Transparent, Water-Repellent, Antiviral, Antistatic, and Flexible Cu-Plasma-Polymerized Fluorocarbon Nanocomposite Thin Films.

Polymer thin films containing fluorine are attracting much attention in various high-tech industries owing to their transparency, flexibility, and excellent water repellency. However, the generation of static electricity due to high electrical resistance limits their application. In this study, highly transparent and flexible Cu-plasma-polymerized fluorocarbon (PPFC) nanocomposite thin films that exhibit hydrophobicity and antistatic properties are proposed. These films, obtained using the mid-range frequency sputtering, exhibited a light transmittance of 84.2%, a water contact angle of 94.6°, and a sheet resistance of 1.2 × 1012 Ω/□. Transmission electron microscopy and small angle X-ray scattering confirmed that Cu nanoparticles with an average size of 4-5 nm were distributed uniformly in the PPFC matrix. In repeated fatigue bending tests, the Cu-PPFC nanocomposite thin films exhibited excellent mechanical robustness and flexibility. Antiviral properties of the Cu-PPFC nanocomposite thin films were evaluated against influenza A virus, and the number decreased by 96.9% after 30 min. Carbon nanotube-Cu-polytetrafluoroethylene composite targets are advantageous for large-area coating and mass production because they can be applied in large-area sputtering and roll-to-roll processes. The transparency, charging characteristics, and water repellency can be easily controlled in Cu-PPFC nanocomposite thin films by controlling the sputtering power density according to the required product. Therefore, these films can be applied in various industries such as flexible displays, medical, automobiles, functional textiles, and aerospace.

A short bevel needle with a very thin tip improves vein puncture performance of peripheral intravenous catheters: An experimental study.

BACKGROUND: Peripheral intravenous catheter placement is frequently unsuccessful at the first attempt. One suggested risk factor is a small vein size, because of the consequences of mechanical forces generated by the needle tip. We developed short bevel needles with a very thin tip and evaluated their puncture performance in two in vitro models. METHODS: Peripheral intravenous catheters with a new needle ground using the lancet method (experimental catheter (L)) or backcut method (experimental catheter (B)) were compared with a conventional peripheral intravenous catheter (Surshield Surflo®) in a penetration force test and a tube puncture test. Penetration forces were measured when peripheral intravenous catheters penetrated a polyethylene sheet. The tube puncture test was used to evaluate whether the peripheral intravenous catheters could puncture a polyvinyl chloride tube at two positions, at the center and at 0.5 mm from the center of the tube. RESULTS: Mean penetration forces at the needle tip produced by experimental catheters (L) (0.05 N) and (B) (0.04 N) were significantly lower than those produced by the conventional catheter (0.09 N) (p < 0.01). At the catheter tip, mean forces produced by experimental catheter (B) and the conventional catheter were 0.16 N and 0.26 N, respectively (p < 0.05). In the tube puncture test, the frequency at which the conventional catheter punctured the center-shifted site on the tube at an angle of 20° and speed of 50 mm/min was low (40%). In contrast, experimental catheters (L) and (B) were 100% successful at puncturing both the center and center-shifted sites at 20°. CONCLUSION: Puncture performance was comparable between the lancet-ground and backcut-ground needles except for penetration forces at the catheter tip. The experimental catheters produced lower penetration forces and induced puncture without target displacement at smaller angles compared with the conventional catheter. Therefore, optimization of the needle can prevent vein deformation and movement, which may increase the first-attempt success rate.

Interpenetrating polymer network-based nanocomposites reinforced with octadecylamine capped Cu/reduced graphene oxide nanohybrid with hydrophobic, antimicrobial and antistatic attributes.

