Fabrication of biodegradable cellulose acetate nanofibers containing Rose Bengal dye by electrospinning technique and their antiviral efficacy under visible light irradiation

Biodegradable cellulose acetate (CA) nanofibers containing Rose Bengal (RB) dye were fabricated by electrospinning technique. RB dye, an anionic photosensitizer, has been used in photodynamic therapy due to its excellent biocompatibility and ability to absorb light to generate reactive oxygen species (ROS), but has a decisive disadvantage of water solubility on infection prevention. Firstly, water-insoluble RB dye was synthesized through complexation with cationic ionic liquid (IL) for antiviral agents. The synthesized water-insoluble RB dyes were embedded into biodegradable CA nanofibers by electrospinning. The electrospun nanofibers passed both antiviral test for φx174 virus under visible light irradiation and biodegradability-test using enzymes. The fabricated RB nanofibers absorbed light and generated ROS to inactivate the virus. As a result, the log reduction (-Log10(N/N0)) of φx174 titer under visible light reached a detection limit of 5.00 within 30 min. Also, the fabricated nanofibers were degraded up to 34 wt % in 9 weeks by lipase and cellulase enzymes compared with non-biodegradable nanofibers.

Fabrication of Ag-doped ZnO/PAN composite nanofibers by electrospinning: Photocatalytic and antiviral activities

Ag-doped ZnO nanoparticles (AZNs) were directly synthesized using sol-gel method to embed into polyacrylonitrile (PAN) nanofibers by electrospinning. The synthesized AZNs were optically and structurally characterized by UV-VIS spectroscopy, photoluminescence spectroscopy, high resolution HR-TEM and XRD. The photocatalytic activity of the AZNs was examined by photocatalytic degradation of methylene blue to correlate with their antiviral efficacy in PAN nanofibers fabricated via electrospinning technique. The PAN nanofibers containing AZNs were characterized using SEM and EDS. Finally, antiviral activity of AZNs/PAN nanofibers was investigated by using virus ϕx174 under visible light irradiation. As a result, the antiviral efficacy of nanofibers increased as the concentration of Ag in AZNs increased. The results show that better antiviral efficacy was obtained in AZNs/PAN nanofibers prepared with AZNs of higher photocatalytic performance.

Fast-ion Dα spectroscopy diagnostic at KSTAR

A fast-ion Dα (FIDA) diagnostics system was installed for core and edge measurements on KSTAR. This system has two tangential FIDA arrays that cover both blue- and redshifted Dα lines (cold: 656.09 nm) in active views along the neutral beam 1 A centerline. The spectral band is 647-662.5 nm, and it covers the Doppler shift of the emission from the maximum energy of the neutral beam (100 keV). A curved filter strip with a motorized stage adequately prevents saturation of the electron multiplying charge-coupled device signal by the cold Dα line from the plasma edge. From comparisons of the measured spectra and FIDASIM modeling code, the FIDA spectra are well matched quantitatively. Moreover, the first measurements show that the FIDA radiance agrees with the neutron rate in the time trace during external heating and perturbation. In addition, responses are observed in the core FIDA radiance during the edge-localized mode cycle.

Alcohol-Treated Porous PTFE Substrate for the Penetration of PTFE-Incompatible Hydrocarbon-Based Ionomer Solutions

For a mechanically tough proton exchange membrane, a composite membrane incorporated with a porous polymer substrate is of great interest to suppress the ionomer swelling and to improve the dimensional stability and mechanical strength of the ionomers. For the composite membranes, good impregnation of substrate-incompatible ionomer solution into the substrate pores still remains one of the challenges to be solved. Here, we demonstrated a facile process (surface treatment with solvents compatible with both substrate and the ionomer solution) for the fabrication of the composite membranes using polytetrafluoroethylene (PTFE) as a porous substrate and poly(arylene ether sulfone) (SPAES) as a hydrocarbon-based (HC) ionomer. Appropriate solvents for the surface treatment were sought through the contact angle measurement, and it was found that alcohol solvents effectively tuned the surface property of PTFE pores to facilitate the penetration of the SPAES/N-methyl-2-pyrrolidone (NMP) solution into ∼300 nm pores of the substrate. Using this simple alcohol treatment, the SPAES/NMP contact angle was reduced in half, and we could fabricate the mechanically tough PTFE/HC composite membranes, which were apparently translucent and microscopically almost void-free composite membranes.

