOR]

Abstract: Pure tin dioxide (SnO2) nanoparticles were synthesized via thermolysis of tin phthalate and tin oxalate in the presence of oleic acid (OA) as solvent. Oleic acid (OA) was employed as an organic solvent, which can be applied to control particle growth and to stabilize the particles. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The orthorhombic phase SnO2 nanoparticles with average size about 12nm were synthesized through thermolysis of tin phthalate in the presence of oleic acid. [Copyright &y& Elsevier]

Abstract: Benzenedicarboxylate complexes, especially phthalate ones, can be significant precursors for the preparation of nano-sized metal and metal oxides. The injection of organic surfactants such as oleic acid (OA) and triphenylphosphine into molecular precursors has yielded samples with size control, narrow size distributions and crystallinity of individual nanocrystals. Fourier transform infrared and X-ray photoelectron spectroscopy revealed that the OA molecules were adsorbed on the ferromagnetic nanoparticles by chemisorption. The temperature-dependent magnetization curve in zero-field-cooled and field-cooled exhibit weak ferromagnetism of the Co3O4 nanoparticles. At 300K the remanent magnetization is 0.02emu/g, the coercive field is 441Oe and the magnetization at saturation is 1.05emu/g. [Copyright &y& Elsevier]

Abstract: A novel manganese coordination polymer [Mn(Pht)(H2O)] n as a precursor was obtained by chemical precipitation involving an aqueous solution of anhydrous manganese acetate and phthalate anion as a potential O-banded ligand. Fourier transform infrared (FT-IR) results proved that phthalate anions coordinate to metal cations as a chelating bidentate ligand, making polymeric structure. The Mn2O3 nanostructures have been prepared via thermal decomposition of as-prepared manganese phthalate polymers as precursor in the presence of oleic acid (OA) and triphenylphosphine (TPP) as a stabilizer and capping. Different approaches such as FT-IR, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied to characterize the products. TEM images and XRD analysis indicated that the as-synthesized chain-like Mn2O3 has a crystal phase of cubic syngony with a mean size of ∼40nm. [Copyright &y& Elsevier]

Abstract: The present investigation reports, the synthesis of manganese oxide (α-Mn2O3) nanobundles using thermal decomposition and its physicochemical characterization. The α-Mn2O3 nanobundles have been prepared using manganese oxalate dihydrate powders as precursor in the presence of oleylamine and triphenylphosphine as solvent and capping agent. Transmission electron microscopy (TEM) analysis demonstrated Mn2O3 nanobundles compose of nanospheres with diameter 30nm. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. Manganese oxide nanocrystals have been prepared under different condition. The controlled experimental results showed that the use of oleylamine and triphenylphosphine as the solvent and capping agent in the chemical process played important role in the formation of the final products. [Copyright &y& Elsevier]

Abstract: This study focuses on the preparation and characterization of single phase NiO nanoparticles. At first, nickel-o-phthalate complexes as precursor were synthesized through semisolid phase reaction method and then NiO nanoparticles were obtained via a solid-state decomposition procedure of layered coordination nickle-o-phthalate complexes formulated as [Ni(pht)(H2O)2] and [Ni(pht)2]. In addition, the effects of calcination temperature and metal-to-ligand ratio on the particle size and morphology of NiO were investigated. Thermogravimetric analysis (TGA) was applied to determine the thermal behavior of complexes. The crystalline structure of products by X-ray diffractometer (XRD), morphology of particles by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were studied. The composition of as-prepared sample was studied by X-ray photoelectron spectroscopy (XPS) spectra. Analysis of FT-IR spectra confirmed the composition of products. The magnetic property was studied with vibrating sample magnetometer (VSM). [Copyright &y& Elsevier]

Abstract: The present study reports the preparation and characterization of PbO nanocrystals obtained via a thermal decomposition route. The PbO nanocrystals were synthesized using lead oxalate powder as a precursor. Nanostructured products were investigated by means of XRD, TEM, FT-IR and XPS. The XRD results indicate that tetragonal phase β-PbO with a particle size of about 30–45nm was obtained when the intermediate precipitate was calcined at 500°C. [Copyright &y& Elsevier]