Designing of mechanically tough elastomeric materials encompassed with intrinsic surface hydrophobicity, antistatic and antimicrobial attributes is in skyrocketing demands, especially to protect the instruments which are submerged in water. Herein, the authors depicted the fabrication of interpenetrating polymer network-based nanocomposites containing different doses of octadecylamine capped Cu/RGO nanohybrid. The structures and morphologies of the synthesized nanohybrid and the fabricated nanocomposites were characterized by using FTIR, XRD, XPS, TGA, FESEM and TEM analyses. Most interestingly the nanocomposites showed good hydrophobicity (static contact angle: 119.2°-129.3°), low surface resistivity (~107 Ω m) and strong antimicrobial activity towards Gram negative (Pseudomonas aeruginosa and Yersinia pestis) and Gram positive (Bacillus cereus) bacterial strains. The fabricated nanocomposites also exhibited antifungal (Candida albicans) activity. In addition, the fabricated nanocomposites showed excellent mechanical properties including high tensile strength (14.03-20.9 MPa), outstanding flexibility (1887-2470%), excellent toughness (249.89-510.1 MJ.m-3), high scratch resistance (>10 kg) and high thermostability (281-288 °C). Therefore, the fabricated nanocomposites can be used as an effective thin film for many advanced applications.

Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept.

PURPOSE: The aim of this study was to analyze systematically the influence of the relative centrifugation force (RCF) on leukocytes, platelets and growth factor release within fluid platelet-rich fibrin matrices (PRF). MATERIALS AND METHODS: Systematically using peripheral blood from six healthy volunteers, the RCF was reduced four times for each of the three experimental protocols (I-III) within the spectrum (710-44 g), while maintaining a constant centrifugation time. Flow cytometry was applied to determine the platelets and leukocyte number. The growth factor concentration was quantified 1 and 24 h after clotting using ELISA. RESULTS: Reducing RCF in accordance with protocol-II (177 g) led to a significantly higher platelets and leukocytes numbers compared to protocol-I (710 g). Protocol-III (44 g) showed a highly significant increase of leukocytes and platelets number in comparison to -I and -II. The growth factors' concentration of VEGF and TGF-ß1 was significantly higher in protocol-II compared to -I, whereas protocol-III exhibited significantly higher growth factor concentration compared to protocols-I and -II. These findings were observed among 1 and 24 h after clotting, as well as the accumulated growth factor concentration over 24 h. DISCUSSION: Based on the results, it has been demonstrated that it is possible to enrich PRF-based fluid matrices with leukocytes, platelets and growth factors by means of a single alteration of the centrifugation settings within the clinical routine. CONCLUSIONS: We postulate that the so-called low speed centrifugation concept (LSCC) selectively enriches leukocytes, platelets and growth factors within fluid PRF-based matrices. Further studies are needed to evaluate the effect of cell and growth factor enrichment on wound healing and tissue regeneration while comparing blood concentrates gained by high and low RCF.

Reduction of the relative centrifugal force influences cell number and growth factor release within injectable PRF-based matrices.

Platelet rich fibrin (PRF) is a blood concentrate system obtained by centrifugation of peripheral blood. First PRF matrices exhibited solid fibrin scaffold, more recently liquid PRF-based matrix was developed by reducing the relative centrifugation force and time. The aim of this study was to systematically evaluate the influence of RCF (relative centrifugal force) on cell types and growth factor release within injectable PRF- in the range of 60-966 g using consistent centrifugation time. Numbers of cells was analyzed using automated cell counting (platelets, leukocytes, neutrophils, lymphocytes and monocytes) and histomorphometrically (CD 61, CD- 45, CD-15+, CD-68+, CD-3+ and CD-20). ELISA was utilized to quantify the concentration of growth factors and cytokines including PDGF-BB, TGF-ß1, EGF, VEGF and MMP-9. Leukocytes, neutrophils, monocytes and lymphocytes had significantly higher total cell numbers using lower RCF. Whereas, platelets in the low and medium RCF ranges both demonstrated significantly higher values when compared to the high RCF group. Histomorphometrical analysis showed a significantly high number of CD61+, CD-45+ and CD-15+ cells in the low RCF group whereas CD-68+, CD-3+ and CD-20+ demonstrated no statistically significant differences between all groups. Total growth factor release of PDGF-BB, TGF-ß1 and EGF had similar values using low and medium RCF, which were both significantly higher than those in the high RCF group. VEGF and MMP-9 were significantly higher in the low RCF group compared to high RCF. These findings support the LSCC (low speed centrifugation concept), which confirms that improved PRF-based matrices may be generated through RCF reduction. The enhanced regenerative potential of PRF-based matrices makes them a potential source to serve as a natural drug delivery system. However, further pre-clinical and clinical studies are required to evaluate the regeneration capacity of this system.

