Faten Al-Hazmi

Myotube formation on gelatin nanofibers – Multi-walled carbon nanotubes hybrid scaffolds

Engineering functional muscle tissue requires the formation of densely packed, aligned, and mature myotubes. To enhance the formation of aligned myotubes with improved contractibility, we fabricated aligned electrospun gelatin multi-walled carbon nanotubes (MWNTs) hybrid fibers that were used as scaffolds for the growth of myoblasts (C2C12). The MWNTs significantly enhanced myotube formation by improving the mechanical properties of the resulting fibers and upregulated the activation of mechanotransduction related genes. In addition, the fibers enhanced the maturation of the myotubes and the amplitude of the myotube contractions under electrical stimulation (ES). Such hybrid material scaffolds may be useful to direct skeletal muscle cellular organization, improve cellular functionality and tissue formation.

A Bioactive Carbon Nanotube-Based Ink for Printing 2D and 3D Flexible Electronics.

The development of electrically conductive carbon nanotube-based inks is reported. Using these inks, 2D and 3D structures are printed on various flexible substrates such as paper, hydrogels, and elastomers. The printed patterns have mechanical and electrical properties that make them beneficial for various biological applications.

Synthesis and characterization of one‐dimensional vertically aligned Sb‐doped ZnO nanowires

Vertically aligned undoped ZnO and Sb-doped ZnO nanowires have been synthesized on a silicon substrate using the vapor–solid technique, without using a catalyst or predeposited buffer layers. The structure and morphology of the assynthesized nanowires are characterized using X-ray diffraction, scanning and transmission electron microscopies, selected area electron diffraction, and electron dispersive X-ray spectroscopy. The results showed that the use of Si(111) is a critical factor for the growth of vertically aligned nanowires. This is a result of the lattice match on Si(111), which is more favorable with the ZnO lattice structure because the Si(111) surface is hexagonal and has a smaller lattice constant of 3.840 Å. The photoluminescence properties were also investigated at room temperature (300 K). The UV peaks of undoped and Sbdoped ZnO nanowires are located at 3.33 and 3.29 eV, respectively. This redshift of 0.04 eV in the Sb-doped ZnO indicates a reduction of the ZnO band gap caused by the Sb dopant. The temperature-dependent photoluminescence spectra of Sb-doped ZnO nanowires from 10 to 300 K were also examined. This measurement showed that at 10 K several peaks appear, at 3.36, 3.23 and 3.04 eV, which were assigned as acceptor-bound excitons, a donor–acceptor pair and a zinc-vacancy-related peak, respectively. These peaks are shifted with the increase of temperature up to 300 K.

Novel rapid synthesis of zinc oxide nanotubes via hydrothermal technique and antibacterial properties.

ZnO nanotubes with the wurtzite structure have been successfully synthesized via simple hydrothermal solution route using zinc nitrate, urea and KOH for the first time. The structural, compositions and morphology architectures of the as synthesized ZnO nanotubes was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and high resolution transmission scanning electron microscopy (HRTEM). TEM showed that ZnO nanotubes exhibited a wall thickness of less than 2 nm, with an average diameter of 17 nm and the length is 2 μm. In addition, the antibacterial activity of ZnO nanotubes was carried out in vitro against two kinds of bacteria: gram - negative bacteria (G -ve) i.e. Escherichia coli (E. coli) and gram - positive bacteria (G +ve) i.e. Staphylococcus aureus. Therefore, this work demonstrates that simply synthesized ZnO nanotubes have excellent potencies, being ideal antibacterial agents for many biomedical applications.

Hydrogels 2.0: improved properties with nanomaterial composites for biomedical applications.

The incorporation of nanomaterials in hydrogels (hydrated networks of crosslinked polymers) has emerged as a useful method for generating biomaterials with tailored functionality. With the available engineering approaches it is becoming much easier to fabricate nanocomposite hydrogels that display improved performance across an array of electrical, mechanical, and biological properties. In this review, we discuss the fundamental aspects of these materials as well as recent developments that have enabled their application. Specifically, we highlight synthesis and fabrication, and the choice of nanomaterials for multifunctionality as ways to overcome current material property limitations. In addition, we review the use of nanocomposite hydrogels within the framework of biomedical and pharmaceutical disciplines.

Development of Fe/Fe3O4 core-shell nanocubes as a promising magnetic resonance imaging contrast agent.

Here, we report the synthesis, characterization, and properties of Fe/Fe3O4 core-shell nanocubes prepared via a simple route. It includes NaBH4 reduction of FeCl3 in an ethylene glycol solution in the presence of 2-mercaptopropionic acid (surfactant) and trisodium citrate (cosurfactant) followed by surface oxidation with trimethylamine N-oxide. The morphology and structure of Fe/Fe3O4 core-shell nanocubes were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, X-ray powder diffraction, and X-ray photoelectron spectroscopy. All of the methods confirm a Fe/Fe3O4 core-shell structure of nanocubes. Magnetic measurements revealed that the Fe/Fe3O4 core/shell nanocubes are superparamagnetic at 300 K with a saturation magnetization of 129 emu/g. The T2 weighted imaging and the T2 relaxation time showed high MRI contrast and sensitivity, making these nanocubes viable candidates as enhanced MRI contrast agents.

On the prospects of conducting polyaniline/natural rubber composites for electromagnetic shielding effectiveness applications

Conductive polymer composites are at the forefront of composites science research because of the huge number of applications that have been developed around their interesting and unique properties. The present article is focused on the fabrication of natural rubber/polyaniline (NR/PANI) compounds for electromagnetic wave shielding applications at microwave frequency. Their microstructures were examined by means of scanning electron microscopy and thermogravimetric analyses. The as-fabricated NR/PANI composite was mechanically characterized to investigate the effect of dispersion of PANI on NR matrix composite. The dielectric spectroscopy, absorption loss, and reflection loss of NR/PANI composite in the frequency range from 1 to 12 GHz have been performed. The total electromagnetic interference shielding effectiveness by absorption and reflection loss depends on PANI content in the composite. Results show that the NR/PANI composite represents a new class of conducting lightweight material that makes the NR/PANI with good electromagnetic shielding effectiveness that is suitable for use in industrial application such as electronic conducting composite in polymer package and for radar absorbing materials.

Synthesis and characterization of nanostructured aluminum borate by sol–gel method

Nanostructured aluminum borate was synthesized using sol–gel technique. X-ray diffraction study revealed that the synthesized aluminum borate was single crystal. These nanorods have very uniform diameter. High-resolution transmission electron microscope images indicate that aluminum borate is well crystallized. The alternating current (AC) conductivity of the aluminum borate was studied as a function of temperature and frequency. The AC conductivity mechanism of the aluminum borate was found to be proportional to ωs. The exponent s is almost independent with temperature. This suggests that AC conductivity mechanism of the aluminum borate can be interpreted by localized hopping model.

Photoconducting and Photovoltaic Properties of ZnO:TiO2 Composite/p-Silicon Heterojunction Photodiode

A photodiode based on titanium dioxide:zinc oxide (TiO2:ZnO) was fabricated to be used in optoelectronics applications. The TiO2:ZnO composite film was prepared by the sol-gel method. The structural properties of the composite film were analyzed by scanning electron microscopy and X-ray diffraction techniques. It is seen that the film is formed from the nanoparticles. The photoresponsivity properties of the TiO2:ZnO composite film/p-type silicon diode were analyzed by phototransient current and photocapacitance techniques. The diode exhibited an optoelectronic device with obtained photovoltaic and photocapacitance behaviors. It is evaluated that the TiO2:ZnO composite film/p-type silicon diode can be used as a optoelectronic device in optic communications and photoelectric applications.