Objectives: To investigate the effects of blood and platelet-rich fibrin (PRF), commonly used scaffolds in regenerative endodontic treatment (RET), on the hydration, microstructure, and color stability of three hydraulic calcium silicate cements (HCSCs), OrthoMTA, RetroMTA, and TotalFill-BC-RRM. Materials and methods: The HCSCs were prepared and placed into polyethylene molds and transferred to Eppendorf tubes containing PRF, blood, or PBS and then incubated for 1 week or 1 month. The microstructure and hydration of the cements were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The chromatic alteration of materials was also measured using a spectrophotometer. The data for color stability were analyzed using 2-way analysis of variance and Tukey post hoc tests. Results: There was no significant difference between the color stability of cements exposed to PBS (p > 0.05). The chromatic alteration of cements exposed to blood was significantly greater than those exposed to PRF and PBS (p < 0.001). In the presence of blood and PRF, the color change of OrthoMTA was significantly greater than that of RetroMTA and TotalFill (p < 0.05), with no significant difference between RetroMTA and TotalFill (p > 0.05). XRD analysis of all cements revealed a calcium hydroxide peak after 1-week and 1-month exposure to the media; however, OrthoMTA and TotalFill exposed to blood and PRF for 1 month showed weaker calcium hydroxide peaks. SEM images revealed cements exposed to PBS had a different surface microstructure compared to those exposed to blood and PRF. Furthermore, the surface microstructure of HCSCs was influenced by the type of cement radiopacifier (bismuth oxide or zirconium oxide). EDS analysis of the elemental composition in all groups displayed peaks of Ca, O, C, Si, P, and Al. Conclusions: Color stability, hydration behavior, and microstructure of HCSCs were affected by exposure to PRF and blood and the type of cement radiopacifier. Clinical relevance: As some important physicochemical properties of HCSCs could be influenced by the environmental conditions and the type of radiopacifier, alternatives to blood clot and HCSCs containing substitutes for bismuth oxide might be more suitable in RETs. [ABSTRACT FROM AUTHOR]

In this research, the authors report the preparation of graphite nanosheets via thermal reduction of graphite oxide (GO) in presence of Ar gas. The GO as an intermediate compound were synthesized through the oxidation of graphite powders by H2SO4, HNO3, KMnO4, and H2O2. The effect of temperature and reduction time was studied in synthesis of the final products. The optimum reduction temperature to form graphite nanosheets was 900°C because the graphite nanosheets were individually exfoliated at temperature around 900°C. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to characterize the products. It was found that the temperature and reduction time were confirmed to be the crucial factors in removal of oxygen functional groups from surface of graphite oxide. [ABSTRACT FROM PUBLISHER]

Skin acts as a protective barrier for the underlying organs against external events such as irradiation of ultraviolet rays, incursion of harmful pathogens, and water evaporation. As the skin is constantly liable to damage, the wound-healing process is vital to the survival of all organisms. Materials design and development for enhanced wound healing and skin tissue regeneration have been found highly valuable in recent years. A wide range of materials and structures, including dressings and tissue-engineered substitutes composed of synthetic and/or natural biopolymers and their composites have been developed and examined. Although some have clinically been proven and are available in the market, mimicking the architecture of native extracellular matrix is still an open challenge with fundamental limitations in reproducing skin appendages, sufficient vascularization, adherence to the wound bed, and scarless wound management. Biomimetic nanofibers with tunable morphological, biological, and physicochemical features are promising candidates to overcome these drawbacks. Combined with advanced biomanufacturing and cell culturing techniques, enabling the incorporation of growth factors and stem cells within morphologically-controlled nanostructures, the fibrous structures allow the regeneration of functional skin. This paper overviews the advances in state-of-the-art strategies for designing biomimetic nanofibrous materials with a high potential for wound healing and skin regeneration. An emphasis is given to multifunctional nanocomposites with mechanobiological properties matching those of natural skin. Opportunities, challenges, and commercial status of these materials for skin repair are outlined, and their future perspective is demonstrated. The advances in smart wound management are also discussed, particularly by highlighting the potential of stimuli-responsive materials and integrated sensors in the progress of next-generation dressings for simultaneous monitoring and on-demand treatment of wounds. [ABSTRACT FROM AUTHOR]