Modifying surface resistivity and liquid moisture management property of keratin fibers through thiol-ene click reactions.

This paper reports on a new method for improving the antistatic and liquid moisture management properties of keratinous materials. The method involves the generation of thiols by controlled reduction of cystine disulfide bonds in keratin with tris(2-carboxyethyl) phosphine hydrochloride and subsequent grafting of hydrophilic groups onto the reduced keratin by reaction with an acrylate sulfonate or acrylamide sulfonate through thiol-ene click chemistry. The modified substrates were characterized with Raman spectroscopy and scanning electron microscopy and evaluated for their performance changes in liquid moisture management, surface resistivity, and wet burst strength. The results have revealed that the thiol-acrylate reaction is more efficient than the thiol-acrylamide reaction, and the keratinous substrate modified with an acrylate sulfonate salt exhibits significantly improved antistatic and liquid moisture management properties.

Control of surface charges by radicals as a principle of antistatic polymers protecting electronic circuitry.

Even minute quantities of electric charge accumulating on polymer surfaces can cause shocks, explosions, and multibillion-dollar losses to electronic circuitry. This paper demonstrates that to remove static electricity, it is not at all necessary to "target" the charges themselves. Instead, the way to discharge a polymer is to remove radicals from its surface. These radicals colocalize with and stabilize the charges; when they are scavenged, the surfaces discharge rapidly. This radical-charge interplay allows for controlling static electricity by doping common polymers with small amounts of radical-scavenging molecules, including the familiar vitamin E. The effectiveness of this approach is demonstrated by rendering common polymers dust-mitigating and also by using them as coatings that prevent the failure of electronic circuitry.

Properties of antibacterial polypropylene/nanometal composite fibers.

Melt spinning of polypropylene fibers containing silver and zinc nanoparticles was investigated. The nanometals were generally uniformly dispersed in polypropylene, but aggregation of these materials was observed on fiber surface and in fiber cross-sections. The mechanical properties of the resulted composite fibers with low concentration of nanometal were comparable to those for the control PP yarns. Extruded composite fibers that contained 0.72% silver and 0.60% zinc nanoparticles had outstanding antibacterial efficacy as documented by the percentage count reduction growth of Escherichia coli and Staphylococcus aureus. Fibers containing silver particles had improved antistatic properties.

Preparation of conductive paper composites based on natural cellulosic fibers for packaging applications.

Conducting paper based on natural cellulosic fibers and conductive polymers was prepared using unbleached bagasse and/or rice straw fibers (as cellulosic raw materials) and polyaniline (PANi) as conducting polymer. These composites were synthesized by in situ emulsion polymerization using ammonium persulfate (APS) as oxidant in the presence of dodecylbenzene sulfonic acid (DBSA) as emulsifier. The prepared composites were characterized using Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimeter (DSC), and their morphology was investigated using scanning electron microscope (SEM). Electrical conductivity measurements showed that the conductivity of the paper sheets increases by increasing the ratio of PANi in the composite. Mechanical properties of the paper sheets were also investigated, the results revealed that the values of breaking length, burst factor, and tear factor are decreased with increasing ratio of added PANi, and this effect is more pronounced in bagasse-based composites. The new conductive composites can have potential use as anti-static packaging material or anti-bacterial paper for packaging applications.

An approach to architecture 3D scaffold with interconnective microchannel networks inducing angiogenesis for tissue engineering.