Reinforced anion exchange membrane based on thermal cross-linking method with outstanding cell performance for reverse electrodialysis

A poly(ethylene)-reinforced anion exchange membrane based on cross-linked quaternary-aminated polystyrene and quaternary-aminated poly(phenylene oxide) was developed for reverse electrodialysis. Although reverse electrodialysis is a clean and renewable energy generation system, the low power output and high membrane cost are serious obstacles to its commercialization. Herein, to lower the membrane cost, inexpensive polystyrene and poly(phenylene oxide) were used as ionomer backbones. The ionomers were impregnated into a poly(ethylene) matrix supporter and were cross-linked in situ to enhance the mechanical and chemical properties. Pre-treatment of the porous PE matrix membrane with atmospheric plasma increased the compatibility between the ionomer and matrix membrane. The fabricated membranes showed outstanding physical, chemical, and electrochemical properties. The area resistance of the fabricated membranes (0.69–1.67 Ω cm²) was lower than that of AMV (2.58 Ω cm²). Moreover, the transport number of PErC(5)QPS-QPPO was comparable to that of AMV, despite the thinness (51 μm) of the former. The RED stack with the PErC(5)QPS-QPPO membrane provided an excellent maximum power density of 1.82 W m⁻² at a flow rate of 100 mL min⁻¹, which is 20.7% higher than that (1.50 W m⁻²) of the RED stack with the AMV membrane.

PErC(5)QPS-QPPO exhibited 20.7% higher MPD than commercial AEM (AMV).

Antimelanogenic Efficacy of Melasolv (3,4,5-Trimethoxycinnamate Thymol Ester) in Melanocytes and Three-Dimensional Human Skin Equivalent

BACKGROUND/AIMS

Excessive melanogenesis often causes unaesthetic hyperpigmentation. In a previous report, our group introduced a newly synthesized depigmentary agent, Melasolv™ (3,4,5-trimethoxycinnamate thymol ester). In this study, we demonstrated the significant whitening efficacy of Melasolv using various melanocytes and human skin equivalents as in vitro experimental systems.

METHODS

The depigmentary effect of Melasolv was tested in melan-a cells (immortalized normal murine melanocytes), α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 murine melanoma cells, primary normal human melanocytes (NHMs), and human skin equivalent (MelanoDerm). The whitening efficacy of Melasolv was further demonstrated by photography, time-lapse microscopy, Fontana-Masson (F&M) staining, and 2-photon microscopy.

RESULTS

Melasolv significantly inhibited melanogenesis in the melan-a and α-MSH-stimulated B16 cells. In human systems, Melasolv also clearly showed a whitening effect in NHMs and human skin equivalent, reflecting a decrease in melanin content. F&M staining and 2-photon microscopy revealed that Melasolv suppressed melanin transfer into multiple epidermal layers from melanocytes as well as melanin synthesis in human skin equivalent.

CONCLUSION

Our study showed that Melasolv clearly exerts a whitening effect on various melanocytes and human skin equivalent. These results suggest the possibility that Melasolv can be used as a depigmentary agent to treat pigmentary disorders as well as an active ingredient in cosmetics to increase whitening efficacy.

Development of efficient adeno-associated virus (AAV)-mediated gene delivery system with a phytoactive material for targeting human melanoma cells

We exploited the emerging potential of gene therapy strategies to design a powerful therapeutic system that combines two key components-AAV vector and [6]-gingerol. In this study, we created an AAV2 construct expressing the proapoptotic protein BIM, which uses HSPG as its primary receptor, to target HSPG-overexpressing melanoma cells. This combination treatment showed promising results in vitro, inducing apoptosis in human melanoma cells. This new platform technology will make a significant contribution to numerous therapeutic applications, most notably for melanoma, including overcoming resistance to conventional anticancer therapies.

Electrospun tungsten trioxide nanofibers decorated with palladium oxide nanoparticles exhibiting enhanced photocatalytic activity

Tungsten trioxide (WO₃) based nanofibers have many advantages as photocatalysts due to its band gap which fits with readily accessible light sources.

Micelle-mediated synthesis of single-crystalline β(3C)-SiC fibers via emulsion electrospinning

Submicroscale SiC fiber mats were prepared by the electrospinning of an oil-in-water(O/W) precursor emulsion, a subsequent thermal curing treatment, and calcination at 1600 °C. Low-molecular-weight PCS micelles entrapped within an aqueous PVP matrix played an important role in forming the continuous and dense core structure, resulting in pure SiC fibers. The manipulation of SiC fiber diameters could be obtained via control of the micellar PCS concentration (10-30 wt %), enabling the production of dense and highly crystallized SiC fiber architectures with diameters ranging from 200 to 350 nm.

