I.H. Hwang

Statistical analysis of gold nanoparticle-induced oxidative stress and apoptosis in myoblast (C2C12) cells.

Nanoscale gold particles (Au-NPs) with a diameter below 20nm are notably important candidates for various important applications because of their extraordinary quantum size effects. Their high surface area-to-volume ratio facilitates their very high reactivities; therefore, they can be utilised in different ways in biomedical applications. For example, these nanoparticles can penetrate into cells and bind with proteins or DNA and are therefore potential nanostructures employed for sensing and detecting various biological identities. In the present work, we synthesised Au-NPs via a colloidal process using chloroauric acid (HAuCl4·4H2O) and trisodium citrate dihydrate (N3C6H5O7) as a reducing agent. The shape evolution and the structural properties of these NPs were investigated in detail using TEM and high resolution HR-TEM investigations. Different doses of Au NPs have been applied to treat C2C12 myoblast cells in a 24-h incubation period, and a dose-dependent study has also been performed. The cells were cultivated in DMEM with FBS and antibiotics (strepto-penicillin) at 37°C in a 5% humidified environment of CO2 and 95% air. Cell viability analysis using MTT assays revealed that increased concentration of Au NPs (100-1000 ng/mL) resulted in a decreased density of cells. The amount of reactive oxygen species (ROS) in C2C12 cells analysed with Au-NPs (in a dose-dependent manner), and the RT-PCR data demonstrated the up-regulation of caspase-3 and caspase-7 genes in C2C12 cells after treatment with Au-NPs. These results have been confirmed by detailed confocal microscopy (CLSM) studies. In addition, the quantitative analysis of the Au-NPs was also confirmed by statistical analytical parameters, such as precision, accuracy, linearity, limits of detection (LOD) and limit of quantitation (LOQ), quantitative recoveries and relative standard deviation (RSD), and the analyses again exhibited a significant and large effect of Au NPs on C2C12 cells.

Zinc oxide quantum dots: multifunctional candidates for arresting C2C12 cancer cells and their role towards caspase 3 and 7 genes

Recently, nanoscale (<100 nm) inorganic materials, especially spherical shaped zinc oxide quantum dots (ZnO-QDs), have received a lot of attention from the broad community because of their potential utilization in various technologies. Due to their large surface to volume (S/V) ratios and extremely high reactivities, they can easily penetrate in various biological identities, such as cells and proteins, and therefore can sense, diagnose and cure different biological systems. The present study describes the facile synthesis of crystalline ZnO-QDs via a solution process. In addition, C2C12 myoblast cancer cells have been treated with different doses of ZnO-QDs at different incubation times (24, 48, 72 and 96 h). The rate of inhibition of cells was observed using an MTT assay, whereas the morphology of the cells was observed by confocal microscopy (CLSM). The MTT and CLSM investigations confirmed that with an increase in the incubation time, the population density of cancer cells was decreased when treated with ZnO-QDs. The dose dependent apoptosis correlated with intracellular production of reactive oxygen species (ROS) from C2C12 cancer cells was also measured in presence of ZnO-QDs. Moreover, the effect/apoptosis of these QDs was also checked in the presence of candidate genes such as caspase 3/7 with GAPDH. Reverse transcription polymerase chain reaction (RT-PCR) analysis demonstrates the up-regulation of caspase 3/7 genes in cells subsequently treated with ZnO-QDs at low and high concentrations.

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.

Electrospun antimicrobial hybrid mats: Innovative packaging material for meat and meat-products

To prevent the development and spread of spoilage/pathogenic microorganisms via meat foodstuffs, antimicrobial nanocomposite packaging can serve as a potential alternative. The objective of this study was to develop a new class of antimicrobial hybrid packaging mat composed of biodegradable polyurethane supplemented with virgin olive oil and zinc oxide via electrospinning. Instead of mixing antimicrobial compounds directly with food, incorporation in packaging materials allows the functional effect at food surfaces where microbial activity is localized. The nanofibers were characterized by SEM, EDX, XRD and TEM. The antibacterial activity was tested against two common foodborne pathogens viz., Staphylococcus aureus and Salmonella typhimurium. The present results indicated that incorporation of olive oil in the polymer affected morphology of PU nanofibers and nanocomposite packaging were able to inhibit growth of pathogens. Thus; as-spun mat can be used as prospective antimicrobial packaging, which potentially reduces contamination of meat/meat-products. Moreover, introduced biodegradable packaging for meat products could serve to replace PVC films and simultaneously help to protect natural environment.

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.

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.

