Development of a poly(arylene sulfide sulfone) antibacterial electrospun film as a skin wound dressing application

Tissue engineering has become a hot issue for skin wound healing because it can be used as an alternative treatment to traditional grafts. Nanofibrous films have been widely used due to their excellent properties. In this work, an organic/inorganic composite poly(arylene sulfide sulfone)/ZnO/graphene oxide (PASS/ZnO/GO) nanofibrous film was fabricated with the ZnO nanoparticles blending in an electrospun solution and post-treated with the GO deposition. The optimal PASS/ZnO/GO nanofibrous film was prepared by 2% ZnO nanoparticles, 3.0[Formula: see text]g/mL PASS electrospun solution, and 1% GO dispersion solution. The morphology, hydrophilicity, mechanical property, and cytotoxicity of the PASS/ZnO/GO nanofibrous film were characterized by using scanning electron microscopy, transmission electron microscope, water contact angle, tensile testing, and a Live/Dead cell staining kit. It is founded that the PASS/ZnO/GO nanofibrous film has outstanding mechanical properties and no cytotoxicity. Furthermore, the PASS/ZnO/GO nanofibrous film exhibits excellent antibacterial activity to both Escherichia coli and Staphylococcus aureus. Above all, this high mechanical property in the non-toxic and antibacterial nanofibrous film will have excellent application prospects in skin wound dressing.

A Highly Sensitive Ammonia Gas Sensor Using Micrometer-Sized Core–Shell-Type Spherical Polyaniline Particles

A highly sensitive NH3 gas sensor based on micrometer-sized polyaniline (PANI) spheres was successfully fabricated. The PANI microspheres were prepared via a facile in situ chemical oxidation polymerization in a polystyrene microsphere dispersion solution, resulting in a core–shell structure. The sensor response increased as the diameter of the microspheres increased. The PSt@PANI(4.5) sensor, which had microspheres with a 4.5 μm average diameter, showed the largest response value of 77 for 100 ppm dry NH3 gas at 30 °C, which was 20 times that of the PANI-deposited film-based sensor. Even considering measurement error, the calculated detection limit was 46 ppb. A possible reason for why high sensitivity was achieved is simply the use of micrometer-sized PANI spherical particles. This research succeeded in providing a new and simple technology for developing a high-sensitivity NH3 gas sensor that operates at room temperature.

Indigo-Mediated Semi-Microbial Biofuel Cell Using an Indigo-Dye Fermenting Suspension

Aizome (Japanese indigo dyeing) is a unique dyeing method using microbial activity under anaerobic alkaline conditions. In indigo-dye fermenting suspensions; microorganisms reduce indigo into leuco-indigo with acetaldehyde as a reductant. In this study; we constructed a semi-microbial biofuel cell using an indigo-dye fermenting suspension. Carbon fiber and Pt mesh were used as the anode and cathode materials, respectively. The open-circuit voltage (OCV) was 0.6 V, and the maximum output power was 32 µW cm−2 (320 mW m−2). In addition, the continuous stability was evaluated under given conditions starting with the highest power density; the power density rapidly decreased in 0.5 h due to the degradation of the anode. Conversely, at the OCV, the anode potential exhibited high stability for two days. However, the OCV decreased by approximately 80 mV after 2 d compared with the initial value, which was attributed to the performance degradation of the gas-diffusion-cathode system caused by the evaporation of the dispersion solution. This is the first study to construct a semi-microbial biofuel cell using an indigo-dye fermenting suspension.

Effect of SnO2 Colloidal Dispersion Solution Concentration on the Quality of Perovskite Layer of Solar Cells

The electron transport layer (ETL) is critical to carrier extraction for perovskite solar cells (PSCs). Moreover, the morphology and surface condition of the ETL could influence the topography of the perovskite layer. ZnO, TiO2, and SnO2 were widely investigated as ETL materials. However, TiO2 requires a sintering process under high temperature and ZnO has the trouble of chemical instability. SnO2 possesses the advantages of low-temperature fabrication and high conductivity, which is critical to the performance of PSCs prepared under low temperature. Here, we optimized the morphology and property of SnO2 by modulating the concentration of a SnO2 colloidal dispersion solution. When adjusting the concentration of SnO2 colloidal dispersion solution to 5 wt.% (in water), SnO2 film indicated better performance and the perovskite film has a large grain size and smooth surface. Based on high efficiency (16.82%), the device keeps a low hysteresis index (0.23).

Influence of Powder and Liquid Multi-Wall Carbon Nanotubes on Hydration and Dispersion of the Cementitious Composites

Two types of multi-walled carbon nanotubes (MWCNTs), powder and liquid, were added to cementitious composites to build self-sensing concrete. To properly evaluate and quantify the effect of MWCNTs on electrical resistance, various tests, including isothermal conduction calorimetry, were carried out. One of primary issues of self-monitoring concrete is dispersion, so ultrasonication was used to properly mix the CNTs in the dispersion solution, and silica fume was employed to make the specimens. Scanning electron microscopy (SEM), Raman spectroscopy, and porosity analyses were performed to investigate the physical properties of the composites and to confirm uniform dispersion. The distance of the electrical resistance was also measured, and the dosages and types of MWCNTs were analyzed.