The angiogenesis of 3D scaffold is one of the major current limitations in clinical practice tissue engineering. The new strategy of construction 3D scaffold with microchannel circulation network may improve angiogenesis. In this study, 3D poly(D: ,L: -lactic acid) scaffolds with controllable microchannel structures were fabricated using sacrificial sugar structures. Melt drawing sugar-fiber network produced by a modified filament spiral winding method was used to form the microchannel with adjustable diameters and porosity. This fabrication process was rapid, inexpensive, and highly scalable. The porosity, microchannel diameter, interconnectivity and surface topographies of the scaffold were characterized by scanning electron microscopy. Mechanical properties were evaluated by compression tests. The mean porosity values of the scaffolds were in the 65-78% and the scaffold exhibited microchannel structure with diameter in the 100-200 µm range. The results showed that the scaffolds exhibited an adequate porosity, interconnective microchannel network, and mechanical properties. The cell culture studies with endothelial cells (ECs) demonstrated that the scaffold allowed cells to proliferate and penetrate into the volume of the entire scaffold. Overall, these findings suggest that the fabrication process offers significant advantages and flexibility in generating a variety of non-cytotoxic tissue engineering scaffolds with controllable distributions of porosity and physical properties that could provide the necessary physical cues for ECs and further improve angiogenesis for tissue engineering.

Degradation Behavior of 3D Porous Polydioxanone-b-Polycaprolactone Scaffolds Fabricated Using the Melt-Molding Particulate-Leaching Method.

Recently, polydioxanone (PDO) and polycaprolactone (PCL) have been applied in applications for tissue engineering owing to their flexibility, as well as biocompatibility and biodegradability, even though their degradation rates are usually either too fast or too slow for many applications. In this study, we synthesized poly(dioxanone-b-caprolactone) co-polymers (PDOCLs) with different DO/CL ratio (0:10-10:0) by ring-opening polymerization. The synthesized co-polymers were characterized by (1)H-NMR, the measurement of inherent viscosity (IV), GPC and DSC. PDOCL scaffolds with different DO/CL ratio were fabricated by a melt-molding particulate-leaching method without using any organic solvents during the scaffold fabrication process. The degradation behavior (in vitro) of the PDOCL scaffolds was evaluated in PBS at 37°C for up to 56 days by the changes in molecular weight, mechanical strength, gross weight and pH. It was observed that the degradation rate of PDOCL scaffolds could be controlled by adjusting the DO/CL ratio of the co-polymers (increasing CL composition leads to slower degradation rate). The PDOCL scaffolds did not lead to a significant drop in pH during the degradation, not even for the PDO-dominant PDOCL scaffolds showing a fast degradation rate, indicating the formation of a small amount of acidic by-products compared to the PLGA scaffolds. From the results, it was expected that the PDOCLs can be a new flexible scaffolding material with different degradation rate for various tissue-engineering applications.

Solid lipid extrusion with small die diameters--electrostatic charging, taste masking and continuous production.

The aim of this work was to develop a continuous solid lipid extrusion process that includes post-process milling of the extrudates. Die diameters smaller than 0.5 mm should be used for taste masking of the bitter tasting anthelmintic praziquantel. During lipid extrusion with small die diameters, electrostatic charging of the extrudates occurred. This could be avoided by adding liquid polyethylene glycol (PEG) as antistatic agent. Further, extrusion with PEG as antistatic agent was possible with small diameter down to 0.2 mm and with up to 80% praziquantel load. Dissolution of praziquantel extrudates was shown to be faster with smaller extrudate diameter due to surface enlargement. Anyhow, different praziquantel extrudates with small diameter, drug load up to 70% and PEG content up to 20%, were proven to be sufficiently taste masked in a randomised palatability study with 40 cats. Within a scale-up experiment, lipid extrusion and milling of the extrudates in a centrifugal mill afterwards were conducted continuously. Extrudates from continuous and batchwise production revealed small differences in terms of size distribution and surface habit, but were similar in drug dissolution rate.

Fabric softeners: nearly instantaneous characterization and quality control of cationic surfactants by easy ambient sonic-spray ionization mass spectrometry.

A tiny droplet of typical samples of fabric softeners from different commercial brands placed on a smooth paper surface was subjected to easy ambient sonic-spray ionization mass spectrometry (EASI-MS). With no need for sample-preparation or pre-separation procedures, EASI-MS and EASI-MS/MS identify nearly instantaneously the main surfactants and the homologous series employed in their formulations. Adulterated and low quality samples containing no or less efficient softeners are also easily recognized.