Myung-Seob Khil

Morphology and crystalline phase study of electrospun TiO2–SiO2 nanofibres

Nanofibres of TiO2–SiO2 (Ti:Si = 50: 50 mol%) with diameters of 50–400 nm were prepared by calcining electrospun nanofibres of polyvinyl acetate (PVac)/titania–silica composite as precursor. These PVac/titania–silica hybrid nanofibres were obtained from a homogenous solution of PVac with a sol–gel of titanium isopropoxide (TiP) and tetraethoxysilane by using the electrospinning technique. The nanofibres were characterized by scanning electron microscopy (SEM), wide-angle x-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller (BET) surface area. SEM, WAXD and FTIR results indicated that the morphology and crystalline phase of TiO2–SiO2 nanofibres were strongly influenced by the calcination temperature and the content of titania and silica in the nanofibres. Additionally, the BET results showed that the surface area of TiO2–SiO2 nanofibres was decreased with increasing calcination temperature and the content of titania and silica in nanofibres.

GeO2 fibers: Preparation, morphology and photoluminescence property

Nanomicron to submicron fibers of GeO(2) have been prepared using poly(vinyl acetate) and germanium dioxide sol by electrospinning followed by high temperature calcination. The morphology of the fibers have been studied by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. X-ray diffraction indicates that the fibers are single crystal with hexagonal alpha-phase quartz-like structure. At room temperature, the fibers show photoluminescence under excitation at 325 nm. The fibers may have potential applications in one-dimensional optoelectronic nanodevices.

Smart copper oxide nanocrystals: Synthesis, characterization, electrochemical and potent antibacterial activity

We report herein the synthesis and characterization of novel CuO nanocrystals and their electrochemical and potent antibacterial activity. The utilized CuO nanocrystals were prepared by wet chemical method using copper acetate and hexamethylenetetramine (HMTA) as precursors. The physicochemical properties of the synthesized CuO nanocrystals having size ~6 nm were determined by X-ray diffractometer (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM) and ultra violet-visible (UV-Vis) spectroscopy. The antibacterial study was carried out by minimum inhibitory concentration (MIC) using E. coli as model organism. The MIC of the CuO nanocrystals was found to be 2.5 μg/ml and the TEM analysis reveals that CuO nanocrystals caused disturbance to the cell wall which led to the irreversible damage to the cell envelope eventually leading to cell death. Furthermore, mechanism of bactericidal action of novel CuO nanocrystals is discussed in the light of our findings. Additionally, the synthesized CuO nanocrystals were applied as electrode material for supercapacitor. The specific capacitance of CuO nanocrystals measured at a potential scan rate of 5 mV/s was as high as 164.9 F g(-1).

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.

TiO2 nanorods via one-step electrospinning technique: a novel nanomatrix for mouse myoblasts adhesion and propagation.

This study was 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 field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. To examine the in vitro cytotoxicity, mouse myoblast C2C12 cells were treated with different concentrations of as prepared TiO(2) nanorods and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of the cells attached with nanorods were examined by Bio-SEM. Cytotoxicity experiments indicated that the mouse myoblast cells could attach to the TiO(2) nanorods after being cultured. We observed that TiO(2) nanorods could support cell adhesion and growth and guide spreading behavior of myoblasts. We conclude that the electrospun TiO(2) nanorods scaffolds with unique morphology had excellent biocompatibility. Thus, the current work demonstrates that the as-synthesized TiO(2) nanorods represent a promising biomaterial to be exploited for various tissue engineering applications.

Virgin olive oil blended polyurethane micro/nanofibers ornamented with copper oxide nanocrystals for biomedical applications

Recently, substantial interest has been generated in using electrospun biomimetic nanofibers of hybrids, particularly organic/inorganic, to engineer different tissues. The present work, for the first time, introduced a unique natural and synthetic hybrid micronanofiber wound dressing, composed of virgin olive oil/copper oxide nanocrystals and polyurethane (PU), developed via facile electrospinning. The as-spun organic/inorganic hybrid micronanofibers were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis, X-ray diffraction, electron probe microanalysis, and transmission electron microscopy. The interaction of cells with scaffold was studied by culturing NIH 3T3 fibroblasts on an as-spun hybrid micronanofibrous mat, and viability, proliferation, and growth were assessed. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results and SEM observation showed that the hybrid micronanofibrous scaffold was noncytotoxic to fibroblast cell culture and was found to benefit cell attachment and proliferation. Hence our results suggest the potential utilization of as-spun micronanoscaffolds for tissue engineering. Copper oxide–olive oil/PU wound dressing may exert its positive beneficial effects at every stage during wound-healing progression, and these micronanofibers may serve diverse biomedical applications, such as tissue regeneration, damaged skin treatment, wound healing applications, etc. Conclusively, the fabricated olive oil–copper oxide/PU micronanofibers combine the benefits of virgin olive oil and copper oxide, and therefore hold great promise for biomedical applications in the near future.

Preparation, characterization, and cytotoxicity of CPT/Fe2O3-embedded PLGA ultrafine composite fibers: a synergistic approach to develop promising anticancer material

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Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: prospective matrix for satellite cell adhesion and cultivation.

We report the fabrication of novel Fe3O4/TiO2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe3O4/TiO2 hybrid nanofibers were prepared by facile sol-gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe3O4/TiO2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe3O4/TiO2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe3O4/TiO2 composite nanofibers after being cultured. We observed that Fe3O4-TiO2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe3O4/TiO2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine.

Fabrication and characterization of II-VI semiconductor nanoparticles decorated electrospun polyacrylonitrile nanofibers.

Semiconductor nanoparticles incorporated highly aligned electrospun polyacrylonitrile (PAN) composite nanofibers were obtained via a simple, scalable and low-cost dip coating technique at room temperature. The resultant PAN nanofibers exhibited good incorporation of CdS, ZnS and CoS semiconductor nanoparticles. The detailed characterizations of these composite nanofibers were investigated. The incorporation of semiconductor nanoparticles on the surfaces of PAN nanofibers were confirmed by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction analysis. The current-voltage (I-V) characteristics revealed that the electrical conductivity of these composite nanofibers were higher than that of the pristine PAN nanofibers. Overall, the feasibility of obtaining uniformly dispersed semiconductor nanoparticles on PAN nanofibers can be utilized for the realization of various nanotechnological device applications.

Classy non-wovens based on animate L. gasseri-inanimate poly(vinyl alcohol): upstream application in food engineering

We explored electrospinning as a feasible and practicable mode for encapsulation and stabilization of Lactobacillus gasseri. The utilized nanocomposite was prepared using sol-gel composed of animate L. gasseri and inanimate PVA. The objective was to examine the ability of electrospinning method to protect functional properties of probiotic L. gasseri. The PVA was used as an encapsulation matrix as it is biocompatible and hydrophilic in nature thus facilitate an easy revival of bacteria. The characterization of as-spun bioproduct was done by energy-dispersive X-ray spectrometer, SEM, and TEM, whereas thermal behavior was analyzed by thermogravimetry. The viability was confirmed by traditional pour plate method and fluorescence microscopy. Furthermore, to test whether the functionality of L. gasseri was affected, the encapsulated L. gasseri were fed to mouse for colonization. Our results pointed out that encapsulated bacteria were viable for months, and their metabolism was not affected by immobilization; thus, they could be used in food engineering and trade.