Thermal effect on wave propagation behavior of viscoelastic carbon nanotubes conveying fluid with the spinning and longitudinal motions

In this paper, the thermal effect on wave dispersion characteristic induced by the spinning and longitudinal motions in the viscoelastic carbon nanotubes (CNTs) conveying fluid is presented. Hamilton’s principle is utilized to derive the governing equation of this nanotube based on the non-local strain gradient and Euler–Bernoulli beam theories. Then, the dispersion solution is found by using the Naiver method. Based on this, the influences of the spinning and longitudinal motion velocities, structural damping, temperature and flow velocity on dispersion relation of the nanotubes are discussed according to numerical simulation. In view of the results of numerical examples, some interesting conclusions can be drawn. The existence of spinning motion leads to the coupling between the vibration in the [Formula: see text] and [Formula: see text] directions, which induces that the first-order transverse wave frequency increases/decreases for small/large wave number and the second-order one increases. The important solutions presented in the work will provide the useful information for the designation of the nanotubes conveying fluid with the spinning and longitudinal motion.

Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation

The article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous concrete models were compared with theoretical results for homogeneous concrete characterized by the averaged macroscopic material parameters. The analysis indicated that not only do the averaged material parameters influence the dispersion solution, but also the amount and size of aggregate particles. The study shows that Lamb waves propagate with different velocities in homogeneous and heterogeneous models and the difference increases with aggregate ratio and particle size, which is a particularly important observation for wave-based diagnostic methods devoted to concrete structures.

Controlling the Structures, Flexibility, Conductivity Stability of Three-Dimensional Conductive Networks of Silver Nanoparticles/Carbon-Based Nanomaterials with Nanodispersion and their Application in Wearable Electronic Sensors

This research has successfully synthesized highly flexible and conductive nanohybrid electrode films. Nanodispersion and stabilization of silver nanoparticles (AgNPs) were achieved via non-covalent adsorption and with an organic polymeric dispersant and inorganic carbon-based nanomaterials—nano-carbon black (CB), carbon nanotubes (CNT), and graphene oxide (GO). The new polymeric dispersant—polyisobutylene-b-poly(oxyethylene)-b-polyisobutylene (PIB-POE-PIB) triblock copolymer—could stabilize AgNPs. Simultaneously, this stabilization was conducted through the addition of mixed organic/inorganic dispersants based on zero- (0D), one- (1D), and two-dimensional (2D) nanomaterials, namely CB, CNT, and GO. Furthermore, the dispersion solution was evenly coated/mixed onto polymeric substrates, and the products were heated. As a result, highly conductive thin-film materials (with a surface electrical resistance of approximately 10−2 Ω/sq) were eventually acquired. The results indicated that 2D carbon-based nanomaterials (GO) could stabilize AgNPs more effectively during their reductNion and, hence, generate particles with the smallest sizes, as the COO− functional groups of GO are evenly distributed. The optimal AgNPs/PIB-POE-PIB/GO ratio was 20:20:1. Furthermore, the flexible electrode layers were successfully manufactured and applied in wearable electronic sensors to generate electrocardiograms (ECGs). ECGs were, thereafter, successfully obtained.

Lamb Waves in Anisotropic Functionally Graded Plates: A Closed Form Dispersion Solution

ABSTRACTPropagation of harmonic Lamb waves in plates made of functionally graded materials (FGM) with transverse inhomogeneity is studied by combination of the Cauchy six-dimensional formalism and matrix exponential mapping. For arbitrary transverse inhomogeneity a closed form implicit solution for dispersion equation is derived and analyzed. Both the dispersion equation and the corresponding solution resemble ones obtained for stratified media. The dispersion equation and the corresponding solution are applicable to media with arbitrary elastic (monoclinic) anisotropy.

Picoliter Cuvette inside an Optical Fiber to Track Gold Nanoparticle Aggregation for Measurement of Biomolecules

This study demonstrated a measurement approach for biomolecules at the picoliter scale, using a newly developed picoliter cuvette inside an optical fiber constructed via near-ultraviolet femtosecond laser drilling. The sensing capacity was estimated to be within 0.4–1.2 pL due to an optical path length of 3–5 microns, as measured by scanning electron microscopy (SEM). The picoliter cuvette exhibited a change in the optical extinction spectrum after addition of biomolecules such as L-cysteine, in conjunction with a gold nanoparticle (GNP) dispersion solution, following a simple measurement configuration involving a small white light source and a compact spectrometer. A linear attenuation of the spectral dip near a wavelength of 520 nm was observed as the L-cysteine concentration was increased at 4 wt% of the GNP mass concentration. The measurement resolution of the concentration using the picoliter cuvette was evaluated at 0.125 mM. The experimental results showed the difference in aggregation processes caused by a different concentration of GNPs. Moreover, they revealed the ability of the picoliter cuvette to verify whether the concentration of GNPs in the liquid sample correspondingly determines homogeneous or inhomogeneous GNP aggregation, as supported by SEM observation and numerical calculations based on Mie theory.