Well-organized highly efficient white organic light emitting diodes using fluorescent emitting materials

New type of White-Light Emitting Diode (WOLED) that emits three primary colors of red, green and blue has been demonstrated. WOLED is properly laid out with emitting layers so that all three wavelengths of light can be emitted by using fit energy level, and the organic functional layer named white balanced layer (WBL) is introduced. As for the material used as WBL, the experiment used NPB that has electron blocking effect with its large LUMO value. The color purity of such WOLED can be easily adjusted through the adjustment of the number of electron carriers injected into light emitting layer. Therefore, the experiment organized WOLED by using doping concentration of highest efficiency demonstrated by RGB single color device, and adjusted color purity of white color through the adjustment of WBL thickness adjustment. In the case of WOLED device that possesses the device structure of ITO/m-MTDATA 40 nm/NPB 5 nm/NPB + P-1 (3%) 3 nm/NPB 0.1 nm/Alq3 + C-545T(5%) 0.5 nm/IDE-120 + IDE-105(7%) 35 nm/LiF 1 nm/Al 150 nm in this study, color coordinate was (0.341, 0.424) and light emitting efficiency was 16.5 cd/A at current density 10 mA/cm2, so the WOLED demonstrated highly efficient characteristics of over commercial level.

Hollow ZnO nanofibers fabricated using electrospun polymer templates and their electronic transport properties

Thin (0.5 to 1 microm) layers of nonaligned or quasi-aligned hollow ZnO fibers were prepared by sputtering ZnO onto sacrificial templates comprising polyvinyl-acetate (PVAc) fibers deposited by electrospinning on silicon or alumina substrates. Subsequently, the ZnO/PVAc composite fibers were calcined to remove the organic components and crystallize the ZnO overlayer, resulting in hollow fibers comprising nanocrystalline ZnO shells with an average grain size of 23 nm. The inner diameter of the hollow fibers ranged between 100 and 400 nm and their wall thickness varied from 100 to 40 nm from top to bottom. The electronic transport and gas sensing properties were examined using DC conductivity and AC impedance spectroscopy measurements under exposure to residual concentrations (2-10 ppm) of NO(2) in air at elevated temperatures (200-400 degrees C). The inner and outer surface regions of the hollow ZnO fibers were depleted of mobile charge carriers, presumably due to electron localization at O(-) adions, constricting the current to flow through their less resistive cores. The overall impedance comprised interfacial and bulk contributions. Both contributions increased upon exposure to electronegative gases such as NO(2) but the bulk contribution was more sensitive than the interfacial one. The hollow ZnO fibers were much more sensitive compared to reference ZnO thin film specimens, displaying even larger sensitivity enhancement than the 2-fold increase in their surface to volume ratio. The quasi-aligned fibers were more sensitive than their nonaligned counterparts.

Preparation of highly monodispersed hybrid silica spheres using a one-step sol-gel reaction in aqueous solution

The successful one-step preparation method of monodisperse hybrid silica particles was studied using organosilane chemicals in aqueous solution. In general, almost all of the hybrid silica materials were made by a complex method where organic materials were coated on the surface of silica substrate via chemical reaction. However, our novel method can be applied to prepare colloidal hybrid particles without using substrate material. This method has three advantages: (i) this simple method gives the opportunity to prepare hybrid particles with high monodispersity through the self-hydrolysis of various organosilane monomers in aqueous solution, (ii) this efficient method can be applied to load lots of organic functional groups on the surface of silica particles through a one-step preparation method using only organosilane, and (iii) this effective method can be used to control the particle size of the product by changing the experimental conditions such as the concentration of the precursor or the reaction temperature. Detailed characterization of the hybrid particles by scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis (TGA) was performed to elucidate the morphologies and properties of the hybrid silica particles.