Myocardial infarction is a major cause of death worldwide and remains a social and healthcare burden. Injectable hydrogels with the ability to locally deliver drugs or cells to the damaged area can revolutionize the treatment of heart diseases. Herein, we formulate a thermo-responsive and injectable hydrogel based on conjugated chitosan/poloxamers for cardiac repair. To tailor the mechanical properties and electrical signal transmission, gold nanoparticles (AuNPs) with an average diameter of 50 nm were physically bonded to oxidized bacterial nanocellulose fibers (OBC) and added to the thermosensitive hydrogel at the ratio of 1% w/v. The prepared hydrogels have a porous structure with open pore channels in the range of 50–200 µm. Shear rate sweep measurements demonstrate a reversible phase transition from sol to gel with increasing temperature and a gelation time of 5 min. The hydrogels show a shear-thinning behavior with a shear modulus ranging from 1 to 12 kPa dependent on gold concentration. Electrical conductivity studies reveal that the conductance of the polymer matrix is 6 × 10−2 S/m at 75 mM Au. In vitro cytocompatibility assays by H9C2 cells show high biocompatibility (cell viability of >90% after 72 h incubation) with good cell adhesion. In conclusion, the developed nanocomposite hydrogel has great potential for use as an injectable biomaterial for cardiac tissue regeneration. [ABSTRACT FROM AUTHOR]

For the first time, a Schiff base compound derived from 1,8-diamino-3,6-dioxaoctane and 2-hydroxybenzophenone marked as (2-HBP)-(DaDo) was synthesized, characterized and then used as capping agent for the preparation of PbTe micro/nanostructures. Besides the as-synthesized Schiff base compound, Pb(NO) and Te powders were applied as lead and telluride precursors. In addition, effect of preparation parameters like reaction time and temperature in hydrothermal synthesis on the morphology of the final products was tested. The products were analysed with the aid of SEM, XRD, FT-IR and EDS. Based on the obtained results, it was found that pure cubic phased PbTe has been obtained by this method. According to SEM images, it was found that uniform PbTe micro/nanocubes have been obtained at 180 °C for 12 h. On the other hand, by increasing the reaction temperature from 3 to 24 h, the production of cubic-like shapes increased. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pure tetragonal phase LaVO4 nanoparticles were produced by ultrasound irradiation. [•] Tris(acetylacetonato)lanthanum hydrate ([La(acac)3·3H2O]) was used as a novel precursor. [•] The XRD results showed that monoclinic phase LaVO4 could be obtained without sonication. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nano-sized PbTe powders were prepared with the aid of Schiff-base compound. [•] Hydrothermal method was employed to fabricate PbTe powders. [•] The effect of preparation parameters on the morphology of PbTe was investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] For the first time, Pb(OH)I nanostructures were produced via a simple sonochemical route. [•] N,N-bis(salicylidene)-ethylenediamine (H2salen) was synthesized and applied as surfactant. [•] Different morphologies of Pb(OH)I including nanorods, nanoparticles and nanodisks were formed. [•] XRD analyses proved that pure orthorhombic phase Pb(OH)I could be obtained by this method. [ABSTRACT FROM AUTHOR]

Highlights: [•] PbTe nanostructures were prepared with the aid of Schiff-base compound. [•] Sonochemical and hydrothermal methods were employed to fabricate PbTe nanostrucrues. [•] The effect of preparation parameters on the morphology of PbTe was investigated. [Copyright &y& Elsevier]

In this work, Pb(II) N,N-bis(salicylidene)-ethylenediamine; [Pb(salen)]; was applied as lead precursor to synthesis PbSe nanostructures. Besides [Pb(salen)], SeCl and reducing agents like NH·HO have been employed for the production of PbSe nanostructures via a solvothermal route at 180 °C for 3 h in propylene glycol. The effect of preparation factors such as temperature, reaction time, and surfactant on the morphology of PbSe nanostructures was investigated. The experimental results indicated that PbSe synthesized at 150 and 210 °C was composed of agglomerated particles. On the other hand, the use of KBH as reducing agent led to produce PbSe with higher particle size and agglomeration. The as-prepared PbSe nanostructures were characterized by XRD, SEM, TEM, EDS, and FT-IR. [ABSTRACT FROM AUTHOR]

