In situ synthesis of long tubular water-dispersible polyaniline with core/shell gold and silver@graphene oxide nanoparticles for gas sensor application.

Gold nanoparticles (Au NPs) with graphene oxide (GO) shell (Au@GO), silver nanoparticles (Ag NPs) with GO shell (Ag@GO), and gold silver nanoparticles (AuAgNPs) with GO shell (AuAg@GO) were synthesized employing a cationic surfactant. The prepared core@shell structures were used for in situ synthesis of long tubular polyaniline structures employing cetyl trimethyl ammonium bromide (CTAB) as a soft template. This process led to a notable enhancement in the tubular nanostructure of PANI, extending its length beyond 10 µm, in the case of using core/shell Au@GO, Ag@GO, and AuAg@GO structures. To evaluate their applicability and compatibility, the dispersibility of these nanocomposites was assessed in three distinct solvents: water, dimethyl sulfoxide (DMSO), and N-Methyl-2-pyrrolidone (NMP). Subsequently, the dedoping of PANI within the prepared nanocomposites was scrutinized using UV-Visible (UV-Vis) spectroscopy, which revealed a reduction in the I750/I315 ratio from 1.00 to 0.66 when subjected to water and NMP solvents, respectively. Notably, the dedoping of the AuAg@GO/PANI nanocomposite was predominantly observed in NMP, attributable to the presence of hydrogen bonding interactions and the basic properties of NMP. In terms of ionic conductivity, it was observed that the prepared nanocomposite exhibited its highest conductivity in a water-based medium, registering at 1982 µs. Furthermore, the AuAg@GO/PANI nanocomposite exhibited superior sensing capabilities in comparison to PANI-based gas sensor devices, particularly when exposed to acetone, CO2, NO2, and H2S. Remarkably, at room temperature (25 °C), the AuAg@GO/PANI nanocomposite displayed rapid response and recovery times, with values of 279 s, 431 s, 335 s, and 509 s for 1 ppm concentrations of CO2, NO2, H2S, and acetone, respectively. The sensitivity of these sensors towards acetone, CO2, NO2, and H2S, was quantified by analyzing the slope of the response versus the target gas concentration, revealing the AuAg@GO/PANI nanocomposite to exhibit the highest sensitivity, particularly towards NO2.

Design and characterization of Poly(glycerol sebacate)/Poly(3-hydroxybutyrate)/bioglass/curcumin nanocomposite scaffold for wound healing application.

Various applications have been developed for biopolymers, such as scaffolds for tissue engineering. Nanocomposite materials are considered promising for wound healing applications in many unique fields. New nanocomposite scaffold biopolymers were synthesized through the salt leaching technique. Curcumin and bioglass nanoparticles as antibacterial agents were added to Poly(glycerol sebacate)/Poly(3-hydroxybutyrate) nanocomposite scaffolds with different concentrations. Several properties were explored, including morphology, physicomechanical properties, contact angles, antibacterial efficacy, and in vitro studies. The morphology of nanocomposite scaffolds was characterized using SEM and EDX. Additionally, nanocomposite scaffolds Poly(glycerol sebacate)/Poly(3-hydroxybutyrate) showed a water contact angle of 79.8°. The hydrophilicity and water vapor transition rate significantly improved by adding bioglass nanoparticles which were 55° and 2182 g m-2 day-1 for Poly(glycerol sebacate)/Poly(3-hydroxybutyrate)/5 %Bioglass/3 %Curcumin. Samples containing 3 wt% Curcumin had the highest swelling ratio (347 ± 12 %) and the lowest water contact angle. Furthermore, NIH/3T3 fibroblast cells showed significant attachment and viability in in-vitro biocompatibility tests. Bioglass and Curcumin inhibited bacterial growth effectively. Additionally, an in-vitro cell viability, cell attachment, and in-vitro scratch wound healing assay demonstrated that the Poly(glycerol sebacate)/Poly(3-hydroxybutyrates)/5 % Bioglass/3 % Curcumin nanocomposite scaffold could promote wound healing.