New approach to the immobilization of glucose oxidase on non-porous silica microspheres functionalized by (3-aminopropyl)trimethoxysilane (APTMS)

The immobilization and encapsulation of glucose oxidase (GOD) onto the mesoporous and the non-porous silica spheres prepared by co-condensation of tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) in the water-in-oil (W/O) emulsion system were studied. The terminal amine group was used as the important functionality for GOD immobilization on the silica substrate. When only TEOS is used as a silica source, the disordered mesoporous silica microspheres are obtained. As the molar ratio of APTMS to TEOS (R(AT)) increases, the surface area and pore volume of the silica particles measured by nitrogen adsorption and desorption method and SEM decrease rapidly. Particularly, the largest change of the surface morphology is observed between R(AT)=0.20 and R(AT)=0.25. The amount and the adsorption time of immobilized enzyme were measured by UV spectroscopy. About 20wt% of GOD was immobilized into the silica substrates above R(AT)=0.60 and was completely adsorbed into the substrate of R(AT)=0.80 with lapse of 4h after addition. In the measurement of the thermal stability, GOD dissolved in buffer solution loses nearly all of its activity after 30 min at 65 degrees C. In contrast, GOD immobilized on the surface-modified silica particles still retains about 90% of its activity after the same treatment. At this temperature, the immobilized glucose oxidase retained half of its initial activity after 4h. It is shown that the suitable usage of functionalizing agent like APTMS as well as the control of surface morphology is very important on the immobilization of enzyme.

A novel preparation route for platinum–polystyrene heterogeneous nanocomposite particles using alcohol-reduction method

Platinum nanoparticles are homogeneously immobilized onto the polystyrene surface using alcohol-reduction method for the first time. Sulfonate groups were employed as a chemical protocol to make a binding between platinum nanoparticle and polystyrene surface. A large number of quasi-spherical platinum nanoparticles with a size of approximately 5 nm in diameter are formed and strongly attached to the polystyrene surface modified with sulfonate groups. The formation mechanism of composite materials was discussed briefly. The most distinguished features of this novel preparation route include simple operation, and absence of the toxic reducing agent. In addition, this novel preparation route can be extended to the preparation of other noble metal-polymer heterogeneous nanocomposites such as silver, gold, palladium, iridium and ruthenium.

Loading of gold nanoparticles inside the DPPC bilayers of liposome and their effects on membrane fluidities

Gold nanoparticles were loaded in the bilayer of dipalmitoylphosphatidylcholine (DPPC) liposomes, named as gold-loaded liposomes. Above the gel to liquid-crystalline phase transition temperature, membrane fluidities of DPPC liposomes were changed by loading the gold nanoparticles. Compared with liposomes without loading the gold nanoparticles, gold-loaded liposomes showed the lower fluorescence anisotropy values. That is, the membrane fluidities of DPPC bilayer were increased by loading the gold nanoparticles. The membrane fluidities were increased as the amount of gold nanoparticles increased. The existence of gold nanoparticles in the DPPC bilayer was observed by transmission electron microscopy. Through the energy dispersive X-ray spectrometer, the particles in DPPC bilayer were confirmed to be gold nanoparticles.

Controlled release of retinol from silica particles prepared in O/W/O emulsion: The effects of surfactants and polymers

Spherical silica particles containing retinol were fabricated by using O/W/O multiple emulsion and sol-gel method. In this study, when both hydroxypropyl cellulose (HPC) and surfactants such as Tween 20 and Span 80 were used, multiple emulsion encapsulating retinol was prepared successfully. The size of water droplets and the amount of released retinol depended on the concentration of surfactants and PEG polymer. In addition, PEG, PVP, and Pluronic P123 were introduced as a stabilizer in the water phase to investigate the effect of polymers on the encapsulation efficiency. In the case of PVP, encapsulation efficiency of retinol in the silica particles was 7.35% and the lowest. On the other hand, in the case of Pluronic P123, it was 30.89% and the highest among obtained silica particles. The morphologies of multiple emulsion and silica particles were observed by optical microscope (OM) and field emission scanning electronic microscope (FE-SEM). In vitro release test and encapsulation efficiency were characterized by HPLC.

Effects of silver nanoparticles on the fluidity of bilayer in phospholipid liposome

This paper describes the formation and characterization of liposome entrapping the silver nanoparticles in bilayer. Silver nanoparticles were entrapped in the bilayer of dipalmitoylphosphatidylcholine (DPPC) liposome, named as silver-loaded liposome. Specifically, above the gel to liquid-crystalline phase transition temperature of this lipid (i.e., 41 degrees C), it was observed that membrane fluidities of silver-loaded liposomes were increased, and fluorescence anisotropy values were reduced from 0.114 to 0.097. This might be due to the structural modifications and interactions between DPPC molecules and silver nanoparticles within the bilayer. It was also confirmed that silver nanoparticles were entrapped in hydrophobic region of lipid bilayer with transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) measurements.