Application of cell co-culture system to study fat and muscle cells

Animal cell culture is a highly complex process, in which cells are grown under specific conditions. The growth and development of these cells is a highly unnatural process in vitro condition. Cells are removed from animal tissues and artificially cultured in various culture vessels. Vitamins, minerals, and serum growth factors are supplied to maintain cell viability. Obtaining result homogeneity of in vitro and in vivo experiments is rare, because their structure and function are different. Living tissues have highly ordered complex architecture and are three-dimensional (3D) in structure. The interaction between adjacent cell types is quite distinct from the in vitro cell culture, which is usually two-dimensional (2D). Co-culture systems are studied to analyze the interactions between the two different cell types. The muscle and fat co-culture system is useful in addressing several questions related to muscle modeling, muscle degeneration, apoptosis, and muscle regeneration. Co-culture of C2C12 and 3T3-L1 cells could be a useful diagnostic tool to understand the muscle and fat formation in animals. Even though, co-culture systems have certain limitations, they provide a more realistic 3D view and information than the individual cell culture system. It is suggested that co-culture systems are useful in evaluating the intercellular communication and composition of two different cell types.

One-step facile construction of high aspect ratio Fe3O4 decorated CNFs with distinctive porous morphology: Potential multiuse expectations

The objective of our study was to develop a new class of Fe3O4 nanocrystals decorated CNFs with characteristic porous morphology by straightforward approach. The utilized CNFs-Fe3O4 hybrid was prepared by sol-gel electrospinning employing polyacrylonitrile and iron (III) nitrate nonahydrate as precursors. Scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction techniques were employed to characterize novel CNFs-Fe3O4 composite. Nanofibers are having porous morphology, diameter size in the range of ~260±20 nm. In order to demonstrate the broad applicability of CNFs-Fe3O4 scaffold, we performed different analysis. The antibacterial activity was tested using Escherichia coli as model organism. With NIH 3T3 mouse fibroblasts, cytotoxicity of prepared high aspect ratio CNFs-Fe3O4 composite was evaluated by thiazoyl blue tetrazolium-bromide (MTT) assay, and fibroblast cell growth behavior with electrospun porous scaffolds was also examined. Interestingly, the prepared nanofibers exhibited enhanced bactericidal performance (minimum inhibition concentrations (MIC) from 5 μg/mL to 80 μg/mL) and CNFs-Fe3O4 composite as scaffolds indicated favorable enhancement in cell proliferation. Results from this study suggest that CNFs-Fe3O4 scaffold with small diameters coincidence with unique porous configuration can mimic the natural extracellular matrix (ECM) well and provide potential promises for applications in the fields of tissue engineering and regenerative medicine. Our findings clearly suggest wide application potentials of this (CNFs-Fe3O4) multifunctional composite and the nanofiberous mat can be a very good candidate as a filter for water purification, antibiofouling filtration and ECM for tissue engineering.

Systemic Mechanism of Taste, Flavour and Palatability in Brain

Taste is considered as one of the five traditional senses and has the ability to detect the flavour of food and certain minerals. Information of taste is transferred to the cortical gustatory area for identification and discrimination of taste quality. Animals have memory recognition power to maintain the familiar foods which are already encountered. Animal shows neophobic response when it encounters novel taste and shows no hesitation when the food is known to be safe. Palatability is the hedonic reward provided by foods and fluids. Palatability is closely related to neurochemicals, and this chemical influences the consumption of food and fluid. Even though, the food is palatable that can become aversive and avoided as a consequence of postingestional unpleasant experience such as malaise. This review presents the overall view on brain mechanisms of taste, flavour and palatability.

Biological Differences between Hanwoo longissimus dorsi and semimembranosus Muscles in Collagen Synthesis of Fibroblasts

Variations in physical toughness between muscles and animals are a function of growth rate and extend of collagen type I and III. The current study was designed to investigate the ability of growth rate, collagen concentration, collagen synthesizing and degrading genes on two different fibroblast cells derived from Hanwoo m. longissimus dorsi (LD) and semimembranosus (SM) muscles. Fibroblast cell survival time was determined for understanding about the characteristics of proliferation rate between the two fibroblasts. We examined the collagen concentration and protein expression of collagen type I and III between the two fibroblasts. The mRNA expression of collagen synthesis and collagen degrading genes to elucidate the molecular mechanisms on toughness and tenderness through collagen production between the two fibroblast cells. From our results the growth rate, collagen content and protein expression of collagen type I and III were significantly higher in SM than LD muscle fibroblast. The mRNA expressions of collagen synthesized genes were increased whereas the collagen degrading genes were decreased in SM than LD muscle. Results from confocal microscopical investigation showed increased fluorescence of collagen type I and III appearing stronger in SM than LD muscle fibroblast. These results implied that the locomotion muscle had higher fibroblast growth rate, leads to produce more collagen, and cause tougher than positional muscle. This in vitro study mirrored that background toughness of various muscles in live animal is likely associated with fibroblast growth pattern, collagen synthesis and its gene expression.