Abstract: In this work, pomegranate juice was used not only as reductant, but also as capping agent for self-assembly of trigonal nanostructures to form flower-like CuI microstructures. Pomegranate juice was applied as reductant because of the presence of anthocyanin molecules in its ingredients. Besides pomegranate juice, Cu(NO3)2.3H2O and LiI were used as copper and iodide sources for the preparation of CuI nanostructures via a simple precipitation method at ambient conditions. By using different amounts of pomegranate juice, various morphologies of CuI have been obtained. It was found that uniform flower-like CuI microstructures composed of trigonal nanostructures have been successfully produced using 8mL of pomegranate juice. [Copyright &y& Elsevier]

In this investigation, different morphologies of ZnO nanostructures including nanoparticles have been produced by solid-state thermal decomposition of bis(acetylacetonato)zinc(II) nanostructures obtained by the sublimation of bis(acetylacetonato)zinc(II) powder. The sublimation process of the Zn(acac)2 powder was carried out in the range of 110–140°C. The as-synthesized products were analyzed by SEM, TEM, XRD, and EDS. The SEM images showed that the sublimation process in the range of 110–120°C and 130–140°C led to the production of Zn(acac)2 nanofibers and nanorods, respectively. On the other hand, nanofibers and nanoparticles of ZnO were obtained by solid-state thermal decomposition of the as-synthesized Zn(acac)2 nanostructures. [ABSTRACT FROM AUTHOR]

Abstract: In this work, nanostructured PbSe materials have been prepared via a solvothermal method at 180°C with the aid of new lead precursors like Schiff-base compounds; Pb(salpn) and Pb(salophen). Besides lead complexes as lead precursor, SeCl4, and N2H4·H2O as starting materials and propylene glycol as solvent were applied. On the other hand, the effect of preparation factors such as type of reducing and capping agent on the morphology of PbSe nanostructures was investigated. The as-prepared PbSe nanostructures were characterized by XRD, SEM, TEM, EDS, and FT-IR. The SEM micrographs of the products indicated that PbSe nanostructures with lower particle size were obtained after solvothermal treatment for 3h at 180°C in the presence of hydrazine hydrate as reducing agent. The as-obtained results indicated that pure and homogeneous PbSe nanostructures have been form by using Pb(salpn) as precursor. [Copyright &y& Elsevier]

Abstract: For the first time, (1,8-diamino-3,6-dioxaoctan)copper(II) sulfate, [Cu(DADO)]SO4, and bis(propylenediamine)copper(II) sulfate, [Cu(pn)2]SO4, complexes as copper precursors have been used to prepare CuInS2 (CIS) nanoparticles in the presence of microwave irradiation. InCl3 anhydrous, thioacetamide (TAA), and propylene glycol were used as indium source, sulfur precursor, and solvent, respectively. Additionally, sodium dodecyl sulfate (SDS) was used as a capping agent. In this method, microwave irradiation created the activation energy for dissociating the precursors and led to the formation of CuInS2 nanoparticles. The effect of preparation parameters such as microwave power, irradiation time, and type of copper precursor on the particle size of the products was studied. To fabricate a solar cell, CdS film was directly deposited on top of the CIS film through the chemical bath deposition method. The as-deposited CdS/CuInS2 films were used for the photovoltaic measurements. According to I–V curves, it was found that the CIS nanoparticles synthesized by [Cu(DADO)]SO4 complex as precursor was better for solar cell applications. [Copyright &y& Elsevier]

Silver selenide nanoparticles were synthesized by the reaction between silver benzoate and SeCl via a sonochemical method. The as-synthesized AgSe nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra and energy-dispersive X-ray microanalysis. Facile preparation and separation were important features of this route. To the best of our knowledge, it is the first time that silver benzoate was used as silver precursor for the synthesis of silver selenide nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Shape- and size-controlled single-phase α-Fe2O3 (hematite) nanoparticles have been successfully synthesized via a simple and facile thermal treatment route using modified precursors. At first, various ferric-surfactant systems such as: ferric-sugars, ferric-hydrazine, ferric-oleic acid, and ferric-sugar-hydrazine were prepared via a wet-chemical precipitation method and then, these intermediate adducts as precursor were decomposed in at ordinary atmosphere to iron oxide. The morphology and particle size of products were investigated by SEM and TEM images and XRD patterns. These results revealed that the best quality α-Fe2O3 nanoparticles are synthesized through thermal decomposition of ferric-glucose precursor with molar ratio of 1:8 heated at 500°C in a step-wise manner. [Copyright &y& Elsevier]

[Display omitted] • A temperature sensitive hydrogel based on alginate/gelatin/ZrO 2 NPs was successfully prepared. • ZrO 2 NPs were applied as a reinforcement to improve mechanical properties. • The addition of ZrO 2 as a reinforcement directed to a decrease in the pore sizes of microstructures. • Addition of ZrO 2 into hydrogel network increased cell attachment and bioactivity. The desire to regenerate and repair native tissues can be immediately performed by multiple tissue engineering procedures. Gelatin and alginate are biocompatible and biodegradable polymers. The addition of ZrO 2 nanoparticles (NPs) into the alginate-gelatin hydrogel is considered to improve mechanical and chemical properties. Therefore, nanocomposite hydrogels have been manufactured by the freeze-drying procedure utilizing oxidized alginate-gelatin with ZrO 2 NPs as a reinforcement. The fabricated nanocomposite hydrogels were character-ized by FTIR, FESEM, and rheometer. The hydrogels containing a higher ZrO 2 NPs content (1.5%) have better mechanical properties than the hydrogels without NPs. Besides, the swelling behavior, in vitro biodegradation, cell viability and cell attachment of the nanocomposite hydrogels were studied. The outcomes revealed better swelling and regulated biodegradation compared to the hydrogel without NPs. Cell viability investigations confirmed the non-toxic nature of the nanocomposite hydrogels. Cells were observed to be attached to the surfaces and regularly separated through the hydrogels. These outcomes recommended that the advanced nanocomposite hydrogels have the prerequisites for cartilage tissue regeneration and could be utilized for numerous cartilage tissue engineering purposes. [ABSTRACT FROM AUTHOR]

[Display omitted] Stem cell treatment is promising in the various disorders treatment, but its effect is confined by the adverse conditions in the damaged tissues. The utilization of hydrogels has been suggested as a procedure to defeat this issue by developing the engraftment and survival of injected stem cells. Specifically, injectable hydrogels have drawn much attention due to their shape adaptability, ease of use, and the capability to reach body parts that are hard to access. In this study, the thermosensitive injectable hydrogels based on oxidized alginate, gelatin, and carbon nitride quantum dots (CNQDs) have been fabricated for tissue engineering. The mechanical characteristics of the nanocomposite hydrogels were investigated by rheology analysis. The results show that increasing the amount of CNQDs improve the mechanical strength of the nanocomposite hydrogels. The Cross-section morphology of freeze dried hydrogels comprising 0.25, 1.5, and 3.0% CNQDs indicate porous structure with interrelated pores. Besides, the result of in vitro degradation reveals that the hydrogels comprising CNQDs are more durable than the one without CNQDs. A reduction in the biodegradation and swelling ratio is perceived with the addition of CNQDs. The cell viability and attachment show that the nanocomposite hydrogels are biocompatible (>88%) with great cell adhesion to osteosarcoma cell line MG63 depending on the presence of CNQDs. [ABSTRACT FROM AUTHOR]

In the expanding field of tissue engineering (TE), improvement of biodegradability and osteoconductivity of biomaterials are required. The use of non-toxic reagents during manufacturing processes is also necessary to decrease toxicity and increase cell viability in vivo. Herein, we present a novel approach to prepare hydroxyapatite (HA) nanorods from sea bio-wastes through a green and eco-friendly wet-chemical processing for bone TE. Highly porous natural polymer-ceramic nanocomposites made of HA, gelatin (Ge) and carboxymethyl cellulose (CMC) hydrogels are then introduced. It was found that cross-linking of the hydrogel matrix by glucose as a green reagent affected all characteristics of the scaffolds including pore size, swelling, biodegradability, and mechanical properties. The homogeneous microstructure with pore sizes in the range of 100–200 μm were attained at 10–20 wt% glucose concentration. With regard to stability and swelling in phosphate buffer saline (PBS), however, more glucose concentrations were desirable. The high biocompatibility and osteoblast activity of the scaffolds were assayed by MTT and calcium content on cell-cultured scaffolds with mesenchymal stem cells (MSCs). The developed CMC/Ge hydrogels modified with bio-derived HA nanorods have a great potential to be used for non-load bearing applications in bone TE. • A novel approach was used to prepare HA nanorods from sea bio-wastes. • Highly porous natural polymer-ceramic nanocomposites were prepared for TE. • Cross-linking of the hydrogel by glucose affected all characteristics of the scaffolds. • Cross-linking with 20% glucose was suitable for attaining homogeneous microstructure with good stability and swelling. [ABSTRACT FROM AUTHOR]

There has been a great interest in injectable hydrogels for cartilage tissue regeneration since it can simply fill damaged defects within minimum invasive surgical therapies. Injectable nanocomposite hydrogels provide a three-dimensional (3D) scaffold that fits perfectly with the defects and combines the structure of an extracellular matrix to mimic cartilage cells. In this research, we present novel thermoresponsive injectable gelatin (GEL)/oxidized alginate (OA) hydrogels reinforced by zinc oxide nanoparticles (ZnO NPs) and N-hydroxysuccinimide (NHS)/1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as chemical cross-linkers of polymer chains in the 3D scaffold system. The effect of ZnO NPs concentrations was investigated on the mechanical properties of scaffolds, and the outcomes revealed that boosting ZnO NPs content improved the storage modulus of the hydrogel by more than five folds. Comprehension of the injectable hydrogel viscoelasticity is essential in the formulation of suitable GEL/OA/ZnO nanocomposite scaffolds for cartilage tissue engineering. The morphology of the scaffolds possesses porous structures. The scaffold containing 0.05% ZnO NPs has a denser structure compared with uncross-linked hydrogel, and the pore size reduces by increasing the amount ZnO NPs. The in vitro swelling ratio has decreased at higher quantity of ZnO, due to the smaller pore sizes in the scaffolds, which minimizes the water absorption. The in vitro biodegradation reveals that the scaffold containing a higher amount of ZnO NPs (0.05%) is more durable than the one without ZnO NPs. The nanocomposite scaffold exposed biocompatibility >90% for MTT assay and excellent cell adhesion to MG-63 cells. • An injectable hydrogel based on alginate/gelatin/ZnO NPs was successfully fabricated. • ZnO NPs were utilized as a reinforcement to improve mechanical strength. • The resistance to degradation of hydrogels was increased by increasing the ZnO NPs content. • The incorporation of ZnO NPs in the hydrogels increased cell proliferation. [ABSTRACT FROM AUTHOR]

Abstract: Pure cubic phase lead telluride (PbTe) nanostructures have been produced by using a Schiff-base complex as a precursor in the presence of microwave irradiation. The Schiff base used as ligand was derived from salicylaldehyde and ethylenediamine. The Schiff-base complex was marked as [Pb(salen)]. In addition, the effect of the irradiation time and the type of reducing agent on the morphology and purity of the final products was investigated. The as-synthesized PbTe nanostructures were characterized extensively by techniques like X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The microwave formation mechanism of the PbTe nanostructures was studied by XRD patterns of the products. Although it was found that both ionic and atomic mechanisms could take place for the preparation of PbTe, the main steps were according to the atomic reaction process, which could occur between elemental Pb and Te. [Copyright &y& Elsevier]

[Display omitted] • Mixed transition metal oxysulfide nanowires on CVD growth 3DG was introduced. • Enhanced catalytic activity for oxygen evolution reaction was shown. • EIS determined effective charge transfer after sulfurization step in thiourea. • Synergistic effects between graphene and the nanowires were demonstrated. Precious metal-free electrocatalysts based on two-dimensional nanomaterials have efficiently been used for oxygen evolution reaction; however, the low activity and stability of these materials as compared with noble metals are still distractive. We present a novel and high-performance electrocatalyst based on nanowires of mixed transition metal oxysulfide supported by three-dimensional highly porous graphene networks. Electrochemical studies indicated that the high electron transport medium of nanowires and bilayer graphene nanosheets as well as their high active surface area promote the kinetics of oxygen evolution reaction (OER). A quite small overpotential of 260 mV at the current density of 20 mA.cm−2 in 1.0 M NaOH is achieved, which outperforms most of the current carbon-based supported nanostructured electrocatalysts. The electrocatalyst is also very stable in the alkaline medium with a low Tafel slope of 56.8 mV dec−1 and turnover frequency (TOF) of 0.85 mol O 2 per sec. These figures of merit demonstrate the higher performance of the hybrid anode over other noble metal-free electrocatalysts based on both carbon and metal nanostructures. [ABSTRACT FROM AUTHOR]