Design and characterization of bio-elastomers containing biomaterials for tissue engineering application.

AIMS: The purpose of this research is to fabricate a new type of bio-elastomer based on Poly(glycerol-sebacate)-co-Poly(hydroxybutyrate) (PGS-co-PHB) with varying amounts of bioglass 45S5 (BG) nanoparticles (1, 3 and 5 wt%) through the green polycondensation polymerization for tissue engineering applications. MATERIALS AND METHODS: Fabricated composite films are characterized by FTIR, 1H NMR, SEM, EDX, contact angle, DMTA, biodegradability, and biocompatibility. The cell viability and morphology of L929 cells are investigated by indirect MTT assay and SEM analysis, and the antibacterial activity of composite film is determined by the disk diffusion method. Furthermore, the bioactivity of the composite film is measured by soaking in simulated body fluid (SBF), and XRD and SEM determined the formation of a hydroxyapatite (HA) layer. KEY FINDINGS: The hydrophilicity improved by adding BG nanoparticles, and the water contact angle was reduced to 63.46°. Furthermore, the average cell viability of composite film is about 94 %, and the SEM images show that L929 fibroblast cells are well spread on the surface of the composite film. BG has a significant influence on the antibacterial activity of composite film as PGS-co-PHB/5 %BG shows more antibacterial properties due to the higher amount of BG. SEM and XRD analyses confirmed the presence of crystalline HA on the surfaces of the composite film, indicating their potential for high bioactivity. SIGNIFICANCE: The results indicate that the antibacterial composite films are excellent supports for cell growth and proliferation and could be promising candidates for tissue engineering applications.

A novel poly(2-mercaptobenzothiazole) coated magnetic nanoadsorbent derived from ZIF-8 for preconcentration/determination of palladium and silver.

Herein, a novel poly(2-mercaptobenzothiazole) coated magnetic nanoadsorbent derived from zeolitic-imidazole framework-8 (ZIF-8) was synthesized and then employed for the extraction/preconcentration of trace amounts of palladium and silver in various real matrixes. In this way, magnetite was fabricated first, and then functionalized with tetraethyl orthosilicate. After that, the synthesized magnetite@silica was coated with the ZIF-8 to obtain magnetic ZIF-8. Afterward, the magnetic ZIF-8 was pyrolyzed under the protection of a nitrogen atmosphere to get a magnetic carbon nanoadsorbent. Finally, the magnetic carbon was functionalized with a conductive polymer (poly-2-mercaptobenzothiazole). Fabrication of the nanoadsorbent was affirmed with scanning and transmission electron microscopies, elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The method is linear from 0.25 to 200 µg L-1 for silver, and from 0.5 to 250 µg L-1 for palladium. The detection limits are 0.07 and 0.15 µg L-1 for Ag and Pd, respectively. The precision was evaluated at three concentration levels (1, 75, 200 µg L-1, n = 5) and all the relative standard deviation (RSD) values were lower than 10.3%. In the end, the new method was utilized for the preconcentration/determination of trace amounts of palladium and silver in various real matrixes, satisfactorily (relative recovery: 86% to 104%; RSD%: 4.0-9.5%).

Enhanced efficiency in hollow core electrospun nanofiber-based organic solar cells.

Over the last decade, nanotechnology and nanomaterials have attracted enormous interest due to the rising number of their applications in solar cells. A fascinating strategy to increase the efficiency of organic solar cells is the use of tailor-designed buffer layers to improve the charge transport process. High-efficiency bulk heterojunction (BHJ) solar cells have been obtained by introducing hollow core polyaniline (PANI) nanofibers as a buffer layer. An improved power conversion efficiency in polymer solar cells (PSCs) was demonstrated through the incorporation of electrospun hollow core PANI nanofibers positioned between the active layer and the electrode. PANI hollow nanofibers improved buffer layer structural properties, enhanced optical absorption, and induced a more balanced charge transfer process. Solar cell photovoltaic parameters also showed higher open-circuit voltage (+ 40.3%) and higher power conversion efficiency (+ 48.5%) than conventional architecture BHJ solar cells. Furthermore, the photovoltaic cell developed achieved the highest reported efficiency value ever reached for an electrospun fiber-based solar cell (PCE = 6.85%). Our results indicated that PANI hollow core nanostructures may be considered an effective material for high-performance PSCs and potentially applicable to other fields, such as fuel cells and sensors.

Fabrication of a novel magnetic metal-organic framework functionalized with 2-aminothiophenol for preconcentration of trace silver amounts in water and wastewater.

Herein, a novel magnetic metal-organic framework functionalized (MMOF) with 2-aminothiophenol (2-ATP) was fabricated and employed for separation/preconcentration of trace silver amounts. At first magnetite nanoparticles (Fe3O4 NPs) were synthesized and then coated with SiO2. Thereafter, the Fe3O4@SiO2 nanoparticles were modified with 2-ATP. Finally, the functionalized MMOF was prepared by the fabrication of MIL-101(Cr) in the presence of Fe3O4@SiO2@2-ATP NPs. MIL-101(Cr)/Fe3O4@SiO2@2-ATP nanocomposite was characterized with FT-IR, SEM, elemental analysis, XRD and VSM and then utilized in the separation/determination of silver ions in various real samples. The effects of diverse experimental variables such as pH, uptake time, adsorbent amount, desorption time, eluent concentration and volume were studied comprehensively employing experimental design methodology. After optimization, LOD and linearity were 0.05 ng mL-1 and 0.2-200 ng mL-1, respectively. Repeatability of the new method was determined based on RSD value for 5, 50, 150 ng mL-1 (n = 5) concentrations which was 9.3%, 6.8% and 4.5%, respectively. Ultimately, the outlined method was utilized in the separation/determination of silver ions in various water and wastewater samples satisfactorily.

Fabrication of biocompatible antibacterial nanowafers based on HNT/PVA nanocomposites loaded with minocycline for burn wound dressing.

Bacterial infections of burn wounds are a significant problem that usually slows or stops the process of burn wounds healing. The use of topical antibiotics based on a novel drug delivery system could overcome the limitations of burn wound healing. In this work, the development of new wound dressings based on nanocomposite film of polyvinyl alcohol (PVA) and halloysite nanotubes (HNT) for the delivery of minocycline was investigated. These elastomeric nanocomposites were prepared based on HNT surface modification by APTES and then PVA coating by LbL strategy. The resulting nanocomposites were characterized by FT-IR, XRD, zeta potential, Tg analysis, FESEM, and antibacterial studies. The biodegradability and water uptake of the film were evaluated, the results of which revealed the absorption of scarring and non-degradation of the nanocomposite during treatment. Because minocycline decomposes by light, increasing photostability was another goal that was achieved. The release profile of the drug from the nanocomposite was studied, and it was found to be consistent with the Korsmeyer-Peppas model. In-vitro studies showed the antibacterial effect of nanocomposite on exposure to Gram-positive and Gram-negative bacteria. Due to the properties of the resulting nanocomposite film, it can be considered as a promising candidate for wound healing. In-vivo studies, cell culture, neuroprotective and anti-inflammatory effects may be investigated to develop this wound dressing in the future.

Obtention of 74:26 polyester/cellulose fabric blend with super-hydrophobic and super-hydrophilic properties by air corona discharge treatment and their characterization.

A facile method was used to create both of the super-hydrophilic and super-hydrophobic properties on polyester/cellulose fabric blend. The fabric was exposed to air corona discharge treatment without any extra chemical modification. The static contact angle of 0° and 167° was indicated for super-hydrophilic and super-hydrophobic samples, respectively. The decrease of intensity of active functional groups and the increase of roughness with a nano-scale pattern presented a super-hydrophobic surface that confirmed by ATR-FTIR, AFM and FESEM analysis. This is while the increase of intensity of the active functional groups and the surface roughness with a micro-scale pattern was shown for the super-hydrophilic sample. The wettability tests show the enhancement of hydrophobic and hydrophilic properties for 300 W-10 min and 800 W-10 min corona discharge treated samples, respectively. Therefore, there is a critical point of the corona discharge process that enables it to create hydrophobic and/or hydrophilic properties on the substrates.

Enhancing the photovoltaic performance of bulk heterojunction polymer solar cells by adding Rhodamine B laser dye as co-sensitizer.

Ternary blend (TB) strategy has been considered as an effective method to enhance the photovoltaic performance of bulk heterojunction (BHJ) polymer solar cells (PSCs). Here, we report on TB-based PSCs containing two donor materials; poly-3-hexylthiophene (P3HT) and Rhodamine B (RhB) laser organic dye, and [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) as an acceptor. The influence of RhB weight percentage and injection volume was extensively studied. To gain insight into the influences of RhB on the photovoltaic performance of PSCs, physicochemical and optical properties of TBs were compared with those of BHJ binary blend as a standard. RhB broadened the light absorption properties of the active layer and played a bridging role between P3HT and PC61BM. The PCE and short-circuit current density (Jsc) of the optimized TB-based PSCs comprising of 0.5 wt% RhB reached 5% and 12.12 mA/cm2, respectively. Compared to BHJ standard cell, the PCE and the generated current was improved by two orders of magnitude due to higher photon harvest of the active layer, cascade energy level structure of TB components and a considerable decrease in the charge carrier recombination. The results suggest that RhB can be considered as an effective material for application in PSCs to attain high photovoltaic performance.

Fabrication of in situ polymerized poly(butylene succinate-co-ethylene terephthalate)/hydroxyapatite nanocomposite to fibrous scaffolds for enhancement of osteogenesis.

A combination of elastic poly(butylene succinate-co-ethylene terephthalate) and rigid nano-hydroxyapatite were used to prepare an in-situ synthesized nanocomposite mimicing bone structure. The microstructure, morphology, and dispersion of nanoparticles in the nanocomposites were studied using proton nuclear magnetic resonance (1 HNMR), scanning electron microscope (SEM), and transmission electron microscopy (TEM), respectively. Then, electrospinning method was used to produce nanofiber matrix with lowest fiber diameter. Presence of chemical bonds among nanoparticles and polymer leads to the excellent particle dispersion and solution phase stability. SEM results show that continuous and bead-free nanofibers were produced and incorporating nanoparticle slightly increased fibers diameter. Elastic modulus, tensile strength, crystallinity, hydrophilicity and hydrolytic degradability of resulted nanofiber increased with nanoparticle but elongation at break slightly decreased. Proliferation and osteogenic differentiation of human mesenchymal stem cell significantly improved by introducing nanoparticle which indicate that electrospun nanofibers could be used as scaffolds for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2622-2631, 2017.

Microfluidic-assisted self-assembly of complex dendritic polyethylene drug delivery nanocapsules.

Microfluidic platform for the synthesis of complex nanocapsules is presented via a controlled self-assembly. The monodisperse nanocapsules in the range of 50-200 nm consist of a dendritic polyethylene core and a Pluronic copolymer shell. The resultant nanocarriers encapsulate large amount of hydrophobic anticancer drug like paclitaxel while providing a low complement activation as well as sustained release profile with high tunability.

(E)-2-tert-Butyl-6-[(naphthalen-1-yl)imino-meth-yl]phenol.

The asymmetric unit of the title Schiff base compound, C(21)H(21)NO, contains two crystallographicaly independent mol-ecules. The dihedral angles between the naphthalene mean plane and the benzene ring are 29.28 (8) and 26.92.(8)° in the two mol-ecules. An intra-molecular O-H⋯N hydrogen bond and weak intra-molecular C-H⋯O hydrogen bonds stabilize the structure of each independent mol-ecule.