Novel silicificated PVAc/POSS composite nanofibrous mat via facile electrospinning technique: potential scaffold for hard tissue engineering.

This study presents the fabrication of novel porous silicificated PVAc/POSS composite nanofibers by facile electrospinning technique and the interaction of synthesized mats with simulated body fluid (SBF). The physicochemical properties of the electrospun composites were determined by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electron probe micro-analysis, X-ray diffraction and thermogravimetry analysis. To examine the in vitro cytotoxicity, mouse myoblast C2C12 cells were treated with pristine and composite nanofibrous mats and the viability of cells was analyzed by cell counting kit-8 assay at regular time intervals. Our results indicated the enhanced nucleation and the formation of apatite-like structures at the surface of silicificated PVAc/POSS during the incubation of electrospun mats in SBF solution. Cytotoxicity experiments designated that the myoblasts could attach to the composite after being cultured. We observed in the present study that PVAc/POSS nanofibrous mat could support cell adhesion and guide the spreading behavior of myoblasts. We conclude that the new electrospun silicificated PVAc/POSS composite scaffold with unique porous morphology have excellent biocompatibility. Consequently, our investigation results showed that the as-spun porous PVAc/POSS composite nanofibrous scaffold could be a potential substrate for the proliferation and mineralization of osteoblasts, enhancing bone regeneration. The biocomposite mats represent a promising biomaterial to be exploited for various tissue engineering applications such as guided bone regeneration.

Fabrication, characterization and antibacterial effect of novel electrospun TiO2 nanorods on a panel of pathogenic bacteria.

This study is aimed at the synthesis and characterization of novel Titania nanorods by sol-gel electrospinning technique. The physicochemical properties of the synthesized nanorods were determined by FE-SEM, EDX, TEM, TGA and XRD. We investigated the photocatalytic activity of Titania nanorods for degrading Rhodamine 6G dye and discussed the antibacterial activity and interaction mechanism against four pathogenic bacteria viz., S. aureus, E. coli, S. typhimurium and K. pneumoniae by taking five different concentrations (5-45 microg/mL). The antibacterial effect of electrospun Titania nanorods was tested both in liquid culture and on agar plates. Our investigation reveals that the lowest concentration of Titania nanorods solution inhibiting the growth of microbial strain was found to be 5 microg/mL for all the tested pathogens. The photocatalytic activity of TiO2 nanorods showed better performance for dye degradation than commercially available P25. Moreover, Bio-TEM examination demonstrated that the exposure of the selected microbial strains to the Titania nanorods led to disruption of the cell membranes and leakage of the cytoplasm which cause bacteria to die eventually. Our results point the oxidative attack from exterior to the interior of the bacteria by hydroxyl radicals as the primary mechanism of photocatalytic inactivation.

Controlled synthesis of Mn2O3 nanowires by hydrothermal method and their bactericidal and cytotoxic impact: a promising future material.

Mn2O3 nanowires with diameter ~70 nm were synthesized by a simple hydrothermal method using Mn(II) nitrate as precursor. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy techniques were employed to study structural features and chemical composition of the synthesized nanowires. A biological evaluation of the antimicrobial activity and cytotoxicity of Mn2O3 nanowires was carried out using Escherichia coli and mouse myoblast C2C12 cells as model organism and cell lines, respectively. The antibacterial activity and the acting mechanism of Mn2O3 nanowires were investigated by using growth inhibition studies and analyzing the morphology of the bacterial cells following the treatment with nanowires. These results suggest that the pH is critical factor affecting the morphology and production of the Mn2O3 nanowires. Method developed in the present study provided optimum production of Mn2O3 nanowires at pH ~ 9. The Mn2O3 nanowires showed significant antibacterial activity against the E. coli strain, and the lowest concentration of Mn2O3 nanowires solution inhibiting the growth of E. coli was found to be 12.5 µg/ml. TEM analysis demonstrated that the exposure of the selected microbial strains to the nanowires led to disruption of the cell membranes and leakage of the internal contents. Furthermore, the cytotoxicity results showed that the inhibition of C2C12 increases with the increase in concentration of Mn2O3 nanowires. Our results for the first time highlight the cytotoxic and bactericidal potential of Mn2O3 nanowires which can be utilized for various biomedical applications.

Giant mesenteric lipoma as an unusual cause of abdominal pain: a case report and a review of the literature.

We report a rare case of giant mesenteric lipoma presenting with colicky abdominal pain. A 29-yr-old woman underwent laparoscopic resection for a giant mesenteric lipoma causing compression of the ileal loop. The resected ileal segment was encased by a giant fatty tissue, and normal mucosal fold patterns of the resected ileum were effaced by the mass. Microscopically, the mass was characterized by homogenous mature adipose tissue without cellular atypia, which was compatible with the diagnosis of a mesenteric lipoma. Despite the benign nature of this tumor, total excision with or without the affected intestinal loop should be considered if intestinal symptoms such as abdominal pain are present.

Roles of work of adhesion between carbon blacks and thermoplastic polymers on electrical properties of composites.

The effect of the work of adhesion between carbon blacks and different thermoplastic polymers on the positive temperature coefficient (PTC) of composites was investigated. Thermoplastic polymers, such as EVA, LDPE, LLDPE, HDPE, and PP, were used with the addition of 30 wt% of carbon blacks. The work of adhesion based on the surface free energy of a composite was studied in the context of two-liquid contact angle measurements using deionized water and diiodomethane. It was observed that the resistivity on PTC behavior was greatly increased near the crystalline melting temperature, due to the thermal expansion of polymeric matrix. It was shown that the PTC intensity defined as the ratio of the maximum resistivity (rho(max)) to the resistivity at room temperature (rho(RT)) had the largest value on CB/HDPE composites. From the experimental results, the decrease in the work of adhesion induced by interactions between carbon black surfaces and polymer chains is an important factor in the fabrication of a